Oral-History:L. Eric Cross
About L. Eric Cross
Cross was born and raised in Yorkshire, England. After excelling in electrical engineering and troubleshooting during his service in the Admiralty in WWII, Cross earned his B.S. (1948) and Ph.D. (1952) in Physics at the Unversity of Leeds, where he began his lifelong research on ferroelectrics. In 1961,he joined the Electrical Engineering Department at Penn State University, where he had been ever since. At Penn State, he helped found the Materials Research Laboratory and mentored over fifty doctoral students. In addition to his breakthroughs and publications in the field of ferroelectricity, Cross has been involved in numerous international research efforts and even consulted on the Hubble Telescope.
In this interview Cross describes his childhood in the wool manufacturing village of Morley; his Admiralty service during WWII and assignment to HFDF; and his research on ferroelectrics at Leeds and mentorship by E. C. Stoner and Richard Whittington. Cross discusses his long research career at Penn State, where he helped found the Materials Research Lab and collaborated with the Electrical Research Association, the Office of Naval Research, as well as a myriad of international scholars and institutions. He offers an insight into the diplomacy of research and the complications of geopolitics; the dilemma of secure funding for scientific research; and the rewards of pedagogy and mentorship as a professor.
About the Interview
L. ERIC CROSS: An Interview Conducted by John Vardalas, IEEE History Center, July 27, 2011.
Interview #566 for the IEEE History Center, the Institute of Electrical and Electronics Engineers Inc.
Copyright Statement
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It is recommended that this oral history be cited as follows:
L. Eric Cross, an oral history conducted in 2011 by John Vardalas, IEEE History Center, Piscataway, NJ, USA.
Interview
INTERVIEWEE:
L. Eric Cross
INTERVIEWERS:
John Vardalas, Glen Fox
DATE:
27 July 2011
PLACE:
Vancouver, British Columbia, Canada
Early Life and Education in Yorkshire
Vardalas:
On behalf of the IEEE History Center and the Ultrasonics, Ferroelectrics & Frequency Control Society, we want to thank you for graciously agreeing to participate in IEEE’s Oral History Program. By the way, if I may say, we have over 500 oral histories already in this collection--
Cross:
Oh my gracious.
Vardalas:
--of distinguished people, and you’re going to add to that distinguished list.
Cross:
Jolly good.
Vardalas:
We are conducting this interview in the City of Vancouver, Canada. The date is the 27th of July 2011, and the time is 9:20.
We would like to start this interview at the beginning, which are the memories of your youth.
Cross:
That’s a good place to begin.
Vardalas:
Can you recall when in your childhood you first became interested in science and math?
Cross:
Yes, I think, it was when I first went into grammar school.
Vardalas:
Tell us about that please.
Cross:
Well, my father was a school teacher, which meant that we were able to survive the Great Depression quite well, but we did move from a small manufacturing town called Morley to a very tiny village just outside Morley. It’s called Gildersome. And this influenced my early education because the village school actually did the teaching in dialect, and I could speak a language which my parents couldn’t understand at all.
Vardalas:
What dialect is this, by the way?
Cross:
The Yorkshire dialect. This was in the West Riding of Yorkshire, which was the woolen manufacturing area of the United Kingdom at that time. And Morley, the small town I was born in, is famous for rags and shoddy. That’s what the mills specialized in. There, within the site of the council house in which I was born, there were 17 mill chimneys, and the local saying was, “Wherever there’s muck there’s brass,” which meant that where there was dirt there was money. [laughter]. But the worst place I’ve ever seen is what was called the willie-ing hole. The willie-ing hole is where they tore apart all these old rags, blankets, and garments. And it was absolutely filthy. It was a dreadful environment.
Vardalas:
So how did you develop your interest in science?
Cross:
Well, my father was an art teacher. But he was an interesting person because he really wanted to be an inventor. He was a reluctant but good art teacher. He was a very good artist, and he did teach me all the elementary rules of perspective, so that I was able to draw cubes on the board and then I could draw crystals. Most people who draw on a blackboard make a terrible mess, [laughter] because they don’t understand the rules of what the thing should look like if it’s to stand out from the paper.
And my brother and I interacted. He was a very nice elder brother. He was three years older than me and his interest was in chemistry. He was a chemist. So I had to be interested in something else. So my interest turned to electronics. And electronics at that time was valves, of course. There were no such things as transistors. I did become very interested in [electronics], and I used to fabricate loudspeakers with my father so that we could listen to music because my mother was very much interested in music.
It was a nice growing up period because we had a caravan on the east coast, which meant that we could get away almost every weekend. My mother was a compulsive swimmer. We would often go to Scarborough which is a very cold city on the east coast, and she would break the ice on the swimming pool so that we could swim.
Vardalas:
Oh my.
Cross:
[laughter]
Vardalas:
So as a boy you were involved with valves.
Cross:
As a boy, yes. I was involved. I was making, moving iron loudspeakers and primitive valve circuits. This [became] awfully useful because during the war, I was moved to HFDF, which was the weapon that really terminated the submarine menace. Something that most people didn’t realize is the immense debt of gratitude we have to the Poles, the free Polish because they, in fact, stole the first code machine from the Germans.
Vardalas:
Right.
Cross:
The Germans were absolutely convinced that their code was absolutely unbreakable.
Vardalas:
Yes. Yes.
Cross:
So they put all of the information on the frequencies the U-boats were going to use in code. What we were doing was, in fact, calibrating the direction finders on the frequencies the U-boats were going to use next month.
Vardalas:
Well, we’ll get to that. That’s fascinating.
Cross:
Which was interesting.
Vardalas:
Did your interest in science translate to school? Did you find yourself a good student? Did you like school?
Cross:
[laughter] The school was interesting because it was very small. You know, in the schools over here you expect about 100 people in the class. Over there, there were 350 people in total in the school. This was the Morley Grammar School, and it was a good school. My father was the art teacher there. The science teachers were terrible; in fact, they were so bad that in the 6th form two senior students, myself and another guy, took over and taught the classes.
Vardalas:
Really.
Cross:
Really, because he was terrible. He wasn’t interested. He was interested in Gilbert and Sullivan and not, in fact, in teaching at all. But he was absolutely stupid. I hate Gilbert and Sullivan. I think its absolute stupidity, but never mind. [laughter]
Vardalas:
[laughter] Okay, so we won’t go into any verses of Gilbert and Sullivan.
[general laughter]
Cross:
[laughter] True. But it’s good, you know, if you’re teaching something, you’ve really got to understand it. [Here] we were answering all the questions from the students, this other student and I, in the top of the 6th form. It really taught us that we had to understand how the damn things worked. That is very useful because most people don’t really go deep enough to understand what it is that motivates the system.
Vardalas:
I see. Did this happen in what we call high school here?
Cross:
Yes. This was the grammar school; what we call high school.
Vardalas:
So elementary and high school were rolled into one.
Cross:
No. There was an elementary school but I was able to sidestep elementary school and go straight into grammar school at 10 years old. The great advantage to me was stepping over from the 5th form to the 6th form because in the 5th form we had 7 subjects that we had to deal with. [In the 6th] we could narrow it down to 3. I chose Physics, Chemistry, and Mathematics as the three subjects that I specialized in. And I could really then do the things that I was most interested in, which was nice.
I was lucky because education in Britain was highly competitive at that time. I was never more than 22nd in a class of 30 when I was a very young student because there were so many other interesting things to do. I couldn’t bother with what the teacher was ruffling about. And I never would have made it. So my parents were able to pay for me to go into grammar school. I was a paid student. That was immensely helpful because the teaching in the grammar school was, as you can imagine, significantly better than the teaching in the elementary school which was a village school where the teachers were really just interested in keeping the students out of trouble because, this again, the village was dominated by a few woolen mills.
We shared a house with the major mill owner - Wilson’s Mill. Wilson had a son who was just about my age and he and I used to play together all the time. That was awfully nice because I was a very sick child because, unfortunately, I have allergic asthma. And my mother didn’t realize it. Being a Yorkshire mother the first thing she did was to wrap me in beautiful woolen blankets. She didn’t realize I had an allergy to wool.
Vardalas:
Wow.
Cross:
It almost killed me.
Vardalas:
Oh.
Cross:
Because I was always short of breath. You realize how important breathing is if you can’t breathe. [laughter]
Fox:
So was your grammar school a boarding school?
Cross:
No. It was a day school.
Fox:
Okay.
Cross:
But what happened was that when my brother and I both were going to the day school, the parents decided that they would move from Gildersome. We moved back into Morley, which was the little town, and we chose a house which was very close. They were able to purchase a house. It was very close to the school, so it was very easy for me to go in and out of school, and often we used to play rugby because that was the game. It was useful because most of the girls all followed the rugby team. This was a school with both males and females. It was a good early education. [laughter]
Vardalas:
So your health was good enough for you to play rugby.
Cross:
Yes.
Vardalas:
Did you go directly into the military service after high school?
Cross:
No.
WWII Service and HFDF
Vardalas:
Can you talk about the transition period just before you go into military service and after you leave school?
Cross:
Well, while I was still at high school World War II started.
Vardalas:
Right.
Cross:
And I was able to get a radio bursary to go to Leeds University. So I took one year at Leeds University. And as I was at the university, the first thing I did, like an idiot, was volunteer for commandos. So I took commando training. The thing that saved my life was they found out that I had asthma at my military medical exam. Out! You had given the game away if you had an asthma attack.
Vardalas:
What ever possessed you to go into commando as an enlisted man?
Cross:
[laughter] Well, you know, you want to have this enthusiasm. It was obvious that Hitler was a hell of a menace in Europe, and this was something truly evil — Everybody felt, you know if you do something to combat [Hitler] that would be useful. So, I volunteered. I took all the training. I’m a rotten athlete in every way, but I was able to succeed where other people, whose usual enthusiasm, failed, which was surprising to me. And so I was well qualified. I was kind of horrified when I just couldn’t pass the medical exam. But that meant then that I was posted to a civilian occupation and the nice thing was that I was posted to HFDF. I was posted to the Admiralty, not the Navy.
Vardalas:
The Admiralty, right.
Cross:
I was a civilian.
Vardalas:
Right. Okay.
Cross:
But I was a civilian carried on His Majesty’s ships.
Vardalas:
Now, correct me if I’m wrong, HFDF, was that called Huff-Duff at the time?
Cross:
That’s right. High Frequency Direction Finding. It was really the key weapon. The problem for the U-boat was not killing the convoy. It was finding the damn thing. That North Atlantic is a large ocean, and they re-routed the convoys. Every time they came across to a different route. So what the submarines used to do was to spread out at periscope depth. They would look for the convoy. As soon as one spotted a convoy, that night he would surface, radio to the others, and then they would assemble an attack on the convoy knowing where it was. And it was a key to shut that down.
We had the first Captain class frigates that were made here on the west coast by Henry Kaiser. And I had the first one that came over. They were based in Belfast. Fortunately when the first one came in, I thought, “I’d better test this bloody thing out.” So I took a small transmitter down the jetty and switched it on, went in, not a sound. “Oh shit,” so I brought the thing on the deck of the boat, put in on full blast, not a sound. “I’ll fix this bugger,” so I shinned up the mast and attached the transmitter directly to the antenna; still, nothing. So I went inside, took the junction box off the wall and sea water poured out of it. [laughter] The whole thing was shorted out.
This was true for every one of them fitted on the west coast. It was very important that the coaxial cable was bonded to the mast. The British coaxial cable had a solid coaxial. The American was a braided cable, and of course as soon as they cut through the outer insulation, water.
The Captain class frigate was a very fast boat, but it was designed for the Pacific. In the Atlantic, the damn thing rolled 60 degrees away from the vertical because it was bottom heavy. It was a terrible boat to be on. They had to strip out all the bunks in the boat and put hammocks in, otherwise, the people couldn’t get any sleep, because they were tossed out onto the floor. They would go pretty fast, and rolling 60 degrees, you know— and this meant the damn thing was more a submarine than a frigate. This is why all the electronics got inundated. So I had to make a panic signal to the flag officer in charge of Northern Ireland and then they stripped them all back out again and we refitted them with solid coax cable. We had to do that with the group that came across.
Vardalas:
So let me take you back. So now you’re in the Admiralty.
Cross:
I was in the Admiralty.
Vardalas:
Right. Where were you stationed; where were you physically located?
Cross:
Well, I was lucky because I was posted for training to the Humber and this is on the east coast of England. And the Humber was absolutely laced with magnetic mines sown by the Luftwaffe, and the yacht was completely non-magnetic, and I had a very nice two months training in how to deal with the Navy, how to deal with the machines, all of this sort of thing. Then I was posted over to the west coast, to Northern Ireland, to Belfast, and that was a beautiful berth because we had the whole of Belfast Loch. We had a very much segregated calibration berth, because when we were transmitting, nothing within range should be able to pick it up. It was a very weak transmitter. It was arranged so that as soon as anything appeared on the horizon [hand clap], we shut down. Because one thing we didn’t want them to know was that we were transmitting on the frequencies the U-boats were actually using.
So it was very critical and it was completely secret. The guy who came up to the captain and brought this whole set of frequencies, had a briefcase padlocked to his arm. The captain had the key and he opened this—put everything immediately into the safe on the yacht. The guy went; he was with an armed escort which was instructed to shoot if anyone came and tried to interdict them. Because it was absolutely critical, you know, you can think of what Churchill had to go through. Because he knew precisely that they were going to come and bomb the hell out of Coventry. He didn’t dare move any of the people because that would have given the game away.
Vardalas:
Right. I see.
Cross:
You see, they were able, in fact, to use the information to interdict the aircraft that came in, because the Germans thought that we had extremely good — they knew we had radar. They thought it was extremely good. It was very good because we knew exactly where they were coming. [laughter] That the Germans didn’t know.
Vardalas:
That was kept tight —
Cross:
That was kept very closely secret. I had no idea where the frequencies were that I was using. I thought, “Why the bloody hell are we doing these odd frequencies, and why don’t we space them uniformly and just draw a curve?” It was critical. We were actually calibrating on the exact frequencies they were going to use. Because the antennae were broken up into segments to try and take out the major resonances. The antennae were not designed for the frequencies the Germans used. This made the rigging on the ship reradiate furiously. You had to know which bearing to decide to move. The bearings would often swing something like 60 degrees away from the direction. We added an extra antenna to get a heart-shaped radiation pattern to correct for the errors. We would plot a curve. We would have a boat circle the destroyer, and we would plot a graph of the difference signal.
Vardalas:
So you plotted an antenna pattern around the boat?
Cross:
Right, around the boat. And then they had one of these for each of the frequencies. But some of them were extremely good. They had one guy in charge of a group. They called him B-bar Walker. He guaranteed if any submarine in his area surfaced and transmitted just one B-bar in Morse code, he would kill it. He did it every time. He had the group very well spread out and they would vector in, steam over, blow the hell out of this piece of ocean, and almost always debris from a submarine would come up.
Vardalas:
Do you remember any of the challenges you faced on working on this project?
Cross:
Well, I was very lucky. When I was posted to the Humber, I was there only for six weeks. The crew was very good. They gave me all the training. About ten days after I left, the boat disappeared. It was blown up.
Vardalas:
What happened?
Cross:
The Luftwaffe had sown the first acoustic mines, and these were designed to blow up a 10,000-ton merchant ship. The 500-ton yacht was just vaporized, so everybody that had trained me—gone.
Vardalas:
Oh my.
Cross:
If I’d been ten days longer there, I would have been gone.
Vardalas:
Were these acoustic mines new, very recent?
Cross:
They were quite recent and these were the first ones that were used. They were littered around the east coast of Britain to shut down the convoys coming in.
Vardalas:
So the ship had to get fairly close to one of these before it set off.
Cross:
That’s right.
Vardalas:
And when you say acoustic, was it—was it listening for engine or was it sending out, as an active thing sending out signals?
Cross:
No. It was listening for engine noise. For the magnetic ones, many of the boats had what they called degaussing girdles and they would, in fact, cancel out the anomaly in the magnetic field produced by the boat.
Vardalas:
Oh, that’s how they did it. I see.
Cross:
I was involved a little bit with that, but it was interesting to see the weapon and then the counter-weapon. U-boats got to know that it was very dangerous to surface and transmit, and so the Germans then put in the Focke-Wulf Condors. These were old three-engine aircraft which had a huge range. They could stay up for something like a week going up and down the east coast. And they were acting then as spotters for the U-boats. So what did we do? We put in what were called the Woolworth carriers. These were 10,000-ton merchant ships where they’d stripped off the whole deck and just put on a landing deck.
And the pilots who worked off those things were incredible guys, because we often met them. And there was always just a 50-50 chance once you took off that you’d get the damn aircraft back on the deck again. Because these things were rolling in the Atlantic. And you had to hit the deck at the right angle, and many of the times they would go just straight over the side. They had an explosive seat which blew them out into the water. Many of these pilots had been swimming three, four, and five times because it was hard to get the thing back. But every time they went off, they knocked down a Focke-Wulf. It got so that the Germans just couldn’t use that as a mechanism for spotting the convoys.
Vardalas:
Would you say then that this wartime experience about, ah, the measures, countermeasures, had an influence in your later life when you worked on sonar?
Cross:
Well, certainly it helped because I knew the ways of the British Admiralty and then the U.S. Office of Naval Research was very much on the same sort of basis, so I knew how to talk to these people. I was lucky that I had early training on how to deal with an absolutely massive bureaucracy.
You know, one of the problems that we had was many of these were wartime fixtures that were put in. The training [was a wartime fixture] for the people who were operating the system, and the system was extremely fragile, and they were instructed to slap the cabinets if it didn’t work. You could see the dents. I mean, you don’t instruct people to do that. They do it automatically, [laughter] which was just stupid. Very frequently I had to rebuild these damn things.
Vardalas:
So you understood the Navy mind then.
Cross:
Right. I knew how stupid they were. So what we did was, in fact, draw full equipments from way back up the line where they’d be fitted, and we would ship them out on a very rough day and then drop the thing over the side, because I’d stripped everything out from inside and that was the way I got my spare parts. And that meant that I really knew how the damn things worked. I knew better than the guy in the Sparker Office [these were the receiving officers on the boat] how the thing worked. So then I would go into these things as they came in from United States, go through it completely, make sure the damn thing worked before it went out onto the calibration berth because half of them were not working.
You know, I learned very quickly. I mean, one of the things that I had to do when I was posted to work in the Physics Department was to build an oscilloscope because we needed one to do the work. [laughter] They were absolutely amazed. I was invited back to Leeds for the 200th anniversary. They had my thesis out. People asked, “You built the bloody oscilloscope?” [laughter] I said it was the only one thing I could do. I had to have one. They couldn’t afford one, so I built it.
Post-War Education at Leeds
Vardalas:
You returned to Leeds. I assume you did that because you had started already one year before.
Cross:
I had a year there, yes.
Vardalas:
You were familiar with it. You were determined to do physics.
Cross:
Right.
Vardalas:
After this technical, electrical, electronics background, did the thought ever enter your mind to go into engineering?
Cross:
[laughter] Well I knew the Physics Department. The man who was in charge of it was a man by the name of E.C. Stoner. He was a world authority on ferromagnetism. And he fingered me as I went in because I had the university scholarship and that said I had some brains. And he wanted me very much in his group. But I was lucky, extremely lucky because coming back from the Office of Naval Research where he’d been posted during the war, was the head of department, Professor Whittington, and he was a much more flakey person than Stoner.
Vardalas:
In what way?
Cross:
He put on my desk a whole pile of papers and said, “Cross, look into these; these look interesting.” These were all the reports from the National Lead Company about the early days of ferroelectrics, all the perovskite ferroelectrics. What I didn’t realize was that he’d pinched them while they were still classified. So I had the whole set of classified Navy papers on my desk to get me started in ferroelectrics.
Fox:
So this was the National Lead Company in the U.S.?
Cross:
National Lead Company was responsible for it. I went to Stoner and said, “Look, I have this opportunity to go into ferroelectrics.” He said, “Cross, you’re going to waste your life on this trivial lattice phenomenon?” [laughter] And I have done. [laughter] [hand clap]
Vardalas:
I don’t think wasted. You spent your whole life on it.
Cross:
[laughter]
Vardalas:
Just to get it straight, who put these documents on your desk again?
Cross:
Professor Whittington. He’d been over in United States during the war. Many scientists from England posted to United States. For example, my two cousins who’d both been at Manchester University were posted over to United States to work on the nuclear bomb. And I knew that that was going to happen before it actually happened. I happened to be on holiday with their mother in the south of England. I’d come back from Northern Ireland and it was interesting to have heard that this weapon had been dropped on Japan. I knew what it was because I’d talked to the boys and they told me. You know it was an extremely hush-hush thing. You never talked about it.
Vardalas:
Ah-hah. So, then, but the person you worked with was still Stoner even though this other gentleman gave you these papers, or did you leave Stoner?
Cross:
No. I left Stoner’s.
Vardalas:
Ah. And this is for your undergraduate work or your graduate work or both?
Cross:
I was changing over from undergraduate to graduate. I spent 2 years and Stoner was the one who looked after the graduating class in Physics. I had a BS honors in Physics, and then he wanted me to go into his group, but I went to an independent group which was put in by Whittington to look at ferroelectrics.
Vardalas:
How did you find Leeds, the educational program, when you were there?
Cross:
It was really good actually. Um, they had a good Physics Department. It is now called the E.C. Stoner Physics Department at Leeds. He was world class, extremely well known in the band theory of ferromagnetism. He was also a close personal friend of the guy in France who did much of the original work on ferromagnetism. And then the two of them—Stoner couldn’t speak French, and the other guy couldn’t speak English. It was a very interesting conversation to listen to, [laughter] but they were two really world class scientists. To hear the interaction was really a privilege.
Stoner had a remarkable brain. There’s something called the Stoner-Main-Smith classification of the elements, and this was the first time that the periodic table had been really laid out and shown what the atomic structures were that gave rise to these periodic changes in the characteristics of the elements. And he was the Stoner of Stoner-Main-Smith.
Vardalas:
I see.
Cross:
He really was a very first class scientist and that’s why they called the department after him.
But he wanted me very much because he was losing a student called Woolfarth who had been helping to run his group, and he wanted to put me into that position, but I didn’t want to—I was interested in the ferroelectric things because it was obvious that that was going to move very quickly. So as great as he was, Stoner was mistaken about this.
Early Research on Ferroelectrics
Vardalas:
So tell us about what you did in ferroelectrics then. After your thesis, what did you work on?
Cross:
Well, I was able, because of the momentum that I got from the papers, to produce a very good thesis. I was then immediately offered an ICI Fellowship, which was really a very prestigious fellowship from the big ICI Chemical Company. That gave me 2 more years in which to specialize. I chose to specialize in ferroelectrics. And I was able to do the work on the anti-ferroelectric behavior of sodium niobate, NaNbO3.
That work really solved a major problem. There was a fight going on between the United States, where the people at Penn State had said that the material was a ferroelectric, and the people in the United Kingdom in Bristol—this was the group of crystallographers in Bristol, who said it was not ferroelectric. It couldn’t be. It was anti-ferroelectric. I was able to demonstrate quite clearly that it was anti-ferroelectric because I could produce double hysteresis loops, show it switched back to the anti-ferroelectric phase, that you could, in fact, put it into a ferroelectric phase, but it wasn’t stable in the ferroelectric phase.
And that was a very useful piece of work, and this is the piece of work that Stoner spotted because I had that published in the Philosophical Magazine, and he always read those papers. And he said, “Eh, it was a good paper, Cross.” [laughter]
Vardalas:
Was this a straightforward thing for you? Was this a challenging project to resolve this problem? Do you recall your days of doing this work?
Cross:
[laughter] Well it was always a challenge to do good work because, you know, the universities in the United Kingdom were extremely poor. The remunerations were not large. And it was difficult to go to meetings, and when I left Leeds, I got a job with the Electrical Research Association in Leatherhead in Surrey. As I say, my life was dominated by chance. I noticed that there was going to be an International Union of Crystallography meeting in Cambridge. I never used to go to those meetings, but this one had work on barium titanate, which had been taking place at Penn State. And so, I said, “Okay, I’d better go to that one”.
I arranged and I paid for myself to go to the meeting, and who should I meet at the registration desk but my old tutor from Leeds. His name was George Brindley. And I had waved farewell to Brindley because he was coming to the United States. He was, in fact, head of the Ceramics Department at Penn State. And when he met me at the desk he said, “Cross, why don’t you come to America?” So I said, “Professor Brindley, why don’t you invite me?” He did. [laughter] And that’s how I came to be here. These long chains of coincidence are kind of interesting.
Vardalas:
When I’ve interviewed people on the challenges of their research, depending on the person, I’ve heard things like, “I got to the point where I was so discouraged and I almost dropped it because I couldn’t crack this thing”. Or, “It went smoothly for me the whole way.” What was your experience in doing this groundbreaking work?
Cross:
I was very lucky because I was able to get information which nobody else had. And thus I could really focus on topics that I knew would be productive - understanding the way in which the alkaline niobates behaved. And I was able to do the phenomenology there. And the other thing that is interesting was that I had made a contact actually with the man—what was the man’s name—who was responsible for the phenomenology of ferroelectrics. He was at Bristol University and —
Fox:
Ginzburg?
Cross: Actually, Devonshire came up to Leeds because I gave a paper on what I did for the British Physical Society paper. He came to my house and had dinner [with me].
So when I had developed the phenomenology of the anti-ferroelectric systems, I thought, God, I can’t publish this because I didn’t know the first thing about it. I knew that it was interesting, so I gave him a telephone call. He said, “Oh, come on down and then we’ll talk.” So I went through this whole thing with him, and he said [hand clap], “This is good Eric, why don’t you publish it?” With his encouragement, I was confident enough then to publish it. This was the beginning of the phenomenologies of anti-ferroelectrics; and again, this was published in Philosophical Magazine and —
Vardalas:
Is this the—when you say Philosophical Magazine, is this the Philosophical Transaction?
Cross:
Phil.-Mag. Yes. And it was interesting that after I’d done my thesis, something that I spotted in the thesis work was the fact that the double hysteresis in barium titanate single crystals was not due to anti-ferroelectricity. It was due to the fact that the phase transition at the Curie point was a first order transition. And in a free crystal you could, in fact, get ferroelectricity induced into the paraelectric phase and get a hysteresis in the paraelectric phase, which again split; and that I did publish in—I sent it to Phil.-Mag.
I had built the oscilloscope myself and I knew the system worked absolutely perfectly, so I said in my paper that, in fact, the number that was accepted for the spontaneous polarization of the barium titanate was wrong. It was too low, because I had already measured 24 micro-Coulombs/cm2 and the accepted value was 16. I said it can’t possibly be 16 because I counted, on a single crystal, 24. And they immediately bounced the paper, of course, because this was a graduate student at Leeds University.
Bell Labs has already said it was 16. Fortunately, the group at Bell had some very nice crystals which were grown by Joe Remeika and he gave them decent crystals for the first time. They then remade the measurement, and they said, “Oh, it’s actually 26 micro-Coulombs/cm2, not 16.” As soon as that paper came out, I had a letter from Phil.-Mag. and they apologized for holding up my paper. They said, “Under the circumstances, I think you would agree that we shouldn’t take a paper from a graduate student, but it happened that you were right and they were wrong.” [laughter] So they apologized to me and published the paper immediately with an explanation of when they first read it and when they first accepted it. So I was able, in fact, to show that the phase transition was first order at the Curie point in barium titanate.
Vardalas:
Now you say that Bell, with better crystals, was able to get a result closer to yours.
Cross:
Yes.
Vardalas:
But how did you get your crystals?
Cross:
I grew them myself.
Vardalas:
Ah. And Bell Labs couldn’t grow —
Cross:
Well, it was interesting. I realized that one of the problems in the sodium niobate that I was most interested in was that the domain structures were extremely complicated. And it was very, very difficult to grow crystals which you could make into single domain crystals. So what I did was miniaturize the techniques [for] making measurements. What I did was, in fact, bolt together 2 pieces of plastic and using a watchmaker’s drill, I was able to drill sub-millimeter holes through, countersink them so I could then use that to sputter electrodes onto extremely small crystals in selected areas. And this was the way in which I could, in fact, measure the single domain properties of materials like sodium niobate, which are extremely difficult.
When I first submitted to Phil.-Mag., this was not the sort of thing you expected from a graduate student.
Fox:
The sodium, sodium niobate work was your first publication then?
Cross:
No. My first publication was the one from my thesis, which was on barium titanate, and that was the one that they held up.
Fox:
Okay.
Cross:
And that was the one from which I got the apology, because Bell Labs did change their number, and so I came in below the Bell Labs number, when they said it was actually 26. I said I had measured 24, but I didn’t say that that was the number. I said it must be at least that or larger.
Fox:
Right. Ah. So shouldn’t there be a Cross method of growing barium titanate crystals?
Cross:
[laughter] No. I was actually copying a method which was used in, in Switzerland. By Bert Mattias. It was a difficult method. I had a graduate student working with me also at the time, and we must have looked at several thousand of these crystals broad casting them and selecting them from solution. From them we selected the ones that had simple domain structures. In this way we were able to measure the properties of a single domain. And that was interesting. But most people, in fact, didn’t bother to miniaturize the measuring techniques. They tried to make large crystals. You could make large crystals, but they were terrible. They were so full of domains and the interlocking walls that you couldn’t do anything with them.
Vardalas:
Did that flash come to you as an obvious thing to do?
Cross:
Hmm. Well I’d had quite a bit of experience by that time with the different crystals. I knew how difficult it was to get rid of the domain structures in some of them. So I thought, “Okay, I’ll select crystals with simple domain structures and we’ll see if those work more easily, and miniaturize the technique for making the measurement.” And they did.
Fox:
Could you explain a little bit why you chose barium titanate as the system that you wanted to study?
Cross:
Well, this was the one which was most interesting because it is still the material which is widely used in the capacitor industry.
Fox:
Yes. But at that time, it—
Cross:
But at that time it was the lead material. It was the one which most people worked on because this was the perovskite that was understood to be ferroelectric, to have three phase transitions, and to have all the characteristics that you expect from perovskites exhibited in one. It wasn’t an easy material, but it was, once you got the right single crystals, you really were in business.
Vardalas:
So this is now your post-doc work or your thesis work?
Cross:
That was my thesis work.
Vardalas:
So are you saying that it was widely recognized at the time amongst leading researchers that barium titanate was the material?
Cross:
Oh yes. Yes.
Vardalas:
And do you recall who, that time, were the leading people working on barium titanate?
Cross:
Oh, it was essentially the people at Bell Labs. At that time, you know, Bell was a different place. It really was the world’s leading solid state lab. I was lucky, when I first came to the United States, to be able to visit it because I knew the people there. I had corresponded with them. And it was a joy to visit because at that time Bell [people] were able to talk. They weren’t regarding themselves as a commercial entity. So they weren’t competing. And they were only too interested to say, “Oh that’s an interesting one. Why don’t you try this and so on?” You could really have a detailed discussion with them, which you couldn’t with any other company, because the company would always say, “Well wait a minute, I don’t know whether I can talk about that one, because that’s something that goes into our production line so and so.”
Vardalas:
Okay. I want to take you back to this 1987 paper you wrote, “History of Ferroelectrics,” which is an overview of the history of ferroelectrics. You identified certain periods. 1940 to 1950 was the “Early Barium Titanate Era.” 1950 to 1960 was the “Period of Proliferation.”
Cross:
Yes.
Vardalas:
And it seems like your undergraduate years fell within the first, and your PhD fell within, between both.
Cross:
Yes.
Vardalas:
And your work at the Electrical Research Association.
Cross:
Yes.
Vardalas:
Yeah. For the second period, the Period of Proliferation, can you talk more about how you see your work within this time frame up to 1960?
Cross:
Well, I really was a sort of follower of the trends that were going on. I was able to make some contributions, but, you know, I mean this was a large area. And my work was sort of—
Vardalas:
Well, let’s talk about your work. How would you situate your work in this, in these two eras?
Cross:
Well, I think I was lucky to be involved, first of all, with barium titanate. That was a choice which was made by Professor Richard Whittington because he was my thesis supervisor, but he was a supervisor in absentia, because Whittington had a yacht on the Norfolk Broads. He spent most of the summer on his yacht [laughter], which was wonderful because it gave me complete, open time when I could do things that I realized were important and not be too heavily supervised, because he was an opinionated person, and it was very difficult to get past him sometimes.
I once made the mistake of telling him that I must have a good capacitor for the Sawyer-Tower circuit that I was building to measure the spontaneous polarization in the ferroelectrics. And he immediately ordered for me a, this size of mirror, and said, “You can make it Eric. You can make an air capacitor and then I’ll get you some thin mica sheets.” I mean, he didn’t realize that the pickup from this thing would be absolutely impossible. [laughter] That was the sort of thing you had to get past.
Vardalas:
So he gave you the idea but then left you alone?
Cross:
Yes. That’s right. Because he disappeared. And that was a blessed relief.
Now with E.C. Stoner it was a different matter because he was a brilliant scientist. You could immediately show him why it was that you wanted to do a particular thing. I told him that I really wanted to look at the high field properties of BaTiO3 because there had been some reports from Bell Labs of double hysteresis and barium titanate. They had misclassified it completely as an anti-ferroelectric because they hadn’t read the phenomenology papers. They were fundamental scientists. They wanted it in terms of molecular bonds and so on, but if you read the phenomenology, you knew that this was a first order phase transition, and that you could, then, induce the other phase by a higher electric field. And this is why I wanted to do the demonstration to show that it was, in fact, a field-driven phase transition—from a para[electric] into a ferro[electric] phase. And that’s what I did for my thesis.
Vardalas:
Did you interact with Stoner for advice or bounce ideas off him while you were doing your thesis work?
Cross:
Oh yes. I used to go out and talk with him. He did, in fact, eventually come around to believing that this might be an interesting area. [laughter]
Fox:
Did you happen to interact with Landau, Ginzburg, or Devonshire as part of your phenomenological development?
Cross:
Yes. Right. A.F. Devonshire was an interesting man because he was at Bristol not because of the university, but because of the swamps. He was a bird watcher. [laughter]
Vardalas:
Can you elaborate more on this?
Cross:
I would go down and visit with him. He had all sorts of interesting friends. [laughter] I remember we were in the university cafeteria and this terribly disheveled looking man who was head to foot in coal dust came in and said, “I’ll be back in a few minutes”. He washed his hands and then came back and sat with us. This was a guy, who was interested in prospecting, was designing a vanning shovel, which is a thing that you use for sorting, in a stream, the heavy particles. You shake the shovel and the light ones go off it. But he’d been practicing in the basement of the university with a pile of coal. [laughter]
Fox:
And this was Devonshire.
Cross:
This was a friend of A.F. Devonshire.
Fox:
Oh, a friend of his.
Cross:
Yes. And he had lunch with us and he wasn’t terribly scrupulous in changing, [laughter] which was a nice dusty dinner.
Fox:
So what kind of interaction did you have in terms of the theory development of barium titanate?
Cross:
The barium titanate was already done. A. F. Devonshire had done the theory properly and fully. What I wanted to do was to adapt it so that we could describe the switching from an anti-ferroelectric to a ferroelectric phase. This meant using a two sublattice model. I designed it, went through the theory, got it down. Then I thought, “Dare I publish this?” So I gave him a call. He said, “Come and talk.” And he went through it with me, and said, “Yeah, it’s a good idea.” He gave me the background information and I then submitted it for publication. This was the first anti-ferroelectric phenomenology, which is still referred to.
Vardalas:
You just made a reference to the fact that in Bell Labs, a physicist work, fundamental physicist looking, wanting to explain things within a certain framework.
Cross:
Yes.
Vardalas:
And they hadn’t considered the phenomenological approach. What was the difference in the way of looking at this material from these two perspectives?
Cross:
Well, in the phenomenology, you simply designed a function which had no relevance to the particular mechanism in the material, but happened to reproduce the behavior of the material. And Bell Labs didn’t like to do that. They liked to have a molecular mechanism that you could track, and that’s very difficult to do in some of the ferroelectrics because these are soft mode materials. It’s difficult, in fact, to mimic that. So the Devonshire phenomenology which uses a Landau expansion of the free energy worked extremely well. I realized that this was the best way to go at it because we just didn’t have enough background to do the full theoretical treatment. And the people at Bell Labs, of course, being right at the top of the tree, wouldn’t admit that to themselves. So they were not very familiar with all the phenomenologies. So this is where I had an advantage of not being equipped with the best teachers.
Fox:
So you found an alternative route, a way around…
Cross:
That’s right. [laughter]
Fox:
To solve the problem.
Cross:
Right. It gave us the clues. It didn’t, in fact, give you the solutions, but it showed you what to expect.
Fox:
Oh, okay.
Cross:
And that was very helpful.
Work at the Electrical Research Assocation
Vardalas:
Can I move you on to your work at the Electrical Research Association?
Cross:
Sure.
Vardalas:
What kind of work did you take on there?
Cross:
It was the same area because they had capacitor companies in membership of the Electrical Research Association, like Erie Technological, and they were interested in ferroelectric materials. And so, I was able to carry on the ferroelectric and anti-ferroelectric work when I was at the Electrical Research Association.
Vardalas:
They supported fundamental research at this association? Because it seems unusual for an association like that to support research.
Cross:
[laughter]
Vardalas:
Normally they’re out promoting as opposed to supporting research.
Cross:
No. They were—actually actively promoting research in-house. They had very small budgets. This was a typical British operation in that it was put together by industry and the government. And, of course, industry thought the government should pay for it and the government thought the industry should pay for it, so nobody paid for it, which means it was poor as a church mouse.
But it did have freedom to do things which were unusual because it wasn’t terribly closely supervised. The budgets were small, but they were much freer than if you were focused on a particular topic. And I was able to do work associated with my understanding of the phenomenology, which in fact gave avenues for things to develop, but wouldn’t have been important to a company.
Vardalas:
I see. Can you elaborate some of the things that come to mind that you worked on while you were there, specific items while you were at Electrical Research Association?
Cross:
I was interested in working on phase transitions and the manner in which the phase transition could modify the properties. The interesting thing is that the transitions project themselves into the behavior, and this is, of course, why lead zirconate titanate is such an interesting material. It has what is called a morphotropic phase boundary. There are two ferroelectric phases which are competing for stability over the whole temperature range, which means that this phase boundary is almost vertical on the phase diagram, so that you can stay close to the phase boundary where things are very soft over a wide range. This was the first material in which you can get both high permittivity and high spontaneous electric polarization, which is necessary if you want to do piezoelectric behaviors.
Vardalas:
Was this a natural extension of your work at Leeds, or was this a new area, a new direction you went in?
Cross:
No. It was really a modification to what I’d already been doing because most of my life has been in this area of ferroelectrics. The nice thing is the fact that I was focused on phase transitions [because it] really was important. It is the manipulation of the phase stabilities within these perovskite oxides which gives you this full wide family of interesting dielectric properties. And we were beginning to feel that out.
Fox:
So were you already investigating the piezoelectric properties of the material?
Cross:
Yes.
Fox:
When you’re working at Electrical Research--?
Cross:
Right. But the point is that I did have contact with a group which was very good in crystallography. This was Professor—it’s a group which actually moved over to Penn State. This was the group that moved, but then I did develop interesting interaction with a group down in Bristol which was Helen Megaw. Professor Megaw was very well known for her early work on barium titanate. She did the first crystal structures, and showed the manner in which the tetragonality of the material dropped off as it approached the tetragonal cubic phase transition, all this sort of thing. She did very good x-ray crystallography at Cambridge, and had connections with the people at Bristol also.
Vardalas:
Oh, I see.
Cross:
The interesting thing is that the guy that I worked with, when I first came to Penn State, he actually was a perfect man for me to be working with because his understanding of crystal symmetry was amazing.
Fox:
Let’s go back to Helen Megaw. You mentioned that —
Cross:
Yes. Well, I deformed her life, I’m afraid, because she was very interested in different types of crystals but she had almost no sources. So I began providing her with crystals of sodium niobate which has a very, very complicated phase system. And she did dedicate a significant part of her life to unpicking the complexities of the sodium niobate system. That was simply because I was a source of crystals for her. [laughter] And these were the small, very small crystals which were not interesting to people who were measuring properties, but for someone who was doing the crystal structure they were sufficiently perfect and she really could do the structure analysis. She was following along doing that as I was doing the optical crystallography, which was very simple to do. Actually it was all done on a borrowed machine. It was a machine that Professor Whittington borrowed from Professor Whytlaw-Gray, who was the Professor of Mineralogy at Leeds. I had this microscope, which was an awfully nice one because it had a rotating stage. No, it had rotating, analyzer and polarizer so they synched together. So you could keep the crystals still and, in fact, examine extinction directions.
Fox:
Okay.
Vardalas:
This is now the later work when you’re at Penn State now, right?
Cross:
No, this was work done at Leeds.
Vardalas:
Oh, so you got this—oh I see, so you had equipment from Penn State at Leeds.
Cross:
Yes.
Vardalas:
You made a remark about women and crystallography. There’s a story that you were involved with DNA. You stated that x-ray crystallography was a natural for women. What did you mean by that?
Cross:
There are extremely good women in this area. Unfortunately, there are very few women in science, I think. And they seem to congregate in crystallography, and I think this is probably an inheritance that’s passed on because the early pioneers in that area involved some very effective women, and they naturally gave people a feeling that, oh, this is a respectable system to be in for a woman. That’s not the case for some of the other areas, which would be just as suitable for females. But it is true that there have been very good women. I’m trying to think of the ladies that I had contact with, but I can’t, unfortunately. It’s getting rusty.
Fox:
Also you mentioned that you had worked with, or you provided samples to Helen Megaw at Cambridge.
Cross:
Yes.
Fox:
She was at Cambridge at that time. Was this when you first met Bob Newnham?
Cross:
Yes. He was also working with Helen because he took a PhD with Helen.
Fox:
Maybe you could describe a little bit about why that name is important.
Cross:
[laughter] Well, she was a very, very good—I mean she did the original crystal structure of barium titanate which is still widely referred to.
Research at Penn State
Fox:
And the name of Bob Newnham, how does that link into your life?
Cross:
[laughter] Well, when I came over, he was still at MIT. I was amazed that we were able to recruit him to Penn State from MIT, because at that time we were just developing the Materials Research Lab at Penn State. And it was really a good opportunity to come in. He and I worked together for, I’d say, a significant number of years, because we really fitted beautifully. I was interested in the quantitative behavior and he was interested in the symmetry behaviors. He was a brilliant crystallographer. He could take one of these very complicated barium titanate type structures and say, “Oh there’s the four-fold axis and oh, there’s the three-fold”. He could find all the symmetry elements just by looking at the blooming crystal structure. A complete mystery to me. [laughter]
Vardalas:
So this is, you think, was the basis for your fruitful collaboration?
Cross:
That’s right. And then we really collaborated over a very wide range of topics, he and I. And we did joint funding and he’s a nice guy to work with. It was a sorry loss [when he passed away].
Vardalas:
How does the feedback work between these two interests? In other words, he does the symmetry or he reveals more about the symmetry properties and then —
Cross:
That’s right.
Vardalas:
And you found that useful to your work and he found yours—I’m trying to understand how this becomes productive.
Cross:
It becomes very productive because you really need to understand the constraints which are imposed by the symmetry. You can then make sure that the properties that you’re measuring satisfy those constraints because the constraints are absolute for a particular known symmetry. You must have equivalence between things measured in this direction and things measured in this direction. And that was extremely important to me, because I was interested in making the full family—and very frequently these things were twinned so that you would have some of this orientation and some of this orientation within the same unit. And these often used to puzzle the behaviors because of the fact that they would mix the orientational behaviors because of the twinning mixing the orientations. To unpick these sometimes was quite a challenge.
Vardalas:
Is there any example where your interest influenced what he did; in other words, his work was useful to you?
Cross:
Yes.
Vardalas:
Is that an example of how your work was useful to him?
Cross:
Well, the point is that the discussions, they come from these interactions.
Vardalas:
Right.
Cross:
Made him think more carefully about the symmetries.
Vardalas:
Okay.
Cross:
And we would always be refining the manner in which these would be, behaviors would be necessary, and it borders together, you know. We would always be talking and that was useful.
Fox:
Maybe for some of the listeners that aren’t as familiar, you could explain a little about how symmetry controls which properties can occur.
Cross:
Right.
Fox:
In material, and about, for example, piezoelectricity.
Cross:
It controls all the orientational dependencies and that’s really critical, particularly where you have materials like barium titanate that can be phenomenally anisotropic.
If you look at the barium titanate true single crystal at room temperature, you measure the permittivity along the polar axis. It’s quite small. It’s only on the order of 100. You measure the permittivity in the perpendicular direction. It’s several thousand, and it’s going up because it’s coming to a phase transition where it will go to a new symmetry and it is because of that phase transition that it’s becoming easy to polarize it away from the direction. Because the vector is going to switch through 45 degrees, and that really then gives you this run-up, but the perpendicular orientation, nothing. These are the sorts of things that symmetry gives you, a real understanding of what is happening.
Vardalas:
How does one come to spot these symmetries? Is it the data that provides symmetries from crystallography work or optical or x-ray or both?
Cross:
Both. Combinations.
Vardalas:
And what kind of talent is needed to spot them? Obviously it’s not trivial to spot these symmetries, is it?
Cross:
No. It’s not trivial at all, but it does also mean that the person involved would like to build models, and Bob was a great model builder. He had whole cupboards full of these little stick models. [laughter]
Vardalas:
Is there a strict methodology or art form to identifying these symmetries?
Cross:
Well, it’s always, in fact, coming back from the data. You look at the way in which things reproduce as you go from different orientations. And you say, “Oh, there must be a three-fold axis, because this is the same as this is the same as this” … that sort of thing, you know.
Vardalas:
But obviously everybody can’t see the same thing from the same data.
Cross:
No. You need several different families of data. And then you see these regular curves and you say okay.
Vardalas:
Okay.
Cross:
This is not just by accident. This is a necessary feature. Now we’ll look at something else and see if that also is dictated by the three-fold symmetry or whatever it is that you’re looking for.
Vardalas:
What I was trying to get at was whether this gentleman had a special skill to spot these things.
Cross:
Oh you bet. But it’s a familiarity of having dealt with the topic over and over.
Vardalas:
Okay. This is a nice segue to Penn State, [laughter]. Why did you leave the United Kingdom to go to Penn State? Were there opportunities for you in the United Kingdom that you might have taken, or was Penn State an obvious thing for you to do next?
Cross:
Well the point is that development in universities in Britain was relatively slow. The opportunity in the United States was to move much, much more quickly. I have been very lucky in that the people that I’d been with have always been willing to explore. I mean, think of it from a perspective of my wife. I mean, she was an average English housewife. She liked stability as do most English housewives. And people don’t realize what produced the Revolution at the end of the war. It was the British housewife, because something that really changed the thinking of British housewives was the evacuation which took place from the major cities. And this moved children from East London, for example, out into the countryside around London, and the average British housewife was absolutely horrified at what she found. They found that these children were sown into their clothes. They were smelly. They were dirty. They had nits in their hair. [The housewives thought], “These are English children? You can’t have something like that. That’s ridiculous.” And this is really what threw the government out at the end of the war.
The British housewives have a vote, and they voted on block to put in the welfare state because those people said, “You can’t have English children like that. This is disgusting. It’s horrifying. It’s not their problem.” They didn’t realize at all what had happened and how these pockets of misery and poverty had developed over time. It was really an eye opener.
Vardalas:
And this stability contributed to you going to the United States?
Cross:
No, it contributed to the change of government. This is how Clement Attlee came in and brought in the whole welfare state business.
Vardalas:
Right, right, right.
Cross:
Because he would say, “They voted Churchill out? Churchill helped to win the war. Why did they vote him out?” That’s why the British housewife got rid of him.
Vardalas:
And is that related to the lack of opportunities at British universities after that? Is that why you left?
Cross:
Well, it happened that the United States was a much more rapidly developing society. It was obvious the opportunity that I had [in the US]. The problem was that I was already established in Britain. We’d already bought a house in Hazelmere, in Surrey. It was a very nice house, a very nice district. It was taking up a major part of our resources as you could imagine, but it’s just the sort of thing that the British family would do. Here was I [wanting] to go to the United States.
Vardalas:
And what did she think about that?
Cross:
Well, my wife was kind of horrified but what I did was to say, “Okay, let’s just give it a try. I’ll take a 2-year leave of absence”. That’s how I managed it. And, of course, once she got over there and realized the opportunities that there were for the children, she said, “I got to rethink this Eric.” [laughter]
Vardalas:
[laughter] I see. So did you inquire to go or did somebody approach you?
Cross:
Again, as I told you, none of my life has been planned. It has been all unusual opportunities. As I say it was at the Electrical Research Association and there was this very nice paper at a crystallography meeting in Cambridge. The International Union, for once, was meeting in Cambridge, and I thought, “Okay, I’ll go”. Who did I meet at the registration desk but my old tutor from Leeds, and he said, “Eric, why don’t you come to America?” So I said, “Well Dr. Brindley, why don’t you invite me”, and he did.
Vardalas:
Oh, that’s how it started.
Cross:
That’s how it started. I got this invitation and I had to decide how to handle it. And I handled it by saying, “Look, dear, let’s just go for a 2-year leave of absence. We can sample what’s available. We can see what it is, see whether it is a really major opportunity.” It turned out to be a life changing decision. But all the things that have happened in my life have been accidents of this sort.
Vardalas: One of your colleagues suggested that we ask you about, going back again to Professor Newnham, about your work together on sonar for the Navy.
Cross:
Yes.
Vardalas:
What are your recollections of that? What was that project about and how you two worked on it?
Cross:
Well, I think I had always had connections with the Navy because one of my students, Robert C. Pohanka, became in charge of the Office of Naval Research Operation. So I had an inside track, as it were, to go in there and talk with them.
And we did have major support from the Office of Naval Research, and we worked on piezoelectrics, the materials which were most widely used by the U.S. Navy for ASDIC [Anti-Submarine Detection Investigation Committee]. Fortunately the ocean is completely opaque to electric magnetic radiation, so that you have to use acoustic radiation to detect things. And they were very interested in ways of generating ultrasound, ways of monitoring ultrasound. Something Newnham and I had put together was an understanding of the way in which composite materials behave. We found that the manner in which you put the phases together can make a complete difference to the behavior of the system. So we developed these composite technologies which are now used everywhere. I mean, you’ve probably had a medical ultrasound. That medical ultrasound depends on a transducer which was developed at Penn State. It was nice that this thing that we developed for destructive purposes for the Navy also turned out to be extremely useful for health reasons.
Vardalas:
You didn’t get involved in the medical—that just came from the work you had done for the Navy.
Cross:
Yes. But we did become involved with it later, of course, because the companies realized that what we’d done could be used in what they were doing. And we had the understanding of how to modify the beam forming behavior in the multilayer structures which were used for medical ultrasound.
Fox:
Was the work with the Navy really the first major foray into piezoelectric activity in the materials, or in let’s say, barium titanate and PZT?
Cross:
It was the first Penn State made.
Fox:
Was that more of the first time that you looked at the application of the material for a piezoelectric …
Cross:
I must admit that I’ve always been this sort of scientist who was interested in working on something which could be used, which could be useful. And throughout we’ve always said, “Well, these are most interesting properties; now what the hell could you use them for? What could you make out of it?” We were interested in getting money, and then, you know, to demonstrate to someone that what you’re interested in can do something useful is a necessary feature if you want to get them to pay for it.
This was a philosophy in our group, which was introduced by the guy who was in charge of the Materials Research Lab at Penn State, Rustum Roy. People used to think he had a magic password in Washington that would get money pouring out of Washington for him. This was not true. He had the connections because the people knew that when he was talking about something, it would be something that might do something useful for them.
Vardalas:
So in other words, research for research sake is not going to get you money easily.
Cross:
It won’t get you a dime in the United States. [laughter]
Vardalas:
Can you elaborate too on this —
Cross:
Well, wait a minute. I’ll correct that. If you go to NSF, you can sell it, but most other places, no.
Vardalas:
People looking for advice on how to get funding should listen to this tape.
Cross:
[laughter]
Vardalas:
I was going to ask you again about the Navy work, the composite material you were saying for sonar for the Navy.
Cross:
Yes.
Vardalas:
Uh, in the beginning, was this classified work?
Cross:
No.
Vardalas:
It was never classified work. Your know-how was reaching the literature, the scientific literature openly.
Cross:
Yes.
Vardalas:
And that’s why the medical community could get a hold of it.
Cross:
That’s right. Yes.
Vardalas:
I’m surprised that the Navy didn’t want anything classified.
Cross:
I think that was lucky because I knew the people there very well, and Wallace Smith is a very effective person. He was the person who is mostly responsible. He came over from North American Phillips labs down to Washington. He’s now been in the federal government for a good long time. He’s looking now at retirement like I am. [laughter]
Vardalas:
So you could say then in a sense that it was the Navy’s interest in sonar and it’s pocketbook that set the technical basis for medical ultrasound.
Cross:
Yes. I believe. There are lots of things that contributed, lots and lots, but the front end is really quite critical, and that is the active element which projects the ultrasound into you and takes the acoustic echo back and analyzes it.
Fox:
Okay. Interesting. Do you want to add anything to that? I was wondering, I just had a—it’s kind of a side question, but since Cady was so key—he did a lot of work in piezoelectrics.
Cross:
Yes.
Fox:
I was wondering —
Cross:
He was my hero.
Fox:
Okay.
Consulting Work at Clevite
Cross:
You know, Cady was a person who didn’t start work on piezoelectric materials until he was 50 years old. He worked to one day short of his 100th birthday. It was unforgivable that he died just before we were to have a celebration for him. [hand clap] But he was brilliant. He was the man actually who trained Hans Jaffe. Jaffe was one of his students. Hans was really the brains behind Clevite. He was the man who persuaded Clevite, which was a branch of Brush Development Company, to buy the Erie patent on polarization biased electrostrictors for piezoelectric activity. While I was still in England, I was acting as a spotter for them because I had very good contact with x-ray capable persons. So we could see immediately who was operating on perovskite materials and using them for piezoelectrics, and therefore, violating the patent.
And so I used to send that information over to the Jaffe’s at Clevite. Of course when I came over, they picked me up as a consultant, which was kind of useful. But it was horrifying to see where they existed. The Clevite Lab is right in the poorest part of the city. It’s at the wrong side of the tracks, and the street is broken windows and trash piled in the streets. This is an American city? I was horrified, but the Jaffes were good people. Hans had a very heavily handicapped daughter and he did very good things for the handicapped in Cleveland, and he was really a very nice man. The two Jaffes were not related at all. One was a very aristocratic German. The other was a Jew.
Bernie was a roly-poly guy and a very effective ceramic processor. He wasn’t a tremendous scientist but he could make good ceramics out of tea leaves. It was incredible. He had a huge talent for making the materials. Hans Jaffe knew what they ought to make, and he was the person who really—and I was very lucky, again, because one day I went in and he showed me something that they were just about to publish. It was an analysis of the manner in which you could drive an anti-ferroelectric into a ferroelectric form, but the analysis was wrong. [laughter] And I pointed out the mistakes in it. He said, “Oh my God, Eric, we could have published that.” [laughter] So I got a position with them. They then picked me up as a consultant, of course. And we have a joint paper which is in the Journal of Applied Physics on the first switching anti-ferroelectric to ferroelectric, and this was a modification of what he had originally shown me.
He was a good scientist, German trained, Berlin trained, very effective scientist. He would spot immediately the weak points in things.
Fox:
And what was the main product at Clevite?
Cross:
Clevite essentially owned the PZT system.
Fox:
Okay.
Cross:
And lead zirconate titanate is still the material of choice for polarization biased electrostrictor piezoelectrics, which are all the piezoelectric ceramics. What I was doing today here at the conference was trying to persuade people to look at flexoelectric composites where we can actually beat the system. The problem with the ferroelectric ceramic is that you depend upon having spontaneous polarization which can be reoriented. That polarization is essential for developing the symmetry which you need for the piezoelectric effect, which means you must be in a ferroelectric phase. You must be spontaneously polarized, and you must have particular properties. The lead cation is ideal for this, which means that people who work for 50 years to try and modify that, to try and develop lead-free materials, no success. PZT is still the major component of that field.
I’m advocating a completely different approach, which says use texture symmetry, don’t use spontaneous polarization. Use the flexoelectric effect. Design systems where the texture symmetry gives you very high gradients and you can use them outside the range where you can use PZT. And lead now is an anathema. It’s much too strongly bonded to the oxygen. You can’t move it with a small stress. The gradient doesn’t shift it. The last thing that you want in the flexoelectric is a lead cation. Now we’ve got an avenue where lead is a disadvantage, non-lead systems are highly advantageous. Now you have the chance of making a lead-free system.
Vardalas:
I see. Very interesting. So what was the fate of the Clevite Company?
Cross:
I think Brush Development Company is still around, and Clevite was a subsidiary of Brush. I think they are still making ceramic materials. The best book in the area is still the Jaffe-Jaffe-Cook book. I call it the Jaffe-Jaffe ‘Cook book’ because it is a cookbook of ceramics, but it also really understands exactly what you’re doing the cooking for.
Fox:
How did the consulting with Clevite influence the work with the Navy and also medical ultrasound?
Cross:
Well, it gave me a measure of respectability, which was useful. The Navy were dependent upon Clevite for the PZT families. They knew that I was known to the guys who’d actually developed all the most interesting formulations. Since I was friendly with them and respected by them, the Navy thought, “He must be all right. He’s got respectability with Clevite”. [laughter] [hand clap] Very helpful.
Vardalas: In your overview of the history of ferroelectrics you described 1960 to 1970 as the “Age of High Science.”
Cross:
Yes. That was when the soft mode behavior was first understood.
Vardalas:
Would you characterize your work as part of that Age of High Science?
Cross:
No.
Vardalas:
No?
Cross:
I was a technologist, not a high scientist. I was interested in making things that worked.
What was the man’s name who did the soft mode work in Scotland? He and I were at the meeting in Kyoto, and this was the second International Meeting on Ferroelectrics, and the group met together, decided where the next meeting was going to be, and made an announcement to the other group—they made a colossal goof. They said, “We’re delighted to say that the next meeting will be in Edinburgh, England”. And I saw Cochran say, “Oh my God.” Then he got up, walked up to the stage and said, “I’m awfully sorry but I must make a correction. Edinburgh is not in England, it is in Scotland.” [laughter] I could see him shaking; “What shall I do?” They made this goof. [laughter]
These are the fun things that happen sometimes. If you know the system, you really know what the problems are.
Vardalas:
You didn’t see yourself as being part of the Age of High Science. You were more a technologist interested in making things that worked.
Cross:
That’s right.
Age of Diversification and Integration
Vardalas:
Didn’t you describe the subsequent periods “Age of Diversification,” “Age of Integration” —
Cross:
Yes.
Vardalas:
Did you participate actively in those?
Cross:
Oh yes.
Vardalas:
Can you say something about how you took part in this Age of Diversification while you were at Penn State?
Cross:
Well, there we were interested in understanding other materials than barium titanate, and this was where I was doing the sodium niobate work, and work on other materials. Sodium potassium niobate is a very interesting family, and these were some of the materials which were competing for transducers in non-lead systems where that lead was absolutely anathema. You couldn’t have it. Then so we were involved in that whole area of development of—I was also at that time lucky that I went to the first International Meeting on Ferroelectrics which was in Prague. There I made contact with the Chairman of the meeting, what was his name? Um, cripes, Fousek, Jan Fousek.
Vardalas:
Jan Fousek.
Cross:
Yes. I was a little green at the time and I invited him to come to Penn State. I paid for him on a Wright Patterson [Air Force base] budget. This was a man from inside the Soviet Union. [laughter] I made the mistake of taking him up to the SAC Air Force base. Oh cripes!
Vardalas:
Well, what happened?
Cross:
All hell broke loose. [laughter] I had to move him out. [laughter] Too bad.
Vardalas:
[laughter] All hell broke loose, huh?
Cross: Right. You can’t take a Russian citizen into a—because they were part of the Soviet Union at that time.
Vardalas:
Right.
Cross:
This is before they broke away.
Vardalas:
So this was the diversification? You were looking for other materials.
Cross:
That’s right.
Vardalas:
Where was the funding for this work coming from?
Cross:
It was still mostly coming from the Navy, but we had other sources coming in. Some of the companies were beginning to become interested because they realized that things were branching out from us, so it was a larger base that was developing.
Vardalas:
What did you mean by the “Age of Integration,” and how did you participate in that?
Cross:
You see essentially what I’m thinking of there is the fact that we had to keep more and more interested in the semiconductor systems that we would be working with. You drive the ultrasonic transducer and you take a high level amplifier to interrogate the signal that comes back to it. So it is very essential that you fit this thing in with the electronics which is going to be necessary.
And we were also interested, of course, in measuring properties. One of the things that was a challenge to me was how can we measure more directly some of the transducing behaviors? And so we began to look at dilatometric techniques that we could adapt for low AC frequencies. This is where we made the double-beam interferometer type systems, and something which I even puzzled myself on was how we could, in fact, resolve small fractions of an angstrom using an optical technique where the wave length of the probe is 1,000 angstroms. It turns out that it is really nice to have a diversified background. Along the way we got calls from the people who were trying to—which company was it now, to make a record for not just acoustic but optical as well. And they were looking at the possibility of making very high frequency sound on a replica and this meant extremely small excursions.
Fox:
For recording medium? This is to record information.
Cross:
Yes, recording optical information.
Fox:
Optical memory.
Cross:
That’s right, an optical memory system. But it was stillborn.
The surprising thing was they had demonstrated already that they could, in fact, record sub-angstrom fluctuations and reproduce them, and follow and track them. And that said to me, well, this is an area here which might be interesting. So we became involved. We did, in fact, develop, based on that understanding, a double-beam interferometer which later Newnham used to make the very first measurements of electrostriction in simple solids, because you’ve got to realize that the ferroelectric solids have something like 105 times the electrostriction behavior of simple solids. We wanted to show behavior in simple solids, and he had a group of students from Turkey who were very interested in working with us in this area, and I was able to give them the ultradilatometer.
And you know, it’s nice, the things fit together and one of the trials that I had, we had very good interaction with the Tokyo Institute of Technology, TIT. I used to enjoy coming back because I would bring back t-shirts that my boys immediately grabbed because they had TIT on the front of them in very large letters. They said, “Dad, I want a TIT.” [laughter] You can imagine.
Kenji Uchino came to work with me. He was from Nomura’s group in TIT. What I didn’t realize was that I employed him as a post-doc, but he actually hadn’t taken his PhD. He was a phenomenally productive person working with me. While he was working with me, we produced 11 papers in the Journal of Applied Physics, which is not trivial. And those are 11 papers which are in his thesis. [laughter] And he was a post-doc. [laughter] Fortunately, the university never found out about it. So I’m still in the clear, but don’t tell them.
Vardalas:
Okay. We’ll make sure they don’t read this transcript. [laughter]
Cross:
Thanks. [laughter] That was the area that we mapped out, and he was involved in making the first dilatometer and then Bob took this up. I showed, first of all, that we could actually measure electrostriction in simple solids, and then he had a whole family of students who came along, used the ultradilatometer, refined it, and made now what are the key measurements that show that this is a universal phenomenon in all insulating solids, but the coefficients are trivially small in simple solids.
Now the nice thing is that the whole of this is now transferable to flexoelectrics, because the flexoelectric constants in simple solids are trivially small, 10-10 volt per meter; if you’re looking at ferroelectric type materials they go to 10-4. That’s 6 or 7 orders of magnitude larger, just like electrostriction. So what I wanted to show is that there is this new avenue for making lead-free materials. Now you don’t need spontaneous polarization. That’s going to be a major thrust in the future.
Materials Research Lab: Between Science and Engineering
Vardalas:
Because of your interesting background, you straddle both science and engineering.
Cross:
Right.
Vardalas:
And it’s hard to find people who can do both. And, I’d like to explore how you move back and forth across these universes, between physics and engineering, and how you are able to talk to both these communities.
Cross:
With difficulty sometimes.
Vardalas:
Do you see them as very different human activities, physics and engineering? By that I mean are these two groups interested in different questions? Do they approach things very differently in your experience?
Cross:
I think they are artificially separated. I think there are many, many things in common between them, in the approaches, and the manners in which one tackles the problems. But the two groups don’t talk to each other; that’s the sad part. The university has all these ivory towers, and the people in one ivory tower look over at the other one and say that’s a very inferior ivory tower. Mine is the tower. This is not what one needs. One needs, in fact, an intermixing of these things, and this is where a place like the Materials Research Laboratory at Penn State draws on the fact that it has people from all the different areas working together. You rub noses. A man says he’s an engineer but he’s not that stupid after all. It’s really amazing. I mean, he understands the tensors. He’s an engineer? This sort of thing. And if you get the people together and get them talking, they each realize that they understand something that the other really needs. And maybe if I approach it from his angle, just try it for a short while, something new [may come of it].
Vardalas:
So this culture you describe at the Materials Research Lab is about bringing these diverse groups together. Was it something you tried to force on the group, or was it there from the very beginning?
Cross:
The key man is the bête noir of the Penn State system, Rustum Roy. Professor Roy was a brilliant man. He was the originator of the Materials Research Lab. I joined him early, Newnham joined him early, Heinz Henish joined him early. We put together a group that involved people from physics, people from electrical engineering, people from ceramics. It really took off because I think most of the people at the university thought he had a magic spigot in Washington that he could just turn on and money would pour out. They didn’t realize how hard he worked. He really was a huge generator of proposals.
And he had the interconnections to the people and he knew what their interests were. He knew where the money was. Most of what is done at the university, you could take it from a helicopter and sprinkle it over Washington. The chances of it getting picked up are that small, but in our particular instance, we had the inside track. And that made it extremely worthwhile to spend time and really develop a proposal of what you wanted to do.
Vardalas:
Is that something you taught your graduate students? It takes a lot of skill in putting together proposals and knowing how to talk to the funding people.
Cross:
That’s what we teach them.
Vardalas:
You do teach them that.
Cross:
Yes. And they participate and they do get enthusiastic, particularly if you show that you have a success rate. Our success rate in the Materials Research Lab was much, much higher than the average success rate at the university, because Rustum knew where to put them. And that is really 90% of the battle.
Research with DARPA
Cross:
I also, you know, I became connected because something that was very helpful to me was that I got associated early on with DARPA, the Defense Advance Research Projects Agency. And I was taken on for the Defense Sciences Research Council. This was a group of academics who were, at the time, put together to advise, not to dictate anything, but to give DARPA advice on areas which were rapidly developing. And for a young professor—I was quite young at that time—this was a huge advantage, because I sat with George Whitesides. He’s brilliant. I mean, this is a man with 20 post-docs—with Millie Dresselhaus, who really knows ferromagnetism like nobody else in the world. And she and her husband had a huge insight into magnetic systems, and all sorts of other—you know, this was the advisory group and they were really brilliant persons too. It was a challenge but I spent a month every year with that group and we helped to design programs for DARPA.
And they would bounce ideas off of us. They would say, “Bring together a group that would advise us on this particular area.” For example, I was able to bring together a group that advised them on what was going on with infrared detectors, thermal type detectors. One of the problems they had in the desert was the fact that the tanks knew where they were going because they had FLIR [thermal cameras] which were very expensive, but the trucks which were supposed to give them gasoline didn’t know where the hell they were going. And so, we needed a cheap infrared system where they could detect the heat and find the vehicle that they were supposed to service. But they couldn’t afford to give them a FLIR. These were too expensive because these were cooled infrared imagers. What we did, in fact, design eventually were the whole family of infrared detectors, the pyroelectric imagers and—
Vardalas:
When you say we, whom do you mean?
Cross:
Well, the group that I was with in DARPA.
Vardalas:
So this is how you kept your finger on the pulse of all the important things going on.
Cross:
That’s right. And there was one brilliant stratagem that that group had. They had to fund through DOD Agencies, which meant that they had to give their money to ONR. ONR then gave the budget to somebody, which is educational both for ONR and for DARPA. DARPA has an original idea but it doesn’t know where the hell it ought to go. ONR has a need and they can go back to these people and say, “Look, that idea could be very useful to us in”— it was really educational for the whole system.
Vardalas:
That’s interesting.
Cross:
I thought it was. If they could have funded through any agency…they could have funded through NSF and then didn’t. This would not have been educational to anyone because NSF can learn from nobody. They are the fundamental people who know everything, this sort of thing. But, you know, the people in the Office of Naval Research, the Air Force Office of Research, the Army Research Office, they are really desperate for background information in many of the areas that they’re dealing with. And this is one of the reasons why I spend time going and visiting these places.
Vardalas:
Right.
Fox:
So would you say these groups also have the same type of view that you need to take a holistic approach instead of separating it out into certain areas of expertise?
Cross:
Absolutely. You’re going to need things which involve good physics, things which involve good chemistry, things which involve good biology; all of these are going to be put together necessarily because you have to interact. You have to design a system which will survive under extremely adverse circumstances, this sort of thing. And it is, I think, a fascinating area to participate in because there’s an awful lot of money which is just wasted. It’s really thrown away.
Fox:
So it’s really driving the science from a view of the end product.
Cross:
That’s right.
Fox:
As opposed to —
Cross:
What am I going to need to get from here over to there? And, you know, as a scientist you can see this sometimes where the people are very close to it. [They think,] “Well, why should I need that?” Then you have to really connect the whole logic path for them. “Oh my God, yes, you’re right. If I’m going to do this, I need to understand that, and”—these sorts of things don’t come to people except if they’ve had practice looking at things [in a holistic manner]. And this is why the Materials Research Lab, I think, was interesting. It was instructing people to look outside their own particular bailiwick and say, “Dr. So and So, he’s a bit of an idiot but, you know, if you can survive talking to him, you’ll pick up some useful information.”
Mentorship and Teaching Philosophy
Vardalas:
Going along those lines, how do you see yourself as an educator and mentor? Because you’ve had doctoral students, yes —
Cross:
[laughter]
Vardalas:
How would you characterize yourself in that role?
Cross:
Well, I think I’ve had some success because the man who’s in charge of the dielectric center in Xi’an Jiaotong University is Professor Yao Xi and he was one of my original Chinese students. He really is brilliant. The lady who is Minister of Education for the whole bloody People’s Republic was one of my post-docs. She calls me up and says, “What are you doing Professor Cross? I’m educating a hundred million children.” It’s a little bit difficult to beat that one. [laughter]
Vardalas:
[laughter]
Cross:
And she is. You know, the Minister of Education has got responsibility all the way up the chain. I think they’ve done a phenomenal job. She’s a very brilliant lady, and I trained her properly.
Vardalas:
So these are your first Chinese PhD students you’re referring to?
Cross:
These are the first Chinese PhDs. I had a group of four that they had selected that came over to Penn State. They are now senior people in their system over there: Chen Xili, Yao Xi, then three more that I had.
Vardalas:
As a supervisor, do you follow your philosophy of giving them an idea and leaving them alone?
Cross:
[laughter]
[general laughter]
Cross:
I follow an open door policy. I am there most of the time, and I say, “Look, if you have a real problem, hammer on the door and come in and talk about it and we’ll see what we can do. I don’t guarantee I can do anything, but at least we can talk about it.” And this has worked remarkably well because I have got people all over the world now who were old Penn Staters. They really are so loyal to the Penn State system. It’s nice to visit with them and know that they themselves are having success locally using the same sorts of attitudes.
It was amazing how much correspondence I’ve had since my wife died a month ago. She used to travel with me and she was very much loved by many of these people because she has a very generous personality, and would, in fact, embrace them into the family. We have always had an interest in children. When I first met her, she was in charge of the nursery school at the National Children’s Home for Orphans in Harrogate in Yorkshire. It’s a long walk from Harrogate to Leeds, and I had to do that walk to give my lecture on time. [laughter]
Contribution to Hubble Telescope
Vardalas:
There are some questions that others who know you have said, make sure you ask him these questions
Cross:
[laughter]
[general laughter]
Vardalas:
Um, first of all, you were involved in the Hubble —
Cross:
Yes.
Vardalas:
Telescope. Can you say something about what your involvement in the Hubble Telescope was, and the context for it?
Cross:
Well, let me think back for a minute about that because I did have connections with them and, what was the original problem?
Vardalas:
Was it a flaw? Was it something to do with a flaw in it or anything that you were involved in?
Cross:
Um, I’m trying to think back now and —
Fox:
If I remember correctly, the original mirror was ground improperly.
Cross:
Oh, that’s right. Yes, and what did we do for that? The point is that they knew what was wrong with it. They were able to make a corrector plate that they could put into the optical path, but the problem is you had to, in fact, orient it completely in the right manner. And the nice thing was that I had been involved with them with the actuators that they needed, and this allowed them to build in correctors which they could control from the ground, so they could, in fact, make the final alignment from the ground.
Vardalas:
How does a man who deals with fundamental materials get involved with the actuators?
Cross:
Well because all the transducers in systems can be receivers —
Vardalas:
Yes, but —
Cross:
But they can also be generators.
Vardalas:
Oh, of course, yes.
Cross:
We had been involved also with ultrasonic motors. The nice thing is that you can make those extremely small, so that the upcoming “Roto Rooters” that will be used to take plaques out of your veins will be, in fact, piezoelectric.
International Research Projects
Vardalas:
What are your recollections of the founding of the U.S.-Japan Seminar on Dielectric and Piezoelectric Ceramics?
Cross:
[laughter] Yes. That involved my interaction with the Chairman of the Defense Academy, and then the man who was in charge of the dielectrics group at the Defense Academy—what was his name? Kioki Okazaki.
Vardalas:
Yes.
Cross:
And my wife would say, "Don’t bring that man in. He has more hands than an octopus and they’re all in the wrong places." [laughter]
Vardalas:
Oh my goodness.
[general laughter]
Vardalas:
That’s the first time I’ve heard that one.
Cross:
[laughter] So he was a devil. [laughter]
Vardalas:
What was the purpose of this seminar? What came out of it?
Cross:
Well, actually we put the thing together, he and I, because we had interest in dielectric ferroic materials. There was a big Japanese and American interest. We thought of techniques on how to put them together. And the first meeting, the Navy was very interested in getting in and understanding. So they insisted that tours were arranged for all the people who went there. Okazaki had sufficient connection with all the Japanese companies, so he was able to arrange visits for the whole group of American persons. This was the first U.S-Japan meeting which really had been constructed so that it would, in fact, provide information from one side, because they were very good on the practical application and we were a little better on the theoretical understanding, and to get these two groups melded together really worked remarkably well.
Vardalas:
Oh, okay.
Cross:
Now I had a problem because for the next meeting, the Navy could not provide me with money to provide travel for the Japanese group, so I had to figure out a method of doing this and I did it.
Vardalas:
I just want to follow up on the statement you made about this U.S.-Japan joint seminar …
Cross:
Yes.
Vardalas:
…which we haven’t discussed. What had been your relationship with Japan in terms of research and development?
Cross:
Well, you know, Japan has always been very active in the area of electroceramics, and I have had interactions with them, starting with the Murata Company and particularly when Erie was bought up by Murata.
So I have, over time, had lots of interactions. I did, in fact, start the Dielectrics Center at Penn State. Fortunately, I passed that over to Clive Randall, and Dr. Randall is now running it. I think he has now, I believe, over 40 companies in membership of the Center for Dielectric Studies. I’m trying now to architect an interrelationship between this one and the international center which is developing in Xi’an, which is, again, being developed by one of my acolytes, Yao Xi. And this will mean that these two groups will collaborate instead of competing, which could be a damn nuisance.
[In] these sorts of things I can help, but you know it also keeps an interest too. I mean, damn it, I am 87. I could simply lie down and have earth put on top of me, but I still have interesting things that I want to do, and that, in fact, keeps one a little bit more…Things do tail away unfortunately, but so far most of the things I need to do, I still can do.
Vardalas:
I want to ask you about something that you already touched upon briefly – your ex-Soviet Bloc colleagues.
Cross:
Yes.
Vardalas:
What about the Cold War? In general, what are your recollections of that whole period of working with that community? You described one disastrous incident, I guess, it was almost a disaster, when you couldn’t take somebody to a SAC base.
Cross:
[laughter] Well, I must admit I’ve always been a little bit skeptical about classification of things, because the very best description I’ve had, the only good description I’ve had of the American system for detecting submarines was from a Soviet admiral.
Vardalas:
Really.
Cross:
All the detail he gave me.
Vardalas:
Really.
Cross:
Because they had obviously penetrated. They know exactly what we do. I didn’t give them a thing because I didn’t need to. [laughter]
Vardalas:
So was it easy to go back? Did you go back—did you go to the Soviet Union that time? Or was that affected by the Cold War exchange of ideas with them?
Cross:
Well, we had to be careful, particularly in the transducer area, about the exchange with people. And it’s been a little difficult for me because I’ve always had extremely good relationships with the people in the Czech Republic. I made very early contact with Jan Fousek. He and his wife came over and worked at Penn State for a while. Their first daughter is called Erica, which is surprising (Note: named for Eric Cross). The nice thing is that their daughter recently married and she presented him with twins. And he is the world leader on the understanding of twinning in crystals. [general laughter] So now he has the biological example, very close to home. [laughter]
Vardalas:
Have you had the opportunity to talk to colleagues who were part of the Soviet Union and reminisce about those days?
Cross:
We do on some occasions, yes.
Vardalas:
Are there any interesting stories that come out?
Cross:
Yes. And this is true across the whole system. I mean, if I could have access to those—where do you think the Soviet admiral got his understanding?
This sort of thing I’m very skeptical of …
Because it was interesting, talking to them. One of the senior Soviet scientists said that he invented a xerography process in his own lab. And word of this got up to the KGB. They came in and immediately confiscated it and stopped all work. They said, “A process like this will make it impossible to keep any secrets.”
Vardalas:
My goodness. Really?
Cross:
Really. And he said that he had the whole process laid out, knew exactly what to do to make a xerographic machine, but they wouldn’t let him. He was an expert on photo phenomena in materials.
Vardalas:
Does his name come to mind at all?
Cross:
I’ll try. I’m trying to think of it.
Vardalas:
You mentioned—Jan Fousek, you pronounced it?
Cross:
Yeah, Jan Fousek.
Vardalas:
Can you say some more about your relationship with him over time?
Cross:
Well, I was lucky to be able to go to the first International Meeting on Ferroelectrics, which was in Prague. And I made contact with Jan. We immediately clicked because he realized that I was interested in the science and not just in the technology. And so I did arrange for him to come over and spend time at Penn State with his wife. She was brilliant, but she was very uncomfortable with the system and —
Vardalas:
The Czech system you mean.
Cross:
The Czech—well with the Soviet intervention in the Czech system.
Vardalas:
Right.
Cross:
It was very difficult for him. I know they would ask me to their house, and I know that I wasn’t supposed to go there, but they did this in spite of the authorities. I did, in fact, back off from visiting with them because of that, but they could visit with me. And here that was all right.
Vardalas:
I see.
Cross:
These all day symmetries occur in these highly regulated systems, but —
Vardalas:
Was there any fear or any expression that they would defect at some point when they came to visit you? Did they ever just say, “I want to stay here”?
Cross:
No, they were okay, and they obviously enjoyed the freedom that one has over here, and we could talk. She was a very good scientist, his wife. I believe she took her own life eventually because she couldn’t stand the system anymore, but that I’ve never been able to fully check on.
Vardalas:
Has Jan passed away?
Cross:
No, but he unfortunately has a mental problem, so he does lose the thread [of a conversation]. If you’re sitting and talking with him, you can bring him back, but he can’t give any public lectures anymore.
Vardalas:
Okay.
Cross:
Because his mind loses the connection.
Fox:
You soon have a book coming out with him …
Cross:
It is already out.
Vardalas:
It’s already out?
Cross:
Yes.
Vardalas:
Okay.
Cross:
It’s also with Tagantsev, Alexander Tagantsev, and—I think it’s a good book. It’s a book on the main walls, and I already have the first from Elsevier. They sent me a check for 500 bucks from royalties on the book, which is not bad.
[general laughter]
Achievements and Regrets
Vardalas:
I wanted to ask one important last question which is always a difficult one to ask, and because it requires a lot of thought over a long career, and it forces people to make very narrow characterizations which are not always easy. Looking back over your career, what are you most proud of? And do you have any big regrets or disappointments? Does anything still haunt you as a disappointment or regret you didn’t do? And what are you most proud of, if you had to pick a few things?
Cross:
I think I’m most proud of the 50 PhDs that I’ve generated, and the fact that these are now all over the world. And then that’s wonderful to go ahead and visit with them and see them really practicing what I was preaching. That is awfully nice.
Vardalas:
So essentially progeny.
Cross:
Yes. I’ve left an inheritance, I think, which is nice.
And they have also, of course, picked up from all the people around me that I have accumulated. We have a good group. I think the disappointment to me has been this constant need to generate monies for research. There are some areas where people are, in fact, supported. Unfortunately, they tend to go to sleep if they’re not in fact hustling. And that can be useless. It means that they are just in fact passengers in the system; but it would be useful if Penn State had some support funds because there are usually gaps between contracts. You find it very difficult to keep continuity, which is important. And that is a damn nuisance.
Vardalas:
Are there any regrets in terms of things you should have taken up as research but didn’t?
Cross:
I think I’ve been very lucky. I’ve been able to follow through on most of the things that I was really excited by. I have things developing now which I think will be important, but those are still in the air, and there are still possibilities that they will, in fact, move forward. What are the biggest disappointments? I think by and large I’ve been a very optimistic person. [laughter] I’ve been lucky in that sense.
Vardalas:
One last question; that was supposed to be my last but I have one more last.
Cross:
[laughter]
Vardalas:
If you had to explain to the general public why this research on ferroelectrics is important to human development and progress, what would you say to a person who doesn’t know this area? Why is this whole area so important, and the history of it?
Cross:
Well, I think, first of all, if you look at electronics, there are families of components and the capacitor components are essentially dependent upon dielectric materials. My whole life’s work has been associated with dielectric materials. High permittivity dielectrics are essentially vital for most modern electronics; and so I’m not disappointed that I have been involved with that area. A more specialized area which I think is interesting both from the point of perspective of defense but also from the perspective of human health is the transducer area. The ultrasonic transducers which are used in medical ultrasound have benefited very much from the work which we have done, particularly on the front end transducers, and on the composites, which is the work between Newnham and myself.
And I’m delighted that has moved forward and that is still evolving because people are now making specialized transducers for special functions, like transducers that can go inside the person; transducers particularly for use looking at eye structures and these sorts of things where you want to get very sharp distance registration, which means very high frequency transducers over short distances, because the human body is a strong absorber of sound. So you can’t go too far, but if you can bring the transducer close to the area, you can, in fact, then see considerable detail. And then these are interesting,
I think also another area which I haven’t had a lot of time to deal with is the optical properties, optical frequency conversion, second harmonic generation; these sorts of areas of optics. And optoelectronics are now moving and the materials that I’m interested in also have roles to play because they have controllable birefringence. They have controllable optical properties. They have controllable spatial features. So that these you can use for a wide range of other applications. I think that the materials families I’m most interested in still are the frontier for many useful technologies.
Vardalas:
Well, on that note, on behalf of the Ultrasonics, Ferroelectrics, and Frequency Control Society and IEEE History Center, which I represent, we want to thank you for this wonderful oral history.
Cross:
[laughter] I hope it’s been useful to you.
