Oral-History:Herbert Freyhardt

About Herbert C. Freyhardt

Herbert C. Freyhardt was born in Kleinbottwar, Germany in 1941. Freyhardt's professional accomplishments serving as head of the “Crystal Growth Laboratory” as well as the “Superconductivity Section” of the Institute of Metallphysik.


This interview is part of the IEEE Council on Superconductivity Oral History Project.

About the Interview

Herbert C. Freyhardt: An Interview Conducted by Mary Ann C. Hellrigel, IEEE History Center, 8 September 2016.

Interview #776 for the IEEE History Center, The Institute of Electrical and Electronics Engineers Inc.

Copyright Statement

This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center.

Request for permission to quote for publication should be addressed to Oral History Program, IEEE History Center at Stevens Institute of Technology, Samuel C. Williams Library, 3rd Floor, Castle Point on Hudson, Hoboken, N.J. 07030 USA or ieee-history@ieee.org. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.

It is recommended that this oral history be cited as follows:

Herbert C. Freyhardt, an oral history conducted in 2016 by Mary Ann Hellrigel, IEEE History Center, Hoboken, NJ, USA.


Interview

INTERVIEWEE: Herbert C. Freyhardt

INTERVIEWER: Mary Ann C. Hellrigel

DATE: 8 September 2016

PLACE: Applied Superconductivity Conference, Denver, CO


Family and Growing Up in Germany

Hellrigel:

This is Mary Ann Hellrigel, the Institutional Historian and Archivist at the IEEE History Center. It is September 8, 2016. I am with Dr. Herbert C. Freyhardt at the Applied Superconductivity Conference in Denver, Colorado. This is the 50th Anniversary Applied Superconductivity Conference. [This interview is part of the IEEE Council on Superconductivity’s oral history project.] Welcome and thank you for agreeing to talk to me.

We will start with a little bit of biography. I know you were born in Germany in 1941.

Freyhardt:

Yes, that is precisely it.

Hellrigel:

How do you pronounce the name of the town?

Freyhardt:

Kleinbottwar is a village in the south of Germany. It is near Stuttgart, south of the ancient Roman Wall. This means there might be some Roman blood in my veins, my Roman God in not forgotten there.

Hellrigel:

Please tell me a little bit about your parents, your mother and your father.

Freyhardt:

Well, now this is a sad story because my father went to war and there exists only one photograph of my father and myself. My father’s name is Karl (he used to write - Carl) Freyhardt.

Hellrigel:

You were a baby.

Freyhardt:

Yes, I was a two-year old baby. He was back from Russia.

Hellrigel:

He was on leave during World War II.

Freyhardt:

Yes. After the Second World War ended, he was missing. We do not know what actually happened. You see, we only know that after the war ended, he was coming back from Russia to Germany. He had asthma. Obviously … I talked to one of those who knew a little bit about this joint ‘march’ back to Germany … it was too difficult a journey for my father.

Hellrigel:

Yes, the journey to get home was too physically difficult for him.

Freyhardt:

The person I talked with said he was bringing my father along with him. It was a very challenging journey and somewhere they were no longer together. We do not know where or when my father was seen last. There is no information.

Hellrigel:

What kind of work did he do before the war? Was he an engineer?

Freyhardt:

No, he wanted to come up with a company of his own to produce furniture. This is what he planned.

Hellrigel:

He was a carpenter, so he wanted a woodworking business.

Freyhardt:

Yes. This is what he wanted to do and this unfortunately was not going to happen. Yes, I was educated and grew up without a father.

Hellrigel:

I see this had a big impact on you, as a similar situation would affect any child and family.

Freyhardt:

Yes, but this created more independence for me right at the beginning. I tried at that time to earn my own money by various ways. I was very independent at the age of fourteen years old. I bicycled around Europe through Pforzheim, Stuttgart, and Strasbourg, and then on to Paris. I continued all the way across the English Channel to London and to Stratford-Upon-Avon to Scotland. In Scotland, I worked on a farm, and then bicycled back to Germany. Just on my own. Just alone.

Hellrigel:

Did you make this bicycle trip just for adventure?

Freyhardt:

Yes, I made the trip both for adventure and to learn about what was happening in other parts of Europe.

Hellrigel:

What a grand bicycling trip in the mid-1950s.

Freyhardt:

This made me independent.

Hellrigel:

Did your mother think you were a little crazy for making this bicycle trip?

Freyhardt:

No, but she cried. She knew she could rely on me not to do anything bad. I simply was interested in acquiring something new.

Hellrigel:

Like many other widows, especially those with children, your mom must have had a difficult time after the war.

Freyhardt:

Yes. This bicycle trip took six weeks, so I was away for a while, but it worked out fine. I returned safely without any problems.

Hellrigel:

Tell me a little bit about your mother. What is her name? What was her education level and occupation?

Freyhardt:

My mother’s name is, was - she passed away already, Frida Freyhardt. No higher education, a dedicated mother, full of love, living for her children.

Hellrigel:

Do you have any brothers or sisters?

Freyhardt:

Yes, there is one brother. He is an electrical engineer. My brother’s name is Werner Freyhardt.

Hellrigel:

Both you and your brother decided to become engineers.

Freyhardt:

Yes. I wrote down a couple of remarks before this interview. These are the remarks. I had excellent teachers in the gymnasium. In Germany, a high school is called a gymnasium. I had excellent teachers in the gymnasium, particularly in mathematics. I also had an excellent language teacher. He taught French and we learned French as the first foreign language. Two other people influenced my life, including the theology teacher and the physics teacher. The students had a very close relationship with the theology teacher. Although he taught theology, he was mainly bringing our brains to philosophy.

Hellrigel:

I noticed your undergraduate work in college.

Freyhardt:

Yes, as an undergraduate, I studied both physics and philosophy, but then I realized that doing everything in parallel is too difficult.

Sure, truly studying both at the same time might be too difficult. Maybe these studies pulled you in different directions.

Yes.

After the war, life must have been difficult in Germany. There may not have been much money for toys and extra things; however, do you recall favorite toys and hobbies? For example, in the United States kids had erector sets, train sets, and models. An erector set is like Legos, but the parts were made of metal.

Yes, I did a lot of woodwork and things like this. You see, I was good in technical stuff.

Sure, you were good with tools, building things, and hands-on work.

Yes, you see I had good connections as a young boy. I liked woodworking and as a boy, I was associated with blacksmithing. In the blacksmith’s shop, I was allowed to do just about everything. I am still proud that I built my first desk with a metal frame. I soldered the metal frame, painted it, and put a wooden plate with beech veneer on top. Yes, this is what I enjoyed.

Hellrigel:

You rode a bicycle. Did you also play sports such as football?

Freyhardt:

At first, I played football and handball, but mainly, it was just bicycling and walking. When we were young, we also did a lot of nonsense.

Hellrigel:

It was a tough time. Germany was rebuilding. At what age did you decide that you were going to focus on technical and scientific matters? When you were a boy, did you think about becoming a philosophy teacher or did you know from an early age that engineering was your future?

Freyhardt:

I went to a gymnasium. At that time, it was not completely decided what I was going to do. It became clearer when I decided to go to university.

University Education and Experiences

Hellrigel:

How did you select a university to attend?

Freyhardt:

In the end, I decided to attend the University of Goettingen, because I wanted to study philosophy and physics. This again was decided, based on the background I mentioned. I was inexperienced in these matters, but I lived near two universities, the University of Stuttgart and the University of Tuebingen. I considered them first; however, I knew the University of Stuttgart was a technical university, and good in engineering and some sciences, but not philosophy. There was one professor teaching philosophy at Stuttgart, but at the time, I did not know it. Tuebingen would be good for philosophy, theology, and all of this, but it was not good in physics, I thought. The information I had might have been incorrect, but that is the information I had at the time. I was an inexperienced person in these matters, and I tried figuring this out on my own. Then I said well, Goettingen is the center of natural physics, quantum physics, and it has well known Nobel laureates, so it is very attractive. It was also good in philosophy. This is how I selected the University of Goettingen.

Hellrigel:

Did you find it competitive to get into the program at Gottingen?

Freyhardt:

Yes. Fortunately, in school I was always at the top of my class, so I got many prizes, excellent prizes. I was well-prepared for Goettingen. The education system in Germany is very different from the one in the U.S.

I will never forget my fifth grade at the gymnasium in Marbach. I was the top fifth grade student. A noteworthy celebration ceremony was held in the home where Friedrich Schiller was born. During this ceremony, I, as awardee, had the honor to place a laurel crown on the well-known bust of Schiller. I was proud.

Hellrigel:

Oh, yes, being recognized and winning prizes must have been fun.

Freyhardt:

Since I did well in school, I was supported financially. You see, my mother was a widow, and not in a position to provide me with this education, so I was supported by national projects.

Hellrigel:

Did your brother have financial support, too?

Freyhardt:

Not as much. He entered engineering school and took a slightly different road.

Hellrigel:

He is older than you by how many years?

Freyhardt:

He is four years older. By the time I started college, he was already an electrical engineer. He has died. This is also something that lays heavily on my mind. Well, 75 percent of my family died from cancer. I am a part of the family that has lived to seventy years of age without problems. I may be just like my mother because she was more than ninety years old when she died.

Hellrigel:

Your brother is your sibling and I am sure you miss him. At some point, everyone might think about her or his life span and mortality. In my family, if you reach sixty-five years of age and have not been diagnosed with cancer, you have a strange chance to live much longer and die in your eighties from heart issues.

Freyhardt:

Yes.

Hellrigel:

Did you enjoy college?

Freyhardt:

Yes. I had many friends and we had good relations with everybody. It was quite enjoyable and I have very good memories.

I also have some sad memories. One of the saddest influences in my young life or my entire life is losing a high school classmate and close friend. He sat next to me. This was just before we graduated. After a New Year’s Eve party, he was walking home and was killed in a car accident. I still see the image of my good friend being buried. All these years later, this image is still there. This was even more difficult to comprehend than seeing all my family members dying.

Hellrigel:

Yes, it made little sense because he was so young and he was walking home from school, something you did every day. Did it make you think that now you have to take life seriously, but not too seriously, and make the most of your time? You could not take life for granted. You had to feel good about each day.

Freyhardt:

Yes.

Hellrigel:

When you were a university student, did you teach or work in a laboratory?

Freyhardt:

I was teaching a lot, not as a student, but later as a professor. I studied physics and I got an extremely solid education in mathematics, but I mainly taught solid-state physics and materials science. Materials science, this is an important field with broad impact for applications. During my teaching career, I supervised about 150 Diploma-Physics and Ph.D. theses, and that is good enough. Now the younger generation can take over.

Hellrigel:

Yes, the next generation can take over supervising the students, especially the graduate students.

Freyhardt:

Yes.

Teaching Preparation and Career

Hellrigel:

Many of the men I interviewed here at the Applied Superconductivity Conference said they decided not to teach. They worked in either industry or national research labs. However, you chose to teach at a university for much of your career.

Freyhardt:

Yes. I wrote something down on this topic … for today’s discussion. I already started teaching in 1976, after I earned what is called a “venia legendi” for materials science after having successfully completed my “Habilitation” exam. Since 1984, I am what is called a university professor at the University of Goettingen.

Hellrigel:

Right.

Freyhardt:

Habilitation is something that is unknown in the U.S. In the past, in Germany, you were not allowed to teach, unless you had earned a venia legend. However, you could not apply to commence the Habilitation procedure because you had to be recommended by your supervising professor.

Hellrigel:

This is a different process than in the U.S. In the U.S., you apply for a post. Then you need letters of recommendation and other material assembled like a portfolio. However, the emphasis is on research, especially at the large research universities. If you are not applying to a research university or a more research-oriented university, the committee is very interested in your teaching skills.

Freyhardt:

In Germany, you were recommended to teach and then you went through the procedure. You prepared the habilitation thesis and you went through the examination. Before I started this Habilitation procedure, I had been a Visiting Scientist at the Argonne National Laboratory, so part of my habilitation thesis was generated and developed at Argonne. After finishing the habilitation, you acquired the right to teach.

Hellrigel:

I see, you wrote one thesis, but you did not complete your studies until you finished the habilitation thesis. You completed the habilitation in 1976. In the end, you wrote two theses.

Freyhardt:

Yes. Generally, after your Ph.D. thesis, you write a further habilitation thesis. Then you acquire the right to teach. This is just like in France, where you have the Thèse d’État. The examination consists of various steps for habilitation. You had to submit the written thesis. You had to give a lecture. Most importantly, you had to stick to the time limit of forty-five minutes. You also had to take a final examination. You could suggest three topics to the examiners.

Hellrigel:

I see, you have to give a lecture to demonstrate your teaching skills. Then you have examinations, too.

Freyhardt:

Yes, teaching the lecture was one thing and the examinations were another requirement. You had to prepare for the examinations, but you could suggest three topics. Generally, the topic was chosen and given to you. In a certain amount of time, two weeks, you worked on that specific topic. You had to demonstrate that you could do it in the allotted time and in a considerate manner.

Hellrigel:

Did you get nervous about working on these requirements? On the other hand, maybe you thought you were ready, so you charged ahead to complete the lecture and examinations?

Freyhardt:

Yes, it is natural to be concerned. You are prepared and then you get the details for each of the three examinations. During graduate school, you prepared for this, so once you get the three examination, you know what you are doing.

Superconductivity Research and International Collaboration

Hellrigel:

Yes. In 1973, you conducted research at labs in the U.S., Europe, and China.

Freyhardt:

Yes.

Hellrigel:

How did you get the connections to go to those labs? What research did you conduct at these labs?

Freyhardt:

These connections were built up gradually over the years. You probably realize that I had good teachers. One of which is Peter Haasen, just like the German word for rabbit, “Hase,” but with double A. He influenced all of what I was doing. Haasen was, amongst other topics, looking into the strengthening of materials in a very broad sense. To create a mechanically strong or hard material you must study the interaction of dislocations with all kinds of obstacles, e.g. precipitates or other dislocations. Similarly, he studied the hardening of magnetic materials. In a magnetically hard material, the Bloch walls have to be pinned by obstacles. This is leading to the third, and for me most appealing research field, the hardening of superconducting materials. It became my first research interest, particularly the pinning of flux lines in type II superconducting materials.

During the 1960s, this is how my research started and then I made many connections with other scientists. Jacques Friedel (1921-2014), a physicist and materials scientist, was the premier scientist in Paris, who also worked in superconductivity. During this time, we established good connections with scientists in Japan, including Kaoru Yamafuji and Fujio Irie, from Kyushu, and we improved connections in the U.K. This was based on joint research interests, and because of the findings, we could communicate. In the 1960s, we truly established many local and international connections.

Hellrigel:

It was a productive period.

Freyhardt:

It was productive. As I mentioned, in 1968, the University of St. Andrews hosted the 11th International Conference on Low Temperature Physics (LT). It was the first LT conference I attended, and I established deep and long-lasting friendships and connections. Yes, we met with friends and made new friends.

Hellrigel:

The conferences were important because that is where you made international connections.

Freyhardt:

Yes, very early on, I started studying flux pinning and I went to conferences. I made professional connections at the first flux pinning conference. I have been building connections worldwide, especially with people in France, Japan, and Russia.

Hellrigel:

Sure, eventually you worked with people in Russia, too.

Freyhardt:

Yes, Russia, too. In previous years, we had a productive Russian or better USSR-German cooperation. I was, to some extent, leading it from the German side for about ten years. After Glasnost/Perestroika, it included Russia, Ukraine, and Germany. I was very involved, so I travelled a great deal.

Hellrigel:

You went to Russia before the Berlin Wall came down in November 1989. Could you expand on this experience? What came out of this cooperation between Russia, Ukraine, and Germany? You were invited, but who else was invited?

Freyhardt:

You asked how I established international relations. I did this through conferences, meetings, and research collaborations. My Russian colleagues invited me very frequently, and often I visited Russia and the Ukraine. I developed very close relations.

Now, for the meeting on flux pinning, I only want to find the correct date. Yes. I recall the correct date.

In 1974, Peter Haasen (1927-1993) and I organized the first International Discussion Meeting on Flux Pinning in Superconductors. It was held near Gottingen at Sonnenberg in the Harz mountains. It was the first truly international discussion meeting on flux pinning. We brought together a small group of scientists from around the world, with whom we already had connections within and outside of Germany. I deepened the already established connections, e.g., with David C. Larbalestier, Archie M. Campbell, and Jan Edgar Evetts (1939-2005). This created the international contact network and it has continued. [Larbalestier is a materials scientist at the National Magnetic Field Laboratory in Tallahassee, Florida. Campbell is in the Engineering Department at Cambridge University.]

I was very active internationally. I reviewed Swiss programs, Austrian programs, Korean programs, and other national programs on superconductivity and applied superconductivity. I was peer reviewer for ten years or so for Jim Daley’s (James C. Daley, 1941-2016) Department of Energy’s High Temperature Superconductivity Program. I have a broad network on connections.

I think there are few people around anymore with my age and background who know the people and have the information of about our broader superconductivity community.

Well, this is the old story. If you live long enough, you know it.

Hellrigel:

Right, you have been so active and you know the history of the field. It is important to document this history. You are the first person I interviewed at this conference who has spoken extensively about international collaboration and travel. Perhaps this is because you are an academic and the other people worked in U.S. national laboratories and private business. Some did a little traveling, but your connections seem more global.

Freyhardt:

Yes, well this is globalization. It is true; I did a lot of travelling. I have tried to figure out how often I circled the world in an airplane. Maybe I have gone around the globe four or five times. I do not know.

Hellrigel:

Oh my, you have travelled often and taken so many flights.

Freyhardt:

Yes. Lufthansa granted me Senator status because at one time I was flying 150,000 miles a year.

Hellrigel:

Whew, you spent a lot of time in the air. You had access to some benefits such as the use of the Lufthansa club, boarding first, and maybe better seats. Although you earned many miles for vacation trips, you may have been tired of airplanes and airports for leisure travel.

Freyhardt:

Yes. This is true. [Laughs] Yes.

Hellrigel:

Then you also have colleagues around the world who have become friends, too. All those places for potential vacations.

Freyhardt:

Yes. Naturally, many friends are here in the U.S.; most are still alive, but some have already died. I cooperate with the superconducting news forum. I am mentioning this because you will see the in-memoriam section at the Applied Superconductivity Conference.

Hellrigel:

Yes. It will be a sad time because you lost friends and colleagues.

Freyhardt:

As we age, it always hurts me to see them passing away. People I closely cooperated with at Cambridge in the U.K., Jan Evetts; others in the U.S., Jon Clem; and Fujio Irie from Japan. Others I do not mention, but you will see the special in-memoriam session at this conference. This hurts. This is hurting.

Hellrigel:

Yes, I noticed there are three special memorial sessions at this conference for Harry Jones, Charles (Chuck) Oberly, and Bill Fowler. The IEEE Council on Superconductivity website posts obituaries, too.

Freyhardt:

Yes. We have a long list of people who have passed away. I could show you.

Hellrigel:

Yes. If you do not mind, please send me the information and I will figure out a way to incorporate the material in the work I am doing to help document the history of the IEEE Council on Superconductivity.

Freyhardt:

Let me see. I should look at this.

Documenting the History of Superconductivity

Hellrigel:

Sure, take your time. I am excited you are gathering material to document the history of superconductivity. Peter Lee is trying to document the history of superconductivity by selecting people to record an oral history.

Freyhardt:

I could give you the data. This is the superconductivity news forum. You would easily find this in the superconductivity news forum and look at the in-memoriam section. Well, I realized we are missing in our present in-memoriam section, some of those mentioned during the opening. Nevertheless, most of them are listed.

Hellrigel:

Yes. I read some of the obituaries posted on the IEEE CSC website. Today, I hope to attend the history session at four o'clock, but I may have an oral history interview at that time.

Freyhardt:

Yes, well yesterday there was also a history session.

Hellrigel:

Yes, I attended. It is great to hear you are also interested in history.

Freyhardt:

Yes, well, at some time you will get interested in this. You see, history is often background to further development. However, history alone is not sufficient -- this is also my personal view, I mentioned this. The university of Goettingen is proud of the many connections to more than forty Nobel laureates. However, at this moment, there are only two Nobel laureates living at Goettingen. After about the year 1960, quite some gap opens up in the “Goettinger Nobelpreiswunder”. You can be proud of, but you cannot always live only on your early achievements.

Hellrigel:

Right, so it was that unique period. Now are other German universities catching up?

Freyhardt: This is very important because you cannot train only based on historical knowledge, this is no good. This is, furthermore, the difficulty with the electronic transfer of knowledge and the quick transfer of knowledge. It is to some extent our ‘little’ brain. You have to sit down and think about what you are doing. The information influx from the internet is enormous for the young people. You have to educate them to evaluate material critically. If the young people want to solve a problem, they just try to find the solution instead of thinking about it.

Hellrigel:

Research skills are so important. Every semester I tell my students they will learn to think and work like an historian. After sending my university history students to find news articles about a particular event, I go around the classroom the next day, looking at the items they found. Some are actual articles, but often I have to say this is a blog, that is an editorial, and that is someone’s uninformed opinion. Then I remind them to start with an established news source such as the BBC, the New York Times, NPR, etc., and bring in an article the next day.

Freyhardt:

I was talking about this often in this way. Friedrich Hund was one of the most prominent theoretical physicists. He lectured about history and quantum mechanics at Goettingen. I proudly attended his lectures and I knew him quite well. When he died, he was nearly one hundred years old. Yes, Friedrich Hund. In the earlier times, you see, they published two solid papers a year. They knew what they were discussing and these were fundamental papers. Now this deep inquiry is to some extent missing because of this high-speed publication.

Hellrigel:

The pressure to publish or perish and a culture of impatience are too common today. When people send you an email they want an immediate response, but sometimes you must think about it. Yes, change. Sometimes technology and the way people use it does not improve things.

Freyhardt:

Yes.

Superconductivity Research, Laboratories, and Patents

Hellrigel:

You have been awarded many patents, too.

Freyhardt:

Yes, I have been awarded more than fifteen patents.

I can talk a little bit about the development of research and my involvement in the area of superconductor. We started out very early, first with elemental, metallic superconductors. Yes, this was Niobium. This was the first material I was investigating, being a trained physicist as well as a materials scientist. I think this was a good combination to develop a real superconductor because both, microstructure and structure determine to a large extent the superconducting behavior.

We were trained scientists, so we knew how a phase was created, how the microstructure would look, and how the microstructure would determine the physical properties. Many times, as physicists, we combined this with the science of superconductivity. I think this was quite helpful for the development of superconductors. This was the starting point.

Early in my career, I grew single crystals of Niobium. I was well known for producing high-quality, single crystals of Niobium. By the way, this is what brought me together with the Ames Laboratory.

Hellrigel:

Sure, the Ames Laboratory in Ames, Iowa near Iowa State University.

Freyhardt:

The Ames Lab had the purest transition metals at that time. Those materials were high-quality materials with enormous low oxygen contents. They were even better than we were, but we also knew now how to do it, and this resulted in a close corporation. Then we looked at the physics. We wanted to investigate flux pinning.

We knew a lot about the behavior of Niobium and all the flux lines in Niobium in the type II superconducting state. Then, as I said, we introduced, in a controlled manner, the obstacles, the dislocations. This was a model system and we wanted to go into the details of this model system to understand or to comprehend fully what needs to be done in order to understand flux pinning through dislocations. To introduce obstacles, dislocations in Niobium single crystals, they were twisted in a controlled manner, what created dislocation networks. In the Type-II superconducting state of Niobium, these dislocations interact with the flux lines, which are pinned. This pinning leads to finite critical currents and to a hysteretic magnetization curve. The latter was employed to determine volume pinning and elementary pinning forces to be compared with the theoretically expected ones. One of the first in depth investigated model flux-pinning systems

This was continued during my stay at the Argonne National Laboratory, where I investigated flux pinning in Niobium by voids. Together with Bruce Brown, this was complemented by investigating flux pinning through radiation-induced defects in Niobium-Titanium alloys. I know Bruce from the early days.

Hellrigel:

It is very interesting.

Freyhardt:

The backbone for the evaluation of the flux-pinning experiments was the phenomenological theory of superconductivity from Ginzburg and Landau. It is a mathematical physical theory used to describe superconductivity, introduced by Vitaly L. Ginzburg (1916-2009) together with Lev Landau (1908-1960), the most prominent theoretical physicist we ever had worldwide.

The theory they developed is a very broad theory. Alexei Abrikosov (born in 1928) found the solutions for the flux distribution in the mixed state of a type-II superconductor, the flux line structures, and the regular arrangements of flux lines. Alex Abrikosov told me, some time back: “I was not allowed to publish this paper with my new theory because Landau was against it.” He told me you could convince Landau only by brilliant logic and Landau was always better than you at logic. Abrikosov was allowed to publish this fundamental paper, only later on, when the existence of flux lines was proven in a neutron diffraction experiment. I forget the exact time of delay, but it was about one and a half years. This is really a fundamental paper.

Hellrigel:

How expensive is this type of work? How much money would you need each year for research? How much did it cost to run your lab at the university?

Freyhardt:

This was very expensive, but as I mentioned, I had been very successful in getting funds. At that time, at the University of Goettingen, I was amongst the researchers who acquired the most research funds. This work is very expensive. If you go to technological applications, it is even more expensive.

Hellrigel:

It might cost millions in Euros.

Freyhardt:

I think, over the years, for the development of coated conductors it must have been of the order of 40 million Euros, total. This is the level of funding I had to raise for research.

Hellrigel:

Wow.

Freyhardt:

This was substantial support.

Hellrigel:

You had substantial support over many years, too. Where did you get funding?

Freyhardt:

Yes. Over the years, I had substantial support from the German Science Foundation, the German ministry of Science and Technology, the German ministry of Trade, the European Union’s commission, as well as from private industry. Yes at the beginning, we were mainly involved in the basic inquiry of the model system for flux pinning through microstructural obstacle. One of those had been precipitates in a type-II superconducting lead-sodium alloy. Therefore, in this alloy system, we investigated the interaction of flux with precipitates. Later, this was further extended and became part of my habilitation thesis.

During my stay at the Argonne National Laboratory, at the DYNAMITRO of ANL, Niobium was irradiated with high-energy nickel ions, with which we could create bubbles in Niobium foils (as pinning centers for the flux lines).

Hellrigel:

Bubbles in the materials?

Freyhardt:

I created bubbles and voids in high-purity Niobium. More so, we had been successful in creating regular bubble arrays in the material. Then the irradiated Niobium had been employed for our basic investigation of flux pinning. Niobium with bubbles -- once you have a regular arrangement of bubbles, interacting with flux lines, which form a lattice, the flux line lattice and the bubble lattice would match. Then you would get an increased flux pinning, a peak effect, as it is called. Moreover, precisely this peak effect we could observe.

Hellrigel:

Then it drops.

Freyhardt:

Yes. Then, once you are beyond it, it will drop. Yes.

Hellrigel:

This originated to work on the conduction of electricity?

Freyhardt:

Not directly; however, those basic studies are well connected with it. This is the ideal situation, for an application network, which is based on fundamental studies. The applied side became more important when we started to look into alloy and compound superconductors. The alloy superconductor Nb-Ti, this is what David Larbalestier was very extensively investigating and was talking about. Our main interest focused on the A15 compound superconductors for applications. For the development Nb-Ti superconducting wires, technical superconductors, we did not do a lot.

Hellrigel:

Like in history, this is what we would call initial phase pure science research to find out what is really going on.

Freyhardt:

Yes.

Hellrigel:

Then you worry about what to do with it.

Freyhardt:

Yes. This is precisely then the next step. Nb-Ti, there was only a short involvement while I was working at Argonne. Together with Tom Blewitt and Bruce Brown, I was involved in low-temperature neutron irradiation of these materials. Because at that time there was an increased interest to use Nb-Ti in a radiation environment, you have to learn what is going on upon irradiation – are you deteriorating the superconducting properties of Nb-Ti?

Hellrigel:

One of the gentlemen I interviewed at this conference said that the U.S. military was irradiating beef to make it last longer and they have been doing it for thirty years.

Freyhardt:

We have been doing many irradiations, so there are many ‘crazy’ stories about it. One story: I was on top of the research reactor at Argonne. My friend, Bruce Brown, extracted the sample holder from the irradiation cryostat. This was a radiation at low temperatures, at helium temperatures. This was a long specimen holder, four meters long or something like that. He pulled it out right from the core of the reactor.

Hellrigel:

He did this with bare hands.

Freyhardt:

Yes. He was grabbing the top end of this long holder. With the holder in his hands, he bent over and walked, stepping across an obstacle and almost falling down. I tried to avoid major damage to the holder by grabbing the bottom part, the part coming right from the core of the reactor.

Hellrigel:

Wow, that sounds rather risky.

Freyhardt:

This was the highest radiation dose I ever got in my life.

Hellrigel:

Yes, now there are probably more rules about handling material.

Freyhardt:

This was the FR2 research reactor at ANL [Nuclear Fusion-Fission Reactor at Argonne National Laboratory]. Yes, but people still do things a little unorthodox. Yes, there are accidents like this happening. That is my brief involvement with Nb-Ti [Niobium-titanium], whereas we did an awful lot with the A15 superconductor materials.

Hellrigel:

You have seventeen patents awarded by either Germany, the European Union, or the United States. They all deal pretty much with superconductivity.

Freyhardt:

Yes.

Hellrigel:

In the U.S. when you do research at the university, usually the university owns the patents. Does the university in Germany own your patents or do you own your patents?

Freyhardt:

In general, we jointly applied for patents. However, some of those patents I created in order to transfer knowledge from academia to industry. The company I created in 1990, Zentrum fuer Funktionswerkstoffe (ZFW), develops multifunctional materials for technical applications and is a link between the fundamental research and industry. It is organized as a non-profit company. It promotes relations between the university and industry. These patents connected to the ZFW were for a coated conductor and this company owned half of the patents. We developed complementary directions for the processing A15 materials. Wires of the A15 superconductor Nb3Sn [Niobium Tin] were generally produced via the bronze route. In the bronze process, for example used by Mas Suenaga [Masaki Suenaga] at Brookhaven National Laboratory, Niobium rods are embedded in a copper-tin matrix, a bronze matrix. The billets are mechanically deformed and drawn to wires, and Nb3Sn was formed during a subsequent thermal annealing treatment. An alternative process would use the internal tinning route.

We, however, started out with a completely different approach. This was the claim of one of the patents. We asked ourselves; can we use powder metallurgy? Starting from Niobium and copper powder. Niobium. This, furthermore, explains our connection with the Ames Lab. We needed very pure Niobium for the mechanical deformation; not much oxygen in the Niobium. Low oxygen content in this material, right! The method to achieve this became the claim of a patent. The idea was to add elements to the powder mixture of copper and Niobium, which formed oxides to take out the oxygen from the Niobium. We got a beautifully purified material. This was essential to our powder metallurgical approach, whereby the Niobium would form very thin filaments after the wire drawing. Copper wire with pure Nb filaments was not the material we wanted. However, these copper wires, with the embedded Nb filaments meant that we already produced high-current carrying copper, which is mechanically very strong and can be broadly used. This was not our goal. We wanted to get the A15 material, Nb3Sn. We had to add tin in an optimum way (by plating the wires with tin) and create a bronze, which would then allow the Nb3Sn to form during a heat treatment. However, this led to additional difficulties. The Nb filaments were about 100 nanometers thick and 2 to 3,000 nanometers wide. During the heat treatment, the Nb filaments can disintegrate into a row of aligned micro-sized Nb particles. This phenomenon is well known from directionally solidified eutectics, which are heat-treated. We could eventually adjust our heat treatment such that the powder metallurgically processed Nb3Sn conductors exhibited good superconducting properties. Knowing what you are doing with the material is a big advantage of being a trained materials scientist. Another advantage is getting this done correctly. From this education, I think I could benefit throughout my life.

Hellrigel:

In the university, do they still train people the way you were trained to be a physicist and materials scientist?

Freyhardt:

Unfortunately, it is not always the ‘standard’ training. I have to mention that we had good teachers helping and instructing us. This is most important, the environment, that you are embedded in. At the university, I was educated following our old traditional system. You see, now they introduced the bachelor-master educational system in Germany. I was very happy that during my time there were no bachelor and master degrees. The old systems offered enormous flexibility. We could follow our interests. Well, this was also because I had Peter Haasen, an excellent teacher. He was a trained theorist, and then he got interested in materials science. The combination was all ready laid out for my personal education. It also always depends on the interest and the environment you are getting into.

Hellrigel:

Right. The environment, the culture, the team, and the teachers. Yes, the team.

Freyhardt:

This was quite helpful.

IEEE Membership and Awards

Hellrigel:

You are a member of IEEE. When did you join IEEE?

Freyhardt:

I think I joined in 2005, and in 2006, I received the IEEE-CSC award. I joined before I got the award.

Hellrigel:

Yes, you received the recently renamed IEEE Dr. James Wong Award for Continuing and Significant Contributions to Applied Superconductor Materials Technology in 2006 in recognition of your contributions to superconductor materials technology. What is the award’s significance to you?

Freyhardt:

It recognizes what I was doing in the development of superconducting materials for application, my research in flux pinning, as well as for organizing many national and international workshops and conferences in applied superconductivity. In 2015, I received the ICMC Lifetime Achievement Award. ICMC stands for International Cryogenic Materials Conferences. These awards recognize what you have been doing in your scientific life and it is great. It also gives you some additional connections. However, you must be realistic because it does not directly influence your career.

Hellrigel:

Yes. It is great to be recognized by your peers. During your career, which societies and associations have been the most important and useful?

Freyhardt:

Well, there are many organizations. The Deutsche Physikalische Gesellschaft (DPG, the German Physical Society), I think, is the largest physical society worldwide, which was most important for me. I was a member … and more closely associated with DPG. You see, there are various sections within the society and I was for some years chairing the so-called low temperature section, which included superconductivity. I am also member of the European Physical Society and early on with the American Physical Society. I am a member of IEEE and ICMC.

Hellrigel:

Are you still active in these societies?

Freyhardt:

Yes. I am still active in IEEE-CSC (IEEE Council on Superconductivity). I am one of three co-editors of the Superconductivity News Forum (SNF), which is a joint publication by CSC and ESAS (European Society for Applied Superconductivity). I publish the IEEE CSC calendar of events. I maintain and continue to expand my international connections.

Hellrigel:

Did your two sons become engineers?


Freyhardt:

They are both connected. One designs games and mainly works with computers. My other son, the eldest, is going to sell hardware. This is computer hardware mainly. But the younger … this was really an enormous development, was going to help developing computer games. There is large money involved in game development. This is incredible. You see, I actually do not know a lot about it. This is to be compared to engineering programs and software, what they are doing there. He is actually not directly designing those computer games, rather involved in an indirect manner. But you see, once they want to bring a new game into the market, very often this is only half done. He is then fixing all those flaws. He seems to be an expert at this.

Hellrigel:

What did they study at university?

Freyhardt: The younger one trained himself; he did not go to university. The elder one studied engineering at university.

Hellrigel:

Are you happy with your career and has it met your dreams and expectations?

Freyhardt:

Well, I think yes. Yes, because I grew under particularly favorable conditions. I grew up during a time when there has been peace in Europe, no war. After the war. This was most stimulating and encouraging---now it is a little bit different. I grew up during a time when we were enormously lucky in a prosperous Germany, Europe without war. Also in science, in physics, and the innovative power therein, we were going through an exciting period, I must admit, this is particularly true for the development superconductors and the development of HTS (high-temperature superconductivity). At some time, people expected this novel material could revolutionized everything.

In general, I was lucky to get sufficient funds in order to do what I was thinking. I feel quite happy the way I could organize my life and my scientific life.

Hellrigel:

What do you think you will do now that you are semi-retired? What are your plans for the future?

Freyhardt:

I am not teaching much, but I am working with two Ph.D. students. Now I am a consultant and I am really doing well. I have some R&D going on and I still have a corporation with some industrial partners. We are trying to come up with new patents. In addition, I am still very active in scientific organizations and fostering international collaboration. I helped found the European Conferences on Applied Superconductivity (EUCAS) in 1993, and the International Workshops on Coasted Conductors for Applications in 2000.

I was always strongly interested in transferring knowledge to industry; not only interested but actually promoting it. In particular by promoting discussions and cooperation between scientists and engineers, providing help in setting up national and European R & D programs, which involve academia, national Labs and industry, and by listening to the needs of industry. I was the driving force establishing a consortium, which formulated a white book “Supraleitung” submitted to German ministries. With the “Zentrum fuer Funktionswerkstoffe”, I established a now-profit company as a link between academia and industry. I still foster this by cooperating with a company to endeavor research in preparation for possible new patents.

Hellrigel:

You founded this company in 1990.

Freyhardt:

No, this is another corporation. I deliberately do not mention those names.

Hellrigel:

That is fine; there is no need to mention names.

Freyhardt:

I am still working and I am in close contact with developments in the field and colleagues in the U.S. and Germany. I am one of those people who recalls a lot of what has been going on in earlier days, so once in a while I am working on history.

Hellrigel:

It is very exciting to hear you are interested in history and collected material for an archive. I have much to learn about superconductivity and its professional associations and activities. I also have to learn about the research, business, and industrial components of the field. There is much to document and many stories to tell.

Freyhardt:

Yes, well I think one should try to do it. Working on history, in one sense this is what is prepared. Because, for example, considering the workshops and meetings, I was establishing and organizing, most of this information will gradually vanish over the years. But, I said, why not set up an archive? A first step is now implemented, together with IEEE-CSC. In addition, at first at least for some of the CCAs (Workshops on Coated Conductors for Application), documentation, an archive, will collect the data. One of the reasons I am interested in this project is because if I am gone, the initial information is probably also gone. This is why I am trying to set up some kind of archive, and this, as a start, for the CCA 2008, which we organized in Houston. We already transferred part of the website and tried to find out how much effort one would need and whether this could then be formed into an archive, which would be complemented by other meeting.

It should be done in a sensible way. Some of the websites still exist, so you can use this information and transfer it to an archives. There might be too much information on the website, so you only save the important documents. The information and presentations for the meetings I was responsible for either have been saved on CD or the PowerPoint Presentations have been saved electronically. They are part of the archives. You have more than the organizational background of the workshop because you are also saving the scientific content.

Hellrigel:

Right, the presentations are saved and you are keeping material to document the organization as well as the technical and scientific developments.

Freyhardt:

One should do this for all previous meetings of the CCA series and continue collecting material from other important meetings and future meetings as well. For example, the ASC or EUCAS, in the future, should save and make the material available. I think it would be helpful. So, history in the form of archives. This is what I would like to do.

Hellrigel:

Is there anything we did not cover that you would like to say?

Freyhardt:

What about the work we had been doing with HTS (High Temperature Superconductivity) materials? This was a story of its own. Yes. I recall - we had a MRS meeting in Boston (December 1987) around the time YBCO (yttrium barium copper oxide) came along, was discovered. Koichi Kitazawa (1943-2014) from the University of Tokyo got the information about YBCO, which, they had been measuring in his lab. The results came by fax, which was also novel at that time. He was presenting the results, YBCO an HTS with a critical temperature of about 90 K, in an overcrowded room. This was the initializing event for me. I went then back to Germany, and tried to synthesize YBCO. Yes, unforeseen things happened during these experiments. With a friend of mine, Klaus Winzer from the University of Goettingen, we tried to synthesize YBaCuO by putting the starting materials in a crucible, which we had to slide in a tube inside a high-temperature furnace. Oxygen gas was flowing through the tube. We needed something to move the crucible it in and out of the tube. We did not have anything that would be good as a pulling rod at high temperatures. Since at that time I was working a lot with Niobium, I had Niobium wires around. To move the crucible, I used the Niobium wire, but left it within the heated tube with flowing oxygen. After the YBCO material was synthesized, we wanted to pull the crucible out. I said, well, we can't pull it out. Our Nb pushing wire had disappeared. [Laughing] I said, “it is gone; it has been converted to Nb oxide.” Nevertheless, we got our YBCO, which showed good properties.

This was an unusual situation because at that time our group in Germany was about the only one still working on superconductors. This had been Niobium-3-aluminum at that time where we had novel roads in order to process them. To support the initial YBCO research in Germany we experienced a very unusual action by the Ministry of Science and Technology. We arranged a group of all the relevant and interested colleagues together for which we received seed many to start investigating YBCO, I think 200,000 Deutsche Marks. The seed money was transferred to the University of Goettingen.

I was in charge of distributing it to relevant groups in order to initiate research in HTS material. It was a very unusual situation, but it worked out pretty well.

This was the initial situation when it started research in HTS materials.

At that time, I was also responsible for laboratory growing single crystals (Kristall-Labor). We had a system to grow cadmium-telluride single crystals. This is a system, I thought, which we could use in order to try to get an YBCO single crystal. I went down to the Heraeus company at Hanau and got a platinum crucible because we knew that the oxides we had to use are very reactive. I really grew a bulk material. I was measuring this bulk material’s critical currents by evaluating their magnetic hysteresis. Of course, I was disappointed because the critical currents were so low and it was not single crystalline. However, in retrospect, I realized it was the first melt-grown YBCO. Yes, it was the first melt textured YBCO, but we did not know it at the time. It was the first melt-grown and melt textured material. Several years later, we followed along at this line and actually processed and investigated melt textured YBCO within a research consortium … even later also for technical applications.

Hellrigel:

You used physics and material science, but you used a lot of chemistry, too.

Freyhardt:

Yes. As a physicist, you are also trained in chemistry to some extent. You have to know chemistry and you get the knowledge you need.

We are still talking about a transfer to industry. Remember our considerable input in the development of coated conductors. This was really something that took off after YBCO was known good enough. We started by first using stainless steel substrates and did IBAD on this with all the basic R&D required, and then pulsed laser the position to put down YBCO. IBAD is the ion-beam-assisted deposition layer processing method for the biaxially textured oxide buffers.

This prototype development was then transferred to industry, and later on sold. So, they redid IBAD plus YBCO-PLD processing of coated conductors. Yes.

Hellrigel:

How did industry use it? What did they manufacture?


Freyhardt:

This is wire production, but also large-area IBAD deposition on ceramic substrate plates. For example, we had a good connection with the Siemens company. From working on the processing methods in the lab, we knew how to do it. At that time, we were the only ones capable of depositing an IBAD layer, YSZ, on large-area substrates. And there in corporation with Siemens, they were depositing YBCO. This was a model system for a current limiting device.

There were several close cooperations with industry. I cannot highlight all of them.

On my computer, I have some files to show you. . [Freyhardt showed a collection of documents.]

Yes, I will find the one I wanted to show. That is an application that you see. The textured materials we processed has been of high quality. This is all the work on coated conductors. Here is the way we have been producing it. This was transferred … and this was our system, IBAD, system. The first images show you the process, which we used to produce large-area IBAD substrates. This is what I wanted to show to you.

The slides help me understand what you are talking about a little more.

Yes. Here, this is a flywheel employing bulk YBCO material for levitating its rotor. This was developed in a consortium with a company located near Gottingen. Where did I put this? Yes, here. These are those large-area plates, which were covered with our biaxially textured YSZ, and subsequently, HTS material was put on it. In this way, Siemens assembled a demonstrator fault current limiter, which was working well. In addition, we had an extended European cooperation with industry to produce a power link. You see, from the generator of a hydroelectric energy storage plant to the first transformer an efficient superconducting power link was designed. This power link, which we developed, provided current limiting features at the same time. Therefore, it is actually current limiting, and our test module would carry a current of 2,500 amps, but would be able to limit full current of 50,000 amps? So this is --I think -- one of the outstanding developments at that time.


Hellrigel:

Now that would stop the waste of energy?

Freyhardt:

Yes, it would. The trick is to get the current from the YBCO into the base material, a high-resistivity material, without “burning” the HTS. We succeeded to accomplish this in an elegant manner. I addressed some of our essential developments utilizing bulk and thin film HTS material… I could continue on this.

Freyhardt:

My mother was born in 1904. She lived in a small village in the south of Germany. Later on, about 1910, she moved to a neighboring village, and at that time in the early twentieth century, it had no electricity. You have to keep in mind the speed with which all of this was developed.

Hellrigel:

Yes. The diffusion process takes time. Electricity might spread village to village as local generating plants are built and service is extended. In the United States, a company received a franchise from a municipal government to build a generating plant and install wires, conduits, and poles in that particular town. In the State of Pennsylvania, it was illegal to generate electricity in one town and send it over the border to another town. The law had to change before regional networks were built.

Freyhardt:

Yes.

Hellrigel:

People had other sources of illumination such as candles, oil lamps, and manufactured gas. Gas lighting remained competitive with electric lighting. In the United States, World War I, for the most part, ended the gas age because wartime restrictions made it difficult to get the coal to make the gas.

Freyhardt:

Yes.

Hellrigel:

What did your mother say about not having electricity in the village? She was very young, but she must have noticed the difference. Did she recall being upset about the move to a village without electricity?

Freyhardt:

Yes, I recall her talking about it. This was a long time ago. She mentioned that there was no electricity, which meant no electric light, no phone, and cooking on a coal stove. Everything had to be done by hand, including clothes washing.

Hellrigel:

The modern home was expected to have indoor plumbing, not an outhouse, and a bathroom with a tub and hot and cold running water, too. Some places in the State of Mississippi did not have electricity until the 1960s. These areas largely were poor, rural, and African American. The electric utility companies did not extend service. In the past, the federal government helped extend electric service through special programs such as the Tennessee Valley Authority (TVA) and the Rural Electrification Act (REA).

Freyhardt:

Nowadays we are so dependent on electricity. During one of my invited or plenary talks, I reminded the audience about the New York City Blackout and the troubles connected with it.

Hellrigel:

Sometimes you no longer need a metal key to unlock a door. You swipe a card. It is all electronic

Freyhardt:

Yes. Why is this not disappearing? No, the blackout. When was it? 2003? In New York, I think, 2003.

Hellrigel:

There was a blackout around 9/11. Then you had the Northeast blackout in during the summer 2003 (14 August 2003). I remember August 14th because it is my brother’s birthday.

Freyhardt:

Yes. There was a blackout in New York City in 2003. I think it clearly illustrated what is happening to the community without electricity. People are lost.

Hellrigel:

Right.

Freyhardt:

Everything.

Hellrigel:

During blackouts and power failures, violence and looting break out in some places. People destroy property, set fires, and break into stores and steal. Why does it become utter mayhem sometimes, but not other times? We have become so dependent on electricity. Cash registers and refrigerators are powered by electricity, so shops close. You cannot buy gasoline without electric. The pumps do not work.

Freyhardt:

Yes.

Hellrigel:

Yes. Most everything runs on electricity. In many places the landline telephones no longer have copper wires, they are fiber optic, so when you lose electric power, you lose telephone service, too. The telephone companies had backup electric power, so you still had phone service. Yes, they had their own generating plant to supply electricity to the copper wire phone lines. This is no longer the situation.

Freyhardt:

Yes. I will see if I can quickly find this information. Yes, New York, 14th of August 2003.

Hellrigel:

Yes. Yes. It happened on my brother's birthday, 14 August.

Freyhardt:

Yes. I will keep this news release. Look at the picture.

Hellrigel:

Yes, people. Yes, the city came to a dead stop as people tried to cope. Traffic lights did not work. You could not buy gasoline because the pumps ran on electricity and gas stations did not have backup generators. When you lose power in Germany, do you have the same situations?

Freyhardt:

Yes, but when a blackout happens it is often not for a long period. While we were developing an energy storage system, the flywheel, we did a study and collected statistics on power outages. At that time, we carefully looked into the frequency and duration of outages in central Europe, and tried to suggest possible solutions. Well, you can get an insurance solution for the outage or you can get a technical solution for the outage.

Hellrigel:

I remember there was problem in Ohio and then the whole system started shutting down. The national system.

Freyhardt:

Yes, I did not bring this along with me. I have a list, at least for outages in Germany. How often are the outages? How long do they last? This is what we need to know in order to come up with feasible solutions.

Hellrigel:

Yes, I remember an outage in New York City in the 1970s.

Freyhardt:

Two days or so ago there was an extensive outage in Florida. They have been without electricity because of the hurricane. David C. Larbalestier informed me about it. [Larbalestier is a materials scientist at the National Magnetic Field Laboratory in Tallahassee, Florida.]

Hellrigel:

Yes. Some of the storms do a lot of damage to power plants and distribution networks. My brother lives in New Jersey too, and during a recent storm, he was without power for one week. It was a major storm, probably a hurricane. This is a big problem for hospitals, so they had need backup generators. The governor of New Jersey said gas stations should get generators to pump gas, but I do not know how many station owners followed the suggestion. It is an added expense, but it would make sense. Sometimes, you resort to the propane powered grill because the natural gas stove in the house does not work. Some gas stoves have an electronic ignition and childproof features, so you cannot light them with a simple match. No, not anymore.

Freyhardt:

This is going back in my private history. When we built our home, we added a chimney. We could have added a stove, but we did not do it at that time. We also could have added a fireplace, but we chose not to do it, too. When we built the house, we thought about just in case situations, but now I am somewhat older and I do worry less. In time, you will see, you stop worrying about certain things. I might live an additional ten years, that is it.

Hellrigel:

Who knows? Maybe you will live an additional twenty or twenty-five years.

Freyhardt:

Yes. I am not worried about that.

Hellrigel:

You may set a record. If you turn one hundred years old in the U.S., the president sends you a card. Does that happen in Germany, too?

Freyhardt:

Yes. I think that is what happens, possibly not the president, rather a local authority.

Hellrigel:

You were busy in the laboratory, teaching, working with students, attending conferences and other professional activities. Did you ever take a vacation or at least set aside time to take a break?

Freyhardt:

Not too many, but a little bit. Very often, I worked eighty to eighty-five hours per week. Yes. I married Ursula in 1963 and we have two sons, Andreas and Jens. During my career, often she has gotten upset because I worked and travelled so much.

Hellrigel:

Maybe we can end now. When you receive the transcript, you will be able to fix mistakes, edit for clarity, and provide a little information. If you want to add extensive additional information, you will write a First Hand History. Let me take down your address and we will end this session. Thank you, sir. Thank you very much for taking the time to record an oral history.