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Vølodymyr Karpan (promotion date: 20 June 2008)

Spintronics: a first-principles study

Promotion date: 20 June 2008

Thesis advisor: Prof. Paul Kelly

Despite the central role played by electron spin in many areas of condensed matter physics, it barely figured in the mainstream of charge-based microelectronics. The situation changed with the discovery of the giant magnetoresistance (GMR) effect, which is exploited now in the majority of magnetic reading heads of hard drive discs.

The GMR effect is a milestone in condensed matter physics for which both A. Fert and P. Gruenberg were awarded the Nobel Prize in Physics, in 2007. From the study and application of this effect a new branch of solid state physics has emerged, which is now called spintronics (short for spin electronics).

In my thesis I present the results of a first-principles study, of both already known and new spin-related transport phenomena.

Can you remember the scientific point from which you started?

As a part of my PhD research, which I had started at the Institute for Theoretical Physics in Kyiv, I was visiting my collaborators in Technical University of Denmark in Lyngby. During my stay there my friend, who had already started his PhD here at the UT, invited me to visit him.

He mentioned the possibility to pay a visit to Prof. Dr. P.J. Kelly who was looking for a PhD student to work on an interesting project. The time I came here I had an interesting discussion with Paul. That was my new scientific starting point.

What track did you, together with Prof. Dr. P.J. Kelly, choose in this research?

What I particularly like about Paul Kelly, as well as about the CMS group as a whole, is that the doors are always open. People with whom I worked, were never too busy to give me advice or to discuss a problem when I needed it. Paul is very experienced in the field of condensed matter physics, as he worked for a long time at the IBM, Philips Research and finally UT.

If Paul had any doubts about my results, he never hesitated to ask me about them. This is very important because you have to be critical, as you are a part of a fair but challenging, scientific competition. I also learned a lot in the seminars and conferences. At MESA+ everybody was receiving my presentation enthusiastically from the start, and I could rely on lots of input at the MESA+ meetings.

Did your personal way of working change in this period?

I guess the most important experience that I have learned here, is working in a big international group. I am much more a team player now. I find it very important to be able to discuss my results with my colleagues.

It is like polishing, you shape your ideas by discussing them with other people. And I have also learned important time management skills. You have to organize your own research, time and time again.

So you like being in Holland?

Well ... the number of plusses is far more than that of minuses, for example, the weather and bureaucratical obstacles. But those are insignificant compared to the conditions of working and living in the Netherlands.

Particularly, I would like to mention the scientific environment here in the Netherlands. My project was sponsored by a large governmental program, called NanoNed, which involves many Dutch universities and research institutes. Working in this project was a really good experience. I enjoyed the meetings for this program, which took place at different universities, every half year. Many PhD students, who were also involved in this project, became good friends.

Do you expect MESA+ will take up your work in the future?

Definitely. The field of spintronics will be popular for a long time ahead, I believe. With the new cleanroom facilities being built now, the number of good experimental studies should increase. Moreover, if I am not mistaken, the offices of theoretical and experimental groups will be much closer situated in the new building than they are now, which is good for collaboration.