Biographical 

Atypical question I am often asked as a Nobel Laureate in physics is “what brought you to physics?” I am not sure but I do know that in school in geography when looking at the presentations of the planets orbiting around the sun I asked myself: “What is the reason for this strange behavior?” It was a real revelation when my physics teacher Mr. Röderer explained to me that this is caused by the balance of the attraction between masses and centrifugal forces. This roused my enthusiasm and whetted my appetite. Still, during my last few years in high school, I spent more time with sports, boy scouting, alpinism, music etc. so my performance in school was reasonable but not more.

Perhaps in this context, it might be of interest to know that my father held a diploma in mechanical engineering from the Technical University of Bruenn (Cechia), and worked for the Skoda factory in Pilsen designing locomotives. He died during the last days of the war, so after our expatriation to the western part of Germany, my mother was left alone to take care of her two children, namely my two-year older sister and myself.

At the age of 19, I started to study physics at the University of Frankfurt and changed to the Technical University of Darmstadt three years later. I finished my diploma thesis there at the age of 26 and my PhD thesis at the age of 29. In both theses, I applied optical spectroscopy to determine crystal field split energy levels of rare earth ions in garnets. The director of the institute was Professor K. H. Hellwege. As I did a lot of computational work for the experiments, he used to say to me when he met me in the corridors: “Above all mathematics, don’t neglect the physical background” which he called “Physikalischer Hosenboden” (lit. “physical bottom”). This must have made a lasting impression on me because I have a strong desire to explain new phenomena which I come across in simple physical pictures and do not feel comfortable with mathematical formalism alone. Today, I would like to pass this attitude on. In computer simulations in particular we would get lost in an abundance of results if we did not maintain a critical view for the source of the effects. This is especially true for phenomena caused by a constructive or destructive interaction of various mechanisms. My direct supervisor for my thesis work was Prof. Stefan Hüfner.

The topics of garnets and crystal fields also brought me to the laboratory of Prof. A. Koningstein in Ottawa, Canada, where I worked as a postdoc for a little less than three years. As was the case until then my goal remained the determination of crystal fields, but here I used the electronic Raman effect to determine the energy levels experimentally. Since Raman scattering is mainly caused by the optical phonons, these were also included in my investigations. A photo of me at the age of 33 is shown in Figure 1.

Figure 1. Peter A. Grünberg (PAG) at the age of 33 when he started his work at the research centre in Jülich. 

In 1972, I was offered a position as a research scientist at the newly founded Institute for Magnetism at the research centre in Jülich. The director was Prof. Werner Zinn. His picture (marked with WZ) is included in the group photo of Figure 2. He was mainly interested in investigating the model magnetic semiconductors EuO and EuS. I also started to work on these compounds, applying optical absorption spectroscopy as well as Raman scattering (RS) from phonons. The RS experiments were performed at the Max Planck Institute for Solid State Physics in Stuttgart in the group headed by M. Cardona. My partner in Stuttgart was Gernot Güntherodt (marked GG in Figure 2) with whom I explored the magnon phonon interaction in EuO and EuS.

Figure 2. Group photo from the conference on thin magnetic films and surfaces in Le Creusot (France in 1988) when GMR was publically announced for the first time.

This photo appears here because it shows many colleagues who are mentioned in the text that follows.

 For the full details, please refer to the source.

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Source:

https://www.nobelprize.org/prizes/physics/2007/grunberg/biographical/