Oscar VogtNovember 28, 1927 — January 21, 2014
On 21. Jan. 2014 Oscar Vogt left us. Born 1927 he was 87 years old.
I learned to know Oscar Vogt and his wife Ditta in 1962, when we both investigated in the Laboratorium für Festkoerperphysik of ETH Zuerich (Swiss Federal Institute of Technology) the magnetic properties of Rare Earth compounds. Oscar was one of the sons of the owner of Vogt and Co. (VoCo), a wire pulling factory, which could also pull exotic wires like tungsten. He received his PhD at ETH Zuerich with Prof G. Busch, who mentioned, that he was the only graduate student not asking for a salary.
He enjoyed fabulous hobbies but was also culturally very involved. But he engaged himself also with great enthusiasm in the research of Rare Earth compounds. We had a long lasting and fruitful friendship.
But when his father died in his seventies the fundamental question arose to choose between physics or the factory. He managed both! Every Monday he spent in the institute and with his technical assistant Kurt Mattenberger grew large and well defined single crystals of Rare Earth compounds and investigated them magnetically. This is by no means trivial, since Rare Earths and their compounds melt only near 2000 degrees C and it was a great challenge to grow crystals at these temperatures, which was only possible in large tungsten crucibles.
But what were the scientific questions behind the research on Rare Earth compounds? The ferromagnetism of iron, cobalt and nickel even today is not completely understood. It originates in not completely occupied inner 3d electron shells of the atoms, which become in solids partially filled bands. In contrast the magnetic 4f shells of Rare Earth atoms or ions are deeply inside the atoms or ions and stay completely localized even in the solid. The magnetism of these materials could be completely explained by quantum mechanical rules within the last 30 years. However, this did not help very much the understanding of magnetism in iron, cobalt or nickel.
Now the idea was promoted to investigate Actinide compounds, where the partially filled 5f atomic shells are nearer the surface of the ions and in solids often form partially filled 5f bands. The heavier Actinides with Pu or Am exhibit a transition to localized 5f states and thus the transition delocalized localized could be studied. Well known problems arise due to the radioactivity of the Actinides, which, however, are only alpha emitters, i.e. emission of He ions, which hardly penetrate a leaf of paper. But we were interested in the magnetism.
Our crystal growth techniques, which have been developed for the Rare Earth compounds could now be used in Karlsruhe by Gerry Lander and his colleagues in the Euratom Institute with melting points also at about 2000 degrees C for the Actinide compounds. These materials were available international for all kinds of research. Encapsulated and without emission of radioactivity at the outside even we could perform magnetic or other measurements. Oscar Vogt could publish about 500 publications as author or coauthor in scientific journals, especially also in cooperation with Barry Cooper, a theorist from Morgantown, WV.
But Oscar Vogt was still and mainly the technical director of his wire pulling factory. When the high Tc superconductors with critical temperatures until about 136 K were discovered, very soon the question of producing superconducting wires came about. But there was a wire pulling factory around! I could motivate Oscar very fast to pull superconducting wires in his factory and he was the first in the world to produce a 1 km long superconducting wire. A graduate student was always at international conferences with rolls of silver tubes filled with superconductors, whereas competitors only had 10 cm long wires.
So Oscar had a rich scientific life and at home his wife Ditta made invitations to a real sensation. Ditta, his children and grandchildren will miss him as husband, father and grandfather.
ETH Zuerich, Switzerland