Obituary for Prof. Dr. Georg A. Busch

Toward the end of January in the year 2000 Georg Busch, honorary member of the Swiss Physical Society since 1976, passed away at age 91.

His career as a physicist was closely connected with ETH Zürich, starting with the diploma in 1933, the doctorate in 1938, habilitation as lecturer in 1942 and finally the full professorship 1949. This position was held until 1978, interrupted only by two sabbatical years at the Universities of Bristol and Pittsburgh.

8 universities in many parts of the world (Ankara, Geneva, Alabama, Bern, Hamburg, Göttingen, Philadelphia, Munich) and some very famous research institutes offered him leading positions which he turned down in favour of his career at ETH Zürich.

The name of Prof. Busch remains closely related to the following innovative discoveries:

• KH₂PO₄ as the second-known ferroelectric compound (1935)
• SiC, α-Sn and Mg₂Pb as new semiconductors (1943, 1951, 1962)
• Temperature-dependent diamagnetism due to free carriers in α-Sn (1951)
• EuS and EuSe as ferromagnetic semiconductors (1962)
• Au-Co eutectic as a ferromagnetic liquid (1968)
• Spontaneous red shift of the absorption edge of EuO (1964)
• Spin polarization of photoelectrons.

The merits of Prof. Busch, published in more than 500 papers, are recognized world-wide. The universities of Turku (1976), Geneva (1982) and Aachen (1986) awarded him with an honorary doctor’s degree. In 1981 he received the highly esteemed Frank H. Spedding Award for research in the field of the rare earth. This award honours his pioneering work in crystal growth, synthesis and characterization of materials.
He was an honorary member of the Swiss Physical society , the Finnish Academy of Sciences, and the New York Academy of Sciences.

The success of his career is due to hard work and a great deal of intuition. He started with research in ferroelectricity but left this field quite early (1944) to be engaged in semiconductor physics. We must remember that in those times not even the existence of “semiconductors” was officially recognized (Silicon was described in every text book as being a “metal”) and nobody could foresee that within the next 40 years semiconductors, mostly in form of transistors or chips, would drastically change the world. It was only in 1956 that Busch could inaugurate his own “Laboratory for Solid State Physics”, integrated into ETH, the first laboratory for solid state physics in Switzerland.

When semiconductor research became widely recognized due to industrial applications, Busch knew that it was time for him to explore new fields. His interest changed to magnetic phenomena, to optics and surface emission problems.

Starting in 1960 the attendance of lectures concerned with solid state physics (Festkörperphysik I & II) became compulsory at ETH, and Busch devoted much of his time to those lectures which up to today represent an unrivaled example of introductory lectures. They are fortunately published in book-form.

In addition, Busch was doing research work and teaching 30 different special topics in solid state physics, i.e. ionic conduction, superconductivity, dielectrica, metal physics, disorder phenomena, transport properties, light and heat radiation, contacts, electronic-emission from metals and semiconductors, low temperature physics and experimental solid state physics. All his lectures were famous amongst students for their clarity and innovative content. They aroused the interest of many physicists, and it is therefore not astonishing that 56 of them decided to do their Ph.D. thesis with Prof. Busch.

Another 167 students did their diploma work in the laboratory of Prof. Busch. The topics he chose for them were vary varied, i.e. synthesis of new kind of compounds, construction of apparatus for physical measurements, research on electronic phenomena (conductivity, thermoelectric power, specific heat), investigations of magnetism, properties of liquids and optical (emission) research.

Besides his academic interests Busch looked for close contacts with industry. The prospect of a possible application for his research topics was always fascinating for him. One example is the storage of hydrogen by solid state technology.

Prof. Busch once defined the virtue of a good physicist: Profound knowledge of the matter, curiosity for anything unexpected, willingness to take risks, and finally having some imagination. By looking at his achievements we readily see that these 4 qualities were the basis of his outstanding success in science.

The clarity of his lectures and his publications were the result of a thorough knowledge of the matter. He always liked to have some chemists and theoretical physicist in his group to assure professionality in the preparation of samples, and in the interpretation of results.
Many of his discoveries were initiated by curiosity, since he never set aside any observation that was not fully understood.
He never hesitated leaving the beaten path and risking to do something new.

Often his ideas or dreams were so revolutionary, that their realization took many years (e.g. the realization of a ferromagnetic liquid or semiconductor) and some of them are not even today brought to a conclusion (storage of H₂ e.g.). If we follow the path he has shown us we can have high hopes to succeed in the end.

Oscar Vogt

[Released: June 2000]