Müller << MOOL uhr >>, Karl Alexander (1927-2023), was a Swiss physicist known for his work on superconductivity, a phenomenon in which some metals, alloys, and ceramics conduct electric current without resistance when extremely cold. In the 1980’s, Müller began to search for higher-temperature superconductors in collaboration with Georg Bednorz of Germany. The two men made important discoveries of superconductivity in some ceramic materials. For this work, they shared the 1987 Nobel Prize in physics. It was the second consecutive year that scientists from the International Business Machines Corporation’s (IBM) Research Laboratory at Ruschlikon, Switzerland, had won the prize.
In 1986, Müller and Bednorz announced an important discovery of superconductivity in a ceramic material at a temperature of 35 degrees Celsius above absolute zero. Metal superconductors, discovered earlier, work at such low temperatures that their practical use is limited. Later, other scientists discovered that a group of materials called perovskites could superconduct at relatively high temperatures, around 90 degrees Celsius above absolute zero, a temperature high enough to allow liquid nitrogen to be used as the cooling agent. Liquid nitrogen is much cheaper and easier to handle than liquid helium, which has to be used to cool superconducting metals and alloys.
Müller was born in Basel, Switzerland, on April 20, 1927. He earned a Ph.D. degree at the Swiss Federal Institute of Technology in Zurich in 1958. He worked as a researcher at the Batelle Institute in Geneva and later as a lecturer at the University of Zurich. In 1963, Müller joined the IBM Zurich Research Laboratory, becoming an IBM fellow in 1982. He died on Jan. 9, 2023.
See also Electricity (Conductivity).
