Johannes Georg Bednorz
Bednorz in 2013
|Known for||High-temperature superconductivity|
|Awards|| Marcel Benoist Prize (1986)|
Nobel Prize in Physics (1987)
|Doctoral advisor||Heini Gränicher,|
K. Alex Müller
Johannes Georg Bednorz (born 16 May 1950) is a German physicist who, together with K. Alex Müller, discovered high-temperature superconductivity in ceramics, for which they shared the 1987 Nobel Prize in Physics.
Bednorz was born in Neuenkirchen, North Rhine-Westphalia, Germany to elementary-school teacher Anton and piano teacher Elisabeth Bednorz, as the youngest of four children. His parents were both from Silesia in Central Europe, but were forced to move westwards in turbulences of World War II.
As a child, his parents tried to get him interested in classical music, but he was more practically inclined, preferring to work on motorcycles and cars. (Although as a teenager he did eventually learn to play the violin and trumpet.) In high school he developed an interest in the natural sciences, focusing on chemistry, which he could learn in a hands-on manner through experiments.
In 1968, Bednorz enrolled at the University of Münster to study chemistry. However, he soon felt lost in the large body of students, and optrf to switch to the much less popular subject of crystallography, a subfield of mineralogy at the interface of chemistry and physics. In 1972, his teachers Wolfgang Hoffmann and Horst Böhm arranged for him to spend the summer at the IBM Zurich Research Laboratory as a visiting student. The experience here would shape his further career: not only did he meet his later collaborator K. Alex Müller, the head of the physics department, but he also experienced the atmosphere of creativity and freedom cultivated at the IBM lab, which he credits as a strong influence on his way of conducting science.
After another visit in 1973, he came to Zurich in 1974 for six months to do the experimental part of his diploma work. Here he grew crystals of SrTiO3, a ceramic material belonging to the family of perovskites. Müller, himself interested in perovskites, urged him to continue his research, and after obtaining his master's degree from Münster in 1977 Bednorz started a PhD at the ETH Zurich (Swiss Federal Institute of Technology) under supervision of Heini Gränicher and Alex Müller. In 1978, his future wife, Mechthild Wennemer, whom he had met in Münster, followed him to Zürich to start her own PhD.
In 1982, after obtaining his PhD, he joined the IBM lab. There, he joined Müller's ongoing research on superconductivity.In 1983, Bednorz and Müller began a systematic study of the electrical properties of ceramics formed from transition metal oxides, and in 1986 they succeeded in inducing superconductivity in a lanthanum barium copper oxide (LaBaCuO, also known as LBCO). The oxide's critical temperature (Tc) was 35 K, a full 12 K higher than the previous record. This discovery stimulated a great deal of additional research in high-temperature superconductivity on cuprate materials with structures similar to LBCO, soon leading to the discovery of compounds such as BSCCO (Tc 107K) and YBCO (Tc 92K).
In 1987, Bednorz and Müller were jointly awarded the Nobel Prize in Physics "for their important break-through in the discovery of superconductivity in ceramic materials".In the same year Bednorz was appointed an IBM Fellow.
Superconductivity is the set of physical properties observed in certain materials, wherein electrical resistance vanishes and from which magnetic flux fields are expelled. Any material exhibiting these properties is a superconductor. Unlike an ordinary metallic conductor, whose resistance decreases gradually as its temperature is lowered even down to near absolute zero, a superconductor has a characteristic critical temperature below which the resistance drops abruptly to zero. An electric current through a loop of superconducting wire can persist indefinitely with no power source.
Unconventional superconductors are materials that display superconductivity which does not conform to either the conventional BCS theory or Nikolay Bogolyubov's theory or its extensions.
Professor Heike Kamerlingh Onnes FRSFor HFRSE FCS was a Dutch physicist and Nobel laureate. He exploited the Hampson–Linde cycle to investigate how materials behave when cooled to nearly absolute zero and later to liquefy helium for the first time, in 1908. He was also the discoverer of superconductivity in 1911.
High-temperature superconductors are operatively defined as materials that behave as superconductors at temperatures above nearly -200 °C (-320 °F).
Yttrium barium copper oxide (YBCO) is a family of crystalline chemical compounds, famous for displaying high-temperature superconductivity. It includes the first material ever discovered to become superconducting above the boiling point of liquid nitrogen (77 K) at about 92 K. Many YBCO compounds have the general formula YBa2Cu3O7−x (also known as Y123), although materials with other Y:Ba:Cu ratios exist, such as YBa2Cu4Oy (Y124) or Y2Ba4Cu7Oy (Y247). At present, there is no singularly recognised theory for high-temperature superconductivity.
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Superconductivity is the phenomenon of certain materials exhibiting zero electrical resistance and the expulsion of magnetic fields below a characteristic temperature. The history of superconductivity began with Dutch physicist Heike Kamerlingh Onnes's discovery of superconductivity in mercury in 1911. Since then, many other superconducting materials have been discovered and the theory of superconductivity has been developed. These subjects remain active areas of study in the field of condensed matter physics.
Karl Alexander Müller is a Swiss physicist and Nobel laureate. He received the Nobel Prize in Physics in 1987 with Georg Bednorz for their work in superconductivity in ceramic materials.
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IBM Research – Zurich is the European branch of IBM Research. It was opened in 1956 and is located in Rüschlikon, near Zurich, Switzerland.
Lanthanum barium copper oxide, or LBCO, was discovered in 1986 and was the first high temperature superconductor. Johannes Georg Bednorz and K. Alex Müller shared the 1987 Nobel Prize in physics for its discovery.
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Paul Michael Grant is an American/Irish physicist and science writer who was involved in discovering and elucidating the structure of Yttrium Barium Copper Oxide which was important as the first high temperature superconductor to exhibit superconductivity above the boiling point of Nitrogen. He was a co-author of IBM's US patent application covering their preparation.
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