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Superconductors beyond 1-2-3

Journal Article · · Scientific American; (USA)

In 1986 physicists K. Alex Mueller and J. Georg Bednorz of the IBM Zuerich Research Laboratory realized that La-Ba-Cu ceramics were the key to developing a new class of high-temperature superconductors that would revitalize superconductivity research and technology. Their discovery began one of the most startling revolutions in solid-state physics. In February, 1987, Maw-Kuen Wu of the University of Alabama, Ching-Wu (Paul) Chu of the University of Houston and their co-workers replaced lanthanum in the Bednorz-Mueller compound with yttrium--a smaller rare-earth element--to form a superconductor whose transition temperature was 90 kelvins. Soon after, R.Bruce van Dover, Bertram Batlogg and the author at AT T Bell Laboratories were the first to determine that the superconductor was the chemical compound now known as 1-2-3 because of the ratio of yttrium to barium to copper atoms. The 1-2-3 material was the first superconductor with a transition temperature above 77 kelvins and therefore could be cooled easily and inexpensively in a bath of liquid nitrogen. During the past four years the efforts of thousands of investigators around the world have produced about a dozen superconductors that have transition temperatures above 40 kelvins as well as a handful above 77 kelvins. So far the highest transition temperature--which was achieved in a compound composed of thallium, barium, calcium, copper and oxygen--is an astounding 125 kelvins.

OSTI ID:
6084475
Journal Information:
Scientific American; (USA), Journal Name: Scientific American; (USA) Vol. 263:2; ISSN SCAMA; ISSN 0036-8733
Country of Publication:
United States
Language:
English