High Temperature Superconductivity in Y-Ba-Cu-O: Identification of a Copper-rich Superconducting Phase

Author(s)

Angelica M. Stacy, University of California - Berkeley
John V. Badding, University of California - Berkeley
Margret J. Gesselbracht, University of California - Berkeley
William K. Ham, University of California - Berkeley
Gary F. Holland, University of California - Berkeley
Renata L. Hoskins, University of California - Berkeley
Steven W. Keller, University of California - Berkeley
Clark F. Millikan, University of California - Berkeley
Hans Conrad zur Loye, University of South Carolina - ColumbiaFollow

Document Type

Article

Subject Area(s)

Chemistry

Abstract

For the past 15 years, advances in superconductivity have come about only slowly and even a 0.5 K increase in transition temperature was noteworthy. Until April 1986, the highest transition temperatures were near 23 K. At that time, Bednorz and Muller reported superconductivity in La-Ba-Cu-0 compounds above 30K. Following this breakthrough, there were further studies of these phases and superconductivity was found also in similar solids containing Sr and Ca instead of Ba. The superconducting phase was identified as a layered perovskite A_2-xB_xCu0₄ with tetragonal symmetry, where A = La³⁺ and B = Ca²⁺, Sr²⁺, or Ba²⁺. The Sr compounds with x = 0.15 show the highest transition temperatures with T_c near 36 K.5 These studies lead to the investigation of other ternary copper oxides and soon thereafter Chu and co-worker found that compounds with a nominal composition of Y_1.2Ba_0.8Cu0₄could be prepared with superconducting transitions near 100 K. In contrast to the La_2-x,Sr_XCuO₄ phases,the analogous Y_2-xBa,Cu0₄ materials contain more than one phase. We report here the composition and properties of a superconducting phase containing Y, Ba, Cu, and 0 which is copper-rich compared with Y_1.2Ba_0.8Cu0₄.

Publication Info

Published in Journal of the American Chemical Society, Volume 109, Issue 8, 1987, pages 2528-2530.

Rights

© 1987 American Chemical Society

DOI: 10.1021/ja00242a056

Publisher's Version: http://dx.doi.org/10.1021/ja00242a056