Chapter 10 Effect of N o m i n a l C o m p o s i t i o n o n S u p e r c o n d u c t i v i t y in
La CuO 2
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S. M. Fine , M. Greenblatt, S. Simizu, and S. A. Friedberg 1
Department of Chemistry, Rutgers—The State University of New Jersey, New Brunswick, NJ 08903 Department of Physics, Carnegie-Mellon University, Pittsburgh, PA 15213
Downloaded by UNIV OF NEW ENGLAND on February 9, 2017 | http://pubs.acs.org Publication Date: August 28, 1987 | doi: 10.1021/bk-1987-0351.ch010
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Samples of LaCuO prepared with a nominal stoichio metry slightly deficient in lanthanum (i.e. La CuO ) showed a greater diamagnetic susceptibility and a sharper resistive transition than samples prepared from stoichiometric amounts of starting materials. The effect of adding K CO to the reaction mixture is also discussed. 2
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Recently Bednorz and Muller (1) reported possible superconductivity at 30 Κ in the metallic-oxide La-Ba-Cu-0 system. Subsequent work by Tanaka and co-workers (2) showed that the high temperature supercon ductivity is due to the solid solution La _ Ba CuO _ which forms in the K NiF -type structure. Making solid solutions with strontium instead of barium, Cava et. al. (3). were able to show bulk super conductivity at 38 Κ in La _ Sr Cu0 _ . While solid solutions of the type La _ M CuO _ (M = Sr, Ba) have been known for some time, (4-5) magnetic and electron transport properties of these compounds had not previously been measured at low temperatures (i.e.
