High-temperature superconductivity in yttrium barium copper oxide (YBa2Cu3O7) and related perovskite oxides: some aspects of solid state chemistry

Rao, CNR and Ganguly, P and Sreedhar, K and Ram, Mohan RA and Sarode, PR (1987) High-temperature superconductivity in yttrium barium copper oxide (YBa2Cu3O7) and related perovskite oxides: some aspects of solid state chemistry. In: Materials Research Bulletin, 22 (6). pp. 849-855.

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Abstract

Thermogravimetry and Cu "K-absorption edge measurements show that the superconducting $YBa_2Cu_30_7$ sample (annealed in $0_2$) contains more oxygen than the nonsupe conducting sample annealed in-$N_2$, the former has s less distorted structure with the actual composition not far from the ideal one. Oxides of the formula $Y_{l-x} Ba_2Cu_30_7$ (x = 0.05, 0.10 and 0.15) annealed in oxygen also possess the perovskite structure and show high-$T_c$ superconductivity. The superconduccting transition temperature seems to generally increase with the nominal $Cu^{3+}/Cu^{2+}$ ratio in the superconducting copper oxides. Control of the $Cu^{3+}/Cu^{2+}$ ratio (and hence the density of states at the metal-nonmetal transition in the non-superconducting state) through the oxygen stoichiometry or an appropriate cation substitution seems to provide a basis for synthesizing high-$T_c$ copper oxides.

Item Type:	Journal Article
Publication:	Materials Research Bulletin
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science
Keywords:	oxides;perovskites;barium;copper;yttrium
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	19 Jun 2008
Last Modified:	19 Sep 2010 04:46
URI:	http://eprints.iisc.ac.in/id/eprint/14363

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