Influence of cobalt doping on superconducting transition in as-grown YBCO single crystals

Elizabeth, Suja and Anand, A and Bhat, SV and Subramanyam, SV and Bhat, HL (1999) Influence of cobalt doping on superconducting transition in as-grown YBCO single crystals. In: Solid State Communications, 109 (5). pp. 333-338.

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Abstract

The role of a charge buffer layer in the superconductivity of high-T-c materials is best studied by cationic substitutions. In this work, the chain copper in YBCO single crystals is substituted by Co3+ ion and consequent effect on superconducting transition temperature (T-c) studied. The T-c is measured using non-resonant Microwave Absorption technique, which is a highly sensitive and contactless method. It is seen that T-c of as-grown crystals is considerably enhanced by cobalt doping in low concentration regime. In contrast, higher T-c is achieved in undoped crystals only after extended oxygen anneal. When dopant concentration increases beyond an optimal value, T-c decreases and the system does not show superconductivity when cobalt content is high (x > 0.5 in YBa2Cu3-xCOxO7+/-delta). This behaviour consequent to cobalt substitution is discussed with reference to the apical oxygen model. Optimal cobalt doping can be thought of as an alternative to extended oxygen anneal in as-grown crystals of YBCO.

Item Type:	Journal Article
Publication:	Solid State Communications
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Superconductors;Crystal growth.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	21 Aug 2009 10:36
Last Modified:	19 Sep 2010 05:30
URI:	http://eprints.iisc.ac.in/id/eprint/19850

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