Singh, Shiva Kumar and Husain, M. and Awana, V. P. S. (2012) Structure and Charge-Transfer Mechanism in Y1-xCaxBa2Cu3O7-delta Through Direct Doping. Journal of Superconductivity and Novel Magnetism, 25 (6). pp. 1701-1706. ISSN 1557-1939

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Abstract

Here we study the effect of Ca doping on the charge-transfer mechanism of polycrystalline YBa2Cu3O7-delta compound. The samples of composition Y1-xCaxBa2 Cu3O7-delta (x = 0.00, 0.05, 0.10, 0.20 and 0.30) are synthesized through standard solid-state reaction route. Carrier doping is controlled by annealing of samples in oxygen and subsequently in reducing atmosphere. Samples are investigated using resistivity, dc magnetization (M-T) and magnetization with field (M-H) measurements. With increase of Ca the transition temperature (T-c) decreases in oxygenated samples, whereas the same increases in reduced samples. Further reduction of samples at higher temperatures (>600 degrees C) though results in non-superconducting nature up to Ca concentration of x = 0.20, the x = 0.30 sample is superconducting below 30 K. This provides a remarkably simple and effective way to study the relationship between structure, superconductivity, and associated electronic properties. Variation in Cu-1-O-4, Cu-2-O-4 and Cu-2-O-2 bond lengths with oxygen content, is seen through the structural refinement of XRD pattern. The effective coordination of Cu-2 atom with oxygen changes with the change in these bond lengths and hence the holes in the CuO2 planes. The charge-transfer mechanism from CuOx chains to CuO2 planes and thus effective hole doping is discussed in the context of the results observed.

Item Type:	Article
Additional Information:	copyright for this article belongs to M/s Springer Verlag
Subjects:	Applied Physics/Condensed Matter
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	19 Aug 2026 10:57
Last Modified:	19 Aug 2026 10:57
URI:	https://npl.csircentral.net/id/eprint/3403

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