A new behaviour of ac losses in superconducting Bi2Sr2CaCu2O8 single crystals

Chockalingam, SP and Sarangi, S and Bhat, SV and Oka, K and Nishihara, Y (2009) A new behaviour of ac losses in superconducting Bi2Sr2CaCu2O8 single crystals. In: Journal of Physics-Condensed Matter, 21 (4). 045704-1.

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Abstract

A new ac loss behaviour is observed in the superconducting state of Bi2Sr2CaCu2O8 single crystals using a novel technique of measuring dissipation at radio frequencies. It is found that the ac loss in the superconducting state is larger than that in the normal state. This counter-intuitive result is explained in terms of the cumulative effect of repetitive decoupling of intrinsic Josephson junctions in the crystals and analysed in the framework of Ambegaokar-Baratoff theory. The ac losses are studied as a function of temperature, rf amplitude and magnetic field applied at different orientations. A peak in ac losses is observed in the superconducting state along the temperature scale. The amplitude of the peak decreases and shifts towards lower temperature with increasing field and also when the field orientation with respect to the c axis of the crystal changes from the perpendicular to parallel direction. The origin of the peak and its behaviour are discussed in the context of coupling energy of Josephson junctions present in the sample. In the presence of a magnetic field another peak in ac losses arises at temperatures close to T-c, which is associated with the Lorentz-force-driven motion of vortices.

Item Type:	Journal Article
Publication:	Journal of Physics-Condensed Matter
Publisher:	Institute of Physics
Additional Information:	Copyright of this article belongs to Institute of Physics.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	04 Nov 2009 06:35
Last Modified:	19 Sep 2010 05:24
URI:	http://eprints.iisc.ac.in/id/eprint/18594

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