Observation of reduced activation energy and the possible existence of decoupled pancake vortices in superconductor/ferromagnet bilayers

Samal, D and Sow, Chanchal and Kumar, Anil PS (2010) Observation of reduced activation energy and the possible existence of decoupled pancake vortices in superconductor/ferromagnet bilayers. In: Journal of Physics: Condensed Matter, 22 (29).

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Abstract

Investigations of different superconducting (S)/ferromagnetic (F) heterostructures grown by pulsed laser deposition reveal that the activation energy (U) for the vortex motion in a high T-c superconductor is reduced remarkably by the presence of F layers. The U exhibits a logarithmic dependence on the applied magnetic field in the S/F bilayers suggesting the existence of decoupled two-dimensional (2D) pancake vortices. This result is discussed in terms of the reduction in the effective S layer thickness and the weakening of the S coherence length due to the presence of F layers. In addition, the U and the superconducting T-c in YBa2Cu3O7-delta/La0.5Sr0.5CoO3 bilayers are observed to be much lower than in the YBa2Cu3O7-delta/La0.7Sr0.3MnO3 ones. This in turn suggests that the degree of spin polarization of the F layer might not play a crucial role for the suppression of superconductivity due to a spin polarized induced pair-breaking effect in S/F bilayers.

Item Type:	Journal Article
Publication:	Journal of Physics: Condensed Matter
Publisher:	Institute of Physics
Additional Information:	Copyright of this artcle belongs to Institute of Physics.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	09 Aug 2010 07:28
Last Modified:	19 Sep 2010 06:13
URI:	http://eprints.iisc.ac.in/id/eprint/31036

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