Phase diagram of the vortex system in layered superconductors with strong columnar pinning

Dasgupta, Chandan and Valls, Oriol T (2005) Phase diagram of the vortex system in layered superconductors with strong columnar pinning. In: Physical Review B, 72 (9).

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Abstract

We present the results of a detailed investigation of the low-temperature properties of the vortex system in strongly anisotropic layered superconductors with a random array of columnar pinning centers. Our method involves numerical minimization of a free energy functional in terms of the time-averaged local vortex density. It yields the detailed vortex density distribution for all local free-energy minima, and therefore allows the computation of any desired correlation function of the time-averaged local vortex density. Results for the phase diagram in the temperature vs pin concentration plane at constant magnetic induction are presented. We confirm that for very low pin concentrations, the low-temperature phase is a Bragg glass, which melts into an interstitial liquid phase via two first-order steps,separated by a Bose glass phase. At higher concentrations, however, the low-temperature phase is a Bose glass, and the melting transition becomes continuous. The transition is then characterized by the on set of percolation of liquid like regions across the sample. In homogeneous local melting of the Bose glass is found to occur. There is also a depinning crossover between the interstitial liquid and a completely unpinned liquid at higher temperatures. At sufficiently large pin concentrations, the depinning line merges with the Bose glass to interstitial liquid transition. Many of the features we find have been observed experimentally and in simulations. We discuss the implications of our results for future experimental and theoretical work.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	Copyright for this article belongs to American Physical Society.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	04 Nov 2005
Last Modified:	19 Sep 2010 04:20
URI:	http://eprints.iisc.ac.in/id/eprint/3935

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