Magneto-transport studies of FeSe0.9-xMx (M = Si, Sb)

Pandya, S. and Sherif, S. and Sharath Chandra, L. S. and Ganesan, V. (2011) Magneto-transport studies of FeSe0.9-xMx (M = Si, Sb). Superconductor Science & Technology, 24 (4). ISSN 0953-2048

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Official URL: https://dx.doi.org/10.1088/0953-2048/24/4/045011

Abstract

We report on the magneto-resistivity of FeSe0.9-xMx (M = Si, Sb, x = 0.05, 0.1) down to 2 K in the presence of magnetic fields up to 14 T. The superconducting transition shows marginal differences for Sb-and Si-doped samples. Normal state resistivity shows marked changes at intermediate temperatures around 100 K, signaling the presence of a structural transition. It also shows linear behavior with temperature, reminiscent of high T-c ceramics. Superconducting parameters like critical fields and coherence lengths are quantified for all samples. The broadening of superconducting transitions is studied through thermally activated flux flow (TAFF) and fluctuation conductivity. The activation energy of these superconductors is found to be one order smaller than the FeAs-1111 system, which may be explained in terms of larger penetration depth. The activation energy of thermally activated flux flow decreases with the Si and Sb doping and is explained by Kramer's scaling for grain boundary pinning. The zero-field and magnetic-field-induced fluctuation conductivity are studied using Aslamazov-Larkin (AL) and lowest Landau level (LLL) theories, respectively. Zero-field fluctuation conductivity shows the 2D to 3D crossover just above the mean-field transition and 3D LLL scaling is obtained near mean-field transitions for magnetic-field-induced fluctuation conductivity. This is a clear indication of the three-dimensional nature of these superconductors. The 3D nature of these superconductors signifies its potential for future technological applications.

Item Type: Article
Subjects: D Physical Science > Physics
Divisions: Department of > Physics
Depositing User: Users 23 not found.
Date Deposited: 26 Jun 2019 09:42
Last Modified: 23 Dec 2020 05:51
URI: http://eprints.uni-mysore.ac.in/id/eprint/2544

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