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Title: Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors

Abstract

The current-carrying capacity of type-II superconductors is decisively determined by how well material defect structures can immobilize vortex lines. In order to gain deeper insights into intrinsic pinning mechanisms, we have explored the case of vortex trapping by randomly distributed spherical inclusions using large-scale simulations of the time-dependent Ginzburg-Landau equations. We find that for a small density of particles having diameters of two coherence lengths, the vortex lattice preserves its structure and the critical current jc decays with the magnetic field following a power-law B-a with a ~ 0:66, which is consistent with predictions of strong pinning theory. For higher density of particles and/or larger inclusions, the lattice becomes progressively more disordered and the exponent smoothly decreases down to a ~ 0:3. At high magnetic fields, all inclusions capture a vortex and the critical current decays faster than B-1 as would be expected by theory. In the case of larger inclusions with diameter of four coherence length, the magnetic-field dependence of the critical current is strongly affected by the ability of inclusions to capture multiple vortex lines. We found that at small densities, the fraction of inclusions trapping two vortex lines rapidly grows within narrow field range leading to amore » shallow peak in jc(B)-dependence within this range. With increasing inclusion density, this peak transforms into a plateau, which then smooths out. Using the insights gained from simulations, we determine the limits of applicability of strong pinning theory and provide different routes to describe vortex pinning beyond those bounds.« less

Authors:
ORCiD logo; ORCiD logo; ORCiD logo; ORCiD logo
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Advanced Scientific Computing Research; USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; USDOE Office of Science - Office of Advanced Scientific Computing Research - Scientific Discovery through Advanced Computing (SciDAC); Swiss National Science Foundation (SNSF)
OSTI Identifier:
1413988
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Superconductor Science and Technology; Journal Volume: 31; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; vortex pinning, critical currents, time-dependent Ginzburg–Landau model, numerical simulations, theory of strong pinning

Citation Formats

Willa, R., Koshelev, A. E., Sadovskyy, I. A., and Glatz, A. Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors. United States: N. p., 2017. Web. doi:10.1088/1361-6668/aa939e.
Willa, R., Koshelev, A. E., Sadovskyy, I. A., & Glatz, A. Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors. United States. doi:10.1088/1361-6668/aa939e.
Willa, R., Koshelev, A. E., Sadovskyy, I. A., and Glatz, A. Mon . "Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors". United States. doi:10.1088/1361-6668/aa939e.
@article{osti_1413988,
title = {Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors},
author = {Willa, R. and Koshelev, A. E. and Sadovskyy, I. A. and Glatz, A.},
abstractNote = {The current-carrying capacity of type-II superconductors is decisively determined by how well material defect structures can immobilize vortex lines. In order to gain deeper insights into intrinsic pinning mechanisms, we have explored the case of vortex trapping by randomly distributed spherical inclusions using large-scale simulations of the time-dependent Ginzburg-Landau equations. We find that for a small density of particles having diameters of two coherence lengths, the vortex lattice preserves its structure and the critical current jc decays with the magnetic field following a power-law B-a with a ~ 0:66, which is consistent with predictions of strong pinning theory. For higher density of particles and/or larger inclusions, the lattice becomes progressively more disordered and the exponent smoothly decreases down to a ~ 0:3. At high magnetic fields, all inclusions capture a vortex and the critical current decays faster than B-1 as would be expected by theory. In the case of larger inclusions with diameter of four coherence length, the magnetic-field dependence of the critical current is strongly affected by the ability of inclusions to capture multiple vortex lines. We found that at small densities, the fraction of inclusions trapping two vortex lines rapidly grows within narrow field range leading to a shallow peak in jc(B)-dependence within this range. With increasing inclusion density, this peak transforms into a plateau, which then smooths out. Using the insights gained from simulations, we determine the limits of applicability of strong pinning theory and provide different routes to describe vortex pinning beyond those bounds.},
doi = {10.1088/1361-6668/aa939e},
journal = {Superconductor Science and Technology},
number = 1,
volume = 31,
place = {United States},
year = {Mon Nov 27 00:00:00 EST 2017},
month = {Mon Nov 27 00:00:00 EST 2017}
}