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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 j c 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 rangemore » leading to a shallow peak in j c(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 [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Univ. of Chicago, IL (United States). Computation Inst.
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Northern Illinois Univ., DeKalb, IL (United States). Dept. of Physics
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21). Scientific Discovery through Advanced Computing (SciDAC); Swiss National Science Foundation (SNSF)
OSTI Identifier:
1413988
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Superconductor Science and Technology
Additional Journal Information:
Journal Volume: 31; Journal Issue: 1; Journal ID: ISSN 0953-2048
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; critical currents; numerical simulations; theory of strong pinning; time-dependent Ginzburg–Landau model; vortex 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}
}

Journal Article:
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