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arXiv:cond-mat/9211018 · Physical review. B, Condensed matter

I-Vcharacteristics of high-temperature superconductors with columnar defects

Mats Wallin, S. M. Girvin

Published Jun 1, 1993• 51 citations
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Abstract

The vortex glass transition in the presence of columnar defects is studied by Monte Carlo simulations of a vortex loop model, suggested by the analogy to the T=0 superconductor-insulator transition for dirty bosons in (2+1) dimensions. From finite-size scaling analysis of the I-V characteristic we find two dynamical exponents describing the nonequilibrium behavior. We obtain ${\mathit{z}}_{\mathrm{\ensuremath{\perp}}}$=6\ifmmode\pm\else\textpm\fi{}0.5 and ${\mathit{z}}_{\mathrm{\ensuremath{\parallel}}}$=4\ifmmode\pm\else\textpm\fi{}0.5 when the current is applied perpendicular and parallel to the columnar defects, respectively.

DOI
10.1103/physrevb.47.14642

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The vortex glass transition in the presence of columnar defects is studied by Monte Carlo simulations of a vortex loop model, suggested by the analogy to the T=0 superconductor-insulator transition for dirty bosons in (2+1) dimensions. From finite-size scaling analysis of the I-V characteristic we find two dynamical exponents describing the nonequilibrium behavior. We obtain z\ensuremath⊥{\mathit{z}}_{\mathrm{\ensuremath{\perp}}}z\ensuremath⊥​=6\ifmmode\pm\else\textpm\fi{}0.5 and z\ensuremath∥{\mathit{z}}_{\mathrm{\ensuremath{\parallel}}}z\ensuremath∥​=4\ifmmode\pm\else\textpm\fi{}0.5 when the current is applied perpendicular and parallel to the columnar defects, respectively.
We study vortex lines in high-temperature superconductors with columnar defects produced by heavy-ion irradiation. We reconsider scaling theory for the Bose-glass transition with tilted magnetic fields, and propose, e.g. , a new scaling form for the shape of the Bose glass phase boundary, which is relevant for experiments. We also consider Monte Carlo simulations for a vortex model with a screened interaction. Critical exponents are determined from scaling analysis of Monte Carlo data for current-voltage characteristics and other quantities. The dynamic critical exponent is found to be z = 4.6 ± 0.3.
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We study the vortex glass transition in disordered high temperature superconductors using Monte Carlo simulations. We use a random pinning model with strong point-correlated quenched disorder, a net applied magnetic field, long-range vortex interactions, and periodic boundary conditions. From a finite size scaling study of the helicity modulus, the rms current, and the resistivity, we obtain critical exponents at the phase transition. The new exponents differ substantially from those of the gauge glass model, but are close to those of the pure three-dimensional XY model.
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