TY - JOUR
T1 - Thermal depinning of flux lines in superconductors
AU - Matsushita, Teruo
AU - Kiss, Takanobu
N1 - Funding Information:
One of the authors (T.M.) acknowledges the support of this study by the Grain-in-Aid for `Characterization and Evaluation of Superconducting Materials' of the National Research Institute for Metals, Japan.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1999/4/1
Y1 - 1999/4/1
N2 - The thermal depinning of flux lines on the irreversibility line is investigated from a viewpoint of thermodynamics using the coherent potential approximation theory, a kind of statistical theory for flux pinning. The effect of thermal activation is approximately introduced by making the pinning potential shallow following the theoretical scheme by Yamafuji et al. It is shown that the thermal depinning is the transition of the second order. Since the vortex glass-liquid transition, which is considered to be identical with the thermal depinning, is originally predicted to be the second-order transition, the present theoretical result is reasonable. The present result also suggests that the irreversibility line observed at higher temperatures and at lower fields than the critical point for weakly pinned superconductors is also the transition line of the second order. In addition, it is shown that the degree of disorder of the flux line lattice decreases fast, suggesting a quick recovery of the order of the lattice with elevating temperature above the critical temperature.
AB - The thermal depinning of flux lines on the irreversibility line is investigated from a viewpoint of thermodynamics using the coherent potential approximation theory, a kind of statistical theory for flux pinning. The effect of thermal activation is approximately introduced by making the pinning potential shallow following the theoretical scheme by Yamafuji et al. It is shown that the thermal depinning is the transition of the second order. Since the vortex glass-liquid transition, which is considered to be identical with the thermal depinning, is originally predicted to be the second-order transition, the present theoretical result is reasonable. The present result also suggests that the irreversibility line observed at higher temperatures and at lower fields than the critical point for weakly pinned superconductors is also the transition line of the second order. In addition, it is shown that the degree of disorder of the flux line lattice decreases fast, suggesting a quick recovery of the order of the lattice with elevating temperature above the critical temperature.
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U2 - 10.1016/S0921-4534(99)00203-8
DO - 10.1016/S0921-4534(99)00203-8
M3 - Article
AN - SCOPUS:0032681833
VL - 315
SP - 12
EP - 22
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - 1
ER -