Magnetization and relaxation curves of fast relaxing high-Tc superconductors

H. G. Schnack; R. Griessen; J. G. Lensink; C. J. van der Beek; P. H. Kes

doi:10.1016/0921-4534(92)90016-6

Magnetization and relaxation curves of fast relaxing high-T_c superconductors

H. G. Schnack
, R. Griessen
, J. G. Lensink
, C. J. van der Beek
, P. H. Kes

Research output: Contribution to journal › Article › peer-review

Abstract

The magnetization curves of rapidly relaxing type-II superconductors are calculated by means of Monte Carlo simulations and numerical solutions of the partial differential equation for thermally activated flux-creep. Several models for the current dependence of the activation energy (U(j)=U_c(1-j/j_c), U(j)=(U_c/μ)((j_c/j)^μ-1) and U(j)=U_c(j_c/j)) are considered. The calcu lated curves reproduce all the features exhibited by experimental magnetization curves, even when the critical current is assumed to be field-independent. This remarkable result shows explicitly that strong flux relaxation effects can lead to spurious field-dependent critical currents. The characteristic features of the magnetization curves are related to the relaxation behaviour of the corresponding flux density profiles. The dependence of hysteresis loops on the magnetic field sweep rate is investigated in detail and is shown to contain basically the same information as the time dependence of the magnetization during relaxation.

Original language	English
Pages (from-to)	337-361
Number of pages	25
Journal	Physica C: Superconductivity and its Applications
Volume	197
Issue number	3-4
DOIs	https://doi.org/10.1016/0921-4534(92)90016-6
Publication status	Published - 10 Jul 1992
Externally published	Yes

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10.1016/0921-4534(92)90016-6

Cite this

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title = "Magnetization and relaxation curves of fast relaxing high-Tc superconductors",

abstract = "The magnetization curves of rapidly relaxing type-II superconductors are calculated by means of Monte Carlo simulations and numerical solutions of the partial differential equation for thermally activated flux-creep. Several models for the current dependence of the activation energy (U(j)=Uc(1-j/jc), U(j)=(Uc/μ)((jc/j)μ-1) and U(j)=Uc(jc/j)) are considered. The calcu lated curves reproduce all the features exhibited by experimental magnetization curves, even when the critical current is assumed to be field-independent. This remarkable result shows explicitly that strong flux relaxation effects can lead to spurious field-dependent critical currents. The characteristic features of the magnetization curves are related to the relaxation behaviour of the corresponding flux density profiles. The dependence of hysteresis loops on the magnetic field sweep rate is investigated in detail and is shown to contain basically the same information as the time dependence of the magnetization during relaxation.",

author = "Schnack, \{H. G.\} and R. Griessen and Lensink, \{J. G.\} and \{van der Beek\}, \{C. J.\} and Kes, \{P. H.\}",

year = "1992",

month = jul,

day = "10",

doi = "10.1016/0921-4534(92)90016-6",

language = "English",

volume = "197",

pages = "337--361",

journal = "Physica C: Superconductivity and its Applications",

issn = "0921-4534",

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TY - JOUR

T1 - Magnetization and relaxation curves of fast relaxing high-Tc superconductors

AU - Schnack, H. G.

AU - Griessen, R.

AU - Lensink, J. G.

AU - van der Beek, C. J.

AU - Kes, P. H.

PY - 1992/7/10

Y1 - 1992/7/10

N2 - The magnetization curves of rapidly relaxing type-II superconductors are calculated by means of Monte Carlo simulations and numerical solutions of the partial differential equation for thermally activated flux-creep. Several models for the current dependence of the activation energy (U(j)=Uc(1-j/jc), U(j)=(Uc/μ)((jc/j)μ-1) and U(j)=Uc(jc/j)) are considered. The calcu lated curves reproduce all the features exhibited by experimental magnetization curves, even when the critical current is assumed to be field-independent. This remarkable result shows explicitly that strong flux relaxation effects can lead to spurious field-dependent critical currents. The characteristic features of the magnetization curves are related to the relaxation behaviour of the corresponding flux density profiles. The dependence of hysteresis loops on the magnetic field sweep rate is investigated in detail and is shown to contain basically the same information as the time dependence of the magnetization during relaxation.

AB - The magnetization curves of rapidly relaxing type-II superconductors are calculated by means of Monte Carlo simulations and numerical solutions of the partial differential equation for thermally activated flux-creep. Several models for the current dependence of the activation energy (U(j)=Uc(1-j/jc), U(j)=(Uc/μ)((jc/j)μ-1) and U(j)=Uc(jc/j)) are considered. The calcu lated curves reproduce all the features exhibited by experimental magnetization curves, even when the critical current is assumed to be field-independent. This remarkable result shows explicitly that strong flux relaxation effects can lead to spurious field-dependent critical currents. The characteristic features of the magnetization curves are related to the relaxation behaviour of the corresponding flux density profiles. The dependence of hysteresis loops on the magnetic field sweep rate is investigated in detail and is shown to contain basically the same information as the time dependence of the magnetization during relaxation.

U2 - 10.1016/0921-4534(92)90016-6

DO - 10.1016/0921-4534(92)90016-6

M3 - Article

AN - SCOPUS:0007168880

SN - 0921-4534

VL - 197

SP - 337

EP - 361

JO - Physica C: Superconductivity and its Applications

JF - Physica C: Superconductivity and its Applications

IS - 3-4

ER -

Magnetization and relaxation curves of fast relaxing high-Tc superconductors

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Magnetization and relaxation curves of fast relaxing high-T_c superconductors