A theory of thermally activated flux creep in nonideal type II superconductors

K. Yamafuji, T. Fujiyoshi, Kiyoshi Toko, T. Matsushita

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

The relaxation of the magnetization due to thermally activated flux creep in a bulk sample of a nonideal type II superconductor is discussed theoretically. Firstly, an expression for the average volume of a flux bundle characterizing its coherent thermal hopping motion is derived by starting with an equation for the local force balance on pinned fluxoids. Secondly, a thermal hopping rate of flux bundles is derived from the Fokker-Planck equation of pinned flux bundles. These results are used to derive expressions for both the time dependence of the magnetization and the induced electric field due to flux creep. It is shown that the present theory can quantitatively explain the existing observed data of the flux-creep rate, not only in conventional superconductors such as Nb-Ta and Pb-Tl but also in strongly-pinning bulk samples of the high-Tc oxide superconductors such as Y-Ba-Cu-O.

Original languageEnglish
Pages (from-to)743-759
Number of pages17
JournalPhysica C: Superconductivity and its applications
Volume159
Issue number6
DOIs
Publication statusPublished - Aug 1 1989

Fingerprint

Superconducting materials
Creep
Fluxes
bundles
Magnetization
Oxide superconductors
Fokker Planck equation
magnetization
Fokker-Planck equation
time dependence
Electric fields
oxides
electric fields
Hot Temperature

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

Cite this

A theory of thermally activated flux creep in nonideal type II superconductors. / Yamafuji, K.; Fujiyoshi, T.; Toko, Kiyoshi; Matsushita, T.

In: Physica C: Superconductivity and its applications, Vol. 159, No. 6, 01.08.1989, p. 743-759.

Research output: Contribution to journalArticle

Yamafuji, K. ; Fujiyoshi, T. ; Toko, Kiyoshi ; Matsushita, T. / A theory of thermally activated flux creep in nonideal type II superconductors. In: Physica C: Superconductivity and its applications. 1989 ; Vol. 159, No. 6. pp. 743-759.
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