Grain size dependence of the current–voltage characteristics and critical current density in the self-field approximation
In the self-field approximation, the influence of the grain radius on the current–voltage characteristics and associated critical current density Jc are investigated by considering the conventional flux flow motion of vortices. It is shown that the direct summation theory of Campbell et al. could be...
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Veröffentlicht in: | Journal of applied physics 1998-09, Vol.84 (6), p.3254-3262 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | In the self-field approximation, the influence of the grain radius on the current–voltage characteristics and associated critical current density Jc are investigated by considering the conventional flux flow motion of vortices. It is shown that the direct summation theory of Campbell et al. could be adopted to the granular systems [A. M. Campbell, J. E. Evetts, and D. Dew-Hughes, Philos. Mag. 10, 333 (1964)]. We found that Jc is enhanced as the size of the grains is decreased. The case of the critical current density being greater for smaller grains, which is consistent with both transport and low-field magnetization measurements is discussed by the weak links between the superconducting grains and also with the percolation model. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.368480 |