NONLINEAR DIFFUSION IN HARD AND SOFT SUPERCONDUCTORS

被引:36
作者
GILCHRIST, J [1 ]
VANDERBEEK, CJ [1 ]
机构
[1] ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA
来源
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS | 1994年 / 231卷 / 1-2期
关键词
D O I
10.1016/0921-4534(94)90154-6
中图分类号
O59 [应用物理学];
学科分类号
摘要
We discuss the diffusion of magnetic flux in a field-cooled (''hard'') superconducting slab in a creep regime in which E proportional to \J\(sigma)J. Bryksin and Dorogovtsev recently discussed flux diffusion in a pinningless (''soft'') superconductor in which E proportional to \B\J. This problem is closely related to the flux-creep one with sigma=1, and provides additional insight into the possible types of behaviour. We list a series of possible long-term asymptotic solutions of a scaling form, which are either analytically exact or accurately calculated. We check numerically that the relevant long-term solution is approached after various initial conditions. Amongst other conclusions we find S=d(1n\M\)/d(1n t)-->-1/sigma or -1/2 sigma, after application and removal of an additional field, according to whether the disturbance has reached the sample centre or not. A relaxing sandpile model appears to have wide validity when creep is only a small correction to the critical state, as when sigma-->infinity.
引用
收藏
页码:147 / 156
页数:10
相关论文
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