磁场中的超导膜

本文将文献[1]的理论推广到较厚的超导膜。首先采用能隙是常数的模型,借助于Schrief-fer方法,导出磁场中超导膜的补偿方程和电流方程。利用所得的方程,研究了均匀外磁场对金属膜超导性质的影响,讨论了超导膜在磁场中的相变,给出了确定超导膜的能隙、磁矩、平衡临界场H_c,以及分别相应于过冷和过热区域边界的临界场H_(c1)和H_(c2)的一般公式。所有这些表达式,在局域极限下,化为Гинзбург-Ландау理论的相应结果;在薄膜情形下,回到文献[1]的结果,文中对一般情形下的非局域效应作了具体的讨论。

SUPERCONDUCTING FILMS IN A MAGNETIC FIELD

The theory developed in reference [1] has been extended to thicker films. The compensation equation and current equation are derived for superconducting films in a magnetic field, on the basis of a model which assumes the energy-gap function to be constant over the whole film and by means of Schrieffer's technique. The equations obtained are applied to discuss the influence of an external magnetic field on the superconducting properties of a metallic film and its transition changes. The formulas for determining energy-gap, magnetic moment, and critical fields H_c, H_(c1) and H_(c2) which correspond respectively to equilibrium transition and to boundaries of supercooled and superheated region, are given. All the expressions have been reduced to the well-known results of the Ginzburg-Landau theory in the local limit and to those of reference [1] in the thin film limit. Non-local effects in the general case have been discussed in detail.