Critical fields of multilayered films of Al and Ge
Critical fields of multilayered films of Al and Ge
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Al、Ge多层膜的关键领域
DOI：
10.1103/physrevb.18.2225
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
D. Ast
中科院分区：
文献类型：
--
作者：
T. Haywood;D. Ast
薄膜由多个交替层的Al和Ge制成的可变层间距，和超导性能作为层间距的函数进行测量。临界温度遵循Petitt和Silcox用…beta.. = 0.26和k = 20 A。平行于层的临界场随外推的零温值变化为（1 - t）/sup 1/2/，类似于具有一个Al层厚度的单个膜。垂直于层的临界场显示出显着的正曲率相对于温度在高还原温度。这些调查结果进行了讨论。Gray和Schuller的理论可以用来根据正曲率的程度相当准确地预测层中的晶粒尺寸，但是该理论不能解释平行场中正曲率的缺乏。
Films consisting of multiple alternating layers of Al and Ge were fabricated with variable layer spacing, and the superconducting properties measured as a function of the layer spacing. The critical temperatures followed the theory of Garland as formulated by Petitt and Silcox with ..beta.. = 0.26 and k = 20 A. The critical fields parallel to the layers varied as (1 - t)/sup 1/2/ with extrapolated zero-temperature values similar to a single film with the thickness of one Al layer. The critical fields perpendicular to the layers showed a marked positive curvature with respect to temperature at high reduced temperatures. These findings are discussed. A theory by Gray and Schuller can be used to predict quite accurately the grain size in the layers from the degree of positive curvature, but this theory does not account for the lack of positive curvature in parallel fields.