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The preparation of a metallic diffuse fringe film system by dc-magnetron sputtering is described. The diffuse fringe structure of the film system is clearly observed in the SEM photograph when, during the film deposition process, the distance between the slit shutter and the substrate is large enough. Our experimental results show that the anomalous nonlinear I-V behavior of the system is mainly caused by the diffuse fringe effect. The temperature dependence of the sheet resistance is similar to that of the metallic flat film system in the temperature interval 77-300 K. 相似文献
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In this paper, the fringe effect on critical current has been studied systematically by measuring the electric transport characteristics of a Au-film system with diffuse fringe structure. It is found experimentally that, when the fringe effect becomes obvious, the film will exhibit strange I-R charac-teristics, in which exist a balance current and a critical current. We find that the critical exponents are related lo the diffuse fringe structure of the Films. The detailed analysis shows that the character- biles result from the thermionic-activating conductive effect in the diffuse fringe film sytem. 相似文献
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磁场穿透深度(λ)、相干长度(ξ)和能隙(Δ)是表征超导体处于超导态时其内禀特性的三个物理参量,是了解超导体的独特性质、探索超导机理和建立微观理论的依据和约束。本文在简要介绍传统超导体中有关λ、ξ和Δ的引入与测量方法的基础上,着重评述用于高TC氧化物超导体中有关λ、ξ和Δ的新测量方法,以及目前对各种类型高TC超导体所给出的实验结果。 相似文献
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Anderson局域化不是铜氧化合物高温超导电性变化的原因 总被引:2,自引:0,他引:2
通过对高温超导体中的元素替代效应进行分析,指出无论是在 CuO_2平面的元素替代还是不在 CuO_2平面的元素替代都不能用无序引起的载流子局域化来解释超导电性的变化和正常态性质变化.认为对超导电性根本负责的是 CuO_2平面中一定浓度的 O_(2p)空穴与 Cu3d轨道未配对的 dx~2-y~2电子的某种结合状态. 相似文献
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A series of Y123 single phase samples with various Ba vacancy concentration was prepared by making their Ba contents deviate from the stoichiometric composition. The measurements of their structure, superconductivity and flux pinning behaviour were systematically carried out. It is found that, compared with YBa2Cu3O6.96 sample, the strength of the flux pinning in YBaxCu3O7-δ(1.8≤x<2.0) samples is increased, and that there is an optimum value of Ba vacancy concentration for the maximum flux pinning force density. The possible origin of the flux pinning centers to determine the flux pinning behavior at higher field is discussed in detail. We suggest that the flux pinning effect at lower field may stein from the interaction between the vortex and the surfaces of grains, and that the flux pinning mechanism at higher field belongs to the core interaction. 相似文献