Shapes of flux domains in the intermediate state of type-I superconductors
Shapes of flux domains in the intermediate state of type-I superconductors
复制标题
I型超导体中间态磁通域的形状
DOI：
10.1103/physrevb.57.3058
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
R. Goldstein
中科院分区：
文献类型：
--
作者：
A. Dorsey;R. Goldstein
在超导体的中间状态下，磁通在一组无序的高支化和指状宏观畴中穿透。为了理解这些形状，我们详细研究了最近提出的“电流环”模型@R。E. Goldstein， D. P. Jackson和A. T. Dorsey，物理学家。Rev. Lett. 76, 3818 ~1996！#将中间态建模为沿超导-正法界面流动并受全局通量守恒约束的紧张电流带的集合。通过详细重新分析Landau对层流状态的原始保角映射处理（其中超导体-法线界面在板内呈喇叭形）和密切相关的直线层模型，验证了该模型的有效性。描述了一个简化的动力学模型，阐明了通量条纹和条纹阵列可能的形状不稳定性的本质，并对这些不稳定性的高度非线性状态进行了数值研究，证明了实验中看到的模式。特别令人感兴趣的是在中间状态中常见的屈曲不稳定性。自由边界方法进一步允许计算层流状态的弹性特性，这与近晶液晶的弹性特性非常相似。我们提出了几个探索磁畴形状不稳定性的实验，包括由改变面外磁场引起的埃克豪斯不稳定性和面内磁场引起的smectics的hellich - hurault不稳定性的模拟。@s0163——1829 ~ 98 !01005 - 4 #
In the intermediate state of a thin type-I superconductor magnetic flux penetrates in a disordered set of highly branched and fingered macroscopic domains. To understand these shapes, we study in detail a recently proposed ‘‘current-loop’’ model @R. E. Goldstein, D. P. Jackson, and A. T. Dorsey, Phys. Rev. Lett. 76, 3818 ~1996!# that models the intermediate state as a collection of tense current ribbons flowing along the superconducting-normal interfaces and subject to the constraint of global flux conservation. The validity of this model is tested through a detailed reanalysis of Landau’s original conformal mapping treatment of the laminar state, in which the superconductor-normal interfaces are flared within the slab, and of a closely related straightlamina model. A simplified dynamical model is described that elucidates the nature of possible shape instabilities of flux stripes and stripe arrays, and numerical studies of the highly nonlinear regime of those instabilities demonstrate patterns like those seen experimentally. Of particular interest is the buckling instability commonly seen in the intermediate state. The free-boundary approach further allows for a calculation of the elastic properties of the laminar state, which closely resembles that of smectic liquid crystals. We suggest several experiments to explore flux domain shape instabilities, including an Eckhaus instability induced by changing the out-of-plane magnetic field and an analog of the Helfrich-Hurault instability of smectics induced by an in-plane field. @S0163-1829~98!01005-4#