Vortex Dynamics in Superconductors

超导体中的涡动力学

• 批准号: 9510464
• 负责人: Christopher Lobb
• 金额: $ 22.5万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-07-15 至 1999-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9510464&HistoricalAwards=false
• 关键词: Vortex; Dynamics; Superconductors

9510464 Lobb Vortices in type-II superconductors move in response to external forces, causing a measurable electric field in the superconductor. In spite of significant research on conventional superconductors the advent of high- temperature superconductors has shown that vortex motion is not very well understood. The initial evidence for this was provided by measurements of the Hall effect in the vortex state, which showed motion opposite to the direction predicted by conventional theory. Subsequent measurements have shown anomalies in the Nernst effect, as well as surprising non-linear effects. The proposed work will extend our earlier work in this field, studying Hall and longitudinal conductivity, the dynamics of strongly-driven vortices, vortex motion in ultra-thin superconducting films, vortex motion induced by temperature gradients, a modified Giaever flux transformer experiment, and the effect of order-parameter symmetry on vortexdynamics. . %%% When a magnetic field is applied to type-II superconductors such as high-temperature superconductors, it penetrates the material in the form of vortices containing a quantum of magnetic flux. Motion of these vortices creates an electric filed in the superconductor, which leads, for example, to non-zero resistivity when current is present. Since most applications of superconductors rely on zero resistivity, understanding of vortex motion is important. The research proposed here is aimed toward understanding vortex motion resulting from a number of different driving forces. The resistance and Hall resistance of superconductors will be measured, with emphasis on nonlinear effects as the current is varied, to understand the effect of pinning, vortex-vortex interactions, quantum states in vortex core, and possible effects of order-parameter symmetry. The motion of vo rtices in response to temperature gradients will also be measured, which provides an alternative area for testing theories of vortex motion, as well as providing a unique probe for studying the internal structure of vortices. . ***

II型超导体中的9510464 LOBB涡流会响应外力而移动，从而导致超导体中可测量的电场。 尽管对常规超导体进行了重大研究，但高温超导体的出现表明，涡流运动并不是很好。最初的证据是通过测量涡流状态的霍尔效应的测量结果，该效果与常规理论预测的方向相反。 随后的测量结果显示了Nern的效应异常，以及令人惊讶的非线性效应。拟议的工作将扩大我们在该领域的早期工作，研究大厅和纵向导电性，强驱动涡流的动态，超薄超导膜中的涡流运动，由温度梯度引起的涡流运动，修改的giaever transfors实验，以及订购订单parameter symmeter symmeter on vortexdynexdynamics ot vortexdynamics的效果。 。 当将磁场应用于II型超导体（例如高温超导体）时，它以包含量子磁通量的涡流形式穿透材料。 这些涡旋的运动产生了在超导体中提交的电气，例如，当电流存在时，导致非零电阻率。由于超导体的大多数应用都取决于零电阻率，因此对涡旋运动的理解很重要。这里提出的研究旨在理解许多不同的驱动力引起的涡旋运动。将测量超导体的电阻和大厅电阻，重点是非线性效应，因为电流的变化，以了解固定，涡旋 - 涡流相互作用，涡旋核心中的量子状态以及订单参数对称的可能影响。 VO RTICE对温度梯度的响应运动也将进行测量，这为测试涡流运动理论提供了替代区域，并提供了研究涡旋内部结构的独特探针。 。 ***