Detection of Individual Flux Motion in Superconductors

这项研究旨在开发一种新的系统，可以用来检测高温超导材料中单个磁通线在磁场中的运动。该仪器将配备高温超导薄膜变压器和一个微米大小的拾取线圈，将磁通运动信号耦合到DC SQUID。该探头将通过千分尺控制进行扫描。利用该仪器可以研究磁通线运动的动力学，特别是脱钉过程。一个目标是确定关于高温超导材料中单个钉扎点的信息。这项研究可能会揭示主要的钉扎机制，从而可能导致高温超导材料的临界电流密度的提高。高温超导材料的发现为许多类型的产品提供了巨大的应用潜力。许多实际应用的关键问题是通过控制磁通线运动来提高磁场中的临界电流密度。这笔赠款支持开发一种微型探头，以检测磁通线的运动并确定阻碍或钉住磁通线的缺陷或杂质等材料特性。因此，这项研究可能会为大电流载流超导体的制备带来新的技术。***

w:\awards\awards96\*.doc 9623270 Yeh This research aims at developing a novel system that can be used to detect the motion of individual flux lines in high temperature superconducting (HTS) materials in magnetic fields. The instrument will be equipped with HTS thin film transformers with a micrometer-size pickup coil to couple the flux motion signal to a dc SQUID. This probe will be scanned with micrometer control. With this instrument the dynamics of flux line motion will be investigated, especially the depinning process. An objective is to determine information about individual pinning sites in the HTS material. This research may reveal the main pinning mechanism and thus may lead to an improvement in the critical current density in the HTS materials. %%% The discovery of high temperature superconducting materials provides great potential for applications in many types of products. The key problem for many practical applications is the enhancement of the critical current density in magnetic fields that is governed by control of magnetic flux line motion. This grant supports the development of a microscopic probe to detect the motion of flux lines and determine the material properties such as defects or impurities that impede or pin the flux lines. Thus this research may lead to new techniques for the preparation of high-current carrying superconductors. ***