Detection of Individual Flux Motion in Superconductors

本研究旨在开发一种新颖的系统，可用于检测高温超导（HTS）材料在磁场中的单个磁通线的运动。该仪器将配备带有微米大小拾取线圈的高温超导薄膜变压器，将磁通运动信号耦合到直流SQUID。这个探针将用千分尺控制扫描。用这台仪器将研究磁通线运动的动力学，特别是脱屑过程。目的是确定HTS材料中单个钉钉位置的信息。这项研究可能揭示主要的钉钉机制，从而可能导致提高高温超导材料的临界电流密度。高温超导材料的发现为许多产品的应用提供了巨大的潜力。许多实际应用的关键问题是提高磁场中的临界电流密度，这是由磁通线运动控制的。这笔拨款支持微观探针的发展，以检测通量线的运动，并确定材料特性，如阻碍或固定通量线的缺陷或杂质。因此，这项研究可能会导致制备大电流超导体的新技术。＊＊＊

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. ***