Electronic behavior of spatially distributed junction small inductance dc π-SQUIDs

As investigated theoretically [Annalen der Physik (Leipzig) 8 (1999) 511; Phys. B, in press] spatially distributed junction small inductance dc π-SQUIDs exhibit unusual electric transport properties in both zero-voltage and voltage states. The purpose of this paper is to summarize the peculiarities of this electronic behavior in order to (a) reveal some of the advantages the device has over other known Josephson junctions based configurations when used as a tool to investigate the order parameter symmetry in high-T_c superconductors, and (b) to emphasize its potential for applications in superconducting electronics.     

A FORMULA FOR CALCULATING THE ERRORS OF SUPERCONDUCTING MAGNETIZATION CURVE

Because of field inhomogeneity in the magnetization measurement system, large errors may exist in the decreasing field superconducting magnetization curves, but not in the increasing field curves. The physical origin of the large errors is proposed here. A simple formula for calculating the errors is given. This formula is consistent with the experimental data.     

Analytical Techniques Applied in Optimization of Electrophoretic Deposition of Thin Film YBCO Superconductors

 YBa₂Cu₃O _7−x (x = 0.1–0.2) compounds (YBCO) were produced by the oxalate coprecipitation and the solid state reaction methods. The powders obtained were used for the production of YBCO superconducting coatings on Pt/Si wafers, by the electrophoretic deposition technique. The optimum process conditions for the production of both powders and coatings were found by using a combination of modern analytical techniques. The thermal treatment of the samples was followed by thermogravimetry (TG) and differential scanning calorimetry (DSC). The optimization and characterization of the superconducting properties of the powders and coatings were achieved by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), optical microscopy, magnetic susceptibility and electrical resistivity measurements.     

地磁环境下基于SQUID三轴磁强计的矢量稳场

超导量子干涉器件(Superconducting Quantum Interference Device, 简称 SQUID) 是一种高灵敏度的矢量磁探测器. 本文采用低温超导SQUID 作为传感器, 搭建了一套三轴矢量磁场稳定装置. 该系统由两个三轴 SQUID磁强计模块、 比例积分微分(PID) 控制器和反馈线圈组组成. 在该系统的矢量稳场下, 磁场波动峰峰值在有效带宽内可以降低四个数量级, 可达pT 量级, 稳场效果显著. 此技术可以满足大部分需要稳定磁场, 如高灵敏度磁传感器的标定等应用场合.