高温超导转变温度电输运测量的影响因素研究

A investigation of high temperature superconductor transition temperature and influencing factors

介绍了一种基于小型制冷机的高温超导转变温度测量装置,并且探究了在这套装置基础上进行实验所需要的测试条件。实验包括三项内容:(1)比较了电流换向法、三点Delta法以及偏置欧姆法三种消除热电势的方法,并最终决定采用适合本装置的电流换向法进行测量;(2)对通入样品的测试电流大小对测试的影响进行了研究,进而确定了进行高温超导材料转变温度测试时所通入电流的范围;(3)对钇系和铊系两种高温铜氧化物超导体进行反复测量,确定最大重复性误差小于0.4K。

In this article, we described a device for measuring high - Tc superconducting transition temperature in a small cryocooler and a series of experiments was carried out to explore the best measurement conditions. Firstly, we used the current - reversal method, delta method, and offset - compensated ohms method by controlling the current flow and direction to reduce the thermovoltage effect. Secondly, we changed the current amplitude continually from 0.01 mA to 50mA to get the appropriate exci- tation current. And then, we compared the transition curve of the Y - based and the T1 - based superconductors by repeated measurements to determine the superconducting transition curve and critical temperature accurately. For the measurement system, the maximum repeated measurement error is less than 0.4K.