磁电阻(MR)和巨磁电阻(GMR)测试系统

A Computer-added Measuring System for Magnetoresistance and Giant Magnetoresistance

介绍了一种自动测试一般磁电阻和巨磁电阻材料MR比、GMR比的方法。用直列式四探针加载恒流和读出电压信号，由电磁铁提供外加磁场，在新的测试理论模型基础上通过并行8255A接口，控制多路开关选择，将模拟信号经过A／D数模变换后，再经精密放大器放大，最后采用计算机处理输出测试曲线。该系统在外磁场（μ0H）0-30mT范围，GMR比测试精度为±0．1％。

A method was discribed to measure magnetoresistance and giant magnetoresistance ratio. In this system, the measurement was realized by using in-line four-probe for constant current loading and signal reading, a electromagnet for applied field, and controlling multiway switch by 8255A parallel interface. The obtained analog signal is transformed by A/D conversion and accurately amplified. Then the result was processed and output is displayed by computer. In the applied field range of 0 to 30mT, a measuring precision of giant magnetoresistance ratio of ±0.1% was achieved.