脉冲电流退火的钴基非晶带环巨磁阻抗效应

Giant Magneto-impedance Effect in Toroidal Core of Co-based Amorphous Ribbon Annealed by Pulse Current

将近零磁致伸缩系数的钴基非晶薄带卷成环形后,在16kA/m横向磁场作用下,用密度为25A/mm2的脉冲电流退火30s,并由环形薄带轴线上的直流电流提供环形磁场,可以获得显著的巨磁阻抗效应。分析了巨磁阻抗效应与激励电流的频率和幅值的关系。结果表明,在低频下阻抗变化率随频率升高而增大,达到特征频率后随频率升高而减小,增大激励电流幅值有利于提高磁阻抗效应。样品在频率为5MHz、峰-峰值5mA交流电流激励下阻抗变化率达55.1%。

The giant magneto-impedance effect of the near-zero magnetostriction Co-based amorphous ribbon toroidal core is annealed by 25A/mm^2 pulse current density under a transverse magnetic field of 16kA/m for 30 seconds .The circular magnetic field was supplied by DC current through the centre and parallel to the axes of toroidal core.The dependence of GMI effect on the frequency and amplitude of driving AC current is analyzed.The experimental results show that the GMI ratio increases at first and then decreases with increasing driving current frequency. The maximum GMI ratio of 55.1% has been obtained at frequency of 5 MHz with a driving AC current amplitude of 2.5mA.