同轴电缆结构复合丝巨磁阻抗效应的研究

采用脉冲电沉积工艺在直径为200μm的铜丝表面沉积铁镍合金镀层，形成具有同轴电缆结构的巨磁阻抗复合丝材料。分别改变复合丝磁性外壳厚度与铜丝直径，研究复合丝结构对巨磁阻抗效应的影响。发现巨磁阻抗比值随磁性外壳厚度的增大及铜丝直径的增大而增大，特征频率则向低频端移动。本文还发现在外加直流磁场低于5．57kA／m时，驱动交流电幅值增大，巨磁阻抗效应增大；高于5．57kA／m时，驱动交流电幅值的大小几乎不再影响复合丝的巨磁阻抗效应。在驱动电流上叠加20mA以下的直流偏置对巨磁阻抗效应没有影响。

Study of the giant magnetic impedance effect in complex wire with structure of coaxial cable

FeNi-Cu complex wire having giant magnetic impedance effect(GMI) have been produced by pulse electrodeposing FeNi alloy over cylindrical Cu substrates.One group of samples with different magnetic shell thickness and same Cu wire diameter and the other group of samples with different Cu wire diameter and same magnetic shell thickness have been prepared respectively to investigate the influence of structure on GMI.It was found that the magnetic shell was thicker or Cu wire diameter was bigger,the GMI effect is stronger as well as the charicteristic frequency was lower.It was also found that when DC magnetic field was below 5.57kA/m,complex wire exhibits bigger GMI ratio with the increase of the amplitude of AC current,but when DC magnetic field was over 5.57kA/m,GMI ratio do not depend on amplitude of AC current.GMI effect has no change when adding a DC bias current below 20mA on AC current.