利用化学渡方法制备了芯层为铁磁层和芯层为导电层的两种复合丝,比较研究了它们的巨磁阻抗特性,结果发现芯层为铁磁层的复合丝在60MHz时取得最大值107%,而芯层为BeCu的复合丝在300kHz时就获得最大值108%。这是因为BeCu/绝缘层/NiCoP在低频时有较大的磁电阻效应,同时,由于芯层电阻较小,R与X在较低频就可比拟。磁阻抗比不仅取决于磁电阻比、磁感抗比,还与R和X的相对比值有关。要想获得显著的磁阻抗效应,要求材料不仅具有良好的软磁特性,而且电流通过部分还具有电阻率小的特点。
Using electroless deposition, the composite wires with ferromagnetic core and conductive core were produced. The properties of GMI were investigated, the composite wires with ferromagnetic core obtained the maximum 107% at f=60MHz, and the composite wires with BeCu core obtained the maximum 108% at f= 300kHz. An obvious MR effect is observed in the CuBe/insulator/NiCoP composite wires at lower frequency, then R and X make comparative contribrtion to the total MI ratio. The results show that MI ratio is dependent not only on the values of and but also on the ratio between R and X, so the obvious MI effect can be observed not only soft magnetic properties but also lower resistivity.