磁环中非晶丝的阻抗效应分析

依据Landau-Lifshitz阻尼项和Gilbert阻尼项的磁矩转动方程，提出统一形式的磁化率张量表达式.基于等效磁导率将非晶丝中各向异性的电磁场求解问题转化为等效的各向同性问题，进而分析了套在绝缘磁环或导电磁环中非晶丝的阻抗.采用基于有限元的数值方法仿真磁环中非晶丝的阻抗，仿真结果验证了理论分析结论.理论分析和仿真实验均表明，外磁体的附加阻抗将严重降低阻抗变化率，破坏巨磁阻抗特性.为此，提出采用回路形式降低附加阻抗的方法，并基于仿真实验验证了该方法的有效性. 关键词： 巨磁阻抗效应 非晶材料 Maxwell方程 有限元

Analysis of magnetoimpedance in amorphous wire passing through a magnetic ring

A unified expression of magnetic susceptibility tensor is presented according to the magnetic-moment motion equation with Landau-Lifshitz damping term and Gilbert damping term. The application of equivalent magnetic permeability enables to transform the anisotropy problem to an isotropy one with the same electromagnetic solution in amorphous wire. By this transformation, the impedance of amorphous wire passing through an insulating or conducting magnetic ring are analyzed. Additionally, the magnetoimpedance effect in amorphous wire through a magnetic ring is simulated by the numerical analysis based on the finite element method. The results of theoretical analysis and numerical simulation, which agree with each other, indicate that the additional impedance caused by extra magnetic objects seriously reduces the magnetoimpedance change of amorphous wire and destroy the giant magnetoimpedance characteristic. Therefore, the return wire structure is proposed to diminish the additional impedance. The simulation results verified the effectiveness of this method.