Nonlinear Magnetoimpedance in Field- and Stress-Annealed Amorphous Ribbons

The diagonal and off-diagonal nonlinear magnetoimpedance in amorphous ribbons with well defined magnetic anisotropy is investigated. Field- and stress-annealing are used to produce easy-ribbon-axis and hard-ribbon-axis anisotropy, respectively. The dependence of the first three harmonic components of impedance on applied magnetic field and dc bias current is discussed. The symmetry properties of diagonal and off-diagonal impedance components as functions of applied magnetic field and dc bias current are substantially different. While all the components of diagonal impedance are mainly symmetric functions of field, the off-diagonal impedance is mainly antisymmetric. It is found that the odd harmonics of diagonal impedance can be related to the second harmonic of the off-diagonal impedance and vice versa. A theoretical explanation of the observed behavior, based on the symmetry properties of nonlinear Landau-Lifshitz-Gilbert equation, is proposed.