Magnetoelastic Anisotropy in Glass-Coated Microwires Studied using SAMR Method

A small-angle magnetization rotation (SAMR) experiment carried out on a single piece of glass-coated microwire is presented. The specific conditions of this experiment are discussed. The cylindrical shape of the microwire with small cross-sectional area means that a transverse AC magnetic field of relatively high frequency created by an electric current flowing through the microwire has to be used. It is shown that this experiment provides an opportunity to determine magnetoelastic anisotropy and corresponding axial mechanical stress in the metallic core of the wire. The difference in thermal expansion coefficients between the glass coating and the metallic core causes the magnetoelastic anisotropy field to increase with decreasing temperature. This behaviour, as well as the effect of stress relaxation by annealing, are demonstrated in this experiment based on the SAMR method.