Separation of circumferential magnetic components from MI spectra in laser-annealed Co-based amorphous microwires

A commercial glass-covered Co-based amorphous microwire (Co₆₆Fe_3.8Ni_1.4B_11.5Si_14.6Mo_1.7) with metallic core diameter of 17 μm was annealed in air by illuminating the pulsed Nd:YAG laser beams under longitudinal and transverse annealing fields, denoted by H_l and H_t, respectively. The static susceptibilities by domain-wall motion and magnetization rotation, μ_dw and μ_rot, were separated from the circumferential complex permeability extracted from impedance spectra. The μ_rot shows a maximum value of the laser-annealed sample with H_l=20 Oe, which indicates the increased volume of axial domain in the core by laser-annealing under longitudinal magnetic field. The μ_dw shows maximum value at laser-annealed sample with H_t=20, indicating that the volume of axial domain in core is increased by laser annealing under transverse magnetic field.