High frequency magnetoimpedance response of stress annealed Co_(66.3)Fe_(3.7)Si_(12.0)B_(18.0) amorphous alloy ribbons

摘要

Magnetoimpedance (MI) response of near-zero magnetostriction Co-based amorphous ribbons exhibiting a macroscopic uniaxial magnetic anisotropy induced by stress-annealing (300 MPa at 340, 360, and 400 ℃ during 1 h) is investigated in a frequency range from 10 MHz up to 1000 MHz. Comparison among MI effect of these stress-annealed ribbons with that previously reported in ribbons with similar composition in as-cast state is discussed. It is remarkable that a more spectacular and defined MI effect is observed in the stress-annealed ribbons owing to the presence of a macroscopic uniaxial transverse magnetic anisotropy developed with the stress annealing which enhances the transverse component of the magnetic susceptibility. The influence of a preceding stress relief before the stress-annealing process on the MI effect is also analyzed.