Soft magnetic amorphous ribbons with high frequency Magnetoimpedance for sensors

Magnetoimpedance (MI) response of near-zero magnetostriction Co-based amorphous ribbons in as-cast (with four different wide dimension) state, and exhibiting a macroscopic uniaxial magnetic anisotropy induced by stress-annealing treatment (300 MPa applied tensile stress at different temperature i.e., 340, 360, and 400 °C, respectively, during 1 h) is investigated in the frequency range from 10 MHz up to 1000 MHz. Comparison among MI effect of as-cast state and stress-annealed ribbons 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 treatment that 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.