Temperature dependence of magnetoimpedance in annealed Co-based ribbons

The study on the temperature dependence of magnetoimpedance (MI) response of soft magnetic materials is particularly important for controlling the thermal stability of MI-based sensor devices. In this paper, the MI effect in non-magnetostrictive Co67Fe4Si14.5B14.5 amorphous ribbons at the frequency of 250 kHz in the range of temperature from −170 °C to 66 °C after particular DC and AC current annealing procedures is investigated. Temperature dependence of MI response of DC current annealed sample is different from that of as-quenched one. A nearly temperature independent behavior is observed after subsequent AC current annealing, seemingly as a consequence of the structural changes at the surface of the ribbons by partial devitrification.