Temperature influence on magnetic properties and magnetoimpedance effect of Fe-rich glass-coated microwires

Giant magnetoimpedance, GMI, effect and magnetic properties upon temperature influence of as-prepared and stress-annealed amorphous Fe75B9Si12C4 glass-coated microwires produced by the Taylor-Ulitovsky technique are analyzed. Remarkable change in the hysteresis loops and GMI effect is observed for both samples upon heating. Tuning of the stress-annealing conditions allows one to vary the temperature dependence. Furthermore, it is observed almost complete reversibility of the changes induced by the temperature. Observed dependences are explained by the heating effect on the internal stresses relaxation, by the modification of the thermal expansion coefficients of the metallic nucleus and the glass coating, and by the Hopkinson effect.