Effect of temperature on magnetic properties and magnetoimpedance effect of Co-rich glass-coated microwires

Abstract

We studied the effect of heating on the magnetic properties and giant magnetoimpedance (GMI), effect of Co69.2Fe3.6Ni1B12.5Si11Mo1.5C1.2 glass-coated microwires with vanishing magnetostriction. We observed, that upon heating the hysteresis loop changed its shape from inclined to rectangular. These changes in hysteresis loop shape correlate with modification of magnetic field dependencies of GMI ratio, ΔZ/Z, from double-peak to single-peak and with change in value of maximum GMI ratio. The origin of the observed changes in the hysteresis loop and the GMI effect is discussed in terms of the Hopkinson effect, internal stresses relaxation upon heating, and the temperature dependencies of internal stresses and the magnetostriction coefficient.