Development of magnetically soft microwires with GMI effect

Abstract

Thin amorphous magnetically soft microwires attract recently great attention because of their excellent soft magnetic properties and giant magneto-impedance (GMI) effect, thin dimensions and possibility for applications in magnetic micro-sensors. We overview research in the field of development of microwires with high GMI effect and improved features and report novel results on studies of GMI (diagonal and off-diagonal components) at high frequencies (between 10 MHz and 4 GHz) and its correlation with soft magnetic behaviour of thin amorphous microwires (Co-Fe-rich with nearly-zero magnetostriction constant) with metallic diameter between 3 and 20 μm and on optimization of GMI effect. We studied and analyzed low-field hysteresis of GMI effect and its dependence on circular magnetic field and discuss the nature the low-field hysteresis in terms of helical magnetic anisotropy and the effect of the bias field. Choosing samples composition, annealing conditions and geometry we were able to tailor their magnetoelastic anisotropy and respectively magnetic softness and GMI.