Thermomagnetic properties of nanocrystalline Fe–Si alloys with high Si content

Abstract

We report the structural and temperature dependent magnetic properties of Fe100−xSix (0≤x≤40) alloy powders synthesized by a mechanical alloying process over a wide composition range. We have observed from X-ray diffraction (XRD) that non-equilibrium solid solution could be obtained up to 35at% Si within 100h of milling. As-milled powders have fine crystallites with size around 9nm and dislocation density in the order of 1017m−2. The variations of saturation magnetization and lattice constant with Si substitution show a good correlation between the structural and magnetic properties. Thermomagnetic studies reveal the presence of different magnetic phases in the milled Fe–Si powders with high Si content, which depends on both composition and milling time. Curie temperature of Fe–Si solid solution decreases gradually at a rate of 1.45K/at% Si with increasing Si content. These results are in close agreement with the XRD data obtained for presently investigated nanocrystalline Fe–Si alloys.