Soft magnetic properties of Ge-doped nanocrystalline Fe–Zr–B alloys

Abstract The effects of Ge doping on the coercivity and hyperfine interactions of nanocrystalline Fe89Zr7B3Cu1 have been investigated by means of DC magnetization measurements and 57Fe Mossbauer spectroscopy. The coercivity of Fe89−xZr7B3Cu1Gex annealed for 3.6 ks at 773 and 823 K exhibits a tendency to decrease with increasing Ge content while this effect is not evident at higher annealing temperatures. Our Mossbauer analysis suggests that Ge-induced magnetic softening in Fe89−xZr7B3Cu1Gex is due to the preferential enrichment of Ge into the residual amorphous phase which results in an enhancement of the exchange stiffness in the intergranular region.