Thermal dependence of structural and magnetic properties in an amorphous Fe-Si-B-Cu alloy

Abstract Amorphous Fe 80 Si 9 B 10 Cu 1 ribbons were annealed at various temperatures below the crystallization temperature. The structural change was investigated by the synchrotron radiation X-ray diffraction and reverse Monte Carlo method. Intensities of the first peaks on partial pair distribution functions g Fe-Fe ( r ) and g Fe-Cu ( r ) rise up with the increase of annealing temperature, which implies the Cu clustering and concomitant Fe aggregation. Employing the Voronoi tessellation method, the enhanced phase separation during annealing was revealed by the variation in population of Fe-centered clusters. These findings are then corroborated by Fe 57  Mossbauer spectroscopy. Moreover, annealing enhances the average hyperfine field of the alloy ribbons and induces the rotation of easy axis to the ribbon plane.