Mössbauer study of magnetic anisotropy and atomic short-range order in Fe40Ni40P14B6

Abstract Amorphous ribbons of Fe 40 Ni 40 P 14 B 6 were investigated using 57 Fe Mossbauer spectroscopy and a torsion-vibration magnetometer. The effects of heat treatment at 220, 325 and 450°C for different periods of time are reported. A decrease of the magnetic anisotropy (preference for the ribbon plane) by annealing was detected. Differences in the determination of the magnetic anisotropy using the fit with one sextet or with a distribution function p ( H ) were obtained. Aspects of the atomic short-range order in the amorphous state are discussed on the basis of the field distribution functions p ( H ), of the crystallization behaviour and of the results from the torsion-vibration magnetometer measurements. The short-range order is changed by annealing.