Approach to Magnetic Saturation of Amorphous Gd80Si12B8

Abstract

We present the magnetization sutdy of a melt-spun amorphous alloy Gd80Si12B8 at 4.5 K in magnetic field up to 5.5 T. The ratio of the random magnetic anisotropy constant to the exchange interaction constant is estimated at 0.176. In the intermediate field region the magnetization approaches to saturation as B-1/2 owing to a weak random magnetic anisotropy where B is a magnetic field. The random magnetic anisotropy correlates over 1.0 nm, while the ferromagnetic correlation length is 4.1 nm. We discuss the random magnetic anisotropy of Gd80Si12B8 by comparing with other Gd-based amorphous magnets.