Rare-earth transition metal exchange interactions in amorphous (Fe0.82B0.18)0.9RxLa0.1−x alloys

We have estimated the rare-earth subnetwork magnetization near room temperature for a series of amorphous melt-quenched alloys having the compositions (Fe0.82B0.18)0.9RxLa0.1−x, where R = Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er, by using a combination of bulk magnetization and Mössbauer measurements. To a good approximation the magnetization of the rare earths can be described by a molecular field which is proportional both to the iron subnetwork magnetization and the spin part of the rare-earth moment. The Curie temperatures exhibit small but systematic variations which are also in good qualitative agreement with mean field theory.