Structural and magnetic properties of Y1−xErxFe2

Alloys of nominal composition Y1−xErxFe2 (x=0, 0.25, 0.5, 0.65, 0.75 and 1) have been prepared and investigated for the structural and magnetic properties. The microstructural features of the samples indicate that (Y,Er)Fe2 is the main phase, with the co-existence of a minor phase (Y,Er)Fe3, in different morphologies. The lattice parameter of the main phase is found to decrease, while the Curie temperature is found to increase with Er addition. Compensation in the temperature dependence of magnetization is, however, observed for compositions x=0.5, 0.65, 0.75 and 1. The 57Fe-Mössbauer spectra obtained at 300 K for the samples display a superposition of two six-line patterns in the intensity ratio 1:3, thus indicating that the easy direction of magnetization lies along [1 1 1] crystallographic direction. The average hyperfine fields are found to increase marginally with Er addition, implying an enhancement in the Fe magnetic moment. The Er-Fe interaction is attributed to be the main reason for the marginal increase in the hyperfine fields and in the Curie temperature of Er-added alloys.