Hyperfine interactions in RE2 (Fe, Ni)17 RE = Y, Gd, Dy

Abstract

Mössbauer measurements are performed on RE2(Fe1−xNix)17, RE = Y, Gd, Dy, compounds. The spectra are analyzed using 7 (8) independent subspectra for the samples with the Th2Zn17 (Th2Ni17) structure type. The mean hyperfine fields obtained are nearly independent of the RE atoms. Up to x ≈ 0.2 a small increase in the hyperfine splitting and a constant value for further increasing x is found. This is in line with the magnetic measurements which can be explained by a filling up of the majority spin subband in analogy with the binary (Fe, Ni) alloys at low Ni concentrations (x ≦ 0.15). From the concentration dependence of the quadrupole splitting no change of the easy axis caused by the Ni substitution can be observed and from the isomer shift charge transfers may be excluded.