Magnetic properties of DyFe2H2 from 57Fe, 161Dy Mössbauer effect and magnetization measurements

Abstract

A single phase stable hydride with nominal composition DyFe₂H₂ is shown to have the cubic C15 Laves structure with a 5% larger lattice constant. ⁵⁷Fe Mössbauer spectra show two sites with nearly equal population and with different isomer shifts and hyperfine fields. Based on the average hyperfine field at 4.2 K, an Fe moment of approximately 1.6 μ_B is estimated. From the ¹⁶¹Dy data at 4.2 K, which show a single site, a nearly free‐ion moment of 9.8 μ_B is determined. Relaxation effects in the ¹⁶¹Dy spectra above 77 K, combined with a sharp decrease in the moment with increasing temperature, imply a weakening of the Dy‐Fe magnetic coupling induced by the presence of the hydrogen.