Mössbauer and DSC studies of spin reorientations in Er2−xYxFe14B

Polycrystalline Er2−xYxFe14B (x=0.0, 0.5, 1.0, 1.5) compounds have been studied by 57Fe Mössbauer spectroscopy and differential scanning calorimetry (DSC) in the temperature range 80–370 K. The spin reorientation phenomenon has been studied extensively by narrow step temperature scanning in the vicinity of the spin reorientation temperature. Using the procedure of subtracting the Mössbauer spectra taken for the same compound at different temperatures, it was possible to follow the influence of transition on the shape of spectra. From this procedure it was concluded that in the region of transition, each subspectrum splits into two Zeeman sextets, which are characterised by different hyperfine fields and quadrupole splittings. A consistent way of describing the Mössbauer spectra was proposed. The composition and temperature dependencies of hyperfine interaction parameters and subspectra contributions were derived from experimental spectra. Endothermic DSC peaks were observed for all compounds studied which correspond to the transition from basal plane to axial easy magnetisation direction. The spin reorientation temperatures and the enthalpies of transitions were established from the DSC data. A spin arrangement diagram was constructed and spin reorientation temperatures obtained by different methods were compared.