Spin reorientation studies in Er 2− xGd xFe 14B

Abstract

57Fe Mössbauer spectroscopy, differential scanning calorimetry (DSC), magnetic measurements and X-ray diffraction have been used to study the polycrystalline Er 2− x Gd x Fe 14B ( x = 0.0, 0.5, 1.0, 1.5) compounds. Special emphasis was put on the spin reorientation phenomena (change of spin orientation from planar to axial arrangement) occurring in this series. The spin reorientation in each compound has been investigated mainly by narrow step temperature scanning in the neighborhood of the spin reorientation temperature, T SR. Initial magnetization versus temperature measurements allowed to establish the temperature regions of reorientations and also the Curie temperatures of the compounds. Mössbauer temperature scanning was performed with a step of 1 K in the vicinity of T SR. The obtained spectra were analyzed by using a procedure of simultaneous fitting, and the transmission integral approach. Consistent fits were obtained, T SR and the composition dependencies of hyperfine interaction parameters were derived from fits for all studied compounds. DSC studies proved that the spin reorientations were accompanied by thermal effects. Transformation enthalpy and T SR were determined from these studies. The T SR obtained with different methods were compared and the spin phase diagram for the series was constructed.