155Gd Mössbauer effect and magnetic properties of Gd2Co17Nx

Abstract The ternary nitride Gd 2 Co 17 N x (with x close to 3) was prepared by charging Gd 2 Co 17 with nitrogen gas. We have studied this compound by means of X-ray diffraction, magnetic measurements and 155 Gd Mossbauer spectroscopy. Upon charging, there is an increase in unit-cell volume of about 6.3%. The preferred moment direction changes from easy plane to easy axis and there is a small reduction in the Co-sublattice moment. From the analysis of the 155 Gd Mossbauer spectrum of Gd 2 Co 17 N x it is derived that the electric-field gradient at the Gd nuclei is 14.9 × 10 21 V/m 2 , which is somewhat larger than that found at the Gd sites in Gd 2 Fe 17 N x . The experimental value of V zz is in good agreement with self-consistent band structure calculations made for Gd 2 Co 17 and its ternary nitride. The results of these calculations have also been used to discuss the changes in magnetic moment upon nitrogen take-up.