Fe57 Mössbauer investigations on the Dy0.73Tb0.27Fe2-xNix and Ho0.85Tb0.15Fe2-yNiy systems

Fe57 Mössbauer studies were carried out on the Dy0.73Tb0.27Fe2-xNix and Ho0.85Tb0.15Fe2-yNiy systems (x=y=0, 0.5,1.0,1.5). The spectra were recorded in the temperature range 18675 K. The variation of hyperfine field at 18 K with Ni concentration showed a maximum at x=0.5 as well as y=0.5 which has been attributed to the narrowing of the 3d bands by the substitution of Ni. The Curie temperatures were estimated for all values of x and y from the temperature dependence of the average hyperfine field, which followed the Brillouin function. A monotonic decrease in Curie temperature with Ni concentration is observed and this is attributed to the decrease in net transition-metal sublattice moment. From the Mössbauer spectra, spin reorientation transitions have been observed for compositions with x=y=0, 0.5, and 1.0. © 1995 The American Physical Society.