Magnetism and 166Er Mössbauer spectroscopy of Er2?xPrxCo17

The bulk magnetic properties and ¹⁶⁶Er Mössbauer spectra of Er_2?xPr_xCo₁₇ pseudo-binaries are reported. Incorporation of Pr into Er₂Co₁₇ increases the anisotropy field (H_A) and the saturation magnetization, while resulting in only a slight (5%) decrease in the Curie temperature. The quadrupole interaction deduced from the Mössbauer spectrum suggests that Pr preferentially substitutes for Er in Er₂Co₁₇ at the 2d site. The rise in H_A is a consequence of the preferential substitution, which occurs because spatial constraints at the 2d site are less for the larger Pr³⁺ ion. Coupling between Er-Co and Pr-Co is found to be antiferromagnetic and ferromagnetic, respectively.