161Dy and 57Fe Mössbauer effect studies on Dy2−yYyFe17 compounds

The hyperfine interaction parameters at the 161Dy and 57Fe nuclei in Dy2−yYyFe17 compounds (0⩽y⩽2) have been determined from the Mossbauer effect measurements at 4.2 K. The dysprosium atoms are substituted by the yttrium atoms across the series and then the 5d electrons of Dy are replaced by the 4d electrons of Y. The hyperfine interaction parameters for both nuclei remain constant versus Y content. The full equivalency between 5d and 4d electrons has been deduced. The excess of the hyperfine magnetic field at the 161Dy nuclei and the reduction of the magnetic hyperfine field at the 57Fe nuclei can be explained as a result of the presence of the magnetically polarized 5d (or 4d) electrons in these compounds.