The 161Dy hyperfine field excess and the iron magnetic moment reduction in DyxFey compounds

The magnetically ordered DyxFey intermetallic compounds exhibit an excess of the magnetic hyperfine field at the 161Dy nuclei as compared with the free-ion value. The excess is relatively constant across the series. On the other side the saturated iron magnetic moments in the DyxFey (or other heavy rare earth-iron) compounds are reduced as compared with the pure iron metal value. The moments decrease almost linearly with x/y. The possible mechanisms which can originate the excess and the moment reduction are discussed. The role of the 5d electron is considered.