Mossbauer studies of iron in palladium and in palladium rich, Rh-Pd matrices

Hyperfine magnetic field measurements on the ferromagnetic phase of dilute (∼ 1 at.%) alloys of iron in Pd or Rh-Pd host matrices have yielded values for Curie temperatures and spins associated with local moments. From the line broadening effects observed in the Mossbauer spectra, values have been found for the range of the exchange field distribution surrounding each iron atom. This is found to be a function of matrix susceptibility. The variation of hyperfine field with H / T (where H is a constant applied field and T a variable temperature) for the alloys can be described in terms of a molecular field model only if values of Curie temperature are assumed which are greater than those directly measured. These higher values are consistent with the results of magnetization measurements for Curie temperatures in dilute Fe-Pd alloys