Palladium Hyperfine Field in Ferromagnetic Pd-Fe Alloys

Abstract

We have measured the ¹⁰⁵Pd hyperfine field distribution in a series of Pd‐Fe alloys ranging in composition from 0.5 to 25.0 at.% Fe by the NMR spin‐echo technique. The features of the observed Pd spectra are strongly concentration dependent, and above 10%, are somewhat heat‐treatment dependent, but always display at least two broad maxima. The ratio ${\mathrm{H̄}}_{\mathrm{Pd}}{\mathrm{/\mu ̄}}_{\mathrm{Pd}}$ of the average Pd hyperfine field, obtained from our data, to the average Pd moment, as determined from the neutron scattering and magnetization data (assuming a constant value of 3.0 _μB for the Fe moment), tends to a constant value of about 525 kOe/_μB for Fe concentrations greater than about 4 at.%. As the Fe concentration is reduced below this value, this ratio rises rapidly since ${\mathrm{\mu ̄}}_{\mathrm{Pd}}\text{→0}$ , but ${\mathrm{H̄}}_{\mathrm{Pd}}$ approaches asymptotically a value of about 72 kOe. The interpretation of our data in terms of the long‐range polarization model for the Pd‐Fe system is discussed.