Average Magnetic Hyperfine Fields atPd106Nuclei in Ni-Pd Alloys

Abstract

The average magnetic hyperfine fields at $^{106}\mathrm{Pd}$ nuclei in a series of Ni-Pd alloys have been measured at 77 \ifmmode^\circ\else\textdegree\fi{}K by means of the integral perturbed-angular-correlation method using the (622. 0-511. 8)-keV $\ensuremath{\gamma}$-ray cascade in $^{106}\mathrm{Pd}$. The observed magnetic fields have been corrected for the external applied field and the sample magnetization, and extrapolated to 0\ifmmode^\circ\else\textdegree\fi{} K. The average hyperfine fields ${H}_{\mathrm{hf}}$ at the Pd nuclei were found to be negative in the ferromagnetic alloys over the full concentration range, varying from (-194\ifmmode\pm\else\textpm\fi{}9) kG in Ni metal to (-41\ifmmode\pm\else\textpm\fi{}10) kG in an alloy of 90% Pd. Our estimates for the contribution to the hyperfine field of Pd arising from the local moment on the Pd atom are too small to account for the net measured fields. Thus, we ascribe the origin of the remaining large negative fields to interactions with neighboring atoms through the conduction electrons.