Spin Value and Moment Determination for the Localized Magnetic States of Very Dilute Fe Impurities in Pt and Pd

Abstract

The paramagnetic behavior of very dilute (57Fe. The magnetic behavior of the localized magnetic state is inferred from the measurement of the hyperfine field at the ⁵⁷Fe nucleus. The measurements have been carried out in applied magnetic fields up to 62 kOe and over the temperature range of 0.4° to 300°K. The data were computer‐fit to a Brillouin function to give values for H_sat, the saturation internal hyperfine field, μ, the magnitude of the moment associated with the localized state, and J, the effective‐spin value. The assumption of a localized magnetic state exhibiting free‐spin behavior appears to be valid for Fe in both hosts at 4°K and above. The least‐square parameters obtained for the moment localized on the Fe impurity are: for Pd, H_sat=300.8±1.0 kOe, J=3.76±0.4, μ=11.1±0.3 μ_B; and for Pt, H_sat=316.2±0.2 kOe, J=2.98±0.18, μ=6.46±0.13 μ_B. The value of J for Fe in Pd is significantly lower than that previously reported. Below 4°K both systems exhibit very definite departures from free‐spin behavior. The lowest temperature data have been analyzed with the addition of a parameter, which describes a random coupling between the localized moment and its host environment.