Temperature-dependent study of3smultiplet splitting in ferromagnetic Ni

Abstract

A high-resolution x-ray photoelectron spectroscopy (HRXPS) study of the Ni $3s$ core level is presented. Ni $3s$ HRXPS spectra were compared at $T=298\mathrm{K}$ ${(T=0.47T}_{c})$ and 863 K ${(T=1.37T}_{c}).$ No significant variation with temperature is observed. These HRXPS results, combined with prior spin-resolved x-ray photoelectron spectroscopy studies of Ni core levels, indicate the persistence of atomic magnetism in the paramagnetic phase of Ni on the length scale of \ensuremath{\sim}0.75 \AA{}. The data suggest that temperature-induced changes in the Ni $3d$ spin polarization occur at the periphery of the metallic atom, i.e., outside a radius of 0.75 \AA{}, leaving the spin density within 0.75 \AA{} unaffected.