Observation of a fully localized 3d9configuration for nickel ions in alkali metals

Abstract

The local susceptibilities and the 3d spin dynamics of isolated nickel ions in various alkali-element hosts have been measured, utilizing the perturbed γ-ray distribution method after recoil implantation. In the heavy alkali-metal hosts, Cs, Rb, and K, the local susceptibilities of the isolated Ni ions irrespectively show the temperature behavior of a fully localized spin-orbit-coupled 3${\mathrm{d}}^9$ configuration. Clear host dependence of the magnetic behavior is seen in the spin-fluctuation rates which increase with decreasing host volume. In Na, the magnetic behavior drastically deviates from that of the purely ionic configuration, and Ni ions in Li as well as in Ca and Ba hosts are nonmagnetic.