Systematics in the Knight shift of rare-earth monopnictides

Abstract

The Knight shifts at nonmagnetic sites in the rare-earth group-$\mathrm{V}A$ intermetallic compounds have been analyzed systematically in terms of two major contributions: (i) A largely temperature- dependent part, ${K}_{f}$ due to localized $4f$ electrons and (ii) a temperature-independent part, ${K}_{0}$ due to $s$-like electrons. It is shown that while ${K}_{0}$ is relatively constant with changing rare-earth constituent of the compound, it depends sensitively on the atomic number, $A$, of the group-$\mathrm{V}A$ element. In all the compounds studied, ${K}_{0}$ of a nonmagnetic ion varies approximately as ${A}^{\frac{5}{4}}$. This power law is shown to be largely due to the orthogonalization of the conduction electrons to the occupied core orbitals of the nonmagnetic ion. The available data on Knight shifts in transition and actinide-metal compounds fail to exhibit similar systematics.