Evidence for Strong Localization of5fElectrons in Neptunium Intermetallics

Abstract

The correlation between the magnetic hyperfine field $H_{\mathrm{hf}}$ and the electronic moment $\mu$ at the neptunium site in a number of neptunium conducting compounds is presented. A simple linear relation $H_{\mathrm{hf}}=\left[\frac{\left(1915\mathrm{} \mathrm{kOe}\right)}{{\mu }_{\mathrm{B}}}\right]\mu$ is found. This behavior is similar to that observed in lanthanide systems and suggests a strong localization of the $5f$ electrons in these materials. The implications of this result for our understanding of magnetism in the actinides are considered.