Relation between thegShift and Hyperfine Field in Intermetallic Compounds

The appreciable variation of the gadolinium hyperfine fields from one compound to another in $\mathrm{Gd}{X}_2$ ($X=\mathrm{R}\mathrm{h},\mathrm{I}\mathrm{r},\mathrm{M}\mathrm{n},\mathrm{P}\mathrm{t},\mathrm{A}\mathrm{l}$) is explained by interaction of the nucleus with the conduction electrons. These electrons are polarized by their exchange interaction with the Gd ion. This interaction was investigated experimentally by measuring the Gd $g$ shift by means of electron spin resonance. The $g$ shift was found to vary in both magnitude and sign in these compounds. A relation between the Gd hyperfine field and the Gd $g$ shift is derived, enabling us to calculate the hyperfine field per spin for $6s$ electrons in Gd${\mathrm{Pt}}_2$ to be 2.8×${10}^6$G.