Anisotropic Hyperfine Interactions in Gadolinium Metal

Abstract

Mössbauer studies of the 86-keV transition of ${\mathrm{Gd}}^{155}$ in ${\mathrm{Gd}}_{1-x}{R}_x$ compounds yield the hyperfine interaction parameters as a function of lattice dimensions and the angle $\theta$ between the magnetization and the $c$ axis. The magnetic hyperfine field is anisotropic, $\frac{H_{\mathrm{eff}}(\theta =28\mathrm{}°)}{H_{\mathrm{eff}}(\theta =47\mathrm{}°)}=1.13\mathrm{}$. The ratios between the electric field gradients in various metallic crystals are in agreement with the point-charge model. The absolute values of the gradients are about twice the theoretical values.