Mössbauer study of the hyperfine interaction ofAu197in gadolinium

The combined magnetic dipole and electric quadrupole interaction of ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ in Gd has been investigated by means of the Mössbauer effect. The system was prepared by alloying Gd with 0.5 at.% of ${}_{}{}^{197}{}_{}{}^{}\mathrm{Pt}$ which decays to ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$. At 4 K a magnetic hyperfine field of $\left|H_{\mathrm{hf}}\right(Gd\mathrm{Au}\left)\right|=809\mathrm{}\pm 8$ kG, and an electric field gradient of $V_{\mathrm{zz}}\left(Gd\mathrm{Au}\right)=+(14.4\mathrm{}\pm 0.7)\times {10}^{17}$ ${\mathrm{V}/\mathrm{c}\mathrm{m}}^2$ was observed. The value of the magnetic field is consistent with the assumption that the field is mainly due to conduction-electron polarization. The electric field gradient has the same sign as the ionic lattice gradient but it is one order of magnitude larger.