Mössbauer Effect ofFe57in CubicCd0.98Fe0.02Cr2S4

Mössbauer spectra of ${\mathrm{Cd}}_{0.98}$ ${\mathrm{Fe}}_{0.02}$ ${\mathrm{Cr}}_2$ ${\mathrm{S}}_4$, taken between 5 and 300 K, reveal that there is a magnetically induced, temperature-dependent quadrupole interaction below the Curie temperature (96 K). The observed temperature dependence of $\mathrm{eQ}{V}_{\mathrm{zz}}$ and $H_{\mathrm{hf}}$ can be understood in terms of the combined action of a crystal field, an exchange field, and a spin-orbit interaction. The following constants are derived: $\delta =6(\frac{{\lambda }^2}{{\Delta }_c}+\rho )=12\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, $\mathrm{eQ}{V}_{\mathrm{zz}}\mathrm{}\left(0\right)=5.75\mathrm{}$ mm/sec, $E_{\mathrm{ex}}\mathrm{}\left(0\right)=90\mathrm{}$ K, $\lambda =62\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, $Q=0.24\mathrm{}\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^2$, and $2\kappa =0.83\mathrm{}$. Within experimental error the principal axis of the electric field gradient is parallel to the hyperfine field.