Transferred hyperfine interaction and spin-lattice relaxation time for133Csin aCs2

We investigated the transferred hyperfine interaction due to transfer of the spin density from the ${\mathrm{Co}}^{2+}$ ion to the ${\mathrm{Cs}}^{+}$ ion in a ${\mathrm{Cs}}_{2}{\mathrm{CoCl}}_{4}$ single crystal. The transferred hyperfine interaction ${(H}_{\mathrm{hf}})$ could be expressed by the linear equation ${H}_{\mathrm{hf}}=[0.63T+29.05](\mathrm{Oe});$ thus, ${H}_{\mathrm{hf}}$ increased with increasing temperature. Also, the ${}^{133}\mathrm{Cs}$ spin-lattice relaxation time in this single crystal was measured in the temperature range of 4.2--300 K. The temperature dependence of ${1/T}_{1}$ could be described by the approximation ${1/T}_{1}=[\ensuremath{-}9.55T+(3.22\ifmmode\times\else\texttimes\fi{}{10}^{3})]{(s}^{\ensuremath{-}1}).$ The relaxation behavior of ${}^{133}\mathrm{Cs}$ in a ${\mathrm{Cs}}_{2}{\mathrm{CoCl}}_{4}$ single crystal could be explained by the direct process of scattering from a single phonon. From these results, we know that the relaxation rate is proportional to the square of the transferred hyperfine field.