Estimation ofT1forCo2+ions from the temperature variation of the ESR linewidths forMn2+inCs2Co(SeO4)2⋅6H2O single crystals

The ESR of ${\mathrm{Mn}}^{2+}$ in ${\mathrm{Cs}}_2$Zn(${\mathrm{SeO}}_4$ ${)}_2$⋅${6\mathrm{H}}_2$O and ${\mathrm{Cs}}_2$Co(${\mathrm{SeO}}_4$ ${)}_2$⋅${6\mathrm{H}}_2$O single crystals has been observed from room temperature to 77 K at ∼9.45 GHz. The ${\mathrm{Mn}}^{2+}$ was found to substitute at divalent cation sites. The observation of resolved ${\mathrm{Mn}}^{2+}$ spectra in paramagnetic ${\mathrm{Cs}}_2$Co(${\mathrm{SeO}}_4$ ${)}_2$⋅6${\mathrm{H}}_2$O at room temperature is interpreted in terms of a random modulation of the interaction between the ${\mathrm{Mn}}^{2+}$ and the host ${\mathrm{Co}}^{2+}$ ions by the rapid spin-lattice relaxation of ${\mathrm{Co}}^{2+}$. $T_1$ for ${\mathrm{Co}}^{2+}$ is estimated in ${\mathrm{Cs}}_2$Co(${\mathrm{SeO}}_4$ ${)}_2$⋅6${\mathrm{H}}_2$O from the observed ESR linewidths of ${\mathrm{Mn}}^{2+}$ spectra at different temperatures.