EPR and spin-lattice relaxation of the Jahn-Teller system:Cu2+in Zn(BrO3)2·6H2O

The symmetrical EPR lines for the strain-stabilized doublet of ${\mathrm{Cu}}^{2+}$ in Zn${\left(\mathrm{B}\mathrm{r}{\mathrm{O}}_3\right)}_2$·6${\mathrm{H}}_2$O and the temperature dependence of the corresponding spin-lattice relaxation rate gives a tetragonal strain parameter $F$ equal to 2 ${\mathrm{cm}}^{-1\mathrm{}}$ and a tunneling splitting $3\Gamma$ less than 0.2 ${\mathrm{cm}}^{-1\mathrm{}}$. The nonexponential spin-lattice relaxation recovery for ${\mathrm{Cu}}^{2+}$ in lanthanum magnesium double nitrate is discussed.