Electron-Spin Resonance Studies of Crystal Field Parameters in Mn2+: LiNbO3

ESR studies were performed on a single crystal of ferroelectric LiNbO₃ doped with manganese. Mn²⁺ in an axially symmetric site is described by the spin Hamiltonian $\mathrm{[H=g\beta }\mathrm{H}·\mathrm{S}{\mathrm{+B}}_2^0{D}_2^0{\mathrm{+B}}_4^0{0}_4^0{\mathrm{+B}}_4^3{0}_4^3{\mathrm{+(B}}_4^3{0}_4^3\mathrm{)*+A}\mathrm{S}·\mathrm{I}]$ . Values for $B_4^3{\mathrm{(B}}_4^3{\text{=0,\hspace{0.17em}B}}_4^3\text{I=17\hspace{0.17em}}\mathrm{G})$ reported here, have not been reported previously. By examining the temperature dependence of $B_4^3$ and $B_4^0$ a value for the fractional change in the optical parameter ${\text{Dq[(1/Dq)(∂Dq/∂T)=−3.5 × 10}}^{\text{−3}}\mathrm{\hspace{0.17em}°}{\mathrm{C}}^{\text{−1}}]$ has been calculated. A discussion of the temperature dependence of $B_2^0$ is also given.