The electron paramagnetic resonance spectrum of trigonal Fe3+ centers was investigated and parameters of the spin Hamiltonian obtained for nominally pure congruent LiTaO3 crystals annealed at about 1500K under Li2O vapour pressure corresponding to the pressure over the stoichiometric lithium tantalate. The possibility of calculating the zero-field splitting of the ground state of the impurity ion on the basis of the superposition model was considered.

Fine Structure of the Electron Paramagnetic Resonance Spectrum of Fe3+ Centres in LiTaO3. V.A.Vazhenin, V.B.Guseva, M.Y.Artyomov, R.K.Route, M.M.Fejer, R.L.Byer: Journal of Physics - Condensed Matter, 2003, 15[2], 275-80