Mössbauer study of iron-doped lithium niobate

From Mössbauer spectra of LiNbO₃:⁵⁷Fe(III) single crystals under external fields of 4.92 and 6.2 T, the crystal field and hyperfine parameters are determined. Transmission integral fits indicate a Boltzmann population of the Fe(III) electronic levels with a spin temperature equal to the sample temperature. Spectra at external fields of 0 T and 19 mT can be satisfactorily simulated using an effective spin 1/2, g-factors calculated from spin-expectation values and an internal averaged dipole field of 5.5 mT inclined 20‡ to the c-axis. The simulations indicate cross-relaxation between Nb and Li nuclear spins and the Fe(III) electronic spin.