EPR STUDY OF THE 3 FE3+ CENTERS IN LINBO3

Paramagnetic Fe3+ centers in a LiNbO3 crystal doped with 0.08 wt% of iron, grown by the Czochralski method, have been studied by employing Q-and X-band EPR spectrometers. The experimental data suggest the presence of three Fe3+ centers, namely, a favored center (SO) and two other centers (S1 and S2). The spin Hamiltonian parameters of the S0 center determined by us indicate that this center has axial symmetry about the c-axis. This symmetry can be associated with one of three sites: Li+, Nb5+, or the structural vacancy. Most probably the S0 center is related to Fe3+ at the Li+ site, whereas the S1 and S2 centers can be related to Fe3+ at either the Nb5+ site or the structural vacancy. The spin Hamiltonian parameters of the S1 and S2 centers were also determined.