Relationships between electron paramagnetic resonance parameters and the crystal structure of Fe3+:ZnO crystals were established. On this basis, the electron paramagnetic resonance parameters D, (a-F) and the zero-field splitting δ1, δ2 of the ground state for Fe3+ in Fe3+:ZnO crystals were theoretically investigated by using the complete diagonalization method. The theoretical second-order electron paramagnetic resonance parameter, D, the fourth-order electron paramagnetic resonance parameter, (a-F), and the zero-field splitting of the ground state: δ1, δ2 for Fe3+ in Fe3+:ZnO yielded good agreement with experiment when the three O2- ions below the Fe3+ ion rotated by 0.475 to 0.562°, away from the [111] axis. Thus, the local structural distortion effect played an important role in explaining the spectroscopic properties of Fe3+ ions in Fe3+:ZnO crystals. The present approach took account of spin-orbit interaction as well as of spin-spin, spin-other-orbit and orbit-orbit interactions omitted from previous studies. This showed that, although the spin-orbit interaction was the most important one, the contributions due to the electron paramagnetic resonance parameters from the other three interactions were appreciable and should not be omitted, especially for the electron paramagnetic resonance parameter, D.

Studies of the EPR Parameters and Defect Structure for Tetrahedral Fe3+ Centers in Zinc Oxide. Yang, Z.Y.: Physica Status Solidi B, 2009, 246[8], 1919-24