Studies of the EPR parameters and the local tetragonal distortion of v 4+-doped SrTiO3 crystal

Abstract

The EPR parameters (g factors g∥, g⊥ and hyperfine structure constants A∥, A⊥_) of V 4+ ion in the tetragonal phase of SrTiO3 crystal were studied by high-order perturbation formulas based on a two-spin-orbit-parameter model, where the contributions from the spin-orbit-coupling-parameter of central 3dn ion and that of ligands are considered. It is found that the oxygen octahedron surrounding the impurity ion V4+ changes from elongation along the tetragonal axis in the pure crystal to compression and the magnitude of tetragonal distortion of oxygen octahedron (characterized by |ΔR| = |R∥ -R⊥|) in V4+ center is much greater than the corresponding value in the pure crystal. The cause related to the strong Jahn-Teller effect is discussed. © 2005 Verlag der Zeitschrift für Naturforschung, Tübingen.