The calculation of zero-field splitting parameters for Fe3+ ions doped in rutile TiO2 crystal by superposition model analysis

Abstract

Study of Mn2+/Fe3+:TiO2 (anatase) is extended to Fe3+:TiO2 (rutile). Fe3+ environment is investigated using superposition model (SPM). The zero-field splitting (ZFS) parameters are calculated for Fe3+ ions at the substitutional sites and interstitial positions in rutile TiO2. Orthorhombic (D2h) symmetry aspects bearing on EMR data interpretation are elucidated. Inconsistencies concerning site symmetry are clarified. Three approaches are considered with adjustable model parameters yielding best agreement between the SPM-calculated and EMR-measured ZFS parameters. The predicted lattice distortions involve simultaneous variation of the ligand distances and bond angles and compare favorably with those for Rh4+/Ir4+:TiO2 (rutile). The SPM analysis indicates that satisfactory agreement between the theoretical and experimental ZFS parameters is achievable.