The calculation of zero-field splitting parameters for Fe 3+ ions doped in rutile TiO 2 crystal by superposition model analysis

Abstract

Study of Mn 2+/Fe 3+:TiO <inf>2</inf> (anatase) is extended to Fe 3+:TiO <inf>2</inf> (rutile). Fe 3+ environment is investigated using superposition model (SPM). The zero-field splitting (ZFS) parameters are calculated for Fe 3+ ions at the substitutional sites and interstitial positions in rutile TiO <inf>2</inf>. Orthorhombic (D <inf>2h</inf>) 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 Rh 4+/Ir 4+:TiO <inf>2</inf> (rutile). The SPM analysis indicates that satisfactory agreement between the theoretical and experimental ZFS parameters is achievable. © 2012 Elsevier B.V. All rights reserved. © 2012 Elsevier B.V., All rights reserved.