title: Defect model and EPR parameters for the tetragonal Yb3+ center in KTaO3 crystal.
abstract: The defect model of the tetragonal Yb3+ (at K+ site) center in KTaO3 crystal is suggested, i.e., Yb3+ ion does not occupy the ideal K+ site, but is displaced by an amount DeltaZ along one of 100 axes because of the much smaller ionic radius of Yb3+ compared with that of the replaced K+. Based on the defect model, the EPR parameters (g factors g(parallel), g(perpendicular) and hyperfine structure constants 171A parallel, 171A perpendicular, 173A parallel, 173A perpendicular) are calculated by diagonalizing the 14 x 14 complete energy matrix. The calculated values are in agreement with the observed values and the off-center displacement DeltaZ (approximately 0.2 angstroms) is estimated from the calculations. These results are discussed.
authors.affiliation: Department of Material Science, Sichuan University, Chengdu 610064, PR China.
authors.forename: Wen-Lin
authors.initials: WL
authors.lastname: Feng
authors.forename: Hong-Gang
authors.initials: HG
authors.lastname: Liu
authors.forename: Wen-Chen
authors.initials: WC
authors.lastname: Zheng
mesh_terms: D002412:Cations / Q000737:chemistry; D003460:Crystallization; D004578:Electron Spin Resonance Spectroscopy; D008956:Models, Chemical; D010087:Oxides / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D013635:Tantalum / Q000737:chemistry*; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D002412:Cations; D010087:Oxides; C516825:potassium tantalate oxide; D013635:Tantalum; D015018:Ytterbium; D011188:Potassium