title: Investigations of the local structures and spin Hamiltonian parameters for the trigonal Rh4+ and Ir4+ centers in rhombohedral BaTiO3.
abstract: The local structures and spin Hamiltonian parameters (g factors and the hyperfine structure constants) of the Rh(4+)(4d(5)) and Ir(4+)(5d(5)) centers in rhombohedral BaTiO(3) are theoretically investigated from the formulas of these parameters for a nd(5) (n=4 and 5) ion with low spin (S=1/2) in a trigonally distorted octahedron. From the calculations, the impurity ions are found not to occupy exactly the host Ti(4+) site in BaTiO(3) but to suffer a slight inward shift ( approximately 0.13A) towards the center of the oxygen octahedron along the C(3) axis, yielding much smaller trigonal distortion as compared with that of the host Ti(4+) site. The theoretical spin Hamiltonian parameters based on the above impurity axial shifts are in good agreement with the observed values.
authors.affiliation: Department of Applied Physics, University of Electronic Science and Technology of China, Chengdu 610054, PR China. wushaoyi@netease.com
authors.forename: Shao-Yi
authors.initials: SY
authors.lastname: Wu
authors.forename: Hua-Ming
authors.initials: HM
authors.lastname: Zhang
authors.forename: Xue-Feng
authors.initials: XF
authors.lastname: Wang
authors.forename: Yue-Xia
authors.initials: YX
authors.lastname: Hu
mesh_terms: D001464:Barium / Q000737:chemistry*; D017609:Barium Compounds / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D007477:Ions / Q000737:chemistry; D008962:Models, Theoretical; D015394:Molecular Structure; D014025:Titanium / Q000737:chemistry*
chemical_list: D017609:Barium Compounds; D007477:Ions; C024547:barium titanate(IV); D001464:Barium; D014025:Titanium