材料期刊网

The spin Hamiltonian parameters and local structure for the tetragonal Rh(2+) center in rhombohedral BaTiO(3) are theoretically studied from the perturbation formulas of these parameters for a 4d(7) ion with low spin (S = 1/2) in tetragonally elongated octahedra. This center is ascribed to substitutional Rh(2+) at the Ti(4+) site in BaTiO(3). The [RhO(6)](10-) cluster suffers relative elongation (characterized by the elongation parameter rho approximate to 0.9%) along the [100] axis due to the Jahn-Teller effect. The tetragonal elongation can entirely depress the slight trigonal distortion of the original Ti(4+) site in rhombohedral BaTiO(3). The calculated spin Hamiltonian parameters based on the above Jahn-Teller elongation show good agreement with the experimental results.