材料期刊网

By means of the formulae based on the first-order theory of resonance for a low-spin 2T2 term in trigonal symmetry, the spin-Hamiltonian parameters (g factors g//, g and hyperfine structure constants A//, A) for Rh4+(4d5) and Ir4+(5d5) ions in the low-temperature rhombohedral phase of BaTiO3 are calculated. The calculated results are in reasonable agreement with the experimental values. From the calculations, the off-center displacements of Rh4+ and Ir4+ in the oxygen octahedra of BaTiO3 crystal are acquired. These impurity displacements are much smaller than that of the replaced host ion Ti4+. This point is analogous to the displacements of 3dn impurities Fe3+ and Co2+ in rhombohedral BaTiO3 obtained by analyzing their spin-Hamiltonian parameters.