Spin-Hamiltonian parameters and local structures for Co4+ and Ir4+ impurity centers in the tetragonal phase of SrTiO3

The calculated results in the recent paper about the spin-Hamiltonian (SH) parameters (g factors g//, g⊥ and hyperfine structure constants A//, A⊥) and the local structures of Co4+ and Ir4+ impurity centers in the tetragonal phase of SrTiO3 are doubtful because there are several mistakes in the calculations. So, we restudy the SH parameters and local structures by using the correct methods and parameters. From the studies, for Co4+ and Ir4+ in SrTiO3, the SH parameters are explained rationally, the signs of hyperfine structure constants A//, A⊥ are obtained and the suitable and more detailed local structures are given. The results are discussed.