Studies of the spin Hamiltonian parameters and the local structure of tetragonal Zr3+ Centers in orthophosphate MPO4 (M = Sc, Lu, Y) crystals

The spin Hamiltonian parameters (g factors g(parallel to), g(perpendicular to) and hyperfine structure constants A(parallel to), A(perpendicular to)) of Zr3+ on the tetragonal M3+ (M = Sc, Lu, Y) sites of zircon-type orthophosphate MPO4 crystals are calculated by high-order perturbation formulas of d(1) ions in tetragonal symmetry. The crystal-field parameters are estimated by the superposition model and reasonable local structural data of impurity centers. The results show good agreement with the experimental values. It appears that in the case of size mismatch, the explanation of the spin Hamiltonian parameters of a paramagnetic impurity in crystals should take the impurity-induced local lattice relaxation into account.