Spin-Hamiltonian parameters and local rotational order parameters for Gd3+ ion in the tetragonal phase of SrTiO3 crystal

Using a diagonalization method, the spin-Hamiltonian parameters (g factors g(parallel to), g(perpendicular to) and zero-field splittings b(2)(0), b(4)(0), b(2)(4), b(6)(0), b(6)(4)) for Gd3+ ion at the 12-fold coordinated Sr2+ site in the tetragonal phase of SrTiO3 at T approximate to 4.2 and 77 K are calculated in a unified way. The calculated results are in reasonable agreement with the experimental values. The local rotational order parameters phi(1) of Gd3+ center at the two temperatures are also obtained from the calculations. It is found that the local rotational order parameters phi(1) of Gd3+ impurity center at both temperatures are different from the corresponding parameters phi(h) in the host SrTiO3 crystal and the changes of spin-Hamiltonian parameters with temperature are caused by the change of local rotational order parameter phi(1) with temperature. The results are discussed. (C) 2011 Elsevier B.V. All rights reserved.