材料期刊网

The complete diagonalization (of energy matrix) method (CDM) and the perturbation theory method (PTM) are applied to calculate the spin-Hamiltonian (SH) parameters (electron paramagnetic resonance g factors g(//), g(perpendicular to) and zero-field splitting D) of the trigonal Mo3+ centers in Y3Al5O12 and Lu3Al5O12 crystals. Both methods are based on the cluster approach in which the covalence effect due to the admixture between the d orbitals of central d(n) ion and p orbitals of ligands is considered. The g factors calculated by both methods are close to each other and agree with the experimental values. However, the calculated zero-field splittings D from PTM for both crystals are about 84% those from CDM. The reasons that the CDM is preferable to the PTM in the calculations of SH parameters are discussed. The angular distortions of Mo3+ centers in both garnet crystals are predicted.