Theoretical studies of the spin-Hamiltonian parameters and their stress dependences for Ru 3+ and Ir 4+ ions in Y 3Ga 5O 12 crystals

Abstract

The spin-Hamiltonian parameters ( g factors g ||, g ⊥ and hyperfine structure constants A ||, A ⊥) and the stress dependence of g ⊥ for 4d 5 ion Ru 3+ and 5d 5 ion Ir 4+ in Y 3Ga 5O 12 (YGG) crystals are calculated from the perturbation formulas related to the low-spin 2T 2 term subjected to the trigonal symmetry crystal field. The calculated results are in reasonable agreement with the experimental values. Based on the calculations, the signs of hyperfine structure constants are suggested, and the local bonding angles β (between the metal–ligand bond and C 3 axis) and local angular compressibilities d β/d P (where P|| C 3 axis) are obtained for both systems. It is found that the local angle β and local angular compressibility d β/d P of impurity center are different not only from the corresponding values in the host crystal, but also from impurity to impurity. The results are discussed.