Theoretical studies of the local structures and the EPR parameters for Ru3+ in the garnets

Theoretical studies of the spin-Hamiltonian parameters and their stress dependences for Ru3+ and Ir4+ ions in Y3Ga5O12 crystals

“…For the studied YGG:Ru 3+ , if the model and parameters given in Ref. [14] are applied, one can find Dq ≈ 740 cm −1 . The small Dq will result in Dq/B < 2.8 and hence in the weak-field high-spin configuration for Ru 3+ in YGG.…”

“…Until now no satisfactory and reasonable investigations related to the local structures and the local properties (e.g., local angular compressibility) for the SH parameters and their stress dependences have been made for the Ru 3+ and Ir 4+ impurity centers in YGG. Only in last year, Wu et al [14] studied the SH parameters and defect structures for Ru 3+ in YGG (and also other garnets) from the perturbation formulas based on a two spinorbit (SO) parameter model (in which not only the contribution to SH parameters from the SO coupling parameter of central d n ion, but also that of the ligand ion are considered). However, there are several mistakes in their calculations.…”

“…[14], the reason of the application of the two-SOparameter model is due to the large SO parameter 0 p (≈ 603 cm −1 ) of ligand O 2− ion. The value of 0 p (O 2− ) is quoted from Ref.…”

“…(ii) The trigonal crystal-field parameter v in Ref. [14] is calculated from the point-charge model with the values r n of the free Ru 3+ ion. In fact, the above model and values cannot reproduce the experimental crystal-field parameters.…”

Theoretical investigations of spin‐Hamiltonian parameters for Ru3+ ions in rutile (TiO2) crystal

“…The values of P 0 are obtained from the formula P 0 = g s g N ββ N 〈r [24][25][26] is incorrect because the sign of nuclear magnetic moment μ is not considered and the nuclear spin I is 5/2 rather than 1. Thus, in the above formulas, the four parameters N 2 , Δ, δ and κ are unknown.…”