Spin Hamiltonian parameters and structural disorder analysis for Cr ion in YGG crystals

A new crystalline lattice distortion model has been proposed, on the basis of it, the relations between spin Hamiltonian parameters and crystal micro structure have been established. By taking into account slight magnetic interactions, including spin-spin (SS), spin-other-orbit (SOO), and orbit-orbit (OO) interactions, the local structure of Cr³⁺ ion in YGG crystal has been studied using complete diagonalization method (CDM). The studies show that the local structure in the YGG:Cr³⁺ crystal is of the compressed trigonal distortion. The ligand oxygen plane moved 0.0138 nm toward Cr³⁺ ion along C₃-axis. Accordingly, the SH parameters in YGG:Cr³⁺ crystal are explained successfully.