Calculations of spin Hamiltonian parameters and analysis of trigonal distortions in LiSr(Al,Ga)F6:Cr3+ crystals

The effective spin-Hamiltonian (SH) parameters (zero-field splitting D and g factors g(parallel to) and g(perpendicular to)) for Cr3+ ions in LiSr(Al,Ga)F-6 crystals are calculated from the complete high-order perturbation formulae for a d(3) ion. Parameters of trigonal crystal field acting on the Cr3+ ion are calculated. The magnitude of trigonal distortion of the [CrF6](3-) clusters is related to the experimental measurements of the spin-Hamiltonian parameters in the considered systems. Since in both crystals g(parallel to) < g(perpendicular to), [CrF6](3-) clusters undergo an axial compression along the C-3 axis. Experimental values of the hyperfine structure constants A(parallel to) and A(perpendicular to) are used to evaluate the core polarization constant kappa for Cr3+ ion in both crystals. (c) 2006 Elsevier B.V. All rights reserved.