Electron paramagnetic resonance parameters and local structure for Gd3+ in KY3F10

The electron paramagnetic resonance parameters, zero-field splittings (ZFSs) b 2 0 , b 4 0 , b 4 4 , b 6 0 , b 6 4 and the g factors for Gd3+ on the tetragonal Y3+ site in KY3F10 are theoretically studied from the superposition model for the ZFSs and the approximation formula for the g factor containing the admixture of the ground 8S7/2 and the excited 6L7/2 (L=P, D, F, G) states via the spin-orbit coupling interactions, respectively. By analysing the above ZFSs, the local structure information for the impurity Gd3+ is obtained, i.e., the impurity-ligand bonding angles related to the four-fold (C4) axis for the impurity Gd3+ center are found to be about 0.6° larger than those for the host Y3+ site in KY3F10. The calculated ZFSs based on the above angular distortion as well as the g factors are in reasonable agreement with the observed values. The present studies on the ZFSs and the local structure would be helpful to understand the optical and magnetic properties of this material with Gd dopants.