Theoretical Studies of the EPR Parameters of Nd³⁺ in LiYF₄

Abstract

The perturbation formulas of the electron paramagnetic resonance (EPR) parameters g , g ⊥ , A and A ⊥ for a 4f 3 (Nd 3+ ) ion in tetragonal symmetry are established in this work. In these formulas, the contributions to the EPR parameters arising from the second-order perturbation terms and the admixtures of different states are included. Then the above formulas are applied to a tetragonal Nd 3+ center in LiYF 4 , where the related crystal-field parameters are calculated from the superposition model and the local structural parameters of the Y 3+ site occupied by the impurity Nd 3+ . The EPR parameters and the optical spectra within the 4 I 9/2 and 4 I 11/2 states obtained in this work agree reasonably with the observed values.

Modulation of thermometric performance of single-band-ratiometric luminescent thermometers based on luminescence of Nd3+ activated tetrafluorides by size modification

“…S2 ). This is due to the lower local symmetry around the Nd 3+ ions in the tetragonal LiGdF 4 crystal 79 (eight-fold coordinated Gd 3+ sites in the form of a square anti-prism with local S 4 symmetry) than in the hexagonal counterpart 80 (both RE 3+ sites are nine-fold coordinated tri-capped trigonal prisms with local C 3h symmetry), so that the crystal field results in a more pronounced splitting of the Nd 3+ ion multiplets into Stark levels 81 . Moreover, changing the local symmetry of the ion can also modify the luminescence decay times 82 – 84 (Fig.…”