Effect of the J–J Interaction of Excited States of the Rare-Earth Ion Pr³⁺ on Magnetically Polarized Luminescence of Praseodymium-Yttrium Aluminum Garnet

The spectra of luminescence and magnetic circular polarization of luminescence of praseodymium–yttrium aluminum garnet Pr³⁺ : Y₃Al₅O₁₂ (PrYAG) are studied in the visible spectral region at temperature T = 300 K. An analysis of spectral dependences of magnetooptical and optical spectra makes it possible to identify optical 4 f–4 f-transitions between Stark sublevels of multiplets ³P₀, ³P₁, ³Н₅, and ³Н₆ in PrYAG. It was shown that an important role in the spectrum of the degree of magnetic circular polarization of luminescence of this paramagnetic garnet is played by the effect of quantum-mechanical J–J mixing of states of Stark singlets ³Н₅ and ³Н₆ of non-Kramer rare-earth ion Pr³⁺ in the "green" luminescence band related to forbidden 4 f → 4 f transition ³P₀ → ³Н₅ in the visible spectral region. To interpret the spectra of magnetic circular polarization of luminescence, the energy of experimentally determined Stark sublevels of multiplets under study, their irreducible representations and wave functions determined by numerical simulation of the energy spectrum of the rare-earth ion Pr³⁺ in the garnet structure are used.