Some Interesting Features of the Tb3+ Magneooptics in teh Paramagnetic Garnets

Authors

Gary W. Burdick, Andrews UniversityFollow
Uygun V. Valiev, National University of UzbekistanFollow
John B. Gruber, University of Texas at San AntonioFollow
Anvar K. Mukhammadiev, National University of Uzbekistan
Dejun Fu, Wuhan University
Vasiliy O. Pelenovich, Wuhan UniversityFollow

Document Type

Article

Publication Date

5-2014

Abstract

The spectra of the absorption, luminescence, magnetic circular dichroism (MCD) and magnetic circular polarization of luminescence (MCPL) in the terbium–yttrium gallium garnet Tb³⁺:Y₃Ga₅O₁₂ (Tb:YGG) have been studied within the visible and near ultraviolet (UV) spectral range for temperatures T = 85 and 300 K. The MCD spectrum observed within the UV absorption band for Tb:YGG is associated with spin- and parity-allowed electric-dipole 4f → 5d transitions occurring between levels of the ground ⁷F₆ multiplet and the ⁷D state of the excited 4f⁽⁷⁾5d configuration of the Tb³⁺ ion. Analysis of the spectral and the temperature dependences of the magnetooptical and optical spectra has made it possible to identify magneto-optically-active 4f → 4f transitions occurring between Stark sublevels of the ⁵D₄ and ⁷F₅ multiplets in Tb³⁺:YGG. Quantum mechanical “mixing” of the three lowest energy Stark singlets in the excited ⁵D₄ multiplet by an external magnetic field H leads to the change of the circularly polarized luminescence line intensities. The Zeeman effect in the UV absorption band ⁷F₆ → ⁵L₁₀ of Tb³⁺:YGG at T = 85 K was also studied. The magnetic field dependence of the Zeeman splitting of some absorption lines is found to exhibit unusual behavior: as the magnetic field increases, the band splitting decreases rather than increases. A parameterized Hamiltonian defined to operate within the entire 4f⁽⁸⁾ ground electronic configuration of Tb³⁺ was used to model the experimental Stark levels, their irreducible representations (irreps.) and wave functions. The crystal-field parameters were determined using a Monte-Carlo method in which nine independent crystal-field parameters, were given random initial values and optimized using standard least-squares fitting between calculated and experimental levels. The final fitting standard deviation between 101 calculated and experimental Stark levels is 16.7 cm⁻¹.

Journal Title

Optical Materials

Volume

36

Issue

7

First Page

1101

Last Page

1111

Recommended Citation

Burdick, Gary W.; Valiev, Uygun V.; Gruber, John B.; Mukhammadiev, Anvar K.; Fu, Dejun; and Pelenovich, Vasiliy O., "Some Interesting Features of the Tb3+ Magneooptics in teh Paramagnetic Garnets" (2014). Faculty Publications. 10.
https://digitalcommons.andrews.edu/physics-pubs/10