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Experimental Definition of Zeeman Splitting of Excited States of Tb3+ Ion in Y3Al5O12

“…And as to the MCPL peak, which is related with the luminescence band À1 (%15875 cm À1 ), its amplitude increases with decreasing temperature. This indicates the temperature-dependent ªparamagneticº nature (MCPL C-term [6,7]) of the ªquasidoublet to singletº radiative transition between 5 D 4 and 7 F 3 multiplet states, related with the given magnetically polarized luminescence peak.…”

“…On the one hand, this is evidence of thermally occupied (by Boltzmann statistics) radiative Stark sublevels being responsible for the appearance of the fluorescence bands 1 to 4 which are mainly located in the lower part of the 5 D 4 excited multiplet, and what explains their insignificant band changes with decreasing temperature. On the other hand, the observed MCPL spectrum has ªdiamagneticº nature, as it is mainly formed from so-called MCPL A-terms [6,7] (ªdiamagneticº contribution) which are related with luminescence bands 2 to 4, and are not depending on temperature.…”

“…At the same time, the A-term (ªdiamagneticº contribution of MCPL) is conditioned by the occurrence of allowed (in electrodipole approximation) radiative optical transitions of ªsinglet to quasi-doubletº type [6,7].…”

“…There are some closely located Stark singlets, and the``mixingª of G 2 and G 4 singlet states by the magnetic field H in the 7 F 3 multiplet spectrum at energy % 4700 cm À1 leads to the appearance of a non-zero z-component of the g-factor. Calculations of g z (g z % 7) having been made with wave functions of Stark sublevels of the 7 F 3 multiplet (see Appendix A) have shown that it is not so weak and comparable with the components of the g-factor of quasi-doublets of the 7 F 6 ground multiplet of the Tb 3 ion in YAlG [4,6] by the order of magnitude. Experimental confirmation of the Zeeman splitting of quasi-doublet states (but not a simple shift of Stark singlets in H field) in the spectrum of RE ion excited multiplets in the crystal can be obtained in experiments on magnetic circular polarization of luminescence (MCPL) measurements.…”

“…In accordance with that, in the present paper we made a detailed research of the spectral and temperature dependence of MCPL and luminescence in the ªredº band region (radiative 5 D 4 3 7 F 3 4f±4f transition) of fluorescence paramagnetic YAlG garnets, activated by a small concentration of Tb 3 ions (% 5 wt%). The experimental device and principle of measurement of MCPL were earlier described in [6,9]. Errors in the determination of the value of MCPL degree, P I À I À aI À I À (where I AE are intensities of clockwise and counterclockwise circular polarized components of luminescence) in the central part of the luminescence band were % 2 to 37 and increased on the edge of the band to % 7 to 10%.…”