The features of Pr3+ rare-earth ion magneto-optics in the disordered crystalline surroundings

Abstract

The photoluminescence excitation (PLE) and photoluinescence spectra of the La3Ga5SiO14:Pr3+ single crystal were measured in the spectral ranges of 225–300 and 478–510 nm, respectively, by the VUV spectroscopy at T = 80 K. The absorption band frequency with prima facie form of the wide structureless band and associated with allowed 4f2(3H4) → 4f(1)5d transition in Pr3+ ions was determined on the basis of the spectral studies of the PLE of the La3Ga5SiO14:Pr3+ crystal. Moreover, the disorder in the crystal surroundings of the rare-earth Pr3+ ion in these compounds leads both to the broadening of the observed 3H4 → 3P0,1,2 absorption lines and their strong mutual overlapping in the wavelength range of 400–500 nm. Therefore, the detailed consideration of the crystalline surroundings disorder influence on the RE ions magnetooptics makes it possible to carry out a simplified theoretical consideration of the Pr3+ ion magnetooptical activity (MOA) features in the trigonal Ca-gallogermanate Сa3Ga2Ge4O14:Pr3+ and langasite La3Ga5SiO14:Pr3+ crystals. A spectral dependence of the magnetic circular dichroism (MCD) in the Ca3Ga2Ge4O14:Pr3+ was measured at the temperatures 90 and 300 K in the region of 400–500 nm. From the results of the magnetooptical experiment the ratio of the Judd parameters of the intensity for the transitions Ω6:Ω4 was found. In addition, the experimental determination and theoretical estimation of MOA factor C/D for MCD bands at the 450 and 475 nm were carried out.