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

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 4f(2)(H-3(4)) -> 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 H-3(4 )-> P-3(0,1,2) 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 Cagallogermanate Ca3Ga2Ge4O14:Pr3+ and langasite La3Ga5SiO14:Pr-3(+) crystals. A spectral dependence of the magnetic circular dichroism (MCD) in the Ca3Ga2GeO14: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 Omega(6):Omega(4) 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.