Electron paramagnetic resonance and photoluminescence of NaBi[.sub.2] crystals doped with gadolinium ions

The results of electron paramagnetic resonance (EPR) and photoluminescence studies of large NaBi[(Mo[O.sub.4]).sub.2] crystals grown by the low-gradient Czochralski method and doped with gadolinium ions (0.1 wt %) have been presented. It has been found from the analysis of the angular dependence of EPR spectra that the gadolinium ions enter into the crystal structure in the state [Gd.sup.3+] and occupy the bismuth position. The parameters of the EPR spectra of the gadolinium ions have been calculated and the analogy has been drawn based on these data between the specific features of the incorporation of gadolinium ions into the structures of double tungstates and molybdates. The observed shift of the maximum of the photoluminescence band of the NaBi[(Mo[O.sub.4]).sub.2] crystals doped with [Gd.sup.3+] ions with respect to the spectrum of the undoped crystal suggests the influence of gadolinium ions on the formation of the bottom of the conduction band caused by the states of the [(Mo[O.sub.4]).sup.2-].