Crystal Growth,Properties And XRD Rietveld Structural Refinement Of Molybdate Crystal Doped With Yb³⁺ And Tm³⁺

As characteristics of nano-materials in Photoelectric, Magnetic and Thermal hold a bright prospect have aroused wide attention. The synthesis of molybdate with various morphologies provide main scientific basis for surface engineering of nano-particles. In addition, Tetra-molybdate with highly disordered structure and the birefringence tunable output characteristic in microchip ultrafast laser output realization possesses potential advantages and become research hotspot. In this paper, the growth, spectral properties and crystalline space structure of molybdate crystal doped with Yb³⁺ and Tm³⁺ are investigated. The main research achievements are concluded as follows:1. The Gd₂（MoO₄）₃ nanocrystals doped with Yb³⁺ and Tm³⁺ were synthesized via hydrothermal method and Yb³⁺:BaGd₂（MoO₄）₄ [x(Yb³⁺)=0.01, 0.05, 0.10] single crystals were grown by Czochralski method.2. The structure and cell constants of nanocrystals were determined by Powder X-ray diffraction analysis. The results indicated that Yb³⁺,Tm³⁺:Gd₂（MoO₄）₃ nanocrystals were synthesized with three structure. The crystal structures, lattice constants and cell volumes of Yb³⁺,Tm³⁺:Gd₂（MoO₄）₃ was refined by the Rietveld method, Good agreement between the experimental and calculated profile was reached. The bond distance and angel were calculated and space structure of crystal was obtained. The samples were characterized by scanning electron microscope, high resolution transmission electron microscopy（HRTEM）, absorption spectroscopy and fluorescence spectroscopy. The results show that the central wavelength of the strongest emission peak is 1800 nm. There is a positive correlation between intensity and doping concentration of Yb³⁺. The Raman spectra showed that strongest Raman peak of Gd₂（MoO₄）₃ nanocrystal was observed at 866.5 cm-1.3. The structure and cell constants of single crystals were determined by Powder X-ray diffraction analysis. The results indicated that Yb³⁺:BaGd₂（MoO₄）₄ single crystal belongs to monoclinic（C2/c）, The crystal structures, lattice constants and cell volumes of Yb³⁺:BaGd₂（MoO₄）₄ was refined by the Rietveld method, Good agreement between the experimental and calculated profile was reached. The bond distance and angel were calculated and space structure of crystal was obtained. The crystals were characterized by absorption spectroscopy and fluorescence spectroscopy, the stimulated emission cross-section and absorption cross-sections were calculated. The results indicated that the crystal possesses greater spectral characteristics. Raman spectra showed BaGd₂（MoO₄）₄ single crystal can become potential Raman lasers materials The Raman spectra showed that strongest Raman peak of BaGd₂（MoO₄）₄ single crystal was observed at 858.0 cm-1.