Effects of annealing on the structures and properties of Er,Yb:LuGdVO4 crystal

The Er,Yb:LuGdVO4 crystal was grown by the Czochralski method under the oxygen-deficient atmosphere, and cut into slices, which were annealed in different conditions. The crystalline quality of the as-grown crystal was characterized by high resolution X-ray diffraction (HRXRD). The effects of different annealing conditions on the structures, chemical states and local symmetry of Er,Yb:LuGdVO4 were studied by X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) in detail. The content of V4+ in the crystal obviously decreased after annealing. The distribution of elements in the sample was analyzed by the SR-based X-ray fluorescence (XRF). The specific heat and thermal diffusion of Er,Yb:LuGdVO4 crystal were measured, and absorption spectra of the samples annealed in different conditions were recorded at room temperature. The results show that the annealing process has few influences on the thermal properties and remarkable influences on the optical properties.