Growth and Thermal Properties of Mg-Doped Lithium Isotope Niobate (Mg:7LiNbO3) Crystal

An Mg-doped isotope lithium niobate (Mg:(LiNbO3)-Li-7) crystal was successfully grown from (LiOH)-Li-7, Nb2O5, and MgO using the Crozchralski method. The weight of the as-grown crystal with good quality was about 40 g. The crystal structure was determined as an R-3c space group using the X-ray powder diffraction (XRPD) method, and the crystal composition (Li%) determined using the Raman mode linewidth method was 49.29%. The average transmittance of the crystal in the range of 500-2500 nm was approximately 72%. Various thermal properties, including the specific heat (C-p), the thermal expansion coefficient (alpha), the thermal diffusion coefficient (lambda), and the thermal conductivity (kappa), were carefully determined and calculated, and the value divergences among Mg:(LiNbO3)-Li-7, the undoped isotope lithium niobate ((LiNbO3)-Li-7), and natural lithium niobate (LiNbO3) crystals were mainly related to the differences in microstructure caused by the crystal composition.