Growth and characterization of Ca3NbGa3Si2O14 crystal fibers for high-temperature applications

Ca₃NbGa₃Si₂O₁₄ crystal fibers along <;110> direction were grown by micro-pulling-down method with two different rates. The as-grown crystals were high transparent and had no crack. Due to the shape of die and crystal habit, the shape of as-grown crystals grown at 3 mm/h were approximately circular while they were approximately rectangular when grown at 1.2 mm/h. The center area of as-grown wafers perpendicular to the growth direction was free of second phase and low-angle boundaries. The second phase of Ca-Nb-O system was discovered in the peripheral area and was detected to have Ca₂Nb₂O₇ and CaNb₂O₆ phase and other phases. The as-grown crystals were also investigated to have great optical quality, high electric resistivity and high piezoelectric constant d_n. The research was benefit to the development of shaped-controlled crystals applied to high-temperature sensors.