Characterization of LiNbO₃ micro single crystals grown by the micro-pulling-down method

Crack-free homogeneous LiNbO₃ micro single crystals were grown by the micro-pulling-down (μ-PD) method from the melt of compositions with 48.6, 50 and 58 mol% Li₂O contents. Very thin rod-like crystals (300-800 μ m in diameter), oriented along the x-, y- and z-axes, were obtained at pulling rates in the range between 30 and 120 mm/h. As in the case of Czochralski crystals, facets formed at the surface of μ-PD crystals but with a larger size ratio (ridge width to crystal diameter) when the temperature gradient was too small. They reduced markedly with increasing temperature gradient. The y-oriented crystals, grown from the melt with 48.6 mol% Li₂O, show single domain structure with diameters up to 300 μ m. Crystals with the same orientation, grown from the melt with 58 mol% Li₂O, having a homogeneous axial lattice constant distribution, also show a single domain structure, even up to a diameter of 800 μ m.