Growth of Langasite by the Bridgman Technique

Two-inch LGS single crystals were grown via the vertical Bridgman method assisted by the accelerated crucible rotation technique (ACRT) along [0001] (Z-axis), [211 0] (X-axis) and [0111] (54°-rotated Y-axis) for piezoelectric applications. 

The origin corresponds to the seeding point. T1 and T2 denote the temperature at the crucible bottom and crucible wall, respectively. (Reproduced by the permission of Elsevier Ltd.) 

A two-inch-diameter cyhndrical seed crystal with a 15-20 mm height was placed at the bottom of a cyhndrical platinum tube having a thickness of 0.1 to 0.2 mm, and several source tablets (total weight 600-700 g) were put on the seed. The top end of the platinum tube was sealed. The furnace was heated in air up to about 1500 °C at the seeding position so that all the tablets melted entirely, while only the upper portion of the seed crystal was fused. The furnace was kept under this temperature condition for 10 h to obtain a homogeneous melt with stable physical properties. 

Growth Along [0001] The temperature gradient at the solid/liquid interface was set to lO C/cm. The shape of the interface was concave toward the melt. The 

Note that the seed crystal occupied the bottom 20-mm long section. White materials deposited on the langasite surface 

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