| 摘要 |
PURPOSE:To grow lithium tantalate single crystal free from a crack and little in composition fluctuation resulting from places by regulating Li/Ta molar ratio of single crystal to specified value in the case of growing lithium tantalate single crystal from the melt of lithium tantalate by using single seed crystal. CONSTITUTION:The raw material of lithium tantalate is filled in a crucible and heated at 1,670 deg.C and melted and after the temp. is lowered at 1,650 deg.C, single seed crystal of lithium tantalate which is cut so that the pulling direction is made to an X axis is immersed therein and single crystalline lithium tantalate is grown on the single seed crystal by slowly pulling up it while rotating it. In this case, single crystalline lithium tantalate wherein a crack is not caused in the obtained single crystal and the fluctuation width of Curie temp. in respective parts thereof is extremely small is obtained by regulating Li/Ta molar ratio contained in the raw material of lithium tantalate filled in the crucible to 0.946+ or -0.004.
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