Abstract
$La_{1/3}NbO_3$ and $La_{1/3}TaO_3$ large single crystal was prepared by the infrared floating zone method and their crystal structure and dielectric properties were investigated from the viewpoint of A - site vacancy. In $La_{1/3}TaO_3$ crystal, the crystal symmetry and approximate lattice constants was tetragonal and a $\approx$ 0.397, b $\approx$ 0.397 and c $\approx$ 0.775 from the nonextinction and the reciprocal lattice point length seen on Weissenberg and Precession photographs. The jump of some $2/3La^{3+}$ ions leads to increase the moving paths due to the generation of new vacancies at middle empty sites and thus this result is confirmed to provoke the dielectric anomaly.
$La_{1/3}NbO_3$와 $La_{1/3}TaO_3$의 대형 단결정을 적외선 용융대역법으로 제작하여 A-자리 공공이 유전 특성에 미치는 영향에 대하여 조사하였다. Weissenberg 및 Precession 사진에서 $La_{1/3}TaO_3$ 결정의 대칭성은 tetragonal 이며, 격자정수는 a $\approx$ 0.397, b $\approx$ 0.397, c $\approx$ 0.775이다. 유전이상은 $2/3La^{3+}$ 이온이 공공자리로의 이동에 기인한 것으로 추측하였다.
