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利用相衬显微镜结合化学腐蚀法 ,进行了沿 0 10 方向提拉生长的GdCa4 O(BO3) 3(GdCOB)晶体中的缺陷观察。发现位错是 0 10 方向生长的晶体中的重要缺陷。在不同方向的晶体切片上观察了螺位错和刃位错蚀坑 ,位错塞积 ,平底蚀坑及尖底蚀坑。位错密度随晶体长度的变化而变化。在晶体的尾部观测到位错密度为 10 3/cm2 ,而在晶体的初始部位位错密度很低 ,只有 4 0 /cm2 。在晶体的X ,Z及 4 0 1 方向的切片的正反两面观察到的位错蚀坑现象完全不同 ,可以认为GdCOB晶体为单畴极性晶体 ,自发极化方向沿z轴方向。
Defect observation of GdCa4 O (BO3) 3 (GdCOB) crystal grown in the 0 10 direction was carried out by phase contrast microscopy and chemical etching. Dislocations were found to be important defects in crystals growing in the 0 10 direction. In the different directions of the crystal slice observed screw dislocation and edge dislocation pits, dislocation deposition, flat bottom pit and pit bottom pit. Dislocation density varies with crystal length. The dislocation density was observed at the tail of the crystal to be 10 3 / cm 2 while the dislocation density at the initial part of the crystal was as low as 40 / cm 2. The phenomenon of dislocation pits observed on the front and back of X, Z and 4 0 1 slices of the crystal is completely different. It can be considered that the GdCOB crystal is a single-domain polar crystal with spontaneous polarization in the z-axis direction.