67 Pb(Mg_(1/3)Nb_(2/3))O_3-33PbTiO_3单晶90°铁电畴光学研究

Optical Micoscope Study of 90° Ferroelectric Domain in 67 Pb(Mg_(1/3)Nb_(2/3)) O_3-33PbTiO_3 Solid Solution Single Crystal

采用偏光显微镜观察了６７Ｐｂ（Ｍｇ_（１／３）Ｎｂ_（２／３））Ｏ_３－３３ＰｂＴｉＯ_３固溶体铁电单晶在室温时 ９０°铁电畴结构．铁电畴结构与晶体质量有关，在正交偏光显微镜下光学透明晶体中存在着尺 寸为２～３ｍｍ的均匀大畴，不同极化方向的大畴重叠形成雾状区，使晶体表现出光学质量宏观 不均匀．在光学质量差的雾状晶体中则存在着 ０．１ｍｍ宽的｛１１０｝型带状孪生畴，使晶体形成 表面浮凸，带状畴内还存在着９０°亚畴．并对这些畴的形成作了讨论．

°Ferroelectric domains in 67 Pb(Mg_(1/3)Nb_(2/3)) O_3-33PbTiO_3 single crystal were observed at room temperature by using crossed polaxized light microscope(PLM). Ferroelectric domain structures depend on the quality of single crystals. Large homogeneous domains of 2～3mm exist in optical transparent single crystals. Large domains with different polarization orientation overlap to form opaque regions. {110} type 90° banded a-a domain with 90° sub-domain can be observed in translucent crystals. The dimension of banded twin is about 0.1mm. As a result, surface relief appears on translucent crystal surface. The mechanism of forming these domains was discussed.