扩镁铌酸锂表层的富MgO层特性  

MgO-RICH LAYER CHARACTERISTICS IN THE MAGNESIUM DIFFUSED LITHIUM NIOBATE SURFACE LAYER

作　　者：阙文修[1] 姚熹[1] 

机构地区：[1]西安交通大学电子材料研究室

出　　处：《硅酸盐学报》1996年第4期446-450,共5页Journal of The Chinese Ceramic Society

基　　金：西安交通大学精细功能电子材料与器件实验室开放基金

摘　　要：利用常规Ｘ射线衍射、掠入射Ｘ射线衍射和差热分析，对扩镁铌酸锂表层的富ＭｇＯ层特性进行了分析，提示出在富ＭｇＯ层具有一种未能确认的化合物和ＭｇＮｂ_２Ｏ_６的物相结构。ＭｇＮｂ_２Ｏ_６出现在富ＭｇＯ层的近表层，而未知化合物在次表层，且它们都具有明显的取向性。这些扩镁铌酸锂单晶的Ｃｕｒｉｅ温度先随扩散时间的增长而降低，但与扩散时间超过一定限度后又开始升高，并且出现另一个相变点，这可能是富ＭｇＯ层中未知化合物的相变点。利用阳离子空位理论模型较好地解释了Ｃｕｒｉｅ温度变化的异常现象。MgO-rich layer characteristics in the magnesium diffused lithium niobate surface layer is investigated with the conventional X-ray diffraction,grazing-incidence X-ray diffraction and differential thermal analysis,It is found that the MgO-rich layer exhibits a crystal structure of an unknown compound and MgNb_2O_6.Their appearance indicates that MgNb_2O_6 is in the surface layer of MgO-rich layer, the unknown compound is in the subsurface layer and beneath the layer where MgNb_2O_6 exists,and these compounds have obviously preferred orientation.The Curie temperature of the magnesium diffused lithium niobate single crystal decreases with increase of diffusion time at first,but beyond a limit,the Curie temperature starts to increase again and another phase transition point appears at about 1186℃,which is probably the phase transition point of the unknown compound.These anomalous of the Curie temperature variation are well analyzed by the cation vacancy model.

关 键 词：镁离子 铌酸锂 晶体 掺杂 氧化镁 折射率 

分 类 号：O614.111[理学—无机化学] O734.2[理学—化学]