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采用改进的Bridgman法生长出了尺寸达 2 5mm× 2 5mm× 5 0mm的透明的、压电性能十分优异的弛豫铁电单晶体Pb(Mg1/ 3 Nb2 / 3 )O3 PbTiO3 ,其为纯钙钛矿相的三方或四方结构 .这些单晶主要显露 {0 0 1 }面 ,而 [1 1 1 ]方向的生长速度相对较快 .可以利用负离子配位多面体生长基元理论模型解释PMNT单晶的形貌特征与生长习性 .在光学显微镜和SEM下观察到了散射颗粒、气泡及负晶结构等宏观缺陷 .在对结构缺陷形成机制研究的基础上 ,通过调节生长参数 ,可以减少或消除这些缺陷 .用光学显微镜对三方相单晶的 71°或 1 0 9°电畴、四方相单晶的 90°电畴进行了观察 ,发现微畴 宏畴转变可由成分诱导并存在过渡区 ,分析了电畴结构的形成机理及与铁电相变的关系 .
A modified Bridgman method was used to fabricate a transparent, relaxed piezoelectric ferroelectric single crystal Pb (Mg1 / 3Nb2 / 3) O3PbTiO3 with dimensions up to 2 5mm × 2 5mm × 500mm, which is pure calcium titanium The three-phase or four-phase structure of the ore-forming phase of these single crystals mainly reveals the {0 0 1} plane while the growth rate in the [1 1 1] direction is relatively fast. The theoretical model for the growth of PMNT single crystal Morphology and growth habit.Microstructural defects such as scattering particles, bubble and negative crystal structure were observed under optical microscope and SEM.And the defects were reduced or eliminated by adjusting the growth parameters based on the study of the formation mechanism of the structural defects. The optical domain of 71 ° or 109 ° domains of tetragonal single crystal and the 90 ° domain of tetragonal single crystal were observed by optical microscopy. It was found that the transition of microdomains was induced by the composition and existed in the transition region. Formation Mechanism of Structure and Its Relationship with Ferroelectric Phase Transition.