a[(Mg1/3Ta2/3)0.9Ti0.1]O3 复合钙钛矿电介质陶瓷<001>c 方向相变诱导畴结构
Phase Transition Domains in Ca[(Mg1/3Ta2/3)0.9Ti0.1]O3 Complex Perovskite Dielectric Ceramics in <001>c Direction
本文采用高分辨透射电镜,沿原始立方钙钛矿结构三个特征晶体学方向之一的<100>c方向对Ca[(Mg1/3Ta2/3)0.9Ti0.1]O3复合钙钛矿陶瓷中相变诱导的层片状畴结构进行了系统研究。A位阳离子反平行位移与氧八面体的正向扭转导致的1/2[001]* 与 1/2[110]* 超结构破坏了原始立方钙钛矿的对称性,从而产生畴结构。相变过程中对称面与四次旋转轴的丢失诱导了大量的(010)反射孪生畴与沿[010]与 [001]方向的90o旋转畴。4/mmm四方结构在由原始立方m-3m结构向正交mmm结构相变过程中充当中间桥连相,使无母群-子群关系的一级相变变得连续并以二级相变的形式发生从而形成畴结构。
In this paper, phase transition induced lamellar domain structures together with the phase transition process in Ca[(Mg1/3Ta2/3)0.9Ti0.1]O3 complex perovskite ceramics have been investigated by high resolution transmission electron microscopy (HRTEM) in one of the three characteristic crystalgraphic directions of the parent cubic perovskite structure, <100>c direction. The antiparallel displacement of A-site cations and in-phase oxygen octahedra tilting cause 1/2[001]* and 1/2[110]* superstructure reflections to destroy the symmetry of the parent cubic structure and subsequently induce domain structures. Groups of (010) reflection twin domains and 90o rotation domains along the [010] and [001] directions are refined to be caused by the loss of reflection planes and four-fold rotation symmetry during the pahse transition. Tetragonal 4/mmm structures are revealed to act as the bridging intermediate phase to make the first order phase transitions from the parent cubic m-3m structure to the orthorhombic mmm structure structure without group-subgroup relations continuous and diffusionless, and thus could occur via second order to form domain structures.
刘小强、倪磊、陈湘明、傅茂森、曾跃武
晶体学材料科学物理学
复合钙钛矿畴结构相变高分辨透射电镜
complex perovskitedomain structurephase transitionhigh resolution transmission electron microscopy (HRTEM)
刘小强,倪磊,陈湘明,傅茂森,曾跃武.a[(Mg1/3Ta2/3)0.9Ti0.1]O3 复合钙钛矿电介质陶瓷<001>c 方向相变诱导畴结构[EB/OL].(2013-09-05)[2025-08-25].http://www.paper.edu.cn/releasepaper/content/201309-76.点此复制
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