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Investigation of Lamella‐Twinned Crystallites and Dislocations in Paraelectric Phases of Bi 2 O 3 ‐Doped BaTiO 3
Author(s) -
Feng Qiquan,
McConville Caspar J.
Publication year - 2004
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2004.tb07500.x
Subject(s) - materials science , crystallite , condensed matter physics , dislocation , transmission electron microscopy , lamella (surface anatomy) , crystallography , crystal twinning , dielectric , diffraction , dark field microscopy , electron diffraction , optics , microstructure , microscopy , composite material , chemistry , nanotechnology , physics , optoelectronics , metallurgy
Defects in the paraelectric phases of BaTiO 3 doped with Bi 2 O 3 were analyzed by transmission electron microscopy under two‐beam conditions. (111) twin structures were characterized by selected area diffraction and bright‐field images. The orientation relationships of the (111) twins were determined using stereograms. Lamella‐twinned crystallites included in the paraelectric phases were found in this system. Pure wedge fringes were analyzed in these grains using electron diffraction and imaging techniques. Double diffraction was observed in the overlapped regions of the matrix and the microtwin in the [113] direction, and high‐density dislocation loops were seen in some grains. Weak‐beam dark‐field microscopy techniques were used to observe the dislocation loops, which predominately lay on {100} crystal planes with Burgers vectors a 〈100〉, and were found to be pure edge dislocations. Some dislocations were transformed into crystallographic shear planes.