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Evidence of Cu Deficiency: A Key Point for the Understanding of the Mystery of the Giant Dielectric Constant in CaCu 3 Ti 4 O 12
Author(s) -
Fang TsangTse,
Mei LiThen
Publication year - 2007
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.1551-2916.2006.01419.x
Subject(s) - grain boundary , amorphous solid , dielectric , materials science , transmission electron microscopy , ion , spectroscopy , analytical chemistry (journal) , condensed matter physics , mineralogy , crystallography , chemistry , physics , nanotechnology , microstructure , composite material , optoelectronics , chromatography , quantum mechanics , organic chemistry
The compositions of the grains and the grain boundaries in CaCu 3 Ti 4 O 12 (CCTO) have been characterized by a high‐resolution field emission transmission electron microscope equipped with a high‐angle annular‐dark‐field detector and energy‐dispersive X‐ray spectroscopy (EDS). The excess ions and their clusters at grain boundaries led to the observed strain contrast. These ions are further clarified as Cu ions by Z‐contrast (Z: atomic number) image and EDS. The quantitative EDS analyses further indicate that the grain boundaries of CCTO are Cu rich and the grains are Cu deficient. The Ca‐ or Ti‐rich amorphous phases were observed at corners or edges of the grains of CCTO.