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Combined Analytical Transmission Electron Microscopy Approach to Reliable Composition Evaluation of KTaO 3
Author(s) -
Tchernychova Elena,
Glinšek Sebastjan,
Malič Barbara,
Kosec Marija
Publication year - 2011
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.1551-2916.2010.04288.x
Subject(s) - transmission electron microscopy , materials science , electron microscope , energy filtered transmission electron microscopy , microscopy , scanning transmission electron microscopy , analytical chemistry (journal) , nanotechnology , chemistry , optics , physics , chromatography
We have made an effort to obtain a reliable quantitative composition of KTaO 3 , which belongs to the group of incipient ferroelectrics. A combination of two analytical spectroscopic methods of transmission electron microscopy was employed for the nanoscale analysis: energy‐dispersive X‐ray and electron energy‐loss spectroscopy. Because of the volatile nature of alkali‐based compounds, special attention was paid to optimization of acquisition parameters. The latter were tested on KTaO 3 single‐crystal specimen by applying various electron doses and monitoring the K/Ta ratio. The case study was based on the analysis of calcined KTaO 3 powder prepared from a stoichiometric mixture of K 2 CO 3 and Ta 2 O 5 , and KTaO 3 ceramic prepared from the latter powder by hot pressing. At nanoscale, the particles of microscopically homogeneous powder appeared to have a slight excess of K relative to the nominal composition. Additionally, 5–20 nm sized nanoparticles, possessing both K‐ and Ta‐rich compositions, were found to be attached to the cubic‐shaped powder particles. Hot‐pressed KTaO 3 ceramic revealed exaggerated grain growth with compositional deviations of up to 5% within large grains as well as in matrix grains composition. The majority of analyzed matrix grains, however, showed a slight excess of Ta relative to the nominal composition.