ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Powder dielectric measurement of barium titanate (BaTiO3) fine particles from 17 to 1,000 nm revealed a maximum dielectric constant at a certain particle size. The sizes with maximum dielectric constants were strongly dependent on preparation methods. When BaTiO3 fine particles were prepared in vacuum of 10-2 torr, a dielectric maximum of 15,000 was observed at 70 nm. On the other hand, when BaTiO3 fine particles were prepared in air, a dielectric maximum of 5,000 was observed at 140 nm. Structure refinement of BaTiO3 particles using a Rietveld method revealed that all of BaTiO3 particles were composed of two parts; (a) surface cubic layer and (b) bulk tetragonal layer. Moreover, a thickness of surface cubic layer for BaTiO3 particles prepared in vacuum was much thinner than that for BaTiO3 particles prepared in air. To explain the differences, a new model on the basis of “surface relaxation” was proposed
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/50/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.301.27.pdf
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