FINITE-SIZE EFFECTS IN SUBMICRON BARIUM-TITANATE PARTICLES

Authors
Citation
M. Tanaka et Y. Makino, FINITE-SIZE EFFECTS IN SUBMICRON BARIUM-TITANATE PARTICLES, Ferroelectrics. Letters section (Print), 24(1-2), 1998, pp. 13-23
Citations number
28
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics, Condensed Matter
ISSN journal
0731-5171
Volume
24
Issue
1-2
Year of publication
1998
Pages
13 - 23
Database
ISI
SICI code
0731-5171(1998)24:1-2<13:FEISBP>2.0.ZU;2-4
Abstract
An experimental and theoretical analysis of finite size effects in sub micron barium titanate particles is presented. The dielectric data sho w that the dielectric constant (epsilon = 734) of small particles (d = 20 nm) remains very similar to that of single crystals provided that the particles are grown from an amorphous phase and not mechanically c rushed into powder. This shows that what has in the past been mistaken for true size effects (i.e., depolarization fields) is due to lattice strain, The X-ray data show that the Curie temperature (cubic-tetrago nal transition temperature) decreases monotonically to zero degree Kel vin as particle size is reduced. However this is shown to be a simple function of lattice constant: The lattice constant expands as the part icle diameter d contracts. This is similar to surface relaxation in th in films.