Grain size effect on ferroelectric phase transitions in nano-crystalline perovskite materials

Citation
Rs. Katiyar et Jf. Meng, Grain size effect on ferroelectric phase transitions in nano-crystalline perovskite materials, FERROELECTR, 229(1-4), 1999, pp. 201-206
Citations number
11
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
FERROELECTRICS
ISSN journal
00150193 → ACNP
Volume
229
Issue
1-4
Year of publication
1999
Pages
201 - 206
Database
ISI
SICI code
0015-0193(1999)229:1-4<201:GSEOFP>2.0.ZU;2-P
Abstract
The effects of grain size on the ferroelectric transition temperature in na no-crystalline complex ferroelectric perovskite oxides, have been investiga ted employing micro-Raman scattering spectroscopy as a function of temperat ure and pressure. There appears a distinct soft mode induced phase transiti on in each sample and the transition temperature decreases with decreasing grain size. For example, the observed soft mode Raman frequency in pure PbT iO3, with grain size of 60 nm, remarkably shifts to lower frequency relativ e to single-crystal, powder or thin film data, clearly indicating a lowerin g in its transition temperature. Grain size-induced phase transformation fr om ferroelectric tetragonal to paraelectric cubic phase in nano-crystalline Pb1-xBaxTiO3, is found to occur at x=0.7 and it is associated with the Ba concentration dependence of the soft mode. These studies show possibility o f preparing high efficiency PbTiO3 sensors that can be operated close to am bient temperature.