Properties of BaTiO.sub.3./sub. confined in nanoporous Vycor and artificial opal silica

0350378 - FZÚ 2011 RIV CS eng J - Článek v odborném periodiku
Nuzhnyy, Dmitry - Vaněk, Přemysl - Petzelt, Jan - Bovtun, Viktor - Kempa, Martin - Gregora, Ivan - Savinov, Maxim - Krupková, Radmila - Studnička, Václav - Buršík, Josef - Samoylovich, M.I. - Schranz, W.
Properties of BaTiO₃ confined in nanoporous Vycor and artificial opal silica.
Processing and Application of Ceramics. Roč. 4, č. 3 (2010), s. 215-223. ISSN 1820-6131. E-ISSN 2406-1034
Grant CEP: GA AV ČR KAN301370701
Grant ostatní: FWF(AT) P19284-N20
Výzkumný záměr: CEZ:AV0Z10100520; CEZ:AV0Z40320502
Klíčová slova: nanocomposite * confined BaTiO₃ * porous silica * stiffened soft mode * effective dielectric properties
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
http://www.tf.uns.ac.rs/publikacije/PAC/pdf/PAC%2009%2013.pdf

Using the sol-gel technique, BaTiO3 was embedded into nanoporous Vycor and artificial vitreous opal silica for the first time. About 50 vol% of the pores was filled. In case of the Vycor glass only amorphous phase was revealed by XRD, IR reflectivity and Raman spectra. The RT infrared and Raman spectra clearly show characteristic vibrational modes of the ferroelectrically distorted TiO6 octahedra without any long-range order. In case of the opal matrix, crystallization of the ferroelectric BaTiO3 appeared in coexistence with the amorphous phase, but the penetration depth of the crystalline BaTiO3 was limited. From the apparent temperature independence of the effective wide-frequency dielectric response, we can deduce that no macroscopic percolation of the crystalline BaTiO3 has appeared in our opal matrix. Nevertheless, Raman spectra bring evidence of a diffuse ferroelectric phase transition in the opal-BaTiO3 composite.
Trvalý link: http://hdl.handle.net/11104/0190395