Properties of BaTiO3 confined in nanoporous Vycor and artifical opal silica

Dmitry Nuzhnyy, Premysl Vanek, Jan Petzelt, Viktor Bovtun, Martin Kempa, Ivan Gregora, Maxim Savinov, Radmila Krupková, Václav Studnicka, Josef Bursik, Mihail I. Samoylovich, Wilfried Schranz

Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

Abstract

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 (pore diameter 4–6 nm) only amorphous phase was revealed by XRD, IR reflectivity and Raman spectra. After additional gradual an-nealing, no crystallization was achieved. Chemical reaction with the SiO2 skeleton started at ~1000 K. The room-temperature IR and Raman spectra clearly show characteristic vibrational modes of the ferroelectri-cally distorted TiO6 octahedra without any long-range order. In case of the opal matrix (densely packed silica spheres, pore diameter up to ~50 nm), 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 tem-perature independence of the effective wide-frequency dielectric response due to the essentially temperature independent effective soft mode stiffened to ~100 cm-1, 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.
OriginalspracheEnglisch
Seiten (von - bis)215-223
Seitenumfang9
FachzeitschriftProcessing and Application of Ceramics
Jahrgang4
Ausgabenummer3
PublikationsstatusVeröffentlicht - 2010

ÖFOS 2012

  • 103018 Materialphysik

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