New low temperature multiphase ferroelectric films
This article describes the low-temperature synthesis of new multiphase ferroelectrics containing an inorganic ferroelectric phase entrapped in amorphous silica or in an organically modified silicate (ormosil). Sol gel derived LiNbO{sub 3} and BaTiO{sub 3} crystals were grown in SiO{sub 2} and in RSiO{sub 1.5} glass where R contains a chromophore (TDP) insensitive to hydrolysis and condensation reactions. The LiNbO{sub 3}{endash}SiO{sub 2} and BaTiO{sub 3}{endash}SiO{sub 2} compositions as well as the TDP{endash}LiNbO{sub 3}{endash}SiO{sub 2} and TDP{endash}BaTiO{sub 3}{endash}SiO{sub 2} ormosils exhibit ferroelectric-like properties. This unusual characteristic is due to the presence of small, partially ordered crystallites of the ferroelectric, dispersed in the amorphous matrix. In addition to their ferroelectric properties, the ormosils also exhibit interesting optical characteristics: the TDP{endash}BaTiO{sub 3}{endash}SiO{sub 2} materials are red, whereas the TDP{endash}LiNbO{sub 3}{endash}SiO{sub 2} are yellow. The materials described in this article are representative of two new classes of weak ferroelectrics. In the first class, a ferroelectric is dispersed in an amorphous matrix. The second class may be called {open_quotes}organically-modified crystals{close_quotes}: small ferroelectric crystals embedded in an organically modified matrix. The fabrication of such materials is possible for inorganic crystalline phases forming at temperatures below the decomposition temperature of the organic (about 250{degree}C). This article also contains some theoretical considerations explaining why these materials, although amorphous by x-ray diffraction, exhibit ferroelectric-like properties. {copyright} 2001 American Institute of Physics.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40203765
- Journal Information:
- Journal of Applied Physics, Vol. 89, Issue 11; Other Information: DOI: 10.1063/1.1364647; Othernumber: JAPIAU000089000011006341000001; 048110JAP; PBD: 1 Jun 2001; ISSN 0021-8979
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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