Estrutura e propriedades de filmes finos ferroelétricos do sistema PZT
2011; Linguagem: Inglês
ISSN
2639-6459
Autores Tópico(s)X-ray Diffraction in Crystallography
ResumoThe system ferroelectric PbZr1-xTixO3 (PZT) has been widely studied due to interesting physical properties for compositions near the Morphotropic Phase Boundary (MPB). The understanding of the phenomenology of ferroelectric films is currently under intense investigation, because the phenomenon of ferroelectricity shows an intrinsic dependence with respect to sample size. The film processing is very important for the development of miniaturization of electronic devices with low power consumption and low voltage operation. Therefore, chemical methods have had great progress with respect to obtaining films with good homogeneity and crystallinity. The pyrolysis temperature and crystallization play a key role in the crystallinity of the films. Due to high temperatures for obtaining films with chemical methods, the volatility of lead oxide in the PZT system becomes a fundamental problem for discussion. This observation revealed the presence of an unwanted entitled pyrochlore phase. The ferroelectric and dielectric response of the films obtained with the pyrochlore phase shows a degradation of these properties. To overcome this problem several hypotheses were tested in order to find a way to suppress the pyrochlore phase. Thus, the synthesis of the films was employed in order to study the performance of the excess lead oxide as a function of pyrolysis temperature for different substrates. The transformation of pyrochlore to perovskite phase was reported as a function of pyrolysis temperature. Different experimental techniques were used in this study to map the crystal structure of long and short range along the different thicknesses of the films, the stress/strain residual around the interface film/substrate, morphology, electrical properties, piezoelectric and ferroelectric films. The integrated analysis of the results aims to understand the phenomenology associated with the origins of self-polarization in ferroelectric thin films.
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