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Publications (2)0 Total impact

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    ABSTRACT: By using pulsed laser deposition method, nanostructured BaTiO<sub>3</sub> ferroelectric films (with a thickness of 25 nm) were grown on Si substrates and coated by nanoporous alumina membranes (NAMs) with an average pore size of 25 nm. Metal Pt nanowires were embedded in NAMs as a part of the bottom electrode. The dielectric and ferroelectric properties, and microstructure of the nanostructured BaTiO<sub>3</sub> films were characterized. The results show that the dielectric constant of the BaTiO<sub>3</sub> nanofilms is decreased slowly from 196 to 190 as the increase of measured frequency from 10<sup>3</sup> Hz to 10<sup>6</sup> Hz, and their dielectric loss is increased slowly from 0.005 to 0.007 in the low frequency range from 10<sup>3</sup> Hz to 10<sup>5</sup> Hz, whereas quickly increased up to 0.013 at high frequencies over 10<sup>5</sup> Hz. The remanent polarization and the coercive field of the BaTiO<sub>3</sub> nanofilms are 5 uC/cm<sup>2</sup> and 680 kV/cm, respectively. Cross-sectional (scanning) transmission electron microscope (TEM) images demonstrate that the BaTiO<sub>3</sub> nanofilms contact directly with the Pt nanowires, and the interface between them has some degree of waviness. Suitable post-annealing temperature is the critical processing parameter of fabricating nanostructured ferroelectric films as considering a trade-off between the ordered degree of metal nanowires within NAMs and the crystallinity of ferroelectric nanofilms.
    Journal of Inorganic Materials. 01/2010;
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    ABSTRACT: Epitaxial BiFeO3 nanoislands were fabricated on SrTiO3 (100) single crystal and Nb-doped SrTiO3 (100) single crystal substrates by chemical assembled method. Their phase structure and morphology were characterized by X-ray diffraction, scanning electron microscope, and atomic force microscope, respectively. The results showed that epitaxial BiFeO3 nanoislands could be obtained by post-annealing in the temperature range of 650-800¡æ, and their lateral sizes were in the range of 50-150 nm and height of 6-12 nm. With increasing the post-annealing temperatures, the morphology of BiFeO3 nanoisland in the (100) growth plane evolved from tri-angle to square, and then to long rod shape. By using piezo-force microscope, ferroelectric characteristics of single epitaxial BiFeO3 nanoisland grown on Nb-doped SrTiO3 (100) single crystal substrates with lateral size of about 50 nm and height of 12 nm was characterized. The results demonstrated that fractal ferroelectric domains existed in the single BiFeO3 nanoisland, and self-biased polarization effect was also observed within the nanoisland. This phenomenon was ascribed to interfacial stress caused by the lattice misfit between the BiFeO3 nanoisland and the SrTiO3 single crystal substrate.
    Journal of Inorganic Materials. 01/2010;