Morphology and properties of (Ba, Sr, Ca) titanates synthesized by microwave-assisted hydrothermal method
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2011
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Souza, A. E. [UNESP]
Santos, G. T. A. [UNESP]
Silva, R. A. [UNESP]
Moreira, M. L.
Volante, D. P. [UNESP]
Teixeira, Silvio Rainho [UNESP]
Longo, Elson [UNESP]
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Ba1-xCaxTiO3, Ba1-xSrxTiO3 and Sr1-xCaxTiO3 (x = 0, 0.25, 0.50, 0.75 and 1) nanoparticles were synthesized using the microwave-assisted hydrothermal method. Samples were prepared for 40 minutes at 140°C under a pressure of 3 MPa using an adapted domestic microwave oven. The samples were characterized by X-Ray diffraction (XRD), scanning electron microscopy (FE-SEM), and Raman, photoluminescence (PL) and ultraviolet-visible (UV-Vis) spectroscopies. XRD data show that ceramic powders have crystalline phases associated with a short-range structural disorder. This structural disorder is confirmed by Raman spectral bands indicating multi-phonon processes and the presence of defects or impurities. Such defects account for a broad band in the photoluminescence spectrum in the green light (460 nm) region for all samples. Gap energy variation, obtained from UV-Vis spectra, suggest a non-uniform band structure of these titanates in accordance with the PL results. The morphology of each sample is changed with doping and varies from a spherical to cubic appearance for energy minimization.
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IOP Conference Series: Materials Science and Engineering, v. 18, n. 2011, p. 1-4, 2011.