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The Development of Microstructure and Ferroelectric Properties of Bi4Ti3.96Nb0.04O12 Thin Films

Research paper by H. Z. Chen, M. C. Kao, S. L. Young, C. C. Yu, C. H. Lin, C. R. Ou, C. M. Lee

Indexed on: 26 Jan '10Published on: 26 Jan '10Published in: Journal of Superconductivity and Novel Magnetism



Abstract

Bi4Ti3.96Nb0.04O12 thin films were successfully deposited on Pt(111)/Ti/SiO2/Si(100) substrates by a sol–gel method and rapid thermal annealing. The effects of Nb-substitution and annealing temperature (500–800°C) on the microstructure and ferroelectric properties of bismuth titanate thin films were investigated. X-ray diffraction analysis reveals that the intensities of (117) peaks are relatively broad and weak at annealing temperatures smaller than 700°C. With the increase of annealing temperature from 500°C to 800°C, the grain size of Bi4Ti3.96Nb0.04O12 thin films increases. The Bi4Ti3.96Nb0.04O12 thin films annealed at 700°C exhibit the highest remanent polarization (2Pr), 36 μC/cm2 and lowest coercive field (2Ec), 110 kV/cm. The improved ferroelectric properties can be attributed to the substitution of Nb5+ to Ti4+ in Bi4Ti3O12 assisting the elimination of defects such as oxygen vacancy and vacancy complexes.