Mn-Doped BaTiO3 Thin Film Sintered Using Nanocrystals and Its Dielectric Properties

BaTiO3 thin films homogeneously doped with Mn were prepared by a novel powder-sintering thin-film process. Mn-doped BaTiO3 nanocrystals 5-7 rim in diameter were synthesized by a sot-gel method and sintered to form a highly densified microstructure containing columnar grains epitaxially grown on a (111)-oriented Pt/TiO2/Al2O3 substrate at a low temperature of 800 degrees C. On the basis of the results of various structural analyses, Mn was suggested to act as an acceptor in the perovskite structure of BaTiO3, which was also supported by the experimental finding indicating that the leakage current density was significantly improved compared with that of a nondoped BaTiO3 thin film Moreover, the dielectric constant of the Mn-doped BaTiO3 thin film, 728 at 10 kHz with a loss tangent of 1 3%, was higher than that of the nondoped BaTiO3 thin film, probably owing to the electrostrictive effect induced by in-plane tensile stress These results clearly indicate the feasibility of using doped BaTiO3 nanocrystals in the powder-sintering thin-film process for improving dielectric properties (C) 2009 The Japan Society of Applied Physics