Making a stack: Layered titanate nanosheets (see field‐emission TEM image) ≈10 nm in thickness and with a specific surface area above 400 m2 g−1 were prepared by stacking TiO6 monolayers and ammonium ions through a bottom‐up route in an agar matrix containing TiF4. Higher‐order architectures, such as spherical particles and hollow needles, were produced by self‐organized growth of the nanosheets.

Monodispersed microspheres of vaterite CaCO 3 with a diameter adjusted to the range of 1−10 μm were produced through an amorphous intermediate with polystyrene sulfate. Whereas the microspheres were composed of nanocrystals with a diameter of ca. 20 nm covered with the organic polymer, the crystallographic direction of the entire sphere was evaluated to be macroscopically uniform from its single-crystalline features on polarization anisotropy and morphological evolution into a hexagonal shape with an additional growth process. A particular mosaic with a radially grown backbone structure consisting of oriented nanocrystals was suggested to exist in the microspheres from the electron diffraction patterns. The rigid mosaic framework was covered with a flexible organic component. Thus, various functional organic molecules including hydrophilic and hydrophobic dyes were successfully introduced into the microspheres due to the amphiphilic nature of the organic phase.

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BaTiO 3 thin films homogeneously doped with Mn were prepared by a novel powder-sintering thin-film process. Mn-doped BaTiO 3 nanocrystals 5 -7 nm in diameter were synthesized by a sol-gel method and sintered to form a highly densified microstructure containing columnar grains epitaxially grown on a (111)-oriented Pt/TiO 2 /Al 2 O 3 substrate at a low temperature of 800 C. On the basis of the results of various structural analyses, Mn was suggested to act as an acceptor in the perovskite structure of BaTiO 3 , which was also supported by the experimental finding indicating that the leakage current density was significantly improved compared with that of a nondoped BaTiO 3 thin film. Moreover, the dielectric constant of the Mn-doped BaTiO 3 thin film, 728 at 10 kHz with a loss tangent of 1.3%, was higher than that of the nondoped BaTiO 3 thin film, probably owing to the electrostrictive effect induced by in-plane tensile stress. These results clearly indicate the feasibility of using doped BaTiO 3 nanocrystals in the powder-sintering thin-film process for improving dielectric properties.