The role of substrate orientation on interface registry and nanocrystal shape has been investigated for epitaxial manganese oxide (Mn3O4) nanocrystals. Mn3O4 (101) nanoplatelets and (112)-orientated nanowires have been successfully deposited on (111) and (110) SrTiO3 (STO) substrates, respectively. Under higher magnifications, the (101) platelets were found to exhibit step-like growth, spiraling outward from a local dislocation site at the Mn3O4–STO interface. Selected area electron diffraction analysis from transmission electron microscope (TEM) was carried out to determine the in-plane edge directionalities of (101) and (112) Mn3O4. We found the (101) Mn3O4 orientation to exhibit a complex in-plane epitaxial relation of $[2\overline {31} ]$ Mn3O4//[100]STO and an out-of-plane relation of $[\overline 1 01]$ Mn3O4// $[\overline 1 11]$ STO. Furthermore, lattice misorientations of 58° in-plane and 35° out-of-plane have been calculated, attributed to the shear caused by the spiral growth. For the (112) Mn3O4 nanowires, the TEM diffraction pattern indicates pyramidal cross-sections based along $[0\overline {11} ]$ STO. Subsequent calculations reveal that the (112) nanowires have their long axis (c-axis) such that [001]Mn3O4//[110]STO. Thus the nanowires grow preferentially along its longest axis giving rise to the observed shape and anisotropic nature.

We present the study of the synthesis of (001) nickel oxide (NiO) epitaxial nanocrystals grown on (001) strontium titanate (SrTiO3) single crystal substrates. Pulsed laser deposition of the bismuth nickel oxide (BiNiO3, BNO) perovskite precursor followed by post-deposition processing is carried out to form the NiO nanocrystals. A detailed analysis of the dimensions of nanocrystals reveals that the morphology attained differs from the thermodynamically expected equilibrium shape. The deviations from the equilibrium shape are found to follow a systematic trend where the in-plane basal dimensions, that is, the length and width of the nanocrystals grown differ in discretized dimensions. This discretization suggests that for a given interfacial area of nanocrystals there are multiple stable basal rectangular geometries attainable.

Perfectly (111)-oriented rhombohedral Pb(Zr, Ti)O3 [PZT] films were successfully grown on (111) CaF2 substrates. These films have the polar-axis perpendicular to the substrate surface without non-180o domains. Well saturated polarization (P) –electric field (E) hysteresis loops were observed at various frequencies and temperatures. Temperature dependence of the saturation polarization (P sat.) was in good agreement with the estimated one by Haun et al. using phenomenological approach but did not strongly depend on the measured frequencies. On the other hand, the coercive field (Ec ) increased with decreasing temperature and with increasing the measurement frequency.

Wetting of the pore walls of porous templates is a simple and convenient method to prepare nanoshell tubes. Wafer-scale fabrication of ferroelectric lead zirconate titanate and barium titanate nanoshell tubes was accomplished by wetting porous silicon templates with polymeric precursors. The ferro- and piezoelectric properties of an individual ferroelectric nanoshell tube either of PZT or of BaTiO3 were electrically characterized by measuring the local piezoelectric hysteresis. A sharp switching at the coercive voltage of about 2 V was shown from the hysteresis loop. The corresponding effective remnant piezoelectric coefficient is about 90 pm/V. We have also prepared highly ordered arrays of free-standing ferroelectric nanoshell tubes obtained by partial etching of the silicon template. Such materials might be used as building blocks of miniaturized devices and could have a significant impact in the field of nano-electromechanical systems.