Preparation of oriented ceramics by synthesis in electric and magnetic field starting from nanostructured precursors

Abstract

The functionality of the materials is often related to polarisability (electrical or magnetic) of the crystal structure. Ceramic materials are mainly polycrystalline, and their functional properties which are related to polarisability are average values of parameters measured parallel and perpendicular to the direction of dipole moment. Preparation of oriented ceramics enables anisotropic mechanical, thermal, electrical or magnetic properties, which have values similar to single crystals. It could be expected that anisotropic properties of ceramics open new possibilities for their application. It is well-known that use of external electric or magnetic fields during processing could also result in anisotropic ceramics. Although we have very broad class of polar materials and scientists know the importance of preparation of anisotropic materials, up to now there is no literature data about systematic investigation of possible use of external electrical and magnetic fields in synthesis and processing of these materials. In this project we propose systematic investigation that will involve different types of materials: semiconductors (ZnO and TiO2), ferroelectric (BaTiO3) and multiferroic (YMnO3), but also different synthesis and processing methods (low-temperature chemical synthesis, tape casting, electrophoretic deposition and rf sputtering) to be used in combination with external electrical or magnetic field. We think that the application of external fields in materials synthesis and processing is especially interesting if it is applied on nanostructure powders. Nanostructures often tend to self-organize and application of external field can facilitate process of self-organization and formation of oriented structures. The main goal of the project is to correlate parameters important for synthesis of different anisotropic materials in electrical and magnetic field, i.e. to perform detailed structural, microstructural, and functional characterization of the obtained materials and establish corresponding correlations between field strength, precursor and final ceramics properties. (AU)