D. Suvorov¹, M. Macek-Krzmanc¹ and H. Ursic Nemevsek²

¹Advanced Materials Department, Jožef Stefan Institute, Jamova 39, Ljubljana, Slovenia, 1000

²Electronic ceramics Department, Jožef Stefan Institute, Jamova 39, Ljubljana, Slovenia, 1000

Ferroelectric perovskites exhibit great potential for many applications that require a size down to the nanometre range. For this reason the interest in preparing defined-shape ferroelectric nanoparticles has increased tremendously in the past 10 years. These ferroelectric nanoparticles, with a unique anisotropic shape and size-dependent properties that differ from their bulk counterparts, also represent a challenge to fabricate the nanostructures via their self-assembly. If the direction of spontaneous electric polarization of the ferroelectric particles could be tuned, then these particles or their self-assembled structures are expected to make a significant breakthrough in the field of memory storage, piezoelectric sensors, ferroelectric-photovoltaic devices, photocatalysis and energy harvesting.

Due to the high symmetry of their crystal structure, ABO₃ perovskites do not show a tendency to grow in defined anisotropic shapes such as plates or needles. In this presentation a critical overview of past research will be presented. In addition, a study of the formation and the resulting properties of perovskite Ba_1-xSr_xTiO₃ micro- and nano-plates that were realized by the in-situ topochemical transformation of the layered perovskite Bi₄Ti₃O₁₂ precursor template will be reported. The influence of the Bi₄Ti₃O₁₂ template dimensions, the Ba/Sr ratio and the conversion conditions on the size, tetragonality and orientation of the single-crystalline Ba_1-xSr_xTiO₃ micro and nano-plates were also examined in great detail. The main focus was on preparing highly tetragonal (002)-oriented Ba_1-xSr_xTiO₃ plates with nano dimensions. Their piezoelectric, ferroelectric characteristics and domain structure were studied by means of electron microscopy, differential scanning calorimetry (DSC) and piezo-force microscopy (PFM).

For these materials, the application potential of highly oriented, micro- and nano-plates based on Ba_1-xSr_xTiO₃ will be discussed.