Ferroelectric BaTiO₃ Nanowires by a Topochemical Solid-State Reaction

The possible existence of a new kind of ferroelectric order and the need to explore domain arrangement in ferroelectric nanostructures has stimulated an increasing activity on the growth of ferroelectric nanowires. In the present study, single crystal BaTiO 3 nanowires with tetragonal structure were obtained by an original solid-state process using layered titania nanowires coated with BaCO 3 nanocrystals as reactive templates. Formation of BaTiO 3 occurs at 700 °C by a topochemical reaction. Consequently, the initial morphology of the titania nanowires is retained in the final product. Piezoresponse force microscopy measurements show a strong piezoactivity and stripe domain patterns with domain width of 20−50 nm, predominant in-plane response and 90° domain walls. The proposed synthesis method is quite general and might be adapted to the fabrication different ferroelectric and nonferroelectric oxide nanowires.