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In this work we demonstrate by transmission electron microscopy and piezoresponse force spectroscopy that the polarization direction in hydrothermally synthesized lead titanate (PbTiO3) nanorods can be changed from parallel to the nanorod axis to perpendicular to it by a simple heat treatment above the Curie temperature. The heat treatment also introduced 90° domains, caused a rearrangement of the surface and a reduction in the amounts of defects. The polarization of the heat-treated nanorods could be successively switched in the direction perpendicular to the nanorod axis. This control of the polarization in PbTiO3 nanorods opens up possibilities of tailoring the ferroelectric properties and is therefore highly relevant for the use of ferroelectric nanorods in devices. [ABSTRACT FROM AUTHOR]

Abstract: Nanotubes of ferroelectric lead titanate (PbTiO3) have been made by a template-assisted method. An equimolar Pb–Ti sol was dropped onto porous alumina membranes and penetrated into the channels of the template. Single-phase PbTiO3 perovskite nanotubes were obtained by annealing at 700°C for 6h. The nanotubes had diameters of 200–400nm with a wall thickness of approximately 20nm. Excess PbO or annealing in a Pb-containing atmosphere was not necessary in order to achieve single-phase PbTiO3 nanotubes. The influence of the heating procedure and the sol concentration is discussed. [Copyright &y& Elsevier]