Synthesis and ferroelectric properties of multiferroic BiFeO3 nanotube arrays

We report the synthesis and characterization of ordered multiferroic BiFeO3 (BFO) nanotube arrays. BFO nanotubes with diameters of about 250 nm and lengths of about 6 mu m were fabricated by means of a sol-gel method utilizing nanochannel alumina templates. After postannealing at 700 degrees C, the BFO nanotubes exhibited a polycrystalline microstructure, and x-ray diffraction and transmission electron microscopy study revealed that they are of a perovskite crystal structure. Significant ferroelectric and piezoelectric characteristics of BFO nanotubes have been demonstrated by means of piezoresponse force microscopy measurement