Nanocrystalline multiferroic BiFeO3 ultrafine fibers by sol-gel based electrospinning

Novel nanocrystalline BiFeO3 ultrafine fibers have been synthesized by sol-gel based electrospinning, with fiber diameter in the range of 100-300 nm and grain size of around 20 nm. Phase pure perovskite BiFeO3 can be obtained if the fibers are fired in Ar atmosphere, eliminating impurity phases often observed when fired in air or N-2 atmosphere. Excellent piezoelectricity and clear ferroelectric domain structure of the ultrafine fibers are characterized by high voltage piezoresponse force microscopy. Enhanced weak ferromagnetism arising from the nanocrystalline structure of ultrafine fibers is also observed.