Ferroelectric size effects in multiferroic BiFeO3 thin films

Ferroelectric size effects in multiferroic BiFeO3 have been studied using a host of complementary measurements. The structure of such epitaxial films has been investigated using atomic force microscopy, transmission electron microscopy, and x-ray diffraction. The crystal structure of the films has been identified as a monoclinic phase, which suggests that the polarization direction is close to [111]. Such behavior has also been confirmed by piezoforce microscopy measurements. That also reveals that the ferroelectricity is down to at least 2 nm. (c) 2007 American Institute of Physics.