Probing intrinsic polarization properties in bismuth-layered ferroelectric films

The authors report on an approach to establish intrinsic polarization properties in bismuth-layered ferroelectric films by piezoelectric coefficient and soft-mode spectroscopy, as well as by a direct polarization-electric field hysteresis. In epitaxially grown (Bi4-xNdx)Ti3O12 (0 <= x <= 0.73) films, they show that these complementary characterizations can phenomenologically and thermodynamically represent the intrinsic polarization states in (Bi4-xNdx)Ti3O12 films, and the intrinsic P-s of 67 mu C/cm(2) is estimated for pure Bi4Ti3O12, superior to 50 mu C/cm(2) in bulk single crystal. Their results provide a pathway to draw full potential in ferroelectric thin films. (c) 2007 American Institute of Physics.