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−xNdxTi3O12 films, and the intrinsic Ps of 67 μC/cm2 is estimated for pure Bi4Ti3O12, superior to 50 μC/cm2 in bulk single crystal. Their results provide a pathway to draw full potential in ferroelectric thin films