Probing intrinsic polarization properties in bismuth-layered ferroelectric films

摘要

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 (Bi_(4-x)Nd_x)Ti_3O_(12) (0≤ x ≤ 0.73) films, they show that these complementary characterizations can phenomenologically and thermodynamically represent the intrinsic polarization states in (Bi_(4-x)Nd_x)Ti_3O_(12) films, and the intrinsic P_s of 67 μC/cm~2 is estimated for pure Bi_4Ti_3O_(12), superior to 50 μC/cm~2 in bulk single crystal. Their results provide a pathway to draw full potential in ferroelectric thin films.