Strain Engineered CaBi2Nb2O9 Thin Films with Enhanced Electrical Properties

In this work, strain engineered polycrystalline thin films (similar to 250 nm) of bismuth layer -structured ferroelectric (BLSF) CaBi2Nb2O9 (CBNO) were prepared by using a radio frequency (RF) magnetron sputtering technique. XRD analysis revealed that the films were (200)/(020) and (001) textured with a large in -plane tensile stress. Cross-sectional TEM analyses confirmed the bismuth layered -structure, as well as crystalline orientations and a strain-controlled growth mode of the grains. Result of a quantitative XPS analysis revealed that the composition of the film is close to the chemical stoichiometry. Excellent electrical properties were achieved in the CBNO films, including a high dielectric constant (similar to 280 @5 kHz), a small dielectric loss (tgo < 1.6% up to an applied electric field of -4200 kV/cm) and a large polarization (P-r approximate to 14, mu C/cm(2) @ 1 kHz).