Ferroelectric Property and Microstructures of La-doped Bi_4Ti_3O_(12) Thin Films

摘要

La-doped bismuth titanate (Bi_(4_x)La_xTi_3O_(12): BLT) and pure Bi_4Ti_3O_(12) (BIT) thin films with random orientation were fabricated on Pt/Ti/SiCVSi substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. For the samples with x=0.25 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-V hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.5 and 0.75 the current-voltage characteristics showed simple ohmic behaviors and their P-V hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization (P_r) and co ercive field (E_c) of the BLT ceramic with x=0.75 were above 20μC/cm~2 and 85KV/cm, respectively.