Completely (001)-textured growth and electrical properties of Bi_4Ti_3O_(12)/LaNiO_3 heterostructures prepared by pulsed laser deposition on LaAlO_3 single crystal substrates

摘要

Heterostructures of Bi_4Ti_3O_(12)(BTO)/LaNiO_3(LNO) have been prepared on (001) LaAlO_3 single crystal substrates by pulsed laser deposition (PLD). Analyses of X-ray diffraction (XRD), (including θ-2θ scan, rocking curve), atomic force microscopy (AFM) and scanning electron microscopy (SEM) reveal that the high quality LNO and BTO films are completely c-axis oriented. With Pt top electrodes, the BTO films exhibit a highly insulative characteristic of low leakage current (～ 10~(-7) A/cm~2 at an applied voltage of 6 V) and excellent dielectric properties. At 100 kHz, the dielectric constant and dielectric loss are 238 and 0.033, respectively. Also a well symmetric ferroelectric hysteresis loop is observed with remnant polarization P_r of 4.5 μC/cm~2 and coercive field E_c of 72.5 kV/cm. Our experiments confirm that the use of the LNO as an electrode material can reduce the amount of the interfacial charges, and thus remove the imprint failure due to thermal processes.