BaBi4Ti4O15 ferroelectric thin films grown by pulsed laser deposition

Abstract

BaBi4Ti4O15 (BBiT) is an n=4 member of the Bi-layer-structured ferroelectric oxide family (Aurivillius phases). BBiT thin films with preferred orientations have been grown on epitaxial conducting LaNiO3, electrodes on (001) SrTiO3 by pulsed laser deposition. Cross-section electron microscopy analysis reveals that the films consist of c,-axis oriented regions and mixed at- and ct-axis oriented regions. The mixed at- and ct-axis oriented regions show high surface roughness due to the rectangular crystallites protruding out of the surface, whereas the ct-axis oriented regions show a smooth surface morphology. In the mixed at- and ct-axis oriented regions, the BBiT films exhibit saturated ferroelectric hysteresis loops with remnant polarization Pr of 2 μC/cm2 and coercive field Ec of 60 kV/cm and no polarization fatigue up to 108 cycles. The regions having ct-axis orientation with a smooth surface morphology exhibit a linear P-E curve. The results show that the ferroelectric properties of a planar capacitor consisting of BBiT depend on the crystalline orientation of the film. © 1999 American Institute of Physics.