Enhanced Dielectric Nonlinearity in Epitaxial Pb(0.92)La(0.08)Zr(0.52)Ti(0.48)O(3).

摘要

High quality c-axis oriented epitaxial Pb 0.92 La 0.08 Zr 0.52 Ti 0.48 O3 films were fabricated using pulsed laser deposition on (001) LaAlO 3 substrates with conductive LaNiO 3 buffers. Besides confirmation of the in-plane and out-of-plane orientations using X-ray diffraction, transmission electron microscopy study has revealed columnar structure across the film thickness with column width around 100nm. Characterization of ferroelectric properties was carried out in comparison with polycrystalline Pb 0.92 La 0.08 Zr 0.52 Ti 0.48 O 3 films to extract the effect of epitaxial growth. It is found that the ratio between the irreversible Rayleigh parameter and reversible parameter increased up to 0.028cm/kV at 1kHz on epitaxial samples, which is more than twice of that on their polycrystalline counterparts. While this ratio decreased to 0.022cm/kV with increasing frequency to 100kHz, a much less frequency dependence was observed as compared to the polycrystalline case. The epitaxial Pb 0.92 La 0.08 Zr 0.52 Ti 0.48 O 3 films exhibited a higher mobility of domain wall and the higher extrinsic contribution to the dielectric properties, as well as reduced density of defects, indicating that it is promising for tunable and low power consumption devices.