Size effects in ultrathin epitaxial ferroelectric heterostructures

摘要

In this letter we report on the effect of thickness scaling in model PbZr_(0.2)Ti_(0.8)O_(3)(PZT)/SrRuO_(3) heterostructures. Although theoretical models for thickness scaling have been widely reported, direct quantitative experimental data for ultrathin perovskite (<10 nm) films in the presence of real electrodes have still not been reported. In this letter we show a systematic quantitative experimental study of the thickness dependence of switched polarization in (001) epitaxial PZT films, 4 to 80 nm thick. A preliminary model based on a modified Landau Ginzburg approach suggests that the nature of the electrostatics at the ferroelectric-electrode interface plays a significant role in the scaling of ferroelectric thin films.