Single crystal thin films of conductive oxides SrRuO3 and ferroelectric heterostructures

Abstract

We have grown epitaxial thin films of the conductive oxide SrRuO3 with well controlled surface morphology and domain structure using vicinal (001) SrTiO3 substrates. Scanning tunneling microscopy and x-ray diffraction show that the SrRuO3 thin films on miscut (001) SrTiO3 substrates with miscut angle > 2° grow by step flow in one direction leading to single crystal films. In contrast, the SrRuO3 thin films on exact (001) SrTiO3 substrates grow by two dimensional nucleation resulting in a two domain in-plane structure. The single crystal thin films have been used as electrodes for the growth of epitaxial ferroelectric PbTiO3 and PZT layers. The PbTiO3/SrRuO3 and PZT/SrRuO3 heterostructures have high crystalline quality, coherent interfaces and a cube-on-cube epitaxial growth with respect to the substrate. These epitaxial heterostructures have superior fatigue characteristics and look promising for the fabrication of integrated single crystal ferroelectric devices.