Structural and Ferroelectric Properties of Epitaxial PbZr0.52Ti0.48O3 and BaTiO3 Thin Films Prepared on SrRuO3/SrTiO3(100) Substrates

Abstract

AbstractWe have prepared single crystalline epitaxial PbZr0.52Ti0.48O3 (PZT) and BaTiO3 (BTO) thin films on single crystalline epitaxial SrRuO3 (SRO) thin films grown on SrTiO3 (100) (STO) substrates. PZT and SRO thin films were grown using high-pressure on-axis sputtering and BTO using pulsed laser deposition (PLD). The film thickness ranged between 12 to 165 nm. Their excellent structural properties, surface smoothness and interface sharpness were demonstrated by X-Ray Diffraction measurements (XRD), High Resolution Transmission Electron Microscopy (HRTEM) and Atomic Force Microscopy (AFM). Rutherford Backscattering Spectrometry and Channeling measurements (RBS/C) were used to analyze stoichiometry and crystalline quality. Ferroelectric hysteresis loops were obtained for all films of a thickness down to 12 nm showing a decrease in the remanent polarization Pr and an increase in the coercive field Ec towards thinner film thicknesses. Furthermore we have prepared tunneling junctions with a PZT or BTO barrier thickness of 3-6 nm. Reproducible bi-stable I-V-curves and bias dependence of the conductance were obtained suggesting an influence of the ferroelectric properties of the barrier material on the tunnel current.