A lead titanate epitaxial thin film is one of the important ferroelectric films and lattice matching with strontium titanate is preferable. However, it was thought to be difficult to obtain high insulation property and very few superior hysteresis curves were measured with lead titanate. The hydrothermal method can avoid a lead vacancy and residual strain at the boundary of the substrate due to low reaction temperature of 150°C. Using strontium ruthenium oxide bottom electrode on strontium titanate, the lead titanate thin film was successfully deposited by the hydrothermal method. The single crystal-like DE hysteresis curve showed a remanent polarization of 96.5 μC/cm2. The domain direction was controlled by an applied electric field using a metal coated AFM cantilever probe and the domain pattern was observed by scanning nonlinear dielectric microscopy (SNDM). Minimum dot radius of inverted domain was 12 nm corresponding to data storage density of 1 Tbit/inch2.
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