Thermally Stable Sr2RuO4 Electrode for Oxide Heterostructures.

The use of thermally stable Sr2RuO4 electrodes in high-temperature synthesis of oxide heterostructures was investigated. Atomically smooth Sr2RuO4 thin films were grown on SrTiO3(001) substrates by pulsed laser deposition and used as a bottom electrode for ferroelectric BaTiO3 capacitors grown at temperatures of up to 1000 °C. The thermal stability of Sr2RuO4 electrodes was verified by structural and electrical measurements of the ferroelectric BaTiO3 films. The best growth temperature for the BaTiO3 films was found to be 900 °C, exhibiting the largest spontaneous polarization, dielectric constant, and pyroelectric response. We conclude that Sr2RuO4 films are suitable for use as thermally stable electrodes in heterostructures synthesized at temperatures up to at least 1000 °C and oxygen pressures from 10-6 to 10-1 Torr. This range of growth film conditions is much wider than that for other common oxide electrode materials such as SrRuO3, widening the available process window for optimizing the performance of oxide electronic devices.