Growth and interface engineering in thin-film Ba 0.6 Sr 0.4 TiO 3 / SrMoO 3 heterostructures

Epitaxial heterostructures of ferroelectric Ba0.6Sr0.4TiO3Ba0.6Sr0.4TiO3 and highly conducting SrMoO3SrMoO3 were grown by pulsed laser deposition on SrTiO3SrTiO3 (0 0 1) substrates. Surface oxidation of the SrMoO3SrMoO3 film is suppressed using a thin cap interlayer of Ba0.6Sr0.4TiO3-δBa0.6Sr0.4TiO3-δ grown in reduced atmosphere. As shown by X-ray photoelectron spectroscopy, the Mo4+Mo4+ valence state of the SrMoO3SrMoO3 films is stable upon annealing of the sample in oxygen up to 600 °C. The described oxygen interface engineering enables utilization of the highly conducting material SrMoO3SrMoO3 in multilayer oxide ferroelectric varactors