Preparation of epitaxial La2−xSrxCu04 thin films for dynamic investigations of epitaxial strain

Abstract

Investigations using different single crystalline substrates can only hardly correlate the applied strain with the resulting superconducting properties of thin films directly, since growth conditions and microstructure may severely affect these properties. An alternative approach to study this interaction is the preparation of superconducting films on piezoelectric substrates enabling a dynamical variation of the induced strain by applying an electric field on the substrate. In this work we report on preliminary growth studies of thin epitaxial La2−xSrxCuO4 films on standard and piezoelectric single crystalline substrates. Structural and electrical properties of La2−xSrxCuO4 films on SrTiO3 and SrLaAlO4 substrates using on-axis pulsed laser deposition are shown and compared to films grown in off-axis geometry.Furthermore, we present the first results of the growth of La1.85Sr0.15CuO4 on piezoelectric (001) Pb(Mg1/3Nb2/3)0.72Ti0.28O3 (PMN-PT) substrates using off-axis geometry. Due to a large lattice mismatch between La2−xSrxCuO4 and PMN-PT substrates a buffer layer is required to match the lattice parameters and to support the growth of high quality films. Structural and superconducting properties of thin films grown epitaxial on a SrTiO3 buffer layer are shown and compared to films grown directly on SrTiO3 substrates.