Pulsed laser deposition of LaNiO3 and YBa2Cu3O7−δ/LaNiO3 on SrTiO3 buffered (100) MgO

Multilayer structure YBa2Cu3O7−δ (YBCO)/LaNiO3 (LNO)/SrTiO3 (STO)/MgO has been carefully studied in the hope that it can be used for applications such as quasiparticle injection or Josephson junction fabrication. Deposited by pulsed laser, LNO on STO-buffered (100) MgO has low resistivity, good metallic characteristics, and very smooth surface (with a mean-square-root roughness of less than 3 nm). After the deposition of LNO, YBCO film can be grown in situ on it, showing good superconducting properties with a critical temperature above 81 K and a narrow transition width below 1.5 K. X-ray diffraction analyses have indicated that all the deposited films are highly c-axis-oriented.