Pulsed laser deposition of YBa 2 Cu 3 O 7−δ /I/LaNiO 3 trilayers (I = SrTiO 3 , CeO 2 or Eu 2 CuO 4 )o n(100) SrTiO 3 substrates

To look at a quasi-particle injection into high Tc superconductors, YBa2Cu3O7−δ/insulator/LaNiO3 (YBCO/I/LNO) trilayers have been grown on (100) SrTiO3 substrates in situ by pulsed laser deposition (PLD), where, an insulator (I), SrTiO3 (STO), CeO2 (CO) or Eu2CuO4 (ECO) are used. All the deposited films are highly oriented. The surface morphology of LNO and the insulating films is investigated during fabrications after the films are made, revealing small roughness and low droplet density. The top YBCO layer exhibits good superconducting properties with a critical temperature above 82 K and a transition width as sharp as 1.5 K.