YBa2Cu3O7–δ films prepared by pulsed laser deposition in O2/Ar mixture atmosphere

Abstract

The YBa2Cu3O7-δ(YBCO) superconducting films were fabricated epitaxially on STO(00 l) substrates by pulsed laser deposition method (PLD) in different O2/Ar mixture atmospheres. The surface morphology of the YBCO film is strongly dependent on the O2/Ar ratio of the ambient atmosphere. The surface particle density decreases and the particle size increases with the O2/Ar ratio decreasing. The lattice parameters and the superconducting transition temperature (Tc0) are almost independent on the O2/Ar ratio and are about the same as 1.168 nm and 90 K, respectively, which can be ascribed to the annealing process in 1 atm O2 for all the YBCO samples. Based on the above results, in O2/Ar ratio of 25:75 atmosphere, YBCO:LaAlO3 superconducting composite films with good performance were prepared by co-deposition of PLD with magnetron sputtering method. The experimental results provide a way to control the surface morphology of the YBCO films deposited by PLD method and provide valuable reference for the preparation of YBCO composite thin films by co-deposition of PLD with magnetron sputtering method in Ar/O2 mixture atmosphere.