The importance of the oxygen environment in the laser deposition of YBa2Cu3O7-δfilms and tunnel junctions

Abstract
In situ grown superconducting thin films of YBa2Cu3O7- delta (YBCO) and the tunnel junctions of YBa2Cu3O7- delta /PrBa2Cu3O7/YBa2Cu3O7- delta are deposited at Ts approximately=570 degrees C using plasma-assisted laser ablation. The influence of O2 plasma on the superconducting properties of the films is explored in detail. The films show epitaxial growth on SrTiO3(100) substrates and, have Tc approximately=85-87 K and Jc>or=104 A cm-2 at 83 K. rho -T measurements on the tunnel junctions show that the top and bottom layers of YBCO of the heterostructure have similar superconductive properties. X-ray diffraction results, along with preliminary results of R-T and I-V measurements on the junctions, are discussed.