Epitaxial growth of YBa2Cu3O7-x thin films by a laser evaporation process

Abstract

Thin films of YBa2 Cu3 O7-x have been grown epitaxially in c-axis orientation on 〈100〉 SrTiO3 by pulsed excimer laser evaporation from a stoichiometric 1-2-3 target. The substrate temperature was adjusted between 720 and 780°C, and the oxygen partial pressure during the deposition was chosen in the range 0.1-0.3 mbar. Cooled to ambient temperature in situ for 1 h in flowing oxygen gas, the films showed complete diamagnetism and zero resistance at 90 K with a transition width of 2 K. Critical current densities of 2.2×106 A/cm2 in zero magnetic field and 1.5×105 A/cm2 at 2 T were measured at 77 K. The resistivity at 100 K was about 60 μΩ cm.