In-Situ Production of Superconducting YBa2Cu3O7-y Thin Films by High Pressure Reactive Evaporation with Rapid Thermal Annealing

Abstract

ABSTRACTA high pressure reactive evaporation process has been established that can produce highly oriented YBa2Cu3O7-y high Tc films without the necessity of an extended post-deposition oven anneal cycle. The process is based on the electron beam co-evaporation of the metals Y, Ba and Cu onto heated (600–750 C) substrates in an oxygen partial pressure of 10-3 Torr. In general the films are superconducting when examined directly after termination of the growth process. However a brief rapid thermal anneal step in oxygen, which can be done either in-situ in the growth chamber or elsewhere, is often effective in further improving the superconducting transition. Highly oriented film growth has been obtained on both strontium titanate and yttria-stabilized cubic zirconia substrates. The best films that have been produced thus far with this technique on the cubic zirconia substrates have Tc (zero resistance) = 83 K, transition width ΔTc = 2 K, and room temperature resistivity (ρRT) = 0.5 mQ-cm. Similar results, with somewhat higher values of Tc, have been obtained on SrTiO3. On both substrates the critical current density at 4.2 K is in excess of 106 A/cm2.