Enhancement Of The Superconducting Properties Of Tlba2cacu2o7+Delta Thin Films Via Postannealing

The superconducting properties of TlBa2CaCu2O7+delta(Tl-1212) films are greatly enhanced by annealing in unreactive ambients such as nitrogen at temperatures ranging from T-a=250-600 degrees C. The transition temperature, T-c of these Tl-1212 films as-grown in oxygen is 70 K. Annealing for 1 h at 250 degrees C elevates T-c above 90 K. T-c further increases and sharpens for T-a=600 degrees C. In addition, subtle changes occur in the microstructure correlating with improved critical current density. These results indicate that Tl-1212 films may be of greater relevance for electronics applications than previously believed. (C) 1995 American Institute of Physics.