ENHANCEMENT OF THE SUPERCONDUCTING PROPERTIES OF TLBA2CACU2O7-FILMS VIA POSTANNEALING(DELTA THIN)

The superconducting properties of TlBa2CaCu2O7+delta(Tl-1212) films ar e greatly enhanced by annealing in unreactive ambients such as nitroge n at temperatures ranging from T-a=250-600 degrees C. The transition t emperature, T-c of these Tl-1212 films as-grown in oxygen is 70 K. Ann ealing for 1 h at 250 degrees C elevates T-c above 90 K. T-c further i ncreases and sharpens for T-a=600 degrees C. In addition, subtle chang es occur in the microstructure correlating with improved critical curr ent density. These results indicate that Tl-1212 films may be of great er relevance for electronics applications than previously believed. (C ) 1995 American Institute of Physics.