INSITU PROCESSING OF TEXTURED SUPERCONDUCTING THIN-FILM OF BI(-PB)-CA-SR-CU-O BY EXCIMER LASER ABLATION

We have prepared highly oriented bismuth cuprate thin films (c-axis textured) on yttria-stabilized zirconia (100) YS-ZrO2 substrates at 650 °C by pulsed excimer laser ablation in a 200 mTorr oxygen ambient. The films were annealed in oxygen and nitrogen atmospheres to study the effect on zero-resistance transition temperature (Tc0). Thin films deposited at 650 °C exhibited a Tc0 of 68 K with onset at 110 K. Post-annealing for 1 h at 400 °C in oxygen improved the Tc0 to 82 K, while the onset remained the same. X-ray diffraction, scanning electron microscopy, and Rutherford backscattering channeling studies were performed on these films for correlations between crystal structure, microstructure, and superconducting properties. X-ray diffraction patterns indicated a 2212 type phase with a=5.39 Å and c=30.76 Å; preferential orientation of the c axis perpendicular to the substrate was observed. The lattice parameters and x-ray diffraction patterns were found to be invariant with annealing treatments that improved Tc0 from 68 to 82 K.