LARGE-AREA, LOW MICROWAVE SURFACE-RESISTANCE THIN-FILMS OF YBA2CU3O7 PREPARED BY PULSED-LASER ABLATION

YBa2Cu3O7 (YBCO) superconducting thin films were deposited on (100)LaA lO3 substrates 35 mm in diameter by pulsed laser ablation. The substra tes were heated resistively during deposition by a single-crystal Si h eater and the laser beam was scanned on the rotating YBCO target. The films exhibited a thickness variation of +/- 3.7%, with zero resistanc e temperature T-c0 = 90.6 +/- 0.6 K, critical current density J(c) = 2 .9 +/- 0.9 X 10(6) A/cm(2) at 77 K, and at 10 GHz a surface microwave resistance of < 250 mu Omega at 77 K. The above-mentioned properties s howed that high-quality YBCO thin films over a large substrate area ca n be obtained with this laser ablation system.