Preparation of high Tc and Jc films of Ba2YCu3O7 using laser evaporation of a composite target containing BaF2

High T c and J c superconducting films of Ba2YCu3O7 are prepared on SrTiO3 ?100? substrates using pulsed excimer laser evaporation of a composite target containing BaF2, Y2O3, and CuO, followed by annealing in wet oxygen. High transition temperatures (R=0 from 89.5 to 91 K) and high critical current densities (J c >=7×105 A cm- 2) are obtained. The electrical transport properties of these films are significantly better than films previously grown via laser ablation of Ba-Y-Cu-O targets.