Preparation of high T sub c and J sub c films of Ba sub 2 YCu sub 3 O sub 7 using laser evaporation of a composite target containing BaF sub 2.

High T sub c and J sub c superconducting films of Ba sub 2 YCu sub 3 O sub 7 are prepared on SrTiO sub 100> substrates using pulsed excimer laser vaporization of a composite target containing BaF sub 2, Y sub 2 O sub 3, and CuO, followed by annealing in wet oxygen. High transition temperatures (r+O from 89.5-91k) and high critical current densities (J sub c >= 7x10 sup 5 A-cm sup (-2)) are achieved. The electrical transport properties of these films are significantly better than films previously grown via laser ablation of Ba-Y-Cu-O targets.