Yttrium, barium and copper nitrates are dissolved in de‐ionized water to form a 0.038M: 0.078M: 0.1o5M solution, which is used to generate,in‐situY1Ba2Cu3O7−xsuperconducting films in an argon‐oxygen rf plasma. rf power is operated at 4.5 kW, 13.56 MHz and 760 Torr pressure. The best zero resistance temperature, onset critical temperature and current density measured by the four probe transport method are 86 K, 92 K and 4×105A/cm2at 77 K and zero field. X‐ray diffraction shows the films to be oriented withc‐axis perpendicular to the substrate surface. Variations in the critical temperatures of the films and their microstructure depend on rf power, solution composition, solution concentration, plasma gas and aerosol carrier gas. It has been seen that the concentration of barium in the solution is more critical than that of copper. The concentration of the solution is related to the rf power, to prepare the best film, the concentration and the power levels have to be matched. While the variation of both aerosol carrier gas flow rate and the plasma gas flow rate causes a change in the structure and critical temperature of the film, the control of the former is more critical than the plasma gas flow rate.