Resistive evaporation of superconducting Y-Ba-Cu-O thin films from a single source

A new evaporation method of high-temperature superconducting films, the resistive vaporation from single source, is reported here for the first time. The source material, inserted into a tungsten boat in a conventional vacuum system, consisted of a pulverized mixture of Cu, YF3, and BaF2. The handling of the source material required only grinding and mixing of the raw materials. Its deposition onto SrTiO3 substrates yielding superconducting films with properties very approximately those obtained in a layer-by-layer resistive evaporation of these materials. In particular, a resistive transition onset at 75 K and zero resistance at similar to 40 K, and critical currents of 2000 A/cm2 at ∼10 K have been measured. The broad transition may be attributed to a copper concentration gradient, as measured by Auger depth profiling, or to a residual fluorine-rich phase