Thin films of YBa2Cu3O7−ywere prepared by magnetron sputtering. The films were characterized by x‐ray diffraction,insitux‐ray photoelectron spectroscopy to determine the as‐deposited oxygen content for various substrate temperatures, and scanning electron microscopy to analyze the microstructure. The orthorhombic phase was observed after anexsitu700 °C anneal. We have obtained films which were completely superconducting at 82 K with 6 K transition widths.