An article including a substrate and a layer of a homogeneous metal-oxyfluoride intermediate film disposed on the substrate, the intermediate film containing a rare earth metal, an alkaline earth metal, and a transition metal. The intermediate film has a defect density less than 20 percent and, upon thermal treatment, is capable of converting to a homogeneous rare earth metal-alkaline earth metal-transition metal-oxide superconductor film with a stoichiometric thickness greater than 1 μm and up to 5 μm. Also disclosed is another article including a substrate and the homogeneous superconductor film with a stoichiometric thickness greater than 1 μm and up to 5 μm. Further, methods of making these two articles are described.