Abstract: Improved superconducting thin films are provided having very high T.sub.c (zero) and J.sub.c values, on the order of greater than or equal to 120K and 10.sup.5 A/cm.sup.2 or greater, respectively. The films of the invention are adapted for deposit and support on a compatible substrate, and include a superconductive material, most preferably Tl.sub.2 Ba.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10, with up to about 10% elemental gold admixed with the superconductive material. The preferred method for fabricating the thin film superconductors comprises first forming a non-superconducting precursor film on a compatible substrate which is placed in contact with an unsintered bulk body containing thallium; the substrate with precursor film are sintered with the bulk body to form the desired superconductor material.