Implantation, Damage, and Regrowth of High T sub c Superconductors.

We have observed superconductivity in thin films of (La sub (1-x) Sr sub x ) sub 2 CuO sub y which are fabricated by implanting evaporated La/Cu multilayer films with Sr and annealing in oxygen. The films are insulating and partially transparent as-implanted, but they darken and become conducting at annealing temperatures as low as 500C. The resistive behavior is very sensitive to the annealing conditions and the superconducting layer appears to be buried beneath the surface. Similarly, implantation of F, O, and Ne into single crystals and high quality ( chi sub(min) 30%) thin films of YBa sub 2 Cu sub 3 O sub (7-delta) creates a buried damage layer and renders the films insulating. From Rutherford Backscattering and channeling analysis, we find that some regrowth of the damaged layer does occur on subsequent annealing.