HIGH TEMPERATURE SUPERCONDUCTORS INDUCED BY ION IMPLANTATION

THE RECENT DISCOVERY OF SUPERCONDUCTIONS WITH HIGH CRITICAL TEMPERATURE (TC) HAS LED TO AN INTERNATIONAL FRENZY OF RE- SEARCH ACTIVITY ANDSCORES OF GROUPS HAVE DEMONSTRATED HIGH TC SUPECONDUCTIVITY IN SINTERED SAMPLES OF BA-Y-CU-O AND OTHER ALKALINE EARTH AND RARE EARTHCUPERATE PEROVSKITES. SUPERCONDUCTING HIGH-TC THIN FILMS HAVE ALSO BEEN FORMED, ALTHOUGH IT IS MORE DIFFICULT TO CONTROL THE STOICHIOMETRY AND CRYSTALLINITY OF THIN FILMS THAN IN BULK SAMPLES. THE PROPOSED PROGRAM WILL USE ION IMPLANTA- TION TO TAILOR THE CHEMICAL COMPOSITION AND CRYSTAL STRUC- TURE OF CUPRATE PEROVSKITES TO INDUCE OR ENHANCE HIGH-TC SUPERCONDUCTIVITY IN THIN FILMS. BARIUM, YTTRIUM, COPPER, OXYGEN OR COMBINATIONS OF THESE ELEMENTS WILL BE ION IMPLAN-TED INTO EVAPORATED AND SPUTTER-DEPOSITED FILMS OF BA-Y-CU-OCOMPOUNDS. THE ION IMPLANTATION DOSE ENERGY SUBSTRATE TEM PERATURE AND APPEALING PARAMETERS WILL BE VARIED OVER A BROAD RANGE. THE ELECTRICAL AND MAGNETIC PROPERTIES OF THE THIN FILMS WILL BE MEASURED BEFORE AND AFTER ION IMPLANTA- TION AND ANNEALING. THE FACILITIES AND EXPERTISE OF THE M.I.T. FRANCIS BITTER NATIONAL MAGNET LABORATORY WILL BE UTILIZED, ALONG WITH THOSE OF SPIRE CORPORATION IN ALL TASKSOF THE RESEARCH. A SUCCESSFUL PHASE I DEMONSTRATION OF HIGHTC SUPERCONDUCTIVITY INDUCED BY ION IMPLANTATION INTO NON- SUPERCONDUCTING THIN FILMS WOULD LEAD TO A PHASE II PROGRAM IN WHICH THE TECHNIQUE WOULD BE FURTHER DEVELOPED ANALYZED THEORETICALLY AND EXPERIMENTALLY AND STEPS WOULD BE TAKEN TOWARD PHASE III COMMERCIALIZATION.