PRODUCTION OF SUBSTRATES FOR SUPERCONDUCTING THIN FILMS

THIN FILMS BASED ON YBU2CU3O7 (YBCO) HAVE SHOWN POTENTIAL FOR SUPERCONDUCTING DEVICES; HOWEVER, THESE DEVICES ARE LIMITED IN PERFORMANCE BY THE AVAILABILITY OF SUITABLE SUBSTRATES. BEST RESULTS HAVE BEEN OBTAINED WITH PEROVSKITE SUBSTRATES, LAALO3 AND LAGAO3; HOWEVER THEIR PHASE TRANSITIONS PRESENT PROBLEMS. THE IDEAL SUBSTRATES MUST MEET STRINGENT CRYSTALLOGRAPHIC, ELECTRICAL, MAGNETIC AND DIELECTRIC PROPERTIES. BASED ON AVAILABLE DATA LASRALO4 AND LAO.33NBO3 COMPOUNDS HAVE BEEN PROPOSED FOR SUBSTRATE APPLICATIONS. THESE MATERIALS ARE CURRENTLY NOT AVAILABLE. DURING THE PROPOSED PROGRAM SYNTHESIS OF LASRALO4 AND LA0.33NBO3 WILL BE INVESTIGATED IN DETAIL. IT IS INTENDED TO UTILIZE THE HEAT EXCHANGER METHOD (HEM) FOR DIRECTIONAL SOLIDIFICATION. THE MELTING AND SOLIDIFICATION BEHAVIOR, REACTIVITY WITH CRUCIBLE, AND HEAT TRANSFER PARAMETERS WILL BE DIED TO ESTABLISH VIABILITY FOR GROWTH OF LARGE SINGLE CRYSTALS. SAMPLES WILL BE EVALUATED FOR SUITABILITY OF THESE MATERIALS FOR SUBSTRATES FOR THIN FILM SUPERCONDUCTING DEVICES.