IN SITU THALLIUM FILMS BY LASER ABLATION

IT IS GENERALLY ACCEPTED THAT THE BEST HIGH TEMPERATURE SUPERCONDUCTING FILMS WILL BE EPITAXIALLY GROWN ON SINGLE CRYSTAL SUBSTRATES AND THAT THE PREFERRED ROUTE WILL BE VIA VAPOR PHASE DEPOSITION TECHNIQUES. THE HIGHEST QUALITY FILMS OF YBCO HAVE BEEN PRODUCED USING VAPOR PHASE DEPOSITION, BUT THE BEST FILMS IN THE THALLIUM SYSTEM HAVE BEEN PRODUCED VIA POST DEPOSITION ANNEALLING. PRELIMINARY EXPERIMENTS AT STI HAVE DEMONSTRATED THAT IT IS POSSIBLE TO GROW AT LEAST ONE PHASE OF THE THALLIUM FAMILY (1122) ON A SINGLE CRYSTAL SUBSTRATE (THAT IS MICROWAVE COMPATIBLE) BY LASER ABLATION IN THE PRESENCE OF ACTIVE OXYGEN. THE RESEARCH PROPOSED HERE ADDRESSES TWO PROBLEMS FACING THE SUCCESSFUL GROWTH OF THALLIUM FILMS VIA VAPOR DEPOSITION TECHNIQUES. THESE FILMS SHOULD HAVE FAR SUPERIOR PROPERTIESTO THOSE FILMS PRODUCED BY POST DEPOSITION ANNEAL.ING. INNOVATIVE TECHNIQUES TO CONTROL BOTH OXYGEN ACTIVITY AND THALLIUM VOLATILITY WILL BE TESTED IN PHASE I TO PROVE FEASIBILITY.