Title :
Superconducting Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ thin films prepared by post-annealing in a flow-through multiple-zone furnace
Author :
Pluym, T. ; Muenchausen, R.E. ; Arendt, P.N. ; Wu, X.D. ; Mueller, F.M. ; Campbell, I.H. ; Jia, Q.X. ; Hawley, M.W. ; Peterson, E.J. ; Tiwari, P. ; Holstein, W.L.
Author_Institution :
Los Alamos Nat. Lab., NM, USA
fDate :
6/1/1995 12:00:00 AM
Abstract :
Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ thin films mere prepared first time by use of a multiple-zone flow-through thallination process. Thallous oxide was volatilized from condensed thallium oxide in a low temperature source zone and convectively transported to a higher temperature thallination zone in which initially amorphous Ba/sub 2/CaCu/sub 2/O/sub 5/ precursor films were located. By careful control of the source temperature, film temperature, flow rate, anneal time, and rates of heat up and cool down, smooth Tl/sub 2/Ba/sub 2/CaCuO/sub 8/ thin films ware prepared on [100] LaAlO/sub 3/ with the following properties: inductive T/sub c/ of 107.6 K and 80% transition width of 1.3 K, transport J/sub c/ at 75 K of 1.3/spl times/10/sup 5/ A/cm/sup 2/, and R/sub s/ at 10 GHz and 80 K of 1.3 m/spl Omega/. The scalability of the process to large area film processing was demonstrated by the preparation of Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ thin films on LaAlO/sub 3/ three-inch diameter wafers.<>
Keywords :
annealing; barium compounds; calcium compounds; chemical vapour deposition; critical current density (superconductivity); high-temperature superconductors; superconducting thin films; superconducting transition temperature; surface conductivity; thallium compounds; 1.3 mohm; 10 GHz; 107.6 K; 80% transition width; Ba/sub 2/CaCu/sub 2/O/sub 5/; LaAlO/sub 3/; Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/; Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ thin films; [100] LaAlO/sub 3/ substrate; amorphous Ba/sub 2/CaCu/sub 2/O/sub 5/ precursor films; anneal time control; convective transport; cool down rate; critical current density; critical temperature; film temperature control; flow rate control; flow-through multiple-zone furnace; heat up rate; large area film processing; multiple-zone flow-through thallination; post-annealing; scalability; source temperature control; surface resistance; Amorphous materials; Laboratories; Optical films; Optical microscopy; Powders; Superconducting films; Superconducting microwave devices; Superconducting thin films; Superconducting transition temperature; Transistors;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
