Title :
Low temperature phase formation of Tl-based superconducting thin films in reduced oxygen atmosphere
Author :
Wu, C.Y. ; Foong, F. ; Liou, S.H. ; Ho, J.C.
Author_Institution :
Center for Mater. Res. & Anal., Nebraska Univ., Lincoln, NE, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
Tl-Ba-Cu-Cu-O superconducting thin films were prepared by magnetron sputtering with postannealing in a reduced oxygen atmosphere. Single-phase Tl/sub 2/Ba/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ can form on the MgO substrate at 800 degrees C under P(O/sub 2/) approximately=0.1 atm. However, the phase formation temperature can be affected by the starting composition of the film. Tl/sub 1/Ba/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ phase can be formed by simply lowering the Tl/sub 2/O pressure. The thermal stability of Tl/sub 1/Ba/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ phase was studied by resistivity measurements at high temperatures.<>
Keywords :
X-ray diffraction examination of materials; annealing; barium compounds; calcium compounds; ceramics; high-temperature superconductors; sputtered coatings; superconducting thin films; thallium compounds; 800 degC; HTSC; MgO substrate; Tl-based superconducting thin films; Tl/sub 1/Ba/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/; XRD; magnetron sputtering; postannealing; reduced O/sub 2/ environment; resistivity measurements; thermal stability; Atmosphere; Conductivity measurement; High temperature superconductors; Sputtering; Substrates; Superconducting magnets; Superconducting thin films; Temperature measurement; Thermal resistance; Thermal stability;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
