Title :
Microstructural, transport, and RF properties of multilayer-deposited YBCO films
Author :
Madhavrao, L. Rao ; Track, E.K. ; Drake, R.E. ; Patt, R. ; Hohenwarter, G.K.G. ; Radparvar, M.
Author_Institution :
Hypres Inc., Elmsford, NY, USA
fDate :
3/1/1991 12:00:00 AM
Abstract :
Thin films of Y1Ba2Cu3O7-x (YBCO) have been fabricated by sequential multilayer RF magnetron sputter-deposition from Y2O3, BaCo3, and CuO targets and postannealing in oxygen. This approach readily allows precise control of the film stoichiometry and is promising for applications that require deposition over large areas. Films on different substrates-including SrTiO3, LaAlO3, MgO and sapphire-are found to be c-axis oriented for film thicknesses between 300 Å and 10000 Å. Transport current densities in the range of 106 A/cm2 are obtained on SrTiO3 and LaAlO3 substrates and in the range of 105 A/cm2 on MgO and sapphire. Transition temperatures of 89 K (resistive) and 87 K (inductive) are obtained repeatably with LaAlO 3 substrates. Copper cavity end wall measurements at 77 K and 35.6 GHz set an upper limit for the surface resistance of the YBCO films on LaAlO3 that is equal to the surface resistance of high-quality silver films. The fabrication and properties of these films are discussed
Keywords :
annealing; barium compounds; crystal microstructure; high-temperature superconductors; sputtered coatings; stoichiometry; superconducting thin films; superconducting transition temperature; yttrium compounds; 300 to 10000 Å; 35.6 GHz; 77 K; 87 K; 89 K; Al2O3; Cu cavity end wall measurements; LaAlO3; MgO; SrTiO3; Y1Ba2Cu3O7-x; film stoichiometry; high temperature superconductors; microstructural properties; postannealing; sapphire; sequential multilayer RF magnetron sputter-deposition; superconductor transition temperatures; surface resistance; transport current densities; Current density; Electrical resistance measurement; Magnetic multilayers; Radio frequency; Silver; Sputtering; Substrates; Surface resistance; Temperature; Yttrium barium copper oxide;
Journal_Title :
Magnetics, IEEE Transactions on
