Title :
Growth and characterization of YBCO/insulator/YBCO trilayers
Author :
Missert, N. ; Reintsema, C.D. ; Beall, J.A. ; Harvey, T.E. ; Ono, R.H. ; Rudman, D.A. ; Galt, D. ; Price, J.C.
Author_Institution :
Nat. Inst. of Stand. & Technol., Boulder, CO, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
Multilevel circuits for high-frequency applications of high-T/sub c/ superconductors require low-dielectric-constant insulators between superconducting layers. Initial studies of CeO/sub 2/ thin films as the insulating layer in YBCO/insulator/YBCO structures revealed insufficient isolation between YBCO layers. Trilayer structures employing thin-film composite dielectrics of CeO/sub 2/ and SrTiO/sub 3/ were therefore investigated. Each layer grows epitaxially with a morphology comparable to that of a single YBCO film. Transport critical current density measurements of the top YBCO layer resulted in J/sub c/=2*10/sup 5/ A/cm/sup 2/ at 77 K, a factor of 10 lower than for single films. Trilayer structures had a microwave surface resistance at 10 GHz and 4 K of 50 mu Omega , comparable to that of single films. Preliminary low-temperature measurements of the dielectric constant of composite insulator structures gave values an order of magnitude lower than for pure SrTiO/sub 3/.<>
Keywords :
X-ray diffraction examination of materials; barium compounds; cerium compounds; composite superconductors; critical current density (superconductivity); high-temperature superconductors; microwave measurement; permittivity; pulsed laser deposition; strontium compounds; superconducting thin films; surface conductivity; yttrium compounds; 10 GHz; 4 K; 50 muohm; 77 K; SEM; X-ray diffraction; YBa/sub 2/Cu/sub 3/O/sub 7-x/-SrTiO/sub 3/-CeO/sub 2/; dielectric constant; epitaxial growth; high-frequency applications; insulating layer; low-temperature measurements; microwave surface resistance; morphology; multilevel circuits; pulsed laser deposition; thin-film composite dielectrics; transport critical current density; trilayer structure; Circuits; Dielectric measurements; Dielectric thin films; Dielectrics and electrical insulation; Electrical resistance measurement; Superconducting epitaxial layers; Superconducting thin films; Superconductivity; Surface resistance; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
