Superconductivity in nonsymmetric epitaxial YBa sub 2 Cu sub 3 O sub 7-. delta. -PrBa sub 2 Cu sub 3 O sub 7-. delta. superlattices grown by pulsed laser ablation

Conference · Sun Apr 01 04:00:00 EDT 1990

OSTI ID:6947700

Lowndes, D H; Norton, D P; Budai, J D; Pennycook, S J; Christen, D K; Sales, B C; Feenstra, R

Pulsed KrF (248 nm) excimer laser ablation has been used to grow nonsymmetric epitaxial YBCO/PrBCO superlattices containing 1-, 2-, 3-, 4-, and 8-unit-cell-thick YBCO layers, separated by N-cell-thick insulating PrBCO layers (N = 1 {minus} 16). The 1 {times} N and 2 {times} N structures exhibit a rapid initial decrease of T{sub co} with increasing PrBCO layer thickness, followed by saturation of T{sub co} at a nonzero value, as the YBCO layer's separation is increased further. The limiting T{sub co} values for 1-, 2-, 3-, 4-, and 8-cell-thick YBCO layers isolated in a PrBCO matrix are {approximately}19 K {approximately}54 K, {approximately}71 K, {approximately}87 K , respectively. Single-cell-thick YBCO layers are found to be superconducting even when separated by {approximately}19 nm in a PrBCO matrix. These results are discussed in terms of possible Josephson and/or proximity effects coupling the YBCO layers, and the possibility that PrBCO modifies the electronic structure and depresses T{sub co} in YBCO cells that are immediately adjacent to the PrBCO layers. Finally, high-temperature post-annealing studies show that these superlattice structures are stable and that little diffusion occurs along the c-axis direction of compositional modulation. 14 refs., 3 figs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6947700
• Report Number(s): CONF-900466-48; ON: DE90011637
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABLATION
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DEPOSITION
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HIGH-TC SUPERCONDUCTORS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
RARE EARTH COMPOUNDS
SCATTERING
SUPERCONDUCTIVITY
SUPERCONDUCTORS
SUPERLATTICES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES