Superconducting properties of magnetron sputtered Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O thin films

Conference · Wed Nov 30 23:00:00 EST 1988

DOI:https://doi.org/10.1007/978-1-4684-5658-5_19· OSTI ID:6422863

Kampwirth, R T; Kang, J H; Gray, K E

Thin films of high temperature superconducting Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O have been made using multiple source magnetron sputtering. We will discuss preparation and annealing and how they affect the superconducting properties. The Bi-based films form in at least two compounds, a lower T/sub c/ phase with a 2212 composition and T/sub c0/ approx. 80 K and a higher T/sub c/ phase with a nominal composition of 2223 and a T/sub c/ approx. 105 K. The higher T/sub c/ phase is very difficult to form so that a complete superconducting path exists, requiring long annealing times at temperatures somewhat below the formation temperature. Although superconducting properties are less sensitive to stoichiometry than YBa/sub 2/Cu/sub 3/O/sub 7-x/, annealing temperatures must be held in a narrow range around 865/degree/C to get the best results. Films prefer growing on (100) MgO in a highly textured polycrystalline form, with the c-axis perpendicular to the plane of the film. The Tl-based films form at least three compounds (2212, 1223, 2223) with T/sub c/'s ranging from approx.100 K to 114 K and grow best on (100) and polycrystalline Y-ZrO/sub 2/ substrates. Annealing conditions are particularily difficult because of the volatility of thallium and require samples to be annealed in sealed capsules with a controlled atmosphere of thallium and oxygen. Upper critical field measurements show a large anisotropy (approx.15 for Bi-Sr-Ca-Cu-O and greater than or equal to70 for Tl-Ba-Ca-Cu-O) in the parallel to perpendicular field slope ratio as might be expected from a highly textured anisotropic structure. 20 refs., 6 figs.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6422863
• Report Number(s): CONF-881127-5; ON: DE89009878
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ANISOTROPY
ANNEALING
BARIUM COMPOUNDS
BISMUTH COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILMS
HEAT TREATMENTS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SAMPLE PREPARATION
SCATTERING
SPUTTERING
STRONTIUM COMPOUNDS
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
THALLIUM COMPOUNDS
THIN FILMS
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION