Preparation and characterization of Tl sub 2 Ba sub 2 CaCu sub 2 O sub 8 films on (100) LaAlO sub 3

Conference · Fri Mar 01 00:00:00 EST 1991 · IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (United States)

OSTI ID:5932332

Holstein, W L; Parisi, L A; Kountz, D J; Wilker, C; Matthews, A L ^[1]; Arendt, P N ^[2]; Taber, R C ^[3]

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1. Central Research and Development Dept., Du Pont, P.O. Box 80304, Wilmington, DE (US)
2. Los Alamos National Lab., NM (United States)
3. Superconductivity Lab., Hewlett Packard, Palo Alto, CA (US)

A two-step process for the fabrication of 0.12-1.20 {mu}m-thick Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8} films on (100) LaAlO{sub 3} has been developed. The process involves the deposition of a BaCaCuO precursor film at low temperature by rf magnetron sputtering, followed by annealing in the presence of Tl{sub 2}O vapor to convert the precursor film into Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8}. Over a distance of 4 cm, film composition was Tl:Ba:Ca:Cu = 2.05 {plus minus} 0.09:2.05 {plus minus} 0.06:1.0 {plus minus} 0.3:1.94 {plus minus} 0.6 and thickness was uniform to within 6%. The films contain only trace quantities of secondary phases and are epitaxially oriented, with the c-axis of Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8} perpendicular to the surface and the two a-axes aligned with the pseudo-cubic a-axes of the underlying LaAlO{sub 3} substrate. Films had a T{sub c} for zero dc resistivity of 106.5 {plus minus} 0.5 K,a transport critical current density for continuous current of 2.9 {times} 10{sup 6} A-cm{sup {minus}2} at 77 K, and a sharp ({lt}0.3{degrees} C) ac inductance transition with an onset temperature of 105 {plus minus} 2 K. Surface resistance at 20 GHz less than 2 m{Omega}, about 10X lower than Cu, was routinely achieved for temperatures below 90 K and, for the best films, at temperatures up to 100 K. Surface resistance at about 10 GHz on one film was 0.067 m{Omega} at 4.2 K, 0.36 m{Omega} at 77 K, and 0.74 m{Omega} at 90 K. Films have been reproducibly fabricated on substrates up to 2.54 cm square.

• OSTI ID: 5932332
• Report Number(s): CONF-900944-; CODEN: IEMGA
• Journal Information: IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (United States), Vol. 27:2; Conference: 1990 applied superconductivity conference, Snowmass, CO (United States), 24-28 Sep 1990; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
ANNEALING
DEPOSITION
PHYSICAL PROPERTIES
CALCIUM OXIDES
COPPER OXIDES
THALLIUM OXIDES
ALUMINIUM OXIDES
CRITICAL CURRENT
CRITICAL TEMPERATURE
CURRENT DENSITY
LANTHANUM OXIDES
SPUTTERING
SUBSTRATES
THIN FILMS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
CURRENTS
ELECTRIC CURRENTS
FILMS
HEAT TREATMENTS
LANTHANUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
THALLIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360204 - Ceramics
Cermets
& Refractories- Physical Properties