Effects of microstructure on flux pinning in epitaxial YBa sub 2 Cu sub 3 O sub x films

Journal Article · Tue Oct 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.7607· OSTI ID:5236877

Kim, D H; Miller, D J; Smith, J C; Holoboff, R A ^[1]; Kang, J H; Talvacchio, J ^[2]

---

1. Materials Science Division, Argonne National Laboratory, Argonne, Illinois (USA)
2. Westinghouse Science and Technology Center, Pittsburgh, Pennsylvania (USA)

The role of microstructure on flux pinning in {ital c}-axis-oriented epitaxial YBa{sub 2}Cu{sub 3}O{sub {ital x}} films grown on LaAlO{sub 3} and SrTiO{sub 3} has been studied. For a magnetic field parallel to the Cu-O planes, the resistivity and critical current density {ital J}{sub {ital c}} have been measured as a function of the angle {theta} between the applied field and the direction of the transport current. In addition to a Lorentz-force-independent resistivity, the Lorentz-force-dependent component showed several broad deviations from sin{sup 2}{theta} when a field was aligned parallel to certain microstructural features which vary with the film thickness and substrate material. These features were identified by transmission-electron-microscopy analysis. For films of 5000 A thickness on LaAlO{sub 3}, resistivity dips were observed for a field applied parallel to the {ital substrate} twin boundaries or along misoriented {ital a}-axis grains. In thinner films of 900 A thickness also on LaA1O{sub 3} in which {ital a}-axis grains were negligible, we observed dips corresponding to the orientation of {ital substrate} twin boundaries only. For thin films on SrTiO{sub 3} in which substrate twins are absent, resistivity dips corresponding to the direction of twin boundaries in the {ital film} and, perhaps, interfacial dislocations were observed. Overall, such dips decreased with increasing transport current density and became negligible in {ital J}{sub {ital c}} measurements.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5236877
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:14; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
AMINES
AMMONIUM COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
EPITAXY
FILMS
HIGH-TC SUPERCONDUCTORS
MAGNETIC FLUX
MICROSTRUCTURE
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
QUATERNARY COMPOUNDS
SUPERCONDUCTING FILMS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES