Orientation dependence of grain-boundary critical current densities in high-Tcbicrystals

1995 ◽  
Vol 51 (10) ◽  
pp. 6792-6795 ◽  
Author(s):  
T. Amrein ◽  
L. Schultz ◽  
B. Kabius ◽  
K. Urban
Keyword(s):  
Grain Boundary ◽  
Critical Current ◽  
Orientation Dependence ◽  
Current Densities

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

MgB2 films with very high critical current densities due to strong grain boundary pinning

2004 ◽  
Vol 85 (14) ◽  
pp. 2842-2844 ◽  
Author(s):  
H. Kitaguchi ◽  
A. Matsumoto ◽  
H. Kumakura ◽  
T. Doi ◽  
H. Yamamoto ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Critical Current ◽  
Current Densities ◽  
Grain Boundary Pinning ◽  
Very High

scholarly journals Improved critical current densities in MgB2 tapes with ZrB2 doping

2006 ◽  
Vol 89 (13) ◽  
pp. 132510 ◽  
Author(s):  
Xianping Zhang ◽  
Zhaoshun Gao ◽  
Dongliang Wang ◽  
Zhengguang Yu ◽  
Yanwei Ma ◽  
...  
Keyword(s):  
Critical Current ◽  
Current Densities

Extraction of anisotropic critical current densities and flux pinning potentials

Cryogenics ◽  
1994 ◽  
Vol 34 (4) ◽  
pp. 329-334
Author(s):  
H.L Ji ◽  
Z.X Shi ◽  
Z.Y Zeng ◽  
X Jin ◽  
H.C Fan ◽  
...  
Keyword(s):  
Critical Current ◽  
Flux Pinning ◽  
Current Densities

Characterization of Epitaxial Superconducting YBacuO Thin Films with Three Different Orientations

1989 ◽  
Vol 169 ◽  
Author(s):  
X.K. Wang ◽  
D.X. Li ◽  
S.N. Song ◽  
J.Q. Zheng ◽  
R.P.H. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Orientation Dependence ◽  
Zero Field ◽  
Epitaxial Thin Films ◽  
Oriented Film ◽  
Zero Resistance ◽  
Xrd Patterns

AbstractEpitaxial thin films of YBaCuO were prepared by multilayer deposition from Y, Cu, and BaF2 sources with: (1) the a‐axis perpendicular to (100)SrTiO3; (2) the c‐axis perpendicular to (100)SrTiO3; and (3) the [110] axis perpendicular to (110)SrTiO3. XRD patterns as well as SEM and HREM images confirm that the films are highly oriented, essentially epitaxial. Both the a‐axis oriented and the c‐axis oriented films exhibit zero resistance at 91K. The [110] oriented film shows the sharpest transiton with a transition width of IK and zero resistance at 85K. The zero field critical current density, Jc, determined magnetically, is in excess of 107A/cm2 at 4.4K and 1.04 x 106A/cm2 at 77K for the c‐axis oriented film; for the a‐axis oriented film we obtained 6.7 x 106A/cm2 at 4.4K and 1.2 x 105A/cm2 at 77K. The orientation dependence of the critical current density in the basal plane of the a‐axis oriented film was studied. The largest Jc's occur along the in‐plane <100> axes of the substrate.

scholarly journals Magnetically modulated critical current densities of Co/Nb hybrid

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Zhigang Li ◽  
Weike Wang ◽  
Li Zhang ◽  
Zhaorong Yang ◽  
Mingliang Tian ◽  
...  
Keyword(s):  
Critical Current ◽  
Current Densities

Structure and Functional Properties of Bulk MgB2 Superconductors Synthesized and Sintered under Pressure

2014 ◽  
Vol 792 ◽  
pp. 21-26 ◽  
Author(s):  
Tatiana Prikhna ◽  
Michael Eisterer ◽  
Wolfgang Gawalek ◽  
Athanasios G. Mamalis ◽  
Artem Kozyrev ◽  
...  
Keyword(s):  
Critical Current ◽  
Material Structure ◽  
Bulk Materials ◽  
Critical Fields ◽  
Current Densities ◽  
Upper Critical Fields ◽  
Irreversibility Fields ◽  
Grain Boundary Pinning ◽  
Effect Of Oxygen ◽  
Oxygen Impurities

The high pressure (50 MPa - 2 GPa) – high temperature synthesized MgB2 bulk materials are characterized by nearly theoretical density (1-2% porosity), 80-98% connectivity, extremely high critical current densities (e.g. at 20 K, in 0–1 T jc=1.3–1.0 MA·cm-2 (with 10% SiC) and jc= 0.92 – 0.73 MA·cm-2 (without doping)), large irreversibility fields (Birr(18.4 K) =15 T and Birr (0 K) = 32.5 T) and high upper critical fields (Bc2 (22 K) =15 T and Bc2(0 K) ~ 42.1 T). The transformation of grain boundary pinning to point pinning in MgB2-based materials with increasing manufacturing temperature (from 800 to 1050 oC) under pressures from 0.1 to 2 GPa correlates well with an increase in critical current density in low external magnetic fields caused by the redistribution of boron and the oxygen impurities in the material structure. As the manufacturing temperature increases, the discontinuous oxygen enriched layers transform into distinct Mg-B-O inclusions and the size and amount of inclusions of higher magnesium borides MgBX (X>4) are reduced. The effect of oxygen and boron redistribution can be enhanced by Ti or SiC additions.

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