Spread of critical currents in thin-film YBa/sub 2/Cu/sub 3/O/sub 7-x/ bicrystal junctions

A problems with bulk high temperature superconductors for some time has been obtaining specimens which show high critical currents; typical critical currents in bulk materials lie in the range of 103 Amps/cm2 whereas thin film specimens now routinely reach the 106 Amps/cm2 range. There has recently been indications of higher critical currents in some materials, with suggestions that there is flux pinning by 1/3(301) type defects. We have previously studied in some detail bulk materials with excess copper that contain large number of such defects. In the light of the recent results, we have returned to these materials to study the critical current in addition to the structure.Details of the specimen preparation will be reported elsewhere. The key point is that with the correct preparation conditions, the bulk materials show a fairly sharp transition at 9IK and magnetization measurements indicate (reproducibly) a Jc of more than 106 at 4.5K, using the total size of the specimen and not a smaller grain size.

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Fabrication and critical currents of thin-film-type Bi2Sr2CaCu2Ox intrinsic Josephson junctions

Physica C Superconductivity ◽

10.1016/s0921-4534(01)00682-7 ◽

2001 ◽

Vol 362 (1-4) ◽

pp. 256-260 ◽

Cited By ~ 8

Author(s):

H. Fujino ◽

Y. Kasai ◽

H. Ota ◽

S. Migita ◽

H. Yamamori ◽

...

Keyword(s):

Thin Film ◽

Josephson Junctions ◽

Critical Currents ◽

Intrinsic Josephson Junctions ◽

Film Type

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Anomalous critical currents in split planar thin-film superconductors

Solid State Communications ◽

10.1016/0038-1098(79)91039-1 ◽

1979 ◽

Vol 29 (3) ◽

pp. 205-208 ◽

Cited By ~ 4

Author(s):

G. Dharmadurai ◽

B.A. Ratnam

Keyword(s):

Thin Film ◽

Critical Currents

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Thin-film synthesis of superconductor-on-insulator A15 vanadium silicide

Scientific Reports ◽

10.1038/s41598-021-82046-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Wenrui Zhang ◽

Anthony T. Bollinger ◽

Ruoshui Li ◽

Kim Kisslinger ◽

Xiao Tong ◽

...

Keyword(s):

Thin Film ◽

Critical Temperature ◽

Photoelectron Spectroscopy ◽

Critical Currents ◽

Critical Magnetic Field ◽

Silicon On Insulator ◽

X Ray ◽

Film Synthesis ◽

Silicon Device ◽

A15 Phase

AbstractWe present a new method for thin-film synthesis of the superconducting A15 phase of vanadium silicide with critical temperature higher than 13 K. Interdiffusion between a metallic vanadium film and the underlying silicon device layer in a silicon-on-insulator substrate, at temperatures between 650 and 750 °C, favors formation of the vanadium-rich A15 phase by limiting the supply of available silicon for the reaction. Energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction verify the stoichiometry and structure of the synthesized thin films. We measure superconducting critical currents of more than 106 amperes per square centimeter at low temperature in micron-scale bars fabricated from the material, and an upper critical magnetic field of 20 T, from which we deduce a superconducting coherence length of 4 nm, consistent with previously reported bulk values. The relatively high critical temperature of A15 vanadium silicide is an appealing property for use in silicon-compatible quantum devices and circuits.

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Scanning Electron Microscope Study of Superconducting Transport in a YBa2Cu3O7-δ thin film

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152859 ◽

1989 ◽

Vol 47 ◽

pp. 176-177

Author(s):

R. C. Farrow ◽

Don Monroe ◽

W. S. Brocklesby ◽

M. Hong

Keyword(s):

Thin Film ◽

Electron Microscope ◽

Scanning Electron Microscope ◽

Local Heat ◽

Beam Current ◽

Critical Currents ◽

Weak Links ◽

Scanning Electron Microscope Study ◽

Temperature Bias ◽

Scanning Electron

By combining electron probing with current biasing at low temperatures a map of the transport characteristics of a mixed phase thin film superconductor can be obtained. The electron beam of a scanning electron microscope (SEM) acts as a local heat source. Under the proper conditions of temperature, bias current, and beam current, variations in the superconducting state can be mapped and compared to microstructure and chemical phase information. This method has recently been applied to high Tc superconductors to map critical currents and to identify weak links in superconducting paths. We discuss here the possible application of the technique to identify the superconducting phase within a matrix of non-superconducting material.The sample was an ∼1 μm thin film that was grown by sputtering from a YBa2Cu3O7-δ target onto a [001] SrTiO3 substrate. A more detailed description of the growth procedure is given elsewhere. The morphology, crystallinity, and stoichiometry of the samples were characterized in the SEM. The film had several chemical phases and a morphology consisting of large rectangular platelets (typical size 200х50 μm), covering ∼20-30% of the surface.

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