Relationship between MgO particles addition and critical current density in Bi-2212 thick film grown on oxidized Ni substrate

AbstractMeasurements of the critical current density Jc for ultrathin YBa2Cu307‐X (YBCO) films are presented.A high Jc value at 77K in zero field of 2xl06A/cm2 was obtained in a 30nm thick film and even a 5nm thick film could carry a supercurrent of 3.5x105 A/cm2 at 4.2K in zero field. A very weak field‐dependence of Jc was observed when the field was in the (a,b) plane showing greatly depressed dissipation.

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THREE-DIMENSIONAL TlBaCaCuO THICK FILM DC SQUID

Modern Physics Letters B ◽

10.1142/s0217984993000618 ◽

1993 ◽

Vol 07 (09) ◽

pp. 633-639

Author(s):

YUHUA HUO ◽

SHOUZHEN ZHAO ◽

FANGWU SHAO ◽

CHANGCHUN WEI ◽

LINGWEN ZENG ◽

...

Keyword(s):

Thin Film ◽

Critical Current Density ◽

Thick Film ◽

Critical Current ◽

Current Density ◽

Screen Printing ◽

Three Dimensional ◽

Bias Current ◽

Zero Resistance ◽

Dc Bias

TlBaCaCuO thick films were fabricated by the method of screen printing. Zero resistance temperature of 110 K–118 K and critical current density of about 102 A/cm 2 at 77 K were obtained. The thickness of the film was about 30 μm. Using the thick film we have fabricated three-dimensional DC SQUID. The flux modulated V–I curve, V–H curve, and triangular patterns in response to flux applied at the different dc bias current were measured. The results showed that not only TlBaCaCuO thick film DC SQUID was like that from TlBaCaCuO thin film in good microwave behaviour but also the processes of fabricating thick film DC SQUID were easy.

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Microstructural characterization of YBa2Cu3O7-x thin films formed by metalorganic CVD

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089718 ◽

1991 ◽

Vol 49 ◽

pp. 1080-1081

Author(s):

P. Lu ◽

W. Huang ◽

C.S. Chern ◽

Y.Q. Li ◽

J. Zhao ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Film Growth ◽

Chemical Vapor ◽

Microstructural Characterization ◽

Ion Milling ◽

Conventional Grinding

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164155 ◽

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.

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