The activation entropy for ionic conduction and critical current density for Li charge transfer in novel garnet-type Li6.5La2.9A0.1Zr1.4Ta0.6O12 (A = Ca, Sr, Ba) solid electrolytes

Formation of the high temperature Bi-2223 phase has been studied for samples with nominal composition Bi 3,2-x Pb 0.8 M x Sr 4 Ca 5 Cu 7 O y. M represented V, Nb, Ta, their contents was altered from 0 to 0.6 mol %. The effect of the additives on the growth of the phase 2223, lattice parameters and the superconducting properties of the samples was detected. It was found that the additives enhanced the volume of the 2223 phase, improved the intergrain connection resp. the critical current density. The additives did not affect the lattice parameters and T c significantly.

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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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