Critical current in HgBa2CuOy

1994 ◽  
pp. 331-334 ◽  
Author(s):  
R. Usami ◽  
R. Puzniak ◽  
S. Takano ◽  
C.-J. Liu ◽  
J. Wang ◽  
...  
Keyword(s):  
Author(s):  
P. Lu ◽  
W. Huang ◽  
C.S. Chern ◽  
Y.Q. Li ◽  
J. Zhao ◽  
...  

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.


Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock

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.


2007 ◽  
Vol 463-465 ◽  
pp. 630-632 ◽  
Author(s):  
A. Kinoshita ◽  
K. Takahashi ◽  
H. Kobayashi ◽  
Y. Yamada ◽  
A. Ibi ◽  
...  

1991 ◽  
Vol 58 (11) ◽  
pp. 1205-1207 ◽  
Author(s):  
R. H. Ono ◽  
L. F. Goodrich ◽  
J. A. Beall ◽  
M. E. Johansson ◽  
C. D. Reintsema

2013 ◽  
Vol 10 (4) ◽  
pp. 689-692 ◽  
Author(s):  
Galina Mikhailova ◽  
Landysh Antonova ◽  
Irina Borovitskaya ◽  
Oleg Krokhin ◽  
Alexey Majorov ◽  
...  
Keyword(s):  

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 886
Author(s):  
Xiaoyue Tan ◽  
Wujie Wang ◽  
Xiang Chen ◽  
Yiran Mao ◽  
Andrey Litnovsky ◽  
...  

The tungsten (W) foil laminate is an advanced material concept developed as a solution for the low temperature brittleness of W. However, the deformed W foils inevitably undergo microstructure deterioration (crystallization) during the joining process at a high temperature. In this work, joining of the W foil laminate was carried out in a field-assisted sintering technology (FAST) apparatus. The joining temperature was optimized by varying the temperature from 600 to 1400 °C. The critical current for mitigating the microstructure deterioration of the deformed W foil was evaluated by changing the sample size. It is found that the optimal joining temperature is 1200 °C and the critical current density is below 418 A/cm2. According to an optimized FAST joining process, the W foil laminate with a low microstructure deterioration and good interfacial bonding can be obtained. After analyzing these current profiles, it was evident that the high current density (sharp peak current) is the reason for the significant microstructure deterioration. An effective approach of using an artificial operation mode was proposed to avoid the sharp peak current. This study provides the fundamental knowledge of FAST principal parameters for producing advanced materials.


Sign in / Sign up

Export Citation Format

Share Document