The role of the voltage criterion in the interpretation of flux pinning in epitaxial films of YBa2Cu3O7
作者:
R. Wo¨rdenweber,
M. O. Abd‐El‐Hamed,
期刊:
Journal of Applied Physics
(AIP Available online 1992)
卷期:
Volume 71,
issue 2
页码: 808-812
ISSN:0021-8979
年代: 1992
DOI:10.1063/1.351298
出版商: AIP
数据来源: AIP
摘要:
The determination of the critical current is usually based upon a voltage criterion that is used as an indication that the critical state has been reached in the superconducting regime. Resistive measurements of theI‐Vcharacteristics are carried out on patterned thin films of epitaxially grown andc‐axis‐oriented YBa2Cu3O7. Bridges with widths ranging between 1 and 100 &mgr;m and lengths between a few &mgr;m and 7 mm are characterized. The sensitivity of the measurement is better than 10−9V. The volume pinning force is evaluated for different voltage criteria. Although the absolute values of the volume pinning force change with the value of the criteria, the field and temperature scaling is not affected. They agree with the expectations of the flux‐line sheer model. The value obtained for the width of the weakly pinning channels is independent of the chosen criterion. Finally, model calculations on the basis of a modified flux‐line shear mechanism are carried out that are in good agreement with the experimentally measuredI‐Vcharacteristics.
点击下载:
PDF
(666KB)
返 回