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Evaluation of grain-coupling strength of YBaCuO superconductors by their magnetic-field profile measurements

Conference · · IEEE Trans. Magn.; (United States)
OSTI ID:5916892

In order to evaluate the strength of intergrain coupling, which determines the transport critical-current of polycrystalline oxide superconductors, the authors have studied the relation between the transport critical-current and the spatial distribution of the magnetic flux density for YBaCuO thin films as well as bulk superconductors. They have measured the profile of the magnetic flux trapped inside bulk YBaCuO samples with a small Hall magnetic sensor, and revealed the correlation between critical current densities and the slope of the trapped-flux profile, as can be described by the critical state model. The measurement of the magnetic-field penetration depth of YBaCuO thin films in a Meissner state is also carried out by measuring of the loop inductance of a dc SQUID which is place don the YBaCuO thin film to be measured. Observed magnetic-field penetration depths of polycrystalline films with thickness of 1-3..mu..m deposited on MgO single-crystal substrates amount to --1..mu..m for samples with T/sub c'end/--80K and the critical current density j/sub c/--10'A/cm/sup 2/ at 4.2K.

Research Organization:
3655500
OSTI ID:
5916892
Report Number(s):
CONF-880812-
Journal Information:
IEEE Trans. Magn.; (United States), Journal Name: IEEE Trans. Magn.; (United States) Vol. 25:2; ISSN IEMGA
Country of Publication:
United States
Language:
English