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Title: Irreversibility line in superconductor as line of constant shielding current density

Journal Article · · Advances in Cryogenic Engineering
OSTI ID:482060
;  [1];  [2]
  1. Institute of Electrical Engineering, Bratislava (Slovakia)
  2. Technical Univ. Vienna (Austria); and others

The irreversibility of magnetic properties of superconductors is due to the existence of macroscopic shielding currents persisting for some period of time. The same currents offer nearly lossless electricity transport. Thus, the extent of magnetic irreversibility is directly proportional to the current-carrying capacity of a superconductor. Because the current-carrying capacity is an intrinsic property of the material, various experimental techniques should give the same irreversibility line corresponding to the same macroscopic shielding current density. Following this approach, the authors compared the irreversibility lines obtained from AC susceptibility measurement with those determined from quasistatic magnetization loops recorded with the help of a SQUID susceptometer. An additional parameter which has to be comparable is the electrical field characterizing the rate of change of the magnetic field. Fulfilling these conditions of equivalency, the authors found that it is possible to explain the irreversibility lines obtained by various techniques and at different conditions by the same physical model. They demonstrate that for the data, taken within two orders of magnitude for the current density and more than seven orders of magnitude for the electrical field, a consistent picture expressing all the observed features by the same model can be found. Measurements are presented from YBCO samples.

OSTI ID:
482060
Report Number(s):
CONF-950722-; ISSN 0065-2482; CNN: Contract GAV 2/1087/1994; Contract OWP-35; TRN: 97:001732-0010
Journal Information:
Advances in Cryogenic Engineering, Vol. 42B; Conference: CEC/ICMC `95: cryogenic engineering conference and international cryogenic materials conference, Columbus, OH (United States), 17-21 Jul 1995; Other Information: PBD: 1997
Country of Publication:
United States
Language:
English