Av. Bobyl et al., Symmetry of the remanent-state flux distribution in superconducting thin strips: Probing the critical state - art. no. 184510, PHYS REV B, 6318(18), 2001, pp. 4510
The critical-state in a thin strip of YBa2Cu3O7-delta a is studied by magne
to-optical imaging. The distribution of magnetic flux density is shown to h
ave a specific symmetry in the remanent state after a large applied field.
The symmetry was predicted [Phys. cRev. Lett. 82, 2947 (1999)] for any j(c)
(B), and is therefore suggested as simple tool to verify the applicability
of the critical-slate model. At large temperatures we find deviations from
this symmetry, which demonstrates a departure from the critical-state behav
ior. The observed deviations can be attributed to an explicit coordinate de
pendence of j(c) since both a surface barrier and flux creep would break th
e symmetry in a different way.