Analysis of magnetic relaxation in a thin disk of YBa2Cu3O7-delta superconductor

The relaxation of the magnetic moment of a thin disk of YBa2Cu3O7-delta sup erconductor in a perpendicular magnetic field shows a logarithmic dependenc e on time for the examined temperature range T = 10-60 K. The analysis of t he relaxation data is done within an analytical model. The field and temper ature dependencies of the critical current j(c) and the pinning potential U -o are estimated by fitting the relaxation data. Furthermore the E vs j cha racteristics are quantitatively derived from the relaxation data at the cir cumference of the disk. (C) 2001 Elsevier Science B.V. All rights reserved.