Magnetic relaxation and current-voltage characteristics 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. Data are analyzed within an analytical model. The temperature dependencies of the critical cu rrent j(c), and the pinning potential U-0, are estimated by fitting the rel axation data. Furthermore, the E versus j characteristics are quantitativel y derived from the relaxation data at the circumference of the disk. (C) 20 00 Elsevier Science B.V. All rights reserved.