Field-sweep rate dependence of magnetization and current-voltage characteristics in superconducting disks

We investigated distributions of electric field E and current density J in disk-shaped superconductors exposed to a perpendicular magnetic field B-a that is swept at a constant rate beta = dB(a)/dt. The expressions of the dependence of the magnetization M on the field-sweep rate beta were derived for arbitrary E-J characteristics taking into account the distributions of E and J accurately. We measured the dependence of M on beta in a YBa2Cu3O7 disk, and estimated the E-J characteristics using the theoretical analysis. Furthermore, distribution of J(r) was estimated from the E(r) distribution and E-J characteristics. (C) 1997 American Institute of Physics.