INFLUENCE OF MAGNETIC-FIELD ON THE FLUX MOTION IN SUPERCONDUCTING YBCO PYBCO SUPERLATTICE/

Angular dependent critical current densities J(c)(H,theta) for the YBa 2Cu3O7-y/Pr0.5Y0.5Ba2Cu3O7-y(120 Angstrom/24 Angstrom)x8 superlattice under various magnetic fields were measured to investigate the influen ce of the applied magnetic fields on the dimensionality of the flux pi nning and flux dynamics. J(c)(H,theta) was obtained by applying curren t through x- or y- direction and analyzed by Kes model. It is found th at the dissipation of the flux line system in the mixed state is mainl y due to the pancake motion along ah-plane as II < 1 T, while the flux lines begin to move along c-axis when the magnetic field reached 1 T. The causes will be discussed.