VORTEX SOLID-TO-LIQUID TRANSITION IN DYBA2CU3O7-DELTA (Y0.45PR0.55)BA2CU3O7-DELTA MULTILAYERS/

Current-voltage (I-V) characteristics of a coupled multilayer system c onsisting of thin (24 Angstrom) superconducting layers of DyBa2Cu3O7-d elta each separated by 96 Angstrom of (Y0.45Pr0.55)Ba2Cu3O7-delta have been studied in the mixed state. Analyses of vortex glass scaling and signs of the clean system melting transition in the dynamics of our m ultilayers both suggest that the vortex system is close to three-dimen sional for magnetic fields up to several T. Therefore, the theoretical ly predicted crossover when in-plane vortex correlations become more i mportant than out-of-plane vortex correlations (occurring at a few ten ths of a T in our multilayers) does not correspond to a complete decou pling of the superconducting layers in these materials.