RESISTIVE EVIDENCE FOR VORTEX-LATTICE SUBLIMATION IN BI2SR2CACU2O8

Multiterminal measurements have been made on Bi2Sr2CaCu2O8 crystals to investigate the vortex dimensionality at the fields and temperatures where the first-order transition takes place in the vortex lattice. A sharp hysteretic transition is seen in transport properties with curre nt injected either parallel or perpendicular to the ab planes. The dat a indicate that both resistivity components disappear concurrently, an d the melting and c-axis decoupling transitions occur simultaneously a t a sublimation transition of the vortex lattice.