Vortex lattice in Bi2Sr2CaCu2O8+δ well above the first-order phase-transition boundary

Measurements of non-local in-plane resistance originating from transverse vortex–vortex correlations have been performed on a Bi2Sr2CaCu2O8+δ high-Tc superconductor in a magnetic field up to 9 T applied along the crystal c-axis. Our results demonstrate that a rigid vortex lattice does exist over a broad portion of the magnetic field–temperature (H–T) phase diagram, well above the first-order transition (FOT) boundary HFOT(T). The results also provide evidence for the vortex lattice melting and vortex liquid decoupling phase transitions, occurring above the HFOT(T).