Latent-heat and non-linear vortex liquid at the vicinity of the first-order phase transition in layered high-Tc superconductors

M. I. DOLZ; Y. FASANO; H. PASTORIZA; V. MOSSER; M. LI; M. KONCZYKOWSKI

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2014 vol. 90 p. 1445071 - 1445076

1098-0121

In this work we revisit the vortex matter phase diagram in layeredsuperconductors solving still open questions by  means of AC andDC local magnetic measurements in the paradigmatic  Bi_2Sr_2CaCu_2O_{8+delta} compound. We show that measuring with AC magnetic techniques is mandatory in order to probe the bulk response of vortex matter, particularly at high-temperatures where surface barriers for vortex entrance dominate. From the T_FOT-evolution of the enthalpy and latent-heat at the transition we find that, contrary to previous reports, the nature of the dominant interlayer coupling is electromagnetic in the whole temperature range. By studying the dynamic properties of the phase located at  T >T_FOT, we reveal the spanning in aconsiderable fraction of the phase diagram of a non-linear vortexphase suggesting bulk pinning might play a role even in the liquidvortex phase.