Effect of quenched disorder in the entropy-jump at the first-order vortex phase transition of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8 + \delta}$

M. I. Dolz; P. Pedrazzini; H. Pastoriza; M. Konczykowski; Y. Fasano

doi:10.1007/s10909-014-1239-9

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arXiv · 1409.7309

Effect of quenched disorder in the entropy-jump at the first-order vortex phase transition of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8 + \delta}$

M. I. Dolz·P. Pedrazzini·H. Pastoriza·M. Konczykowski·Y. Fasano

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Abstract

We study the effect of quenched disorder in the thermodynamic magnitudes entailed in the first-order vortex phase transition of the extremely layered Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8 + \delta}$ compound. We track the temperature-evolution of the enthalpy and the entropy-jump at the vortex solidification transition by means of AC local magnetic measurements. Quenched disorder is introduced to the pristine samples by means of heavy-ion irradiation with Pb and Xe producing a random columnar-track pins distribution with different densities (matching field $B_{\Phi}$). In contrast with previous magneto-optical reports, we find that the first-order phase transition persists for samples with $B_{\Phi}$ up to 100\,Gauss. For very low densities of quenched disorder (pristine samples), the evolution of the thermodynamic properties can be satisfactorily explained considering a negligible effect of pinning and only electromagnetic coupling between pancake vortices lying in adjacent CuO planes. This description is not satisfactory on increasing magnitude of quenched disorder.

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M. I. Dolz, P. Pedrazzini, H. Pastoriza, M. Konczykowski, Y. Fasano. 2014-09-25. Effect of quenched disorder in the entropy-jump at the first-order vortex phase transition of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8 + \delta}$. https://doi.org/10.1007/s10909-014-1239-9

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