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Bridoux, G., G. Nieva, and F. de la Cruz. "Phase-coherence effects in vortex transport entropy." PHYSICAL REVIEW LETTERS 101, no. 11 (2008): 117002.
Abstract: Nernst and electrical resistivity measurements in superconducting YBa2Cu3O7-delta and Bi2Sr2CaCu2O8+delta with and without columnar defects show a distinctive thermodynamics of the respective liquid vortex matter. At a field-dependent high temperature region in the H-T phase diagram, the Nernst signal is independent of structural defects in both materials. At lower temperatures, in YBa2Cu3O7-delta, defects contribute only to the vortex mobility, and the transport entropy is that of a system of vortex lines. The transition to lower temperatures in Bi2Sr2CaCu2O8+delta has a different origin; the maximum in the Nernst signal when decreasing temperature is not associated with transport properties but with the entropy behavior of pancake vortices in the presence of structural defects.
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Bridoux, G., P. Pedrazzini, F. de la Cruz, and G. Nieva. "Angular field dependence of the Nernst effect in Bi2Sr2CaCu2O8+delta." PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS 460 (2007): 841–842.
Abstract: The anomalous Nernst effect in hole-doped cuprates has been interpreted in terms of the existence of a superconducting order parameter well above the transition temperature, T-c(H). In order to improve the understanding of this problem, we have measured the angular field dependence of the Nernst signal in Bi2Sr2CaCu2O8+delta single crystals. The experiment was done tilting the magnetic field with respect to the direction of the temperature gradient, above and below T,(H), with applied fields up to 16 T. We have found that all the curves are scaled on one curve against the reduced field Hcos theta at a fixed temperature. (c) 2007 Elsevier B.V. All rights reserved.
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Bridoux, G., M. Villafuerte, J. M. Ferreyra, J. Guimpel, G. Nieva, C. A. Figueroa, B. Straube, and S. P. Heluani. "Franz-Keldysh effect in epitaxial ZnO thin films." Applied Physics Letters 112, no. 9 (2018).
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Haberkorn, N., G. Bridoux, E. Osquiguil, G. Nieva, and J. Guimpel. "Hall effect in a GdBa2Cu3O7-?/La0.75 Sr0.25MnO3 perovskite bilayer." Applied Surface Science 254, no. 1 SPEC. ISS. (2007): 222–224.
Abstract: We present results on the Hall coefficient RH in the normal state for a GdBa2Cu3O7-?/La0.75 Sr0.25MnO3 bilayer and a La0.75Sr0.25MnO3 film grown by dc magnetron sputtering on (1 0 0) SrTiO3. We find that the electric transport on the bilayer can be qualitatively described using a simple parallel layers model. The GdBa2Cu3O7-? layer presents a carrier density approximately equal to that reported for 7 – ? = 6.85 oxygen doping. Also we observe an unexpected presence of two Hall resistivity regimes, effects that may be associated with the internal magnetic field induced on the superconducting layer by the ferromagnetic layer.
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Luccas, R. F., N. Haberkorn, J. Guimpel, G. Bridoux, and G. Nieva. "Growth of GdBa2Cu3O7 thin films on single crystalline substrates of Y1-xPrBa2Cu3O7." PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS 460 (2007): 1377–1378.
Abstract: Superconducting GdBa2CU3O7 thin films were grown by dc magnetron sputtering on Y1-xPrxBa2CU3O7 superconducting bulk single crystals. We optimized the in plane lattice matching with the Pr concentration. The samples were characterized by X-ray diffraction and electrical transport experiments. Magnetization hysteresis loops show high values of the critical currents for the films. (c) 2007 Elsevier B.V. All rights reserved.
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Zapata, C., G. Nieva, J. M. Ferreyra, M. Villafuerte, L. Lanoël, and G. Bridoux. "The s-d exchange model as the underlying mechanism of magnetoresistance in ZnO doped with alkali metals." Journal of Physics: Condensed Matter 31, no. 34 (2019): 345801.
Abstract: High field magnetoresistance has been studied in epitaxial n-type ZnO:Na and ZnO:Li thin films in a temperature range between 4 K and 150 K. The resulting negative magnetoresistance can be well fitted using a semiempirical model of Khosla and Fischer based on third order contributions to the s-d exchange Hamiltonian. The parameters obtained from this model were carefully analyzed. One of these parameters is related to a ratio between electron mobilities at zero field (a non-exchange scattering mobility and an exchange or spin dependent one ). From Hall effect measurements was obtained, displaying a weak temperature dependence in accordance with highly n-doped ZnO while the extracted exhibits an anomalous T-dependence. On the other hand, our magnetoresistance data cannot be properly fitted using Kawabata’s expression based on a weak-localization model.
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