Ridner, A., F. de la Cruz, and E. N. Martinez. "Surface superconductivity and Kapitza resistance." In Phonon Scattering in Condensed Matter, edited by H. J. Maris, 199–202. New York: Plenum Publishing Corp., 1980.
Abstract: It has been shown1 that surface superconductivity can be used as a localized thermomether to study the temperature close to an interface through which heat is being transported. Knowledge of the temperature profile in the interface region provides evidence which any theory of the heat transport mechanism must take into account. For interfaces between pure lead and HeII we have previously found1 clear differences between extrapolated surface temperatures Tk. and Tm, measured within some 1000Ã… of the interface using a superconducting thermometer. (The reader is refered to ref.1 for details on the experimental method).
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Osquiguil, E. J., L. Civale, R. Decca, and F. De La Cruz. "Metallic to variable-range-hopping transition controlled by oxygen content in La-Sr-Cu-O." Physical Review B 38, no. 4 (1988): 2840–2842.
Abstract: We have performed electrical resistivity measurements on the superconductor La1.8Sr0.2CuO4- over a wide range of temperatures and oxygen concentration. The results provide experimental evidence for a transition from a metallic behavior at high temperatures to a variable-range hopping regime at low temperatures. The transition is controlled by the oxygen content. Correlation between both regimes is also shown.
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Osquiguil, E., V. L. P. Frank, and F. de la Cruz. "Two dimensional collective flux pinning in melt spun superconducting amorphous Zr70Cu30." Solid State Communications 55, no. 3 (1985): 227–230.
Abstract: We have measured the critical currents in melt spun amorphous Zr70Cu30 and their evolution with heat treatment. We found that the pinning forces may be interpreted in terms of the Larkin-Ovchinnikov two dimensional collective pinning theory.
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Osquiguil, E., R. Decca, G. Nieva, L. Civale, and F. de la Cruz. "La1.80 Sr0.20 CuO4-delta a clean limit superconductor." Solid State Communications 65, no. 6 (1988): 491–494.
Abstract: The electrical resistivity of the superconductor La1.80Sr0.20Cu04-? has been measured in a wide range of temperatures as a function of oxygen and vacuum heat treatments. The resistivity changes reversibly orders of magnitude with oxygen concentration. There is no sign of saturation at high temperatures, even for samples where the resistivity is increased by heat treatment in vacuum. Using the experimental data and general arguments it is concluded that the ceramic superconductors are high ? materials in the clean limit.
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Osquiguil, E., L. Civale, R. Decca, H. Safar, E. Martinez, G. Nieva, and F. de la Cruz. "The Granular Behavior of LaSrCuO: Oxygen Concentration Effects on the Electrical Resistivity." In High Temperature Superconductors, Mat. Res. Soc. Symposium Proceedings, edited by K. Kitazawa and H. L. Tutler R. C. Dynes ed. M.B. Brosdky, 985. Vol. 99. Pittsburgh, PA: Mater. Res. Soc., 1988.
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Nieva, G., E. N. Martinez, F. de la Cruz, D. A. Esparza, and C. A. D'Ovidio. "Specific heat of La1.8Sr0.2CuO4: Anomaly at the superconducting transition." Physical Review B 36, no. 16 (1987): 8780–8782.
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Morré, E., S. Grigera, E. Osquiguil, G. Nieva, and F. de la Cruz. "Angular restrictions on the glass transition and on the c-axis correlated liquid phase in twinned YBa2Cu3O7-?" Physics Letters A 233, no. 1-2 (1997): 130–134.
Abstract: We have measured the angular dependence of the vortex velocity correlation temperature Tth(H) in twinned YBa2Cu3O7-? single crystals. The data show that the c-axis correlated vortex liquid phase exists up to angles much larger than expected within a single vortex pinning picture. Despite this, the second-order solid-liquid glass transition is shown to be restricted only to external magnetic fields applied within a few degrees from the c-axis direction.
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Monton, C., J. Guimpel, and F. de la Cruz. "Superconducting behaviour of Nb/Co superlattices." Applied Surface Science 254, no. 1 (2007): 375–377.
Abstract: We study the superconducting and magnetic behaviour of Nb/Co superlattices, for superconducting Nb layer thickness of 44 nm and Co layer thickness less than 1 nm. In this limit no ferromagnetism is observed for Co. The superlattice behaves as independent superconducting Nb layers. We obtain the penetration depth and superconducting gap of the material, and analyze the results in terms of microscopic models and theories. (C) 2007 Elsevier B.V. All rights reserved.
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Monton, C., F. de la Cruz, and J. Guimpel. "Magnetic state modification induced by superconducting response in ferromagnet/superconductor Nb/Co superlattices." PHYSICAL REVIEW B 77, no. 10 (2008).
Abstract: Magnetization measurements in superconductor/ferromagnet Nb/Co superlattices show a complex behavior as a function of temperature, applied field, and sample history. Based on a simple model, it is shown that this behavior is due to an interplay between the superconductor magnetization temperature dependence, the ferromagnet magnetization time dependence, and the stray fields of both materials. It is also shown that the magnetic state of the Co layers is modified by the Nb superconducting response, implying that the problem of a superconductor/ferromagnetic heterogeneous sample has to be solved in a self-consistent manner.
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Monton, C., F. de la Cruz, and J. Guimpel. "Magnetic behavior of superconductor/ferromagnet superlattices." PHYSICAL REVIEW B 75, no. 6 (2007).
Abstract: A study of the electromagnetic response of superconductor/ferromagnet Nb/Co superlattices is presented. The dc magnetization is measured as a function of Co layer thickness, applied field H-a, and temperature. For very thin Co layers, no ferromagnetism is detected and the observed response is essentially that of a collection of uncoupled Nb layers. When the Co layer is thick enough for ferromagnetism to be established, prior to the field-cooled magnetization measurements, the Co layers are magnetically saturated in the parallel or antiparallel directions to H-a. In this case, the magnetic response of the otherwise uncoupled Nb layers is found to depend on both H-a and the stray fields.
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