|
|
Arce, R., L. Civale, J. Luzuriaga, J. Guimpel, and F. de la Cruz. "Surface normal regions in superconducting Zr70Cu30 induced by thermal relaxation." Solid State Communications 48, no. 12 (1983): 1027–1030.
Abstract: Penetration depth measurements show that thermal heat treatment in amorphous Zr70Cu30 induces a normal region 5000 Å thick at the surface of ultrarapid quenched ribbons. Upper critical field measurements indicate that the new induced phase is a normal one while the rest of the sample remains as a homogeneous superconducting phase.
|
|
|
|
Arce, R., F. de la Cruz, and P. Esquinazi. "Superconducting penetration depth in amorphous La70Cu30." Physica B+C 108B (1981): 1253–1254.
Abstract: It is shown that weak field penetration depth measurements can be used to determine the change in the normal and superconducting behaviour of amorphous samples, when heat-treated below the crystallization temperature. The results are used to discuss the validity of BCS-Gorkov relations, when applied to these materials.
|
|
|
|
Arce, R., F. de la Cruz, and P. Esquinazi. "Superconducting penetration depth in amorphous metals." Solid State Communications 38, no. 12 (1981): 1253–1255.
Abstract: We show that temperature dependent penetration depth measurements can be used to characterize the superconductive behaviour of amorphous metals.
|
|
|
|
Arce, R., F. de la Cruz, and H. J. Fink. "Model relating superconductive penetration depth and metallurgical phase separation in amorphous La70Cu30." Solid State Communications 42, no. 8 (1982): 575–577.
Abstract: A model is proposed to account for the large increase in the measured penetration depth of superconducting, amorphous La70Cu30 when the specimens are annealed sufficiently long near, but below, the crystallization temperature. It is suggested that a metallurgical phase separation occurs with domain dimensions in the submicrometer range. Penetration depth measurements as a function of temperature in a weak magnetic field are a useful tool to detect changes in phase separation in high-K materials.
|
|
|
|
Arce, R., F. de la Cruz, and J. Guimpel. "Superconducting behavior of amorphous Zr70Cu30." Solid State Communications 47, no. 11 (1983): 885–887.
Abstract: Measurement of the Meissner penetration depth, λ(T) were made in amorphous Zr70Cu30 samples. The results indicate that this amorphous alloy behaves as a BCS superconductor with 2Δ(0)+45 degree rulekTc = 3.8, where Δ(0) is the superconducting energy gap at T=0 and Tc the critical temperature. It is also concluded that the low energy excitation, TLS, characteristics of amorphous material does not contribute to Tc.
|
|
|
|
Bressan, O. J., A. E. Ridner, and F. de la Cruz. "T^5 law and Matthiessen's rule." Journal of Physics F: Metal Physics 5, no. 3 (1975): 481.
Abstract: Precise electrical resistivity measurements on very dilute non magnetic indium alloys show no doubt in a T 5 dependence on temperature between 1-4K and strong deviations from Matthiessen rule. Measurements of thermal resistivity show that the extrapolation method to obtain the data to H=0 is correct. Comparison of the results with recent theories is discussed.
|
|
|
|
Bressan, O. J., A. E. Ridner, and F. de la Cruz. "Low angle electron scattering in thermal resistivity." Journal of Physics F: Metal Physics 5 (1975): 1902–1909.
Abstract: Electrical ( rho ) and thermal (W) resistivity measurements in very dilute In alloys between 1K and 4K show a temperature dependence expressed by rho = rho 0+ beta T5 and WT=(WT)0+AT3+BT5. The BT5 term in the thermal resistivity is due to a contribution from a 'diffusion-like process' of electrons over the Fermi surface, as is the one that describes the temperature dependence of the electrical resistivity. This claim is supported by the experimental fact that the Lorenz number defined as L= beta /B coincides with the value given by L= rho 0/(WT)0 which in turn agrees with the free electron value within 15%.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
Civale, L., and F. de la Cruz. "Anomalous behavior of superconducting samples with a fixed number of vortices." Physical Review B 36, no. 7 (1987): 3560–3564.
Abstract: We report an anomalous reversible temperature dependence of the magnetization of amorphous type-II superconductors. The experimental results were obtained studying the vortex pinning in samples with very low vortex concentration. The anomaly is shown to be a consequence of the lack of flux quantization in finite samples.
|
|
