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de la Cruz, F., M. D. Maloney, and M. Cardona. "Superconductive Supercooling and Superheating of Small Cadmium Spheres: Size Effects." Physical Review B 3, no. 11 (1971): 3802–3811.
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de la Cruz, F., M. D. Maloney, and M. Cardona. "Supercooling and superheating in Al and Zn." Physica 55 (1971): 749–759.
Abstract: We have studied the supercooling and superheating of Al and Zn in the temperature range between 0.5 and 1.2 K. The samples, collections of dispersed and isolated small spheres, were prepared by spraying of the molten metal into liquid nitrogen. The supercooling and superheating fields obtained are, by all indications, close to the theoretical limit. From the supercooling fields observed we determined the Ginzburg-Landau parameter κ(Tc) = 0.015, for both Al and Zn. The superheating field exhibits a strong temperature dependence near Tc, which reflects the extremely non-local electrodynamics of the materials. The results are discussed in the light of recent theoretical work.
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De La Cruz, F., J. Luzuriaga, E. N. Martinez, and E. J. Osquiguil. "Current-voltage characteristics in collective pinning." Physical Review B 36, no. 13 (1987): 6850–6852.
Abstract: The critical-current curves of amorphous samples which exhibit collective flux pinning have been analyzed, and it was found that the nonlinear part can be fitted by an expression of the form V(I)[(I-IK)/IK]. This form, which could be due to critical behavior, is consistent with an interpretation of the unpinning of vortices in the collective regime as a phase transition between the static flux-line lattice (FLL) and the FLL in steady-state movement as has been proposed by Fisher.
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de la Cruz, F., D. López, E. F. Righi, and G. Nieva. "Comparative Study of Vortex Correlation in Twinned and Untwinned YBa2Cu3O7 Single Crystals." In Proceedings of the 10th Anniversary Hts Workshop on Physics, Materials and Applications, edited by B. Batlogg, 395. Singapore: World Scientific Publishing Company, 1996.
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de la Cruz, F., H. J. Fink, and J. Luzuriaga. "Temperature dependence of the superconducting giant-vortex state. Theory and Experiment." Physical Review B 20, no. 5 (1979): 1947–1959.
Abstract: When a type-I superconductor with a surface nucleation field Hc3(T)>Hc(T) (thermodynamic critical field) is thermally cycled in an axially applied magnetic field H0 between the temperatures T(Hc3) and about T(Hc), experiments show that the magnetization changes reversibly. The latter is diamagnetic near T(Hc3) but can be paramagnetic just above T(Hc). This behavior is explained by assuming that the fluxoid quantum number b is fixed at the transition from the normal to the superconducting state and retained at lower temperatures. The value of b is determined almost entirely by the flux at the transition which is enclosed by a contour located at a distance ξ1.7 from the surface inside the cylinder (ξ is the coherence length). The temperature variation of the order parameter f at the surface of the cylinder, the magnetization m, and the temperature at which m=0 for f≠0 are calculated for R>>ξ. Conservation of the fluxoid quantum number, while T is varied causes the two opposing surface currents to become imbalanced. This is the source of the observed para- and diamagnetism.
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de la Cruz, F., M. E. de la Cruz, and J. M. Cotignola. "Longitudinal Magnetomorphic Effect in Indium Films." Physical Review 163, no. 3 (1967): 575–578.
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de la Cruz, F., M. E. de la Cruz, and J. M. Cotignola. Efecto magnetomorfico longitudinal en laminas de In. Buenos Aires, 1968.
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de la Cruz, F., M. E. de la Cruz, L. Civale, and R. Arce. "Hybridization effects between d and s bans in amorphous materials." In Proceedings of LT-17, 1301. Elsevier Science Publishers BV, 1984.
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de la Cruz, F., and O. J. Bressan. "Sensitive Hot Wire Level Detector for Cryogenic Liquids." Review of Scientific Instruments 40, no. 3 (1969): 483–486.
Abstract: A very simple and highly sensitive ``hot wire'' type level detector to be used with cryogenic liquids is described. The hot filament is made of tungsten wire of about 4 µ diam. The tests on the sensor were made moving the filament in and out of the quiescent surfaces of liquid helium and nitrogen. The results showed 0.006 mm sensitivity in the determination of liquid helium level and 0.002 mm sensitivity in the case of liquid nitrogen level. The sensor is assembled in such a way that it can be used without special precautions during indefinite periods of time. For the case when the full capabilities of the sensor are not necessary, a simple circuit is presented.
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de la Cruz, F., D. López, and G. Nieva. "Thermally induced change in the vortex dimensionality of YBa2Cu3O7 single crystals." Philosophical Magazine Part B 70, no. 3 (1994): 773–786.
Abstract: Transport measurements in YBa2Cu3O7 single crystals using a modification of the d.c. flux transformer configuration are reported. We show that, for applied magnetic fields in the crystallographic c direction, the vortex correlation length in this direction is reduced to values smaller than the thickness of the sample. The reduction can be induced either by thermal disorder (linear response) or by flux cutting after the vortices reach a critical velocity (nonlinear response). The results show that, in the transition from a vortex-glass state to a vortex-liquid state, the vortices are effectively three dimensional in character. A two-dimensional regime is induced at higher temperatures well inside the reversibility region.
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