Cotignola, J. M., F. de la Cruz, M. E. de la Cruz, and R. P. Platzeck. "Thermal Conductivity of Polycrystalline Zinc below 1 K." Review of Scientific Instruments 38, no. 1 (1967): 87–92.
Abstract: Measurements of the thermal conductivity of samples of polycrystalline zinc of thickness 0.1 mm have been carried out between 0.12 and 0.9°K in the normal as well as in the superconducting state to investigate the usefulness of zinc as a thermal switch. The conductivity in the normal state shows a linear dependence on temperature. In the superconducting state it shows a behavior typical of electronic conductivity down to the lowest temperature measured. By applying a magnetic field between 40 and 5000 Oe, magnetoresistivity was also investigated and a strong dependence of thermal conductivity on field was found. Electrical resistivity measurements were performed in magnetic fields at liquid 4He temperatures. The resistivity was found to be independent of temperature for fields up to 9000 Oe. The effect of solder joints using Cd, Sn, In, Zn, and Wood's metal was also investigated, Cd giving the least resistance. The measurements show that zinc should be a useful thermal switch for temperatures below 0.1 and 0.2°K, though effect of a magnetic field on the normal conductivity must be carefully considered.
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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., 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., M. D. Maloney, and M. Cardona. "Variation of the Ratio Hc3/Hc2 in the Immediate Vicinity of ${T}_{c}$." Physical Review 187, no. 2 (1969): 766–767.
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Maloney, M. D., F. de la Cruz, and M. Cardona. "Anomalous Behavior of Hc3/Hc2 near Tc for Sn-In and In-Bi Alloy Systems." Physical Review B 2, no. 7 (1970): 2512–2519.
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Kaufman, H. L., and F. de la Cruz. "Fluctuation induced diamagnetism in aluminum." Solid State Communications 9, no. 20 (1971): 1729–1732.
Abstract: The magnetic field and temperature dependence of the magnetization of bulk aluminum near the normal-superconductor transition has been measured. Due to the large amount of supercooling in one of the samples it was possible to extend the measurements well below the critical temperature. A comparison of the experimental results with theory is presented.
Résumé
Nous avons mesuré la dépendance en champ magnétique et en température de la magnétisation d'un échantillon massif d'aluminium au voisinage de la transition état normal-état supraconducteur. Grâce au ‘supercooling’ important d'un des échantillon, nous avons pu étendre nos mesures bien au dessous de la température critique. Nous comparons les résultats expérimentaux à la théorie.
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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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Maloney, M. D., F. de la Cruz, and M. Cardona. "Superconducting Parameters and Size Effects of Aluminum Films and Foils." Physical Review B 5, no. 9 (1972): 3558–3572.
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