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Author Guimpel, J.; de la Cruz, M.E.; de la Cruz, F.; Fink, H.J.; Laborde, O.; Villegier, J.C.
Title Size dependence of the Superconducting critical temperature and fields of Nb/Al multilayers Type Journal Article
Year 1986 Publication Journal of Low Temperature Physics Abbreviated Journal J. Low Temp. Phys.
Volume 63 Issue 1-2 Pages 151-165
Keywords
Abstract The critical temperatureT cof Nb/Al multilayers decreases as the total sample thicknessd Tis decreased while the thickness of each Nb and Al layer is kept constant. To understand this behavior, models based on the proximity effect and on weak two-dimensional (2D) localization are employed. The latter uses a characteristic length, the thermal diffusion length, in relation tod Tto obtain 2D behavior and leads to a reasonable explanation ofT c(d T). It is also found that the slope atT c(d T) of the critical magnetic field perpendicular to the layers is independent ofd Twhen the Nb and Al layer thicknesses are kept constant. The angular dependence of the critical field is also measured.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-2291 ISBN Medium
Area Expedition Conference
Notes ISI:A1986C112200008 Approved no
Call Number BT @ hernan @ Serial 193
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Author de la Cruz, F.; Fink, H.J.; Luzuriaga, J.
Title Temperature dependence of the superconducting giant-vortex state. Theory and Experiment Type Journal Article
Year 1979 Publication Physical Review B Abbreviated Journal Phys. Rev. B
Volume 20 Issue 5 Pages 1947-1959
Keywords
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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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829 ISBN Medium
Area Expedition Conference
Notes ISI:A1979HP51300019 Approved no
Call Number BT @ hernan @ Serial 275
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Author Arce, R.; de la Cruz, F.; Fink, H.J.
Title Model relating superconductive penetration depth and metallurgical phase separation in amorphous La70Cu30 Type Journal Article
Year 1982 Publication Solid State Communications Abbreviated Journal Solid State Commun.
Volume 42 Issue 8 Pages 575-577
Keywords
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.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1098 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 567
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