Critical fields of Nb-Ta multilayers

Abstract

Nb-Ta multilayered films prepared by rnagnetron sputtering have been studied by critical-field measurements.We have examined the effects of substrate orientation and deposition temperature on the properties of the films. Three-dimensional to two-dimensional crossover is observed. For films with larger Nb layer thicknesses an additional transition in H, &~I at lower temperatures is observed which cannot be accounted for by the interfacial regions.Since the original work on Nb-Ta multilayers by Durbin et al. , ' it has been recognized that this system is the closest realization of a perfect metallic superlattice. Outside of the tunneling studies of Hertel et al. , very little work has been done on the superconducting properties of the system. Encouraged by the work of and Nb-Ti (Ref. 5), we have undertaken a study of the critical fields of the Nb-Ta system in order to examine the . . . S-S'-S-S'. . . multilayer where S and S' denote superconductors.We have measured perpendicular and parallel critical fields and their angular dependence for several Nb-Ta multilayers. In addition we examine our results in light of the theoretical analysis of Biagi et al.

Extremely strong-coupling superconductivity in artificial two-dimensional Kondo lattices

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Superconducting properties of fractal Nb/Cu multilayers

“…However, this has nothing to do with the fractal stacking sequence and has also been found in previous studies of periodic SM including Nb/Cu and Nb/Ta multilayers. 13,15 The origin of this curvature in the temperature dependence of B c2Ќ is still unclear. In order to extract an estimate for the Ginzburg-Landau coherence length we calculated ʈ (0) from the slope of B c2Ќ (T) at T c ,…”

Microstructural properties ofBi2Sr2Can−Vailionis1, Brazdeikis2, Flodström3 1996Phys. Rev. B6000View full textAdd to dashboardCite

“…The artificially layered structures exhibit a number of interesting effects such as a dimensional crossover and the proximity effect. [1][2][3][4][5] Multilayers of hightemperature superconductors ͑HTS's͒ offer further possibilities of studying these and also other effects, such as the Kosterlitz-Thouless transition and the electric-field effect. [6][7][8] Various film synthesis techniques have so far been employed for the fabrication of superconducting multilayers, of which the most common are magnetron sputtering, 9,10 laser ablation, 11 and molecular beam epitaxy ͑MBE͒.…”