Upper critical field of periodic and fractal Nb/Cu multilayers

SIDORENKO, A.; SÜRGERS, C.; TRAPPMANN, T.; WOSNITZA, J.; LÖHNEYSEN, H. v.

Upper critical field of periodic and fractal Nb/Cu multilayers

SIDORENKO, A.; SÜRGERS, C.; TRAPPMANN, T.; WOSNITZA, J.; LÖHNEYSEN, H. v.

URI: https://doi.org/10.1007/BF02583676
http://repository.utm.md/handle/5014/12242

Date: 1996

Abstract:

Measurements of the upper critical fieldBc2of superconducting Nb/Cu multilayers with fractal and periodic stacking sequence are reported. A positive curvature of the perpendicular magnetic field Bc2⊥, i.e. an upward deviation towards low temperatures from the linearBc2⊥(T) behavior of the WHH theory is observed. The temperature where this upturn occurs depends on the number of fractal scalesSn.