INFLUENCE OF THE 3D-2D CROSSOVER ON THE CRITICAL-CURRENT OF NB/CU MULTILAYERS

Article

关键词: CRITICAL-FIELD;    PENETRATION DEPTH;    MAGNETORESISTANCE;    SUPERLATTICES;    ANISOTROPY;   

DOI  :  10.1103/PhysRevB.50.1106

来源: SCIE

【 摘 要 】

We report the experimental observation of the Josephson critical current across layers, I(c) perpendicular-to, for Nb/Cu multilayers. Unique samples with a small cross section (20 mum in diameter) consisting of ten Nb/Cu junctions were fabricated for such measurements. A strong influence of the dimensional 3D-2D cross-over on the I(c)perpendicular-to was observed. Thus, as the temperature becomes smaller than T2D, hysteresis in the current-voltage characteristic appears and the behavior of the temperature dependence of the I(c)perpendicular-to changes. For T > T2D the diminishing of the hysteresis is caused by a sharp decrease of the junction capacitance in the 3D regime when the sample becomes uniform across layers. Calculation of the critical-current temperature dependence I(c)perpendicular-to (T) for our multilayers was made. An agreement between experimental and theoretical dependencies I(c)perpendicular-to (T) was found. From the theoretical simulations, we have obtained the dependence of the crossover and the critical temperatures of multilayers on the layer thicknesses, the boundary transparency, and layer conductivity.

【 授权许可】

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