Observation of the crossover between bulk flux pinning and Josephson phase slips in the critical current of granular superconducting NbN/AlN multilayer films
Abstract
The critical current density, Jc in granular NbN/AlN multilayer films shows a sharp crossover with reduced magnetic field, b≡ H/ Hc2 where Hc2 is the upper critical field, from the (1- b) 2 dependence associated with bulk flux pinning at large b to a much weaker dependence at smaller b. We interpret this as coexistence of bulk flux depinning with phase slips in intergranular Josephson junctions, such that the one with the smaller Jc is observed. The dependence on b, pinning strength, Lorentz-force and neutron irradiation are all consistent with such a crossover.
- Publication:
-
Physica C Superconductivity
- Pub Date:
- March 1991
- DOI:
- 10.1016/0921-4534(91)91566-M
- Bibcode:
- 1991PhyC..174..340G