0-π Josephson Tunnel Junctions with Ferromagnetic Barrier
Abstract
We fabricated high quality Nb/Al2O3/Ni0.6Cu0.4/Nb superconductor-insulator-ferromagnet-superconductor Josephson tunnel junctions. Using a ferromagnetic layer with a steplike thickness, we obtain a 0-π junction, with equal lengths and critical currents of 0 and π parts. The ground state of our 330μm (1.3λJ) long junction corresponds to a spontaneous vortex of supercurrent pinned at the 0-π step and carrying ∼6.7% of the magnetic flux quantum Φ0. The dependence of the critical current on the applied magnetic field shows a clear minimum in the vicinity of zero field.
- Publication:
-
Physical Review Letters
- Pub Date:
- December 2006
- DOI:
- 10.1103/PhysRevLett.97.247001
- arXiv:
- arXiv:cond-mat/0605656
- Bibcode:
- 2006PhRvL..97x7001W
- Keywords:
-
- 74.50.+r;
- 74.78.Fk;
- 74.81.-g;
- 85.25.Cp;
- Tunneling phenomena;
- point contacts weak links Josephson effects;
- Multilayers superlattices heterostructures;
- Inhomogeneous superconductors and superconducting systems;
- Josephson devices;
- Condensed Matter - Superconductivity
- E-Print:
- submitted to PRL