Magnetic Josephson Junctions: New Phenomena and Physics with Diluted Alloy, Conventional Ferromagnet, and Multilayer Barriers

Spin Josephson effect in ferromagnet/ferromagnet tunnel junctions

– We consider the tunnel current between two ferromagnetic metals from a perspective similar to the one used in superconductor/superconductor tunnel junctions. We use fundamental arguments to derive a Josephson-like tunnel spin current I J ∝ sin(θ1 − θ2). Here the phases are associated with the planar contribution to the magnetization, 〈c†↑c↓〉 ∼ e . The crucial step in our analysis is the fact ...

Noise Induced Phenomena in Point Josephson Junctions

The investigation of nonlinear properties of Josephson junctions (JJs) is very important due to their broad applications in logic devices. Recently, a lot of attention was payed to Josephson logic devices with high damping. In papers [Rylyakov & Likharev, 1999; Bunyk et al., 2001] a description and analysis of the entire system of single flux quantum logic elements are presented. The noise prop...

Theory of the Josephson effect in superconductor / ferromagnet / superconductor junctions

To reveal the influence of the exchange interaction on the Josephson effect, the d.c. Josephson current in unconventional-superconductor / ferromagnet / unconventional-superconductor junctions is studied. When the two superconductors have d-wave symmetry, the Josephson current is drastically suppressed with the increase of the exchange interaction. On the other hand, when the two superconductor...

Criticality in diluted ferromagnet

We perform a detailed study of the critical behavior of the mean field diluted Ising ferromagnet by analytical and numerical tools. We obtain self-averaging for the magnetization and write down an expansion for the free energy close to the critical line. The scaling of the magnetization is also rigorously obtained and compared with extensive Monte Carlo simulations. We explain the transition fr...

Superconducting Qubits and the Physics of Josephson Junctions