Theory of the Josephson effect in superconductor / ferromagnet / superconductor junctions
نویسندگان
چکیده
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 superconductors have different parities, e.g. s-wave and p-wave, an enhancement of the Josephson current is obtained with the increment of the exchange interaction due to the break-down of SU(2) symmetry in the spin space.
منابع مشابه
Theory of the Josephson effect in unconventional superconducting junctions with diffusive barriers
We study theoretically the Josephson effect in junctions based on unconventional superconductors with diffusive barriers, using the quasiclassical Green’s function formalism. Generalized boundary conditions at junction interfaces applicable to unconventional superconductors are derived by calculating a matrix current within the circuit transport theory. Applying these boundary conditions, we ha...
متن کامل5 O ct 1 99 9 A theory of π / 2 superconducting Josephson junctions
We consider theoretically a Josephson junction with a superconducting critical current density which has a random sign along the junction's surface. We show that the ground state of the junction corresponds to the phase difference equal to π 2. Such a situation can take place in superconductor-ferromagnet-superconductor junctions.
متن کاملQuasiclassical Green’s function theory of the Josephson effect in chiral p-wave superconductor/diffusive normal metal/chiral p-wave superconductor junctions
We study the Josephson effect in chiral p-wave superconductor/diffusive normal metal DN /chiral p-wave superconductor CP/DN/CP junctions using quasiclassical Green’s function formalism with proper boundary conditions. The px+ ipy-wave symmetry of superconducting order parameter is chosen which is believed to be the pairing state in Sr2RuO4. We show that the superconducting pair amplitude induce...
متن کاملp – 0 Transition in Superconductor - Ferromagnet - Superconductor Junctions 1
Superconductor–ferromagnet–superconductor (SFS) Josephson junctions are known to exhibit a transition between π and 0 states. In this letter, we find the π–0 phase diagram of an SFS junction depending on the transparency of an intermediate insulating layer (I). We show that, in general, the Josephson critical current is nonzero at the π–0 transition temperature. Contributions to the current fro...
متن کاملProximity Effects in Superconductor-ferromagnet Heterostructures
The very special characteristic of the proximity effect in superconductor-ferromagnet systems is the damped oscillatory behavior of the Cooper pair wave function in a ferromagnet. In some sense, this is analogous to the inhomogeneous superconductivity, predicted long time ago by Larkin and Ovchinnikov (1964), and Fulde and Ferrell (1964), and constantly searched since that. After the qualitativ...
متن کامل