Odd triplet superconductivity in superconductor/ferromagnet multilayered structures

TL;DR

This paper demonstrates that multilayered superconductor-ferromagnet structures can generate odd-frequency triplet superconductivity due to non-collinear magnetizations, leading to enhanced Josephson effects and tunable coupling types.

Contribution

It introduces the concept of odd-frequency triplet superconductivity in multilayered structures with non-collinear magnetizations, revealing new ways to control Josephson coupling.

Findings

Triplet condensate coexists with singlet in superconductors.

Triplet component decays slowly in ferromagnet.

Josephson coupling can be 0 or π depending on magnetic alignment.

Abstract

We demonstrate that in multilayered superconductor-ferromagnet structures a non-collinear alignment of the magnetizations of different ferromagnetic layers generates a triplet superconducting condensate which is odd in frequency. This triplet condensate coexists in the superconductors with the conventional singlet one but decays very slowly in the ferromagnet, which should lead to a large Josephson effect between the superconductors separated by the ferromagnet. Depending on the mutual direction of the ferromagnetic moments the Josephson coupling can be both of 0 and $\pi $ type.