Inverse proximity effect and influence of disorder on triplet supercurrents in strongly spin-polarized ferromagnets

TL;DR

This paper investigates how impurity scattering and inverse proximity effects influence triplet supercurrents in strongly spin-polarized ferromagnets, revealing disorder-induced reversal of spin-current with temperature.

Contribution

It extends previous models by including impurity scattering and inverse proximity effects self-consistently, overcoming limitations of earlier Usadel theory approaches.

Findings

Disorder and spin-dependent Fermi velocities can reverse spin-current direction.

Self-consistent treatment reveals inverse proximity effects impact triplet supercurrents.

Temperature can induce a reversal of the spin-current due to disorder effects.

Abstract

We discuss the Josephson effect in strongly spin-polarized ferromagnets where triplet correlations are induced by means of spin-active interface scattering, extending our earlier work [Phys. Rev. Lett. 102, 227005 (2009)] by including impurity scattering in the ferromagnetic bulk and the inverse proximity effect in a fully self-consistent way. Our quasiclassical approach accounts for the differences of Fermi momenta and Fermi velocities between the two spin bands of the ferromagnet, and thereby overcomes an important short-coming of previous work within the framework of Usadel theory. We show that non-magnetic disorder in conjunction with spin-dependent Fermi velocities may induce a reversal of the spin-current as a function of temperature.