Measurement of the Geometrical Decay of the Spin Hall Effect in Fe(CsAu) Multi Layers

TL;DR

This study measures how the spin Hall effect in Fe(CsAu) multilayers decays exponentially over a 20nm length, revealing insights into spin current behavior influenced by interface reflection and impurity scattering.

Contribution

It provides the first experimental measurement of the geometrical decay length of the spin Hall effect in Fe(CsAu) multilayers, highlighting the role of interface reflection and impurity scattering.

Findings

Spin current decays exponentially with a 20nm decay length.

Interface reflection causes different mean free paths for spin orientations.

Impurities with strong spin-orbit scattering induce an anomalous Hall effect.

Abstract

The anomalous Hall effect of Fe(CsAu) is investigated. Electrons with spin up and down experience a different degree of specular reflection at the FeCs interface. This yields a different mean free path for the two spin orientations. In the presence of an electric field parallel to the film plane one obtains a spin current in addition to the charge current. If one introduces impurities with a large spin-orbit scattering into the Cs host then the combination of spin current and spin-orbit scattering yields an anomalous Hall effect. By building in situ multi layers of CsAu (5nm of Cs and 0.04 atomic layers of Au) on top of an Fe film one can measure the relative magnitude of the spin current normal to the film. Within the accuracy of the experimental data the spin current in Fe(CsAu) decays exponentially with a decay length of 20nm. PACS: 73.50.-h, 72.25.Ba, 73.40.Jn, 73.21.Cd