Proximity effect of spin orbit coupling in Pt/Co2FeAl and Pt/Permalloy bilayers_810571

TL;DR

This study investigates the proximity effect of spin orbit coupling in Pt/ferromagnet bilayers through anomalous Hall effect measurements, revealing interface-driven enhancements in magnetotransport properties and large Hall and Nernst angles at room temperature.

Contribution

It demonstrates that the proximity effect of spin orbit coupling occurs at the Pt/ferromagnet interface, significantly affecting magnetotransport behaviors in ultrathin ferromagnetic films.

Findings

Enhanced skew scattering, side jump, and intrinsic contributions at thin ferromagnetic layers.

Linear dependence of scattering parameters on reciprocal ferromagnetic layer thickness.

Large anomalous Hall and Nernst angles observed at room temperature.

Abstract

Proximity effect of spin orbit coupling is investigated through anomalous Hall effect in Pt/Co2FeAl and Pt/Permalloy bilayers. A series of nontrivial magnetotransport behaviors, resulting from a strong impact of phonons on skew scattering, is observed in these films with ultrathin ferromagnetic layers. The parameters representing skew scattering, side jump and intrinsic contributions are dramatically enhanced when the ferromagnetic layer is very thin, and they have clear linear dependences on the reciprocal of ferromagnetic layer thickness, indicating a powerful influence of Pt/Ferromagnet interface. Further study on Cu/Co2FeAl and Ta/Co2FeAl bilayers reveals that a simple interface scattering without intense spin orbit coupling is not sufficient to trigger such a phenomenon. The proximity effect of spin orbit coupling is thus suggested to occur at the Pt/Ferromagnet interface, and as a result quite large anomalous Hall angle (0.036) and Nernst angle (0.23) are confirmed in the Pt/CFA films at room temperature.