Spin-orbit proximity effect in Bi/Co multilayer: The role of interface scattering

The spin-orbit proximity effect is the raise of spin-orbit coupling at a layer near to the interface with a strong spin-orbit material. It has been seen in several system such as graphene and ferromagnetic layers. The control of the spin-orbit coupling can be a pathway to discover novel and exotic phases in superconductor and semimetallic systems. Here, we study the magnetoelectrical transport, i.e., magnetoresistance and anomalous Hall effect, in cobalt/bismuth multilayers looking for traces of spin-orbit proximity effect and evaluate the origin of such effect. Our results point for an increase of spontaneous magnetic anisotropy of resistivity and anomalous Hall resistivity at very low thicknesses of cobalt. The analysis of the anomalous Hall resistivity indicate that the bismuth layers change the scattering mechanism of Hall effect to the extrinsic skew-scattering type, indicating that the spin-orbit proximity effect could be related to the elastic scattering of cobalt free carriers by bismuth sites at the interface.

Automated summary

The spin-orbit proximity effect refers to the enhancement of spin-orbit coupling at a layer near the interface with a strong spin-orbit material. It has been observed in multiple systems such as graphene and ferromagnetic layers. Understanding and controlling spin-orbit coupling can lead to the discovery of new and exotic phases in superconducting and semimetallic systems. In this study, the magnetoelectrical transport, specifically magnetoresistance and anomalous Hall effect, was investigated in cobalt/bismuth multilayers to search for evidence of spin-orbit proximity effect and determine its origin. The results indicate an increase in spontaneous magnetic anisotropy of resistivity and anomalous Hall resistivity at very thin cobalt thicknesses, suggesting that the spin-orbit proximity effect may be related to elastic scattering of cobalt free carriers by bismuth sites at the interface.