Physics

Electron scattering

Electron

Magnetization

Asymmetry

Ferromagnetism

Magnetic field

Magnetoresistance

Optics

Hall effect

Magnon

Spintronics

Scattering

Materials science

Condensed matter physics

Spin (aerodynamics)

Quantum mechanics

Electrical resistivity and conductivity

Weak localization

Thermodynamics

Physical Review Letters

Recent studies evidenced the emergence of asymmetric electron transport in layered conductors owing to the interplay between electrical conductivity, magnetization, and the spin Hall or Rashba-Edelstein effects. Here, we investigate the unidirectional magnetoresistance (UMR) caused by the current-induced spin accumulation in Co/Pt and CoCr/Pt bilayers. We identify three competing mechanisms underpinning the resistance asymmetry, namely, interface and bulk spin-dependent electron scattering and electron-magnon scattering. Our measurements provide a consistent description of the current, magnetic field, and temperature dependence of the UMR and show that both positive and negative UMR can be obtained by tuning the interface and bulk spin-dependent scattering.

Origins of the Unidirectional Spin Hall Magnetoresistance in Metallic Bilayers