Large unidirectional magnetoresistance in metallic heterostructures in the spin transfer torque regime
Journal
Physical Review B
Journal Volume
104
Journal Issue
2
Date Issued
2021
Author(s)
Abstract
A large unidirectional magnetoresistance (UMR) ratio of is found in W/CoFeB metallic bilayer heterostructures at room temperature. Three different regimes in terms of the current dependence of the UMR ratio are identified: a spin-dependent-scattering mechanism regime at small current densities (UMR ratio ), a spin-magnon-interaction mechanism regime at intermediate (UMR ratio ), and a spin transfer torque (STT) regime at (UMR ratio independent of J). We verify the direct correlation between this large UMR and the transfer of spin angular momentum from the W layer to the CoFeB layer by both field-dependent and current-dependent UMR characterizations. Numerical simulations further confirm that the large STT-UMR stems from the tilting of the magnetization affected by the spin Hall effect-induced STTs. An alternative approach to estimate dampinglike spin torque efficiencies from magnetic heterostructures is also proposed. ? 2021 American Physical Society
Subjects
Cobalt compounds
Iron compounds
Magnetoresistance
Bi-layer
Current dependence
Magnetic heterostructures
Magnon interactions
Spin angular momentum
Spin dependent scattering
Spin transfer torque
Spin-torque efficiency
Spin Hall effect
Type
journal article