Interfacial contributions to spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers

TY - JOUR

T1 - Interfacial contributions to spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers

AU - Belashchenko, K. D.

AU - Kovalev, Alexey A.

AU - Van Schilfgaarde, M.

PY - 2020/1/17

Y1 - 2020/1/17

N2 - The thickness dependence of spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers is studied using the first-principles nonequilibrium Green's function formalism combined with the Anderson disorder model. A systematic expansion in orthogonal vector spherical harmonics is used for the angular dependence of the torque. The dampinglike torque in Co/Pt and Co/Au bilayers can be described as a sum of the spin-Hall contribution, which increases with thickness in agreement with the spin-diffusion model, and a comparable interfacial contribution. The magnetoconductance in the plane perpendicular to the current in Co/Pt bilayers is of the order of a conductance quantum per interfacial atom, exceeding the prediction of the spin-Hall model by more than an order of magnitude. This suggests that the "spin-Hall magnetoresistance," similarly to the dampinglike torque, has a large interfacial contribution unrelated to the spin-Hall effect.

AB - The thickness dependence of spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers is studied using the first-principles nonequilibrium Green's function formalism combined with the Anderson disorder model. A systematic expansion in orthogonal vector spherical harmonics is used for the angular dependence of the torque. The dampinglike torque in Co/Pt and Co/Au bilayers can be described as a sum of the spin-Hall contribution, which increases with thickness in agreement with the spin-diffusion model, and a comparable interfacial contribution. The magnetoconductance in the plane perpendicular to the current in Co/Pt bilayers is of the order of a conductance quantum per interfacial atom, exceeding the prediction of the spin-Hall model by more than an order of magnitude. This suggests that the "spin-Hall magnetoresistance," similarly to the dampinglike torque, has a large interfacial contribution unrelated to the spin-Hall effect.

UR - http://www.scopus.com/inward/record.url?scp=85078334132&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.101.020407

DO - 10.1103/PhysRevB.101.020407

M3 - Article

AN - SCOPUS:85078334132

SN - 2469-9950

VL - 101

JO - Physical Review B

JF - Physical Review B

IS - 2

M1 - 020407

ER -