Spin-Orbit Torque and Nernst Effect in Bi-Sb/Co Heterostructures

Date
2018-10-12
Authors
Roschewsky, Niklas
Walker, Emily S.
Gowtham, Praveen
Muschinske, Sarah E.
Hellman, Francis
Bank, Seth R.
Salahuddin, Sayeef
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Abstract

Harmonic measurements of the longitudinal and transverse voltages in Bi-Sb/Co bilayers are presented. A large second harmonic voltage signal due to the ordinary Nernst effect is observed. In experiments where a magnetic field is rotated in the film plane, the ordinary Nernst effect shows the same angular dependence in the transverse voltage as the damping-like spin-orbit torque and in the longitudinal voltage as the unidirectional spin-Hall magneto-resistance respectively. Therefore, the ordinary Nernst effect can be a spurious signal in spin-orbit torque measurements, leading to an overestimation of the spin-Hall angle in topological insulators or semimetals.

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