Abstract
Spin-orbit interaction-driven phenomena such as the spin Hall and Rashba effect in ferromagnetic/heavy metal bilayers enables efficient manipulation of the magnetization via electric current. However, the underlying mechanism for the spin-orbit interaction-driven phenomena remains unsettled. Here we develop a sensitive spin-orbit torque magnetometer based on the magneto-optic Kerr effect that measures the spin-orbit torque vectors for cobalt iron boron/platinum bilayers over a wide thickness range. We observe that the Slonczewski-like torque inversely scales with the ferromagnet thickness, and the field-like torque has a threshold effect that appears only when the ferromagnetic layer is thinner than 1 nm. Through a thickness-dependence study with an additional copper insertion layer at the interface, we conclude that the dominant mechanism for the spin-orbit interaction-driven phenomena in this system is the spin Hall effect. However, there is also a distinct interface contribution, which may be because of the Rashba effect.
Original language | English |
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Article number | 3042 |
Journal | Nature communications |
Volume | 5 |
DOIs | |
Publication status | Published - 2014 Jan 9 |
Bibliographical note
Funding Information:We thank Matthew J. Jerry for the assistance in sample fabrication. This work was supported by DOE under grant number DE-FG02-07ER46374 and the University of Delaware Research Foundation. C.N. acknowledges a support by NSF EPSCOR under grant number NSF-0814251. K.J.L. acknowledges a support by NRF under grant number NRF-2013R1A2A2A01013188.
ASJC Scopus subject areas
- General Chemistry
- General Biochemistry,Genetics and Molecular Biology
- General Physics and Astronomy