Quantifying interface and bulk contributions to spin-orbit torque in magnetic bilayers

Xin Fan, Halise Celik, Jun Wu, Chaoying Ni, Kyung Jin Lee, Virginia O. Lorenz, John Q. Xiao

Research output: Contribution to journalArticlepeer-review

261 Citations (Scopus)

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 languageEnglish
Article number3042
JournalNature communications
Volume5
DOIs
Publication statusPublished - 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

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