Spin-orbit torques in NbSe2/permalloy bilayers

Marcos H.D. Guimaraes, Gregory M. Stiehl, David MacNeill, Neal D. Reynolds, Daniel C. Ralph

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Abstract

We present measurements of current-induced spin–orbit torques generated by NbSe2, a fully metallic transition-metal dichalcogenide material, made using the spin-torque ferromagnetic resonance (ST-FMR) technique with NbSe2/Permalloy bilayers. In addition to the out-of-plane Oersted torque expected from current flow in the metallic NbSe2 layer, we also observe an in-plane antidamping torque with torque conductivity σS ≈ 103 (ℏ/2e)(Ωm)−1 and indications of a weak field-like contribution to the out-of-plane torque oriented opposite to the Oersted torque. Furthermore, in some samples we also measure an in-plane field-like torque with the form m̂ × ẑ, where m̂ is the Permalloy magnetization direction and ẑ is perpendicular to the sample plane. The size of this component varies strongly between samples and is not correlated with the NbSe2 thickness. A torque of this form is not allowed by the bulk symmetries of NbSe2 but is consistent with symmetry breaking by a uniaxial strain that might result during device fabrication.
Original languageEnglish
Pages (from-to)1311-1316
Number of pages6
JournalNano Letters
Volume18
Issue number2
DOIs
Publication statusPublished - 14 Feb 2018

Keywords

  • Transition metal dichalcogenides
  • spin-orbit torque
  • spin-orbit coupling
  • van der Waals materials
  • 2D materials
  • spin?orbit torque
  • spin?orbit coupling

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