Room-temperature high spin–orbit torque due to quantum confinement in sputtered Bi xSe(1–x) films

Mahendra Dc, Roberto Grassi, Jun Yang Chen, Mahdi Jamali, Danielle Reifsnyder Hickey, Delin Zhang, Zhengyang Zhao, Hongshi Li, P. Quarterman, Yang Lv, Mo Li, Aurelien Manchon, K. Andre Mkhoyan, Tony Low, Jian Ping Wang

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347 Scopus citations


The spin–orbit torque (SOT) that arises from materials with large spin–orbit coupling promises a path for ultralow power and fast magnetic-based storage and computational devices. We investigated the SOT from magnetron-sputtered BixSe(1–x) thin films in BixSe(1–x)/Co20Fe60B20 heterostructures by using d.c. planar Hall and spin-torque ferromagnetic resonance (ST-FMR) methods. Remarkably, the spin torque efficiency (θS) was determined to be as large as 18.62 ± 0.13 and 8.67 ± 1.08 using the d.c. planar Hall and ST-FMR methods, respectively. Moreover, switching of the perpendicular CoFeB multilayers using the SOT from the BixSe(1–x) was observed at room temperature with a low critical magnetization switching current density of 4.3 × 105 A cm–2. Quantum transport simulations using a realistic sp3 tight-binding model suggests that the high SOT in sputtered BixSe(1–x) is due to the quantum confinement effect with a charge-to-spin conversion efficiency that enhances with reduced size and dimensionality. The demonstrated θS, ease of growth of the films on a silicon substrate and successful growth and switching of perpendicular CoFeB multilayers on BixSe(1–x) films provide an avenue for the use of BixSe(1–x) as a spin density generator in SOT-based memory and logic devices.

Original languageEnglish (US)
Pages (from-to)800-807
Number of pages8
JournalNature Materials
Issue number9
StatePublished - Sep 1 2018

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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