Long spin coherence length and bulk-like spin–orbit torque in ferrimagnetic multilayers

Jiawei Yu, Do Bang, Rahul Mishra, Rajagopalan Ramaswamy, Jung Hyun Oh, Hyeon Jong Park, Yunboo Jeong, Pham Van Thach, Dong Kyu Lee, Gyungchoon Go, Seo Won Lee, Yi Wang, Shuyuan Shi, Xuepeng Qiu, Hiroyuki Awano, Kyoung Jin Lee, Hyunsoo Yang

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16 Citations (Scopus)

Abstract

Spintronics relies on magnetization switching through current-induced spin torques. However, because spin transfer torque for ferromagnets is a surface torque, a large switching current is required for a thick, thermally stable ferromagnetic cell, and this remains a fundamental obstacle for high-density non-volatile applications with ferromagnets. Here, we report a long spin coherence length and associated bulk-like torque characteristics in an antiferromagnetically coupled ferrimagnetic multilayer. We find that a transverse spin current can pass through >10-nm-thick ferrimagnetic Co/Tb multilayers, whereas it is entirely absorbed by a 1-nm-thick ferromagnetic Co/Ni multilayer. We also find that the switching efficiency of Co/Tb multilayers partially reflects a bulk-like torque characteristic, as it increases with ferrimagnet thickness up to 8 nm and then decreases, in clear contrast to the 1/thickness dependence of ferromagnetic Co/Ni multilayers. Our results on antiferromagnetically coupled systems will invigorate research towards the development of energy-efficient spintronics.

Original languageEnglish
Pages (from-to)29-34
Number of pages6
JournalNature Materials
Volume18
Issue number1
DOIs
Publication statusPublished - 2019 Jan 1

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ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Yu, J., Bang, D., Mishra, R., Ramaswamy, R., Oh, J. H., Park, H. J., Jeong, Y., Van Thach, P., Lee, D. K., Go, G., Lee, S. W., Wang, Y., Shi, S., Qiu, X., Awano, H., Lee, K. J., & Yang, H. (2019). Long spin coherence length and bulk-like spin–orbit torque in ferrimagnetic multilayers. Nature Materials, 18(1), 29-34. https://doi.org/10.1038/s41563-018-0236-9