Speakers

Antiferromagnetic spintronics for low-power neuromorphic computing

M_04_Kyung-Jin Lee(photo)
Kyung-Jin Lee
Korea Univ.
16:30~17:10

Abstract :

The mammalian brain is far superior to today’s electronic circuits in intelligence and efficiency. Its functions are realized by the network of neurons connected via synapses. Much effort has been extended in finding satisfactory electronic neural networks that act like brains, i.e., especially the electronic version of synapse that is capable of the weight control and is independent of the external data storage. Ferromagnetic spintronics is a potential candidate for such neuromorphic computing [1] as it combined with the spin-torque effect [2,3] offers various functional devices including memories, oscillators, and random-number generators [4]. Despite attractive features, however, the power consumption of the state-of-the-art ferromagnetic spintronic devices is still far greater than that used in the brain. In this respect, it is crucial to find a spintronics solution that allows a further reduction of power consumption. In this talk, we introduce antiferromagnetic spintronics for this purpose. A key advantage of antiferromagnet is its terahertz resonance frequency, which allows ultrafast information processing and thus reduces power consumption significantly. As an example, we show that spin-orbit spin torques drive antiferromagnetic domain walls much faster than ferromagnetic domain walls [5]. Furthermore, the antiferromagnetic domain wall motion generates terahertz spin-waves, which can be converted into terahertz electric signals through inverse spin Hall effect. We also show that the antiferromagnet generates spin currents and is able to switch nearby ferromagnet [6]. These features allow a large reduction in the power consumption of spin-orbit torque memory and domain wall devices, which is beneficial for neuromorphic applications.

[1] N. Locatelli et al., in 2015 Design, Automation Test in Europe Conference Exhibition (DATE), pp. 994–999 (2015).
[2] J. C. Slonczewski, J. Magn. Magn. Mater., vol. 159, no. 1–2, pp. L1–L7, (1996).
[3] L. Berger, Phys. Rev. B, vol. 54, no. 13, pp. 9353–9358 (1996).
[4] N. Locatelli, V. Cros, and J. Grollier, Nat. Mater., vol. 13, no. 1, pp. 11–20 (2014).
[5] T. Shiino et al., Phys. Rev. Lett. 117, 087203 (2016).
[6] Y.-W. Oh et al., Nature Nanotechnol. Advanced Online Publication; DOI:10.1038/NNANO.2016.109 (2016)

 

Education

  • Ph.D. 2000 Department of Materials Science and Engineering, KAIST, Korea
  • M.S. 1996 Department of Advanced Materials Science and Engineering, KAIST, Korea
  • B.S. 1994 Department of Physics, Korea Adv. Inst. of Sci. and Technol. (KAIST), Korea

 

Professional Activities

  • 2011-2012 CNST Visiting Fellow at the NIST, Gaithersburg and Visiting Associate
    Professor at the Univ. of Maryland (sabbatical leave from Korea Univ.)
  • 2005–Present Korea University, Assiatant/Associate/Full Professor at Dept. of Mater. Sci. & Eng.
  • 2003–2005 SPINTEC, CEA-CNRS/Grenoble/DRFMC, France, Post-doctoral Fellow
  • 2000–2005 Samsung Adv. Inst. of Technol. (SAIT), Senior Researcher

 

Awards & Honors

  • 2016 Focus session organizer, APS 2016 March Meeting
  • 2014~2016 Advisory Committee Member of MMM as a representative of IEEE
  • 2014 Samsung 4th STT-MRAM Global Innovation Forum (Moderator)
  • 2013 100 Future Technologies and Leading Scientists, The National Academy of Engineering of Korea
  • 2013 Joint MMM/INTERMAG, ISAMMA, ECS
  • 2012 ICM
  • 2011 KUCE Crimson Professor, Korea University
  • 2011 INTERMAG Conference
  • 2011 Samsung Semiconductor Future Technology Forum 2011 “STT-MRAM Device Technology” (Moderator)
  • 2010 Excellent Research on Basic Science, MEST, Korea
  • 2010 ICAUMS
  • 2010 Joint MMM/INTERMAG conference
  • 2009 Young Scientist Award, Korea University
  • 2008 Asian Magnetic Conference, ISAMMA07
  • 2005 Korea Patent Award (The 2nd place), Korean Intellectual Property Office (1/4Q)