On-line SPICE-SPIN+X Seminars

On-line Seminar: 23.09.2020 - 15:00 (CET)

Spintronics Nanodevice
- How small can we make it and what else can we use it for -

Hideo Ohno, Tohoku University

Development of spintronics nonvolatile nanodevices and their integration with CMOS circuits has resulted in realizing low-energy, yet high performance integrated circuits suitable for a number of applications such as Internet-of-Things (IoT), high-performance computing and artificial intelligence. Magnetic tunnel junction (MTJ), a spintronics device, plays a central role here, which has been shown to scale down to 20 nm with the perpendicular-easy-axis CoFeB-MgO system [1, 2]. I will first discuss the factors that limit the scalability of such MTJs. Then show how one can extend its scalability to the range of 4-8 nm and below [3, 4] by employing a new (and yet not so new) concept. Current-induced switching of magnetization and high thermal stability of these devices are also shown. I will then describe how one can use less stable MTJs for a novel form of computation, probabilistic computing, to address optimization problems. I show that one can formulate integer factorization as an optimization problem in such a way that the most preferred state in terms of energy gives the factorized result [5]. If I have time I will touch upon proof-of-concept spintronics devices for artificial synapse as well as neuron for neuromorphic applications [6, 7].
Work done in collaboration with S. Fukami and the CSIS team. A portion of the work described here is a result of collaboration with A. Z. Pervaiz, K. Y. Camsari, and S. Datta of Purdue University. Supported in part by the ImPACT Program of CSTI, JST-OPERA JPMJOP1611 and Grant-in-Aid for Specially Promoted Research (17H06093).

[1] S. Ikeda, et al. Nature Materials, 9, 721 (2010).
[2] H. Sato, et al. IEDM 2013 and Appl. Phys. Lett. 105, 062403 (2014).
[3] K. Watanabe, et al. Nature Commun. 9, 663 (2018).
[4] B. Jinnai, et al. Appl. Phys. Lett. (Perspective), 116, 160501 (2020).
[5] W. A. Borders, et al. Nature 573, 390-393 (2019).
[6] W. A. Borders et al. Appl. Phys. Express 10, 013007 (2017).
[7] A. Kurenkov, et al. Advanced Materials 31, 1900636 (2019).

PDF file of the talk available here