Fall Colloquium- Antiferromagnetic spintronics
Dr. Takahiro Moriyama, Institute for Chemical Research, Kyoto University, Japan
Abstract: For a long time, there have been no efficient ways of controlling antiferromagnets. Quite a strong magnetic field is required to manipulate the magnetic moments because of a high molecular field and a small magnetic susceptibility. It was also difficult to detect the orientation of the magnetic moments since the net magnetic moment is effectively zero. Nevertheless, the microscopic magnetic moments should in principle exhibit a similar spintronic effect, such as various magnetoresistance effects and the spin torque effect, as seen in ferromagnets1. Various spintronic operations with antiferromagnets (AFMs), including static and dynamic controls of the magnetic moments, are therefore a key for emerging antiferromagnetic spintronics.
The talk will describe our recent results on spin torque control of the magnetization dynamics with antiferromagnetic materials. I will discuss the demonstrations of sequential antiferromagnetic memory operations with a spin-orbit-torque write, by the spin Hall effect, and a resistive read in various antiferromagnets2,3. I will also discuss the magnetic damping modification of a ferromagnet (FM) reflecting the Neel order in the AFM in exchange coupled FM/AFM bilayers. A wide range control of magnetic damping is shown to be possible by utilizing antiferromagnets, which is quite beneficial for spintronic applications4,5. Discussion will extend to the THz antiferromagnetic dynamics and their emerging spin phenomena.
 V. Baltz, A. Manchon, M. Tsoi, T. Moriyama, T. Ono, and Y. Tserkovnyak, Rev. Mod. Phys. 90, 015005 (2018); T. Jungwirth, X. Marti, P. Wadley, and J. Wunderlich, Nat. Nanotechnol. 11, 231 (2016).  T. Moriyama, K. Oda, T. Ohkochi, M. Kimata, and T. Ono, Sci. Rep. 8, 14167 (2018).  T. Moriyama, W. Zhou, T. Seki, K. Takanashi, and T. Ono, Phys. Rev. Lett. 121, 167202 (2018).  T. Moriyama, M. Kamiya, K. Oda, K. Tanaka, K.-J. Kim, and T. Ono, Phys. Rev. Lett. 119, 267204 (2017).  T. Moriyama, K. Oda, and T. Ono, Phys. Rev. Appl. 11, 011001 (2019).  T. Moriyama, K. Hayashi, K. Yamada, M. Shima, Y. Ohya, and T. Ono, Phys. Rev. Mater. 3, 051402 (2019).