The University of Tokyo Institute for Solid State Physics

Tohoku University

Graduate School of Science, The University of Tokyo

RIKEN

Japan Science and Technology Agency

Summary

Associate Professor Shinji Miwa of the Institute for Solid State Physics and Trans-scale Quantum Science Institutes, the University of Tokyo, Professor Satoshi Nakatsuji of the same institute, the same organizations, and the Graduate School of Science of the University of Tokyo, are joined by Project Associate Professor Takahiro Tomita, Graduate Student Ikhlas Muhammad, Assistant Professor Shoya Sakamoto of the same institute, Project Associate Professor Tomoya Higo of the same Institute, the Assistant Professor Takuya Nomoto and Professor Ryotaro Arita (Team Leader, RIKEN Center for Emergent Matter Science), Graduate School of Engineering, Tohoku University, Assistant Professor Kenshi Iihama, Frontier Research Center for Interdisciplinary Sciences, Tohoku University, and Professor Narumi Mizukami, Institute for Solid State Physics, Tohoku University. Professor Shigemi Mizukami of the Institute for Frontier Research for Interdisciplinary Research, Tohoku University, and Professor Shigemi Mizukami of the Advanced Institute for Materials Research, Tohoku University, have jointly demonstrated that the spin reversal speed of antiferromagnetic metals is as fast as 10 picoseconds (1/100 billionth of a second), which is a characteristic of electrons in materials as magnets.

Electronics technology that utilizes nano-sized magnets is called spintronics. By utilizing spin together with charge, it is expected to create electronic devices with new functions that could not be realized with conventional technologies. Typical devices include magnetic heads for ultra-high-density hard disk drives and nonvolatile memory MRAM. Until now, ferromagnetic metals have been used as magnet materials in spintronics. On the other hand, antiferromagnetic metals are expected to have spin reversal speeds in the picosecond range, 10 to 100 times faster than ferromagnetic metals, and are attracting attention as a new electronic device material. However, there has been no observation of spin motion in antiferromagnetic metals on a time axis, and the ultrafast speed has only been predicted. In this study, using a special manganese alloy called a topological antiferromagnetic metal, we succeeded in capturing the spin motion in real time and demonstrated that the reversal speed is ultrafast at less than 10 picoseconds. This corresponds to a read/write speed 10 to 100 times faster than that of MRAM, which is now in practical use, and the fabrication of electronic devices using this material will enable ultrafast operation.

The research results were published online in the international scientific journal Small Science on April 15, 2021.

Figure: Spin dynamics measurement of antiferromagnetic metal _Mn3Sn using the stroboscopic method

For more details, please visit the website of the Institute for Solid State Physics, The University of Tokyo.