The Future of energy, the challenge of "spintronics"

Ieda, Junichi

FBNews, (528), p.1 - 5, 2020/12

no abstracts in English

The Cutting edge of nuclear science

Orlandi, R.; Hirose, Kentaro; Yaita, Tsuyoshi; Yamagami, Hiroshi; Ieda, Junichi; Kambe, Shinsaku; Ishikawa, Norito

Nippon Genshiryoku Gakkai-Shi, 62(5), p.280 - 284, 2020/05

https://doi.org/10.3327/jaesjb.62.5_280

no abstracts in English

Hard X-ray photoelectron spectroscopy study of Pt/YFeO

Kobata, Masaaki; Yoshii, Kenji; Fukuda, Tatsuo; Kawasaki, Ikuto; Okane, Tetsuo; Yamagami, Hiroshi; Yaita, Tsuyoshi; Harii, Kazuya; Ieda, Junichi; Okayasu, Satoru; et al.

JPS Conference Proceedings (Internet), 30, p.011192_1 - 011192_6, 2020/03

https://doi.org/10.7566/JPSCP.30.011192

High energy X-ray photoelectron spectroscopy (HAXPES) measurements were carried out for the Spin Seebeck system Pt/YFeO(YIG). This system was found to show anomalous Hall effect, possible due to the formation of intermetallic compounds between Fe and Pt. To reveal this possibility, we have measured the Fe 1s photoelectron peaks by using HAXPES. It was found that the Fe ions consist of Fe in YIG and metallic Fe. The formation of the metallic state is consistent with the proposed origin of the anomalous Hall effect. Other spectra such as Pt 4f will be presented at the conference.

Spinmotive force in the out-of-plane direction generated by spin wave excitations in an exchange-coupled bilayer element

Zhou, W.*; Seki, Takeshi*; Imamura, Hiroshi*; Ieda, Junichi; Takanashi, Koki*

Physical Review B, 100(9), p.094424_1 - 094424_5, 2019/09

https://doi.org/10.1103/PhysRevB.100.094424

Radiation and spintronics

Ieda, Junichi

Hoshasen To Sangyo, (146), p.48 - 52, 2019/06

no abstracts in English

Electric field control of magnetic domain wall motion via modulation of the Dzyaloshinskii-Moriya interaction

Koyama, Tomohiro*; Nakatani, Yoshinobu*; Ieda, Junichi; Chiba, Daichi*

Science Advances (Internet), 4(12), p.eaav0265_1 - eaav0265_5, 2018/12

https://doi.org/10.1126/sciadv.aav0265

We show that the electric field (EF) can control the magnetic domain wall (DW) velocity in a Pt/Co/Pd asymmetric structure. With the application of a gate voltage, a significant change in DW velocity up to 50 m/s is observed, which is much greater than that observed in previous studies. Moreover, a DW velocity exceeding 100 m/s is clearly modulated. An EF-induced change in the interfacial Dzyaloshinskii-Moriya interaction (DMI) up to several percent is found to be the origin of the velocity modulation. The DMI-mediated velocity change shown here is a fundamentally different mechanism from that caused by EF-induced anisotropy modulation. Our results will pave the way for the electrical manipulation of spin structures and dynamics via DMI control, which can enhance the performance of spintronic devices.

Magnetic anisotropy by Rashba spin-orbit coupling in antiferromagnetic thin films

Ieda, Junichi; Barnes, S. E.*; Maekawa, Sadamichi

Journal of the Physical Society of Japan, 87(5), p.053703_1 - 053703_4, 2018/05

https://doi.org/10.7566/JPSJ.87.053703

Spin-transfer torques in antiferromagnetic textures; Efficiency and quantification method

Yamane, Yuta*; Ieda, Junichi; Sinova, J.*

Physical Review B, 94(5), p.054409_1 - 054409_8, 2016/08

AA2016-0164.pdf:0.5MB

https://doi.org/10.1103/PhysRevB.94.054409

We formulate a theory of spin-transfer torques in antiferromagnets, which covers the small to large limits of the exchange coupling energy relative to the kinetic energy of the inter-sublattice electron dynamics. Our theory suggests a natural definition of the efficiency of spin-transfer torques in antiferromagnets in terms of well-defined material parameters, revealing that the charge current couples predominantly to the antiferromagnetic order parameter and the sublattice-canting moment in, respectively, the limits of large and small exchange coupling. The effects can be quantified by analyzing the antiferromagnetic spin-wave dispersions in the presence of charge current: in the limit of large exchange coupling the spin-wave Doppler shift always occurs, whereas, in the opposite limit, the only spin-wave modes to react to the charge current are ones that carry a pronounced sublattice-canting moment. The findings offer a framework for understanding and designing spin-transfer torques in antiferromagnets belonging to different classes of sublattice structures such as, e.g., bipartite and layered antiferromagnets.

Spin hydrodynamic generation

Takahashi, Ryo*; Matsuo, Mamoru; Ono, Masao; Harii, Kazuya; Chudo, Hiroyuki; Okayasu, Satoru; Ieda, Junichi; Takahashi, Saburo*; Maekawa, Sadamichi; Saito, Eiji

Nature Physics, 12, p.52 - 56, 2016/01

https://doi.org/10.1038/nphys3526

Spin pumping blocked by single-layer graphene

Haku, Satoshi*; Tashiro, Takaharu*; Nakayama, Hiroyasu*; Ieda, Junichi; Entani, Shiro; Sakai, Seiji; Ando, Kazuya*

Applied Physics Express, 8(7), p.073009_1 - 073009_3, 2015/07

https://doi.org/10.7567/APEX.8.073009

We found that the spin pumping in a NiFe/Pt bilayer is strongly suppressed by inserting single-layer graphene (SLG) at the interface. The spin pumping in the NiFe/Pt bilayer enhances the magnetization damping of the ferromagnetic layer, which is quantified from microwave frequency dependence of ferromagnetic resonance linewidth. We show that the enhancement of the magnetization damping due to the spin pumping disappears in a NiFe/SLG/Pt trilayer. This result indicates that the spin pumping is blocked by the atomic monolayer, demonstrating the crucial role of the interfacial short-range spin-exchange coupling in the spin pumping in metallic systems.