Hydrogen embrittlement resistance of pre-strained ultra-high-strength low alloy TRIP-aided steel

Hojo, Tomohiko*; Kumai, B.*; Koyama, Motomichi*; Akiyama, Eiji*; Waki, Hiroyuki*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Nagasawa, Akihiko*

International Journal of Fracture, 224(2), p.253 - 260, 2020/08

https://doi.org/10.1007/s10704-020-00451-5

In the study, the pre-strain effect on hydrogen embrittlement property of the ultra-high-strength transformation-induced plasticity -aided bainitic ferrite steel was investigated towards application for automobile frame parts. 3-10% tensile pre-strain suppressed hydrogen-induced mechanical degradation relative to total elongation while 12-15% pre-strained specimen did not exhibit elongation after hydrogen charging. The advantageous effect of the 3-10% pre-strain was attributed to the suppression of crack initiation related to retained austenite. The TRIP by pre-straining decreased the volume fraction of retained austenite before hydrogen charging, thereby reducing existing probabilities of preferential crack initiation sites and propagation paths. Conversely, high pre-strain such as 12-15% does not effectively work due to work hardening resulting in increases in hydrogen embrittlement susceptibility and a significant increase in hydrogen content due to the multiplication of dislocations.

Enhancement of domain-wall mobility detected by NMR at the angular momentum compensation temperature

Imai, Masaki; Chudo, Hiroyuki; Matsuo, Mamoru; Maekawa, Sadamichi; Saito, Eiji

Physical Review B, 102(1), p.014407_1 - 014407_5, 2020/07

https://doi.org/10.1103/PhysRevB.102.014407

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.

Topological characterization of classical waves; The Topological origin of magnetostatic surface spin waves

Yamamoto, Kei; Thiang, G. C.*; Pirro, P.*; Kim, K.-W.*; Everschor-Sitte, K.*; Saito, Eiji*

Physical Review Letters, 122(21), p.217201_1 - 217201_5, 2019/05

https://doi.org/10.1103/PhysRevLett.122.217201

Magnetomechanical sensing based on delta-E effect in YFeO micro bridge

Arisawa, Hiroki*; Daimon, Shunsuke*; Oikawa, Yasuyuki*; Seo, Y.-J.*; Harii, Kazuya; Oyanagi, Koichi*; Saito, Eiji

Applied Physics Letters, 114(12), p.122402_1 - 122402_5, 2019/03

https://doi.org/10.1063/1.5090272

Observation of gyromagnetic reversal

Imai, Masaki; Ogata, Yudai*; Chudo, Hiroyuki; Ono, Masao; Harii, Kazuya; Matsuo, Mamoru*; Onuma, Yuichi*; Maekawa, Sadamichi; Saito, Eiji

Applied Physics Letters, 113(5), p.052402_1 - 052402_3, 2018/07

https://doi.org/10.1063/1.5041464

Spin colossal magnetoresistance in an antiferromagnetic insulator

Qiu, Z.*; Hou, D.*; Barker, J.*; Yamamoto, Kei; Gomonay, O.*; Saito, Eiji*

Nature Materials, 17(7), p.577 - 580, 2018/05

https://doi.org/10.1038/s41563-018-0087-4

Colossal magnetoresistance (CMR) refers to a large change in electrical conductivity induced by a magnetic field in the vicinity of a metal-insulator transition. CMR occurs due to a correlation between the magnetic structure and electron conduction and has inspired extensive studies for decades. Here, in the antiferromagnetic insulator CrO, we found a sharp transition between conducting and nonconducting states for spin currents at room temperature. The spin-current transmission changes by two orders of magnitude within a narrow temperature window of 14K around the Neel temperature. The spin conductor-nonconductor transition can be modulated by a magnetic field, giving an isothermal change of spin-current transmission of up to 500%, effectively an on-off switch for spin currents.

Status of study of long-term assessment of transport of radioactive contaminants in the environment of Fukushima; As a part of dissemination of evidence-based information

Tsuruta, Tadahiko; Niizato, Tadafumi; Nakanishi, Takahiro; Dohi, Terumi; Nakama, Shigeo; Funaki, Hironori; Misono, Toshiharu; Oyama, Takuya; Kurikami, Hiroshi; Hayashi, Seiji*; et al.

JAEA-Review 2017-018, 86 Pages, 2017/10

JAEA-Review-2017-018.pdf:17.58MB

Since the accidents at Fukushima Daiichi Nuclear Power Plant following the Tohoku Region Pacific Coast Earthquake on March 11th, 2011, Fukushima Environmental Safety Center has carried out research on natural mobilization of radionuclide (especially radiocesium) and future forecast from forest to water system and surrounding residential areas. The report summarizes the latest results that have been accumulated from each study field, of our agency together with the other related research organizations. The contents of the report is to be used as evidence-based information for the QA-styled pages in the website of JAEA Sector of Fukushima Research and Development at the time of next renewal.

Experimental evidence consistent with a magnon Nernst effect in the antiferromagnetic insulator MnPS

Shiomi, Yuki*; Takashima, Rina*; Saito, Eiji

Physical Review B, 96(13), p.134425_1 - 134425_9, 2017/10

https://doi.org/10.1103/PhysRevB.96.134425

Spin current generation using a surface acoustic wave generated via spin-rotation coupling

Kobayashi, Daima*; Yoshikawa, Tomohide*; Matsuo, Mamoru*; Iguchi, Ryo*; Maekawa, Sadamichi; Saito, Eiji; Nozaki, Yukio*

Physical Review Letters, 119(7), p.077202_1 - 077202_5, 2017/08

https://doi.org/10.1103/PhysRevLett.119.077202