Current-induced crystallisation in a Heusler-alloy-based giant magnetoresistive junction for neuromorphic potentiation

Zhou, Z.*; Frost, W.*; Lloyd, D. C.*; Seki, Takeshi*; Kubota, Takahide*; Ramos, R.*; Saito, Eiji; Takanashi, Koki; Hirohata, Atsufumi*

Journal of Magnetism and Magnetic Materials, 571, p.170575_1 - 170575_5, 2023/04

https://doi.org/10.1016/j.jmmm.2023.170575

Observation of spin-space quantum transport induced by an atomic quantum point contact

Ono, Koki*; Higomoto, Toshiya*; Saito, Yugo*; Uchino, Shun; Nishida, Yusuke*; Takahashi, Yoshiro*

Nature Communications (Internet), 12, p.6724_1 - 6724_8, 2021/11

https://doi.org/10.1038/s41467-021-27011-2

Quantum transport is ubiquitous in physics. So far, quantum transport between terminals has been extensively studied in solid state systems from the fundamental point of views such as the quantized conductance to the applications to quantum devices. Recent works have demonstrated a cold-atom analog of a mesoscopic conductor by engineering a narrow conducting channel with optical potentials, which opens the door for a wealth of research of atomtronics emulating mesoscopic electronic devices and beyond. Here we realize an alternative scheme of the quantum transport experiment with ytterbium atoms in a two-orbital optical lattice system. Our system consists of a multi-component Fermi gas and a localized impurity, where the current can be created in the spin space by introducing the spin-dependent interaction with the impurity. We demonstrate a rich variety of localized-impurity-induced quantum transports, which paves the way for atomtronics exploiting spin degrees of freedom.

Evaluation of edge domains in giant magnetoresistive junctions

Frost, W.*; Seki, Takeshi*; Kubota, Takahide*; Ramos, R.*; Saito, Eiji; Takanashi, Koki*; Hirohata, Atsufumi*

Applied Physics Letters, 118(17), p.172405_1 - 172405_5, 2021/04

https://doi.org/10.1063/5.0049315

Element-specific density of states of CoMnGe revealed by resonant photoelectron spectroscopy

Kono, Takashi*; Kakoki, Masaaki*; Yoshikawa, Tomoki*; Wang, X.*; Sumida, Kazuki*; Miyamoto, Koji*; Muro, Takayuki*; Takeda, Yukiharu; Saito, Yuji; Goto, Kazuki*; et al.

Physical Review B, 100(16), p.165120_1 - 165120_6, 2019/10

https://doi.org/10.1103/PhysRevB.100.165120

MnVAl Heusler alloy thin films; Appearance of antiferromagnetism and exchange bias in a layered structure with Fe

Tsuchiya, Tomoki*; Kobayashi, Ryota*; Kubota, Takahide*; Saito, Kotaro*; Ono, Kanta*; Ohara, Takashi; Nakao, Akiko*; Takanashi, Koki*

Journal of Physics D; Applied Physics, 51(6), p.065001_1 - 065001_7, 2018/02

https://doi.org/10.1088/1361-6463/aaa41a

Enhancement of anomalous Nernst effects in metallic multilayers free from proximity-induced magnetism

Uchida, Kenichi*; Kikkawa, Takashi*; Seki, Takeshi*; Oyake, Takafumi*; Shiomi, Junichiro*; Qiu, Z.*; Takanashi, Koki*; Saito, Eiji

Physical Review B, 92(9), p.094414_1 - 094414_6, 2015/09

https://doi.org/10.1103/PhysRevB.92.094414

Current-induced spin polarization on metal surfaces probed by spin-polarized positron beam

Zhang, H.; Yamamoto, Shunya; Fukaya, Yuki; Maekawa, Masaki; Li, H.; Kawasuso, Atsuo; Seki, Takeshi*; Saito, Eiji*; Takanashi, Koki*

Scientific Reports (Internet), 4, p.4844_1 - 4844_5, 2014/04

https://doi.org/10.1038/srep04844

Spin pumping efficiency from half metallic CoMnSi

Chudo, Hiroyuki; Ando, Kazuya*; Saito, Kesami*; Okayasu, Satoru; Haruki, Rie; Sakuraba, Yuya*; Yasuoka, Hiroshi; Takanashi, Koki; Saito, Eiji

Journal of Applied Physics, 109(7), p.073915_1 - 073915_4, 2011/04

https://doi.org/10.1063/1.3556433

We present spin pumping using a Heusler alloy CoMnSi/Pt bilayer film. A spin current is produced by a ferromagnetic resonance (FMR) technique. The pure spin current injected into the Pt layer from the CoMnSi layer is detected by the inverse spin-Hall effect (ISHE), which converts the spin current into an electric current. We estimated a damping constant of the CoMnSi/Pt bilayer film from an angular dependence of FMR spectra. Using the damping constant efficiency of spin pumping from the CoMnSi layer is evaluated. We found that a mixing conductance at the CoMnSi/Pt interface is comparable to that at a permalloy/Pt interface.

Probabilistic safety assessment on experimental fast reactor Joyo; Level1 PSA for internal events

Ishikawa, Koki; Takamatsu, Misao; Kawahara, Hirotaka; Mihara, Takatsugu; Kurisaka, Kenichi; Terano, Toshihiro; Murakami, Takanori; Noritsugi, Akihiro; Iseki, Atsushi; Saito, Takakazu; et al.

JAEA-Technology 2009-004, 140 Pages, 2009/05

JAEA-Technology-2009-004.pdf:2.0MB

Probabilistic safety assessment (PSA) has been applied to nuclear plants as a method to achieve effective safety regulation and safety management. In order to establish the PSA standard for fast breeder reactor (FBR), the FBR-PSA for internal events in rated power operation is studied by Japan Atomic Energy Agency (JAEA). The level1 PSA on the experimental fast reactor Joyo was conducted to investigate core damage probability for internal events with taking human factors effect and dependent failures into account. The result of this study shows that the core damage probability of Joyo is 5.010 per reactor year (/ry) and that the core damage probability is smaller than the safety goal for existed plants (10 ry) and future plants (10/ry) in the IAEA INSAG-12 (International Nuclear Safety Advisory Group) basic safety principle.

Evaluation on materials performance of hastelloy alloy XR for HTTR uses-3; Manufacture of filler metal and its weldability

Watanabe, Katsutoshi; Nakajima, Hajime; Saito, Teiichiro*; Takatsu, Tamao*; Koikegami, Hajime*; Higuchi, Makoto*; Nakanishi, Tsuneo*; Sahira, Kensho*; Marushichi, Koki*; Takeiri, Toshiki*

JAERI-Research 94-046, 50 Pages, 1994/12

JAERI-Research-94-046.pdf:2.23MB

no abstracts in English