Koki Shimose
Osaka University
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Publication
Featured researches published by Koki Shimose.
Japanese Journal of Applied Physics | 2017
Takuya Tsukahara; Takeshi Kawabe; Koki Shimose; Taishi Furuta; Risa Miyakaze; Kohei Nawaoka; Minori Goto; Takayuki Nozaki; Shinji Yuasa; Yoshinori Kotani; Kentaro Toyoki; Motohiro Suzuki; Tetsuya Nakamura; Yoshishige Suzuki; Shinji Miwa
The magnetic moments of a Pt|Fe(0.5 nm)|MgO film at an external electric field of in a 0.35 V/nm were characterized by analyzing the X-ray magnetic circular dichroism (XMCD) at the L-edges of Fe using a partial fluorescence yield method with a precision 40 times greater than that in our previous study. The XMCD induced by the electric field was negligible (<0.2%). Furthermore, although an induced orbital magnetic moment seemingly existed, it was within the precision error (0.3%). This paper demonstrates that slight electron doping and/or redistribution without any electrochemical reaction causes voltage-controlled magnetic anisotropy at Fe|MgO interfaces.
Applied Physics Express | 2018
Takeshi Kawabe; Koki Shimose; Minori Goto; Yoshishige Suzuki; Shinji Miwa
A single-crystal multilayer consisting of Fe, cobalt phthalocyanine (CoPc), and MgO was grown on an fcc-MgO(001) substrate. The reflection high-energy diffraction observation showed that the ultrathin fcc-MgO(001) film could be grown on bcc-Fe(001)/CoPc when the thickness of CoPc was less than 0.7 nm (about two molecular layers). A tunnel junction with a bcc-Fe(001)/CoPc/fcc-MgO(001)/bcc-Fe(001) layer achieved a tunnel magnetoresistance of about 20% and an electric field endurance of more than 1 V/nm at room temperature. The novel multilayer in the present study will enable us to advance the frontiers of molecular spintronics.
Applied Physics Express | 2017
Motohiro Suzuki; Takuya Tsukahara; Risa Miyakaze; Taishi Furuta; Koki Shimose; Minori Goto; Takayuki Nozaki; Shinji Yuasa; Yoshishige Suzuki; Shinji Miwa
The voltage-controlled magnetic anisotropy of ferromagnetic metals may offer potential applications of nonvolatile memories with ultralow power consumption. For achieving ultrafast recording and long-time endurance, voltage-induced effects without undesirable lattice distortions should be ensured. In this study, in-situ extended X-ray absorption fine structure analysis of an Fe/Pt/MgO junction demonstrated the unaltered interfacial atomic structure, in which the radial distances between the Pt and the neighboring Fe, Pt, O, and Mg atoms changed by less than ±0.01 A under electric fields of ±0.18 V/nm. Therefore, the anisotropy change is driven by a purely electronic mechanism without lattice deformation or atomic relaxation.
The Japan Society of Applied Physics | 2018
Koki Shimose; Ryoto Enoki; Hiromu Gamou; Takeshi Kawabe; Takuya Tsukahara; Yoshinori Kotani; Kentaro Toyoki; Tetsuya Nakamura; Minori Goto; Yoshishige Suzuki; Junsaku Nitta; Makoto Kohda; Shinji Miwa
IEEE Transactions on Magnetics | 2018
S. Takizawa; K. Kondou; H. Isshiki; Koki Shimose; Takeshi Kawabe; Shinji Miwa; Y. Otani
Bulletin of the American Physical Society | 2018
Koki Shimose; Takeshi Kawabe; Minori Goto; Yoshishige Suzuki; Shinji Miwa
The Japan Society of Applied Physics | 2017
Takeshi Kawabe; Koki Shimose; Takuya Tsukahara; Kohei Nawaoka; Minosri Goto; Yoshinori Kotani; Tetsuya Nakamura; Yoshishige Suzuki; Shinji Miwa
The Japan Society of Applied Physics | 2017
Koki Shimose; Takeshi Kawabe; Kohei Nawaoka; Minori Goto; Yoshishige Suzuki; Shinji Miwa
The Japan Society of Applied Physics | 2017
Takuya Tsukahara; Takeshi Kawabe; Koki Shimose; Taishi Furuta; Risa Miyakaze; Kohei Nawaoka; Minori Goto; Takayuki Nozaki; Shinji Yuasa; Yoshinori Kotani; Kentaro Toyoki; Motohiro Suzuki; Tetsuya Nakamura; Yoshishige Suzuki; Shinji Miwa
The Japan Society of Applied Physics | 2017
Takuya Tsukahara; Motohiro Suzuki; Takeshi Kawabe; Koki Shimose; Taishi Furuta; Risa Miyakaze; Kohei Nawaoka; Minori Goto; Takayuki Nozaki; Shinji Yuasa; Yoshinori Kotani; Kentaro Toyoki; Tetsuya Nakamura; Yoshishige Suzuki; Shinji Miwa
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National Institute of Advanced Industrial Science and Technology
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