Microscopic origin of voltage-controlled magnetic anisotropy in FePt/MgO epitaxial multilayer

ORAL

Abstract

Spin-transfer has surpassed current-induced magnetic fields as the preferred technology for magnetization switching in nanoscale magnets. However, spin-transfer switching exhibits Joule heating that remains too large to ignore. Thus, a novel method offering magnetization control without electric current is highly desirable. Because voltage-controlled magnetic anisotropy (VCMA) in Fe/MgO-based devices [1] can be an ultimate technology for spintronics devices, a novel method to increase the VCMA is important.
In this study, we will show a new mechanism to enhance VCMA in FePt/MgO epitaxial tunnel junction device proved by X-ray magnetic circular dichroism spectroscopy [2]. Electric field at metal/dielectric interface couples with a electrric quadrupole of an electron shell in metals. The induced electric quadrupole produces the intra-atomic magnetic dipole Tz term and influences magnetic anisotropy through spin-flip process. Our finding enables the design of novel materials showing VCMA larger by more than a factor of 10.
[1] T. Maruyama et al., Nat. Nanotechnol. 4, 151 (2009).
[2] S. Miwa et al., Nat. Commun. 8, 15848 (2017).ua

*A part of this work was supported by the ImPACT and JSPS KAKENHI (No. JP26103002, JP15H05420).

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Presenters

  • Shinji Miwa

    • Graduate School of Engineering Science, Osaka University
    • Graduate school of Engineering Science, Osaka University, Center for Spintronics Research Network, Osaka University

Authors

  • Shinji Miwa

    • Graduate School of Engineering Science, Osaka University
    • Graduate school of Engineering Science, Osaka University, Center for Spintronics Research Network, Osaka University

  • Motohiro Suzuki

    • Japan Synchrotron Radiation Research Institute (JASRI)

  • Masahito Tsujikawa

    • Research Institute of Electrical Communication, Tohoku University

  • Takayuki Nozaki

    • Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST)

  • Minori Goto

    • Graduate School of Engineering Science, Osaka University
    • Graduate school of Engineering Science, Osaka University, Center for Spintronics Research Network, Osaka University

  • Yoshinori Kotani

    • Japan Synchrotron Radiation Research Institute (JASRI)

  • Tadakatsu Ohkubo

    • Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS)

  • Eiiti Tamura

    • Graduate School of Engineering Science, Osaka University

  • Frederic Bonell

    • Graduate School of Engineering Science, Osaka University

  • Kazuhiro Hono

    • Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS)

  • Tetsuya Nakamura

    • Japan Synchrotron Radiation Research Institute (JASRI)

  • Masafumi Shirai

    • Research Institute of Electrical Communication, Tohoku University

  • Yoshishige Suzuki

    • Graduate School of Engineering Science, Osaka University
    • Graduate school of Engineering Science, Osaka University, Center for Spintronics Research Network, Osaka University