Electric-field-induced changes in magnetic moments and magnetic anisotropy in Co/MgO multilayer

ORAL

Abstract

Voltage controlled magnetic anisotropy (VCMA) in Fe/MgO-based devices has been intensively studied [1]. One explanation for the VCMA is an induced change in orbital magnetic moment. However, electric field induced changes in orbital magnetic moment has never been confirmed experimentally. It has recently been pointed out the significance of the magnetic dipole Tz term to the VCMA in Pt with proximity-induced spin polarization [2]. In a Fe/Pt/MgO, the Tz term induction, correlating with electric quadrupole induction, induces a VCMA.
In this study, we report direct evidence of the electric-field-induced changes in orbital magnetic moment of Co ultrathin films in terms of in-situ X-ray magnetic circular dichroism spectroscopy [3]. In a Fe/Co/MgO multilayer, we find an induced change in orbital magnetic moment of 0.013μB in an electric field of ±0.2 V/nm. Moreover, the VCMA in the system is well estimated by the induced change. While we also found the magnetic dipole Tz term induction in Co, the induced Tz term only contributed little to the VCMA.
[1] T. Maruyama et al., Nat. Nanotechnol. 4, 158 (2009).
[2] S. Miwa et al., Nat. Commun. 8, 15848 (2017).
[3] T. Kawabe et al., arXiv 1708.08549.

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

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Presenters

  • Takeshi Kawabe

    • Graduate School of Engineering Science, Osaka University

Authors

  • Takeshi Kawabe

    • Graduate School of Engineering Science, Osaka University

  • Kohei Yoshikawa

    • Graduate School of Engineering Science, Osaka University

  • Masahito Tsujikawa

    • Research Institute of Electrical Communication, Tohoku University

  • Takuya Tsukahara

    • Graduate School of Engineering Science, Osaka University

  • Kohei Nawaoka

    • Graduate School of Engineering Science, Osaka University

  • Yoshinori Kotani

    • Japan Synchrotron Radiation Research Institute (JASRI)

  • Kentaro Toyoki

    • Japan Synchrotron Radiation Research Institute (JASRI)

  • Minori Goto

    • 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)

  • 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

  • Shinji Miwa

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