Centers & Labs

RIKEN Center for Emergent Matter Science

Emergent Spin Structure Research Unit

Unit Leader: Taro Nakajima (D.Sci.)
Taro  Nakajima(D.Sci.)

In strongly correlated electron spin systems, symmetry of magnetic structure may play important role to induce emergent phenomena such as spin-driven ferroelectricity in multiferroics and topological Hall effect in magnetic skyrmion systems. We study these phenomena by means of neutron and synchrotron radiation x-ray scattering, which are powerful tools to reveal the magnetic structures, their collective excitations and fluctuations. We also develop new techniques in neutron and x-ray scattering to resolve (temporal) changes in magnetic structure under extreme conditions, for example, application of electric current and anisotropic stress.

Main Research Field

Mathematical and physical sciences

Related Research Fields

Interdisciplinary science and engineering

Condensed matter physics II


  • Magnetic materials
  • Neutron Scattering
  • Synchrotron radiation x-ray scattering

Selected Publications

  1. Nakajima, T., Inamura, T., Ito, T., Ohishi, K., Oike, H., Kagawa, F., Kikkawa, A., Taguchi, Y., Kakurai, K., Tokura, Y., and Arima, T.:
    “Phase-transition kinetics of magnetic skyrmions investigated by stroboscopic small-angle neutron scattering”
    Phys. Rev. B 98, 014424 (2018)
  2. Kurumaji, T., Nakajima, T., Ukleev, V., Feoktystov, A., Arima, T., Kakurai, K., Tokura, Y.:
    “N'eel-type Skyrmion lattice in the tetragonal polar magnet VOSe2O5”
    Phys. Rev. Lett. 119, 237201 (2017).
  3. Nakajima T., Oike H., Kikkawa A., Gilbert E. P., Booth N., Kakurai K., Taguchi Y., Tokura Y., Kagawa F., Arima T.,
    "Skyrmion lattice structural transition in MnSi"
    Sci. Adv. 3, e1602562 (2017).
  4. Nakajima T., Tokunaga Y., Matsuda M., Dissanayake S., Fernandez-Baca J., Kakurai K., Taguchi Y., Tokura Y., Arima T.:
    "Magnetic structures and excitations in a multiferroic Y-type hexaferrite BaSrCo2Fe11AlO22"
    Phys. Rev. B 94, 195154 (2016).
  5. Nakajima T., Takahashi Y., Kibayashi S., Matsuda M., Kakurai K., Ishiwata S., Taguchi Y., Tokura Y., Arima T.:
    "Electromagnon excitation in the field-induced noncollinear ferrimagnetic phase of Ba2Mg2Fe12O22 studied by polarized inelastic neutron scattering and terahertz time-domain optical spectroscopy"
    Phys. Rev. B 93, 035119 (2016).
  6. Nakajima T., Tokunaga Y., Taguchi Y., Tokura Y., Arima T.:
    "Piezomagnetoelectric Effect of Spin Origin in Dysprosium Orthoferrite"
    Phys. Rev. Lett. 115, 197205(2015).
  7. Nii Y., Nakajima T., Kikkawa A., Yamasaki Y., Ohishi K., Suzuki J., Taguchi Y., Arima T., Tokura Y., Iwasa Y.:
    "Uniaxial stress control of skyrmion phase"
    Nat. Commun. 6, 8539 (2015).
  8. Nakajima T., Tokunaga Y., Kocsis V., Taguchi Y., Tokura Y., Arima T.:
    "Uniaxial-Stress Control of Spin-Driven Ferroelectricity in Multiferroic Ba2CoGe2O7"
    Phys. Rev. Lett. 114, 067201 (2015).

Contact information

Quantum-Phase Electronics Center,
School of Engineering,
The University of Tokyo,
7-3-1 Hongo, Bunkyo-ku,
113-8656, Japan

Email: taro.nakajima [at]