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RIKEN Center for Emergent Matter Science Dynamic Emergent Phenomena Research Unit

Unit Leader: Fumitaka Kagawa (Ph.D.)

Research Summary

Fumitaka  Kagawa(Ph.D.)

Our research unit explores dynamic phenomena exhibited by strongly correlated electron systems in both bulk specimen and device structures to construct a new principle in condensed matter science. In particular, we study external-field-driven dynamic phenomena exhibited by sub-micron-scale structures, such as topological spin textures and domain walls, using spectroscopy of dielectric responses and resistance fluctuations from the millihertz to gigahertz region. We also pursue real-space observations and measurements of local physical properties using scanning probe microscopy as a complementary approach. We are aiming to control novel physical properties exhibited by topological structures in condensed matter systems on the basis of knowledge obtained from these methods.

Main Research Fields

  • Mathematical & Physical Sciences

Related Research Fields

  • Interdisciplinary Science & Engineering
  • Engineering

Keywords

  • Metal-insulator transition
  • Phase-change memory
  • Scanning probe microscopy
  • Magnetic skyrmion

Selected Publications

  • 1.H. Oike, M. Kamitani, Y. Tokura, and F. Kagawa.:
    “Kinetic approach to superconductivity hidden behind a competing order”
    Sci. Adv. 4, eaau3489 (2018)
  • 2.H. Oike, M. Suda, M. Kamitani, A. Ueda, H. Mori, Y. Tokura, H. M. Yamamoto, and F. Kagawa.:
    “Size effects on supercooling phenomena in strongly correlated electron systems: IrTe2 and θ-(BEDT-TTF)2RbZn(SCN)4
    Phys. Rev. B 97, 085102 (2018)
  • 3.F. Kagawa, H. Oike, W. Koshibae, A. Kikkawa, Y. Okamura, Y. Taguchi, N. Nagaosa, and Y. Tokura.:
    “Current-induced viscoelastic topological unwinding of metastable skyrmion strings”
    Nat. Commun. 8, 1332 (2017)
  • 4.F. Kagawa and H. Oike
    “Quenching of Charge and Spin Degrees of Freedom in Condensed Matter”
    Adv. Mat. 29, 1601979 (2017)
  • 5.Y. Okamura, F. Kagawa, S. Seki, and Y. Tokura.:
    “Transition to and from the skyrmion lattice phase by electric fields in a magnetoelectric compound”
    Nat. Commmun. 7, 12669 (2016)
  • 6.F. Kagawa, N. Minami, S. Horiuchi, and Y. Tokura.:
    “Athermal domain-wall creep near a ferroelectric quantum critical point”
    Nat. Commun. 7, 10675 (2016)
  • 7.H. Oike, A. Kikkawa, N. Kanazawa, Y. Taguchi, M. Kawasaki, Y. Tokura, and F. Kagawa.:
    “Interplay between topological and thermodynamic stability in a metastable magnetic skyrmion lattice”
    Nat. Phys. 12, 62 (2016)
  • 8.Y. Okamura, F. Kagawa, S. Seki, M. Kubota, M. Kawasaki, and Y. Tokura
    “Microwave Magnetochiral Dichroism in the Chiral-Lattice Magnet Cu2OSeO3”
    Phys. Rev. Lett. 114, 197202 (2015)
  • 9.H. Oike, F. Kagawa, N. Ogawa, A. Ueda, H. Mori, M. Kawasaki, and Y. Tokura.:
    “Phase-change memory function of correlated electrons in organic conductors”
    Phys. Rev. B 91, 041101(R) (2015)
  • 10.F. Kagawa, S. Horiuchi, N. Minami, S. Ishibashi, K. Kobayashi, R. Kumai, Y. Murakami, and Y. Tokura.:
    “Polarization Switching Ability Dependent on Multidomain Topology in a Uniaxial Organic Ferroelectric”
    Nano Lett. 14, 239 (2014)

Recent Research Results

Related Links

Lab Members

Principal investigator

Fumitaka Kagawa
Unit Leader

Core members

Takuro Sato
Postdoctoral Researcher
Keisuke Matsuura
Special Postdoctoral Researcher
Hiroshi Oike
Visiting Scientist

Contact Information

209 Frontier Research Laboratory
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan
Email: fumitaka.kagawa [at] riken.jp

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