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RIKEN SPring-8 Center Materials Dynamics Group

Group Director: Alfred Baron (Ph.D.)

Research Summary

Alfred  Baron(Ph.D.)

The focus of the laboratory is the dynamics of materials on meV energy scales (THz frequencies) and atomic length scales, using non-resonant inelastic x-ray scattering to measure the dynamics structure factor, S (Q,ω). We recently constructed the world’s most powerful x-ray instrument for these measurements, and are now moving toward specific applications, with, generally, a focus on the information content available in various scattering experiments. Areas of present work include the dynamics of crystalline materials, including those under extreme pressure, thermal transport in crystals, the dynamics of disordered materials, including liquids and glasses, as well as various projects in instrumentation development. Presently the strongest push of the laboratory is measurements of dynamics with unprecedented resolution at low momentum transfers, where, to date, there has been no instrument available. We are striving to create an experimentally robust and conceptually clear interpretation of dynamics of disordered materials on the mesoscale.

Research Subjects:

  • Investigations of liquid and glass dynamics.
  • Elastic constants of materials in extreme conditions.
  • Investigation of phonons and electronic scattering crystalline materials.
  • Development of new x-ray scattering techniques.

Main Research Fields

  • Mathematical & Physical Sciences

Related Research Fields

  • Engineering
  • Chemistry
  • Environmental Science
  • Interdisciplinary Science & Engineering
  • Biological Sciences
  • Condensed matter physics
  • Physical Chemistry
  • Earth and planetary science
  • Cluster and nano materials
  • Earth's interior material science
  • Applied condensed matter physics


  • Phonons and Lattice Dynamics of Crystals
  • Dynamics of Liquids
  • Magento-Elastic Coupling
  • Elasticity
  • Thermal transport

Selected Publications

  • 1. D. Ishikawa & A.Q.R. Baron:
    "Interaction of Acoustic and Quasi-Elastic Modes in Liquid Water on Nanometer Length Scales"
    J. Phys. Soc. Japan 90, 83602 (2021).
  • 2. A.Q.R. Baron:
    "High-Resolution Inelastic X-Ray Scattering I: Context, Spectrometers, Samples, and Superconductors"
    Synchrotron Light Sources and Free-Electron Lasers pp 1643-1719 (2016)
  • 3. A.Q.R. Baron:
    "High-Resolution Inelastic X-Ray Scattering II: Scattering Theory, Harmonic Phonons, and Calculations"
    Synchrotron Light Sources and Free-Electron Lasers pp 1721-1757 (2016)
  • 4. D. Ishikawa & A.Q.R. Baron:
    "Practical measurement of the energy resolution for meV-resolved inelastic X-ray scattering"
    Journal of Synchrotron Radiation, 28 (2021) 804,
  • 5. Y. Nakajima, S. Imada, K. Hirose, T. Komabayashi, H. Ozawa, S. Tateno, S. Tsutsui, Y. Kuwayama, and A.Q.R. Baron:
    "Carbon depleted outer core revealed by sound velocity measurements of liquid Fe-C alloy"
    Nature Communications, 6, (2015)
  • 6. T. Sakamaki, E. Ohtani, H. Fukui, S. Kamada, S. Takahashi, T. Sakairi, A. Takahata, T. Sakai, S. Tsutsui,6 D. Ishikawa, R. Shiraishi, Y. Seto, T. Tsuchiya, A. Q. R. Baron:
    "Constraints on Earth’s inner core composition inferred from measurements of the sound velocity of hcp-iron in extreme conditions"
    Sci. Adv. 2016; 2 : e1500802
  • 7. N. Murai, T. Fukuda, T. Kobayashi, M. Nakajima, H. Uchiyama, D. Ishikawa,S. Tsutsui, H. Nakamura, M. Machida, S. Miyasaka, S. Tajima, and A. Q. R. Baron:
    "Effect of magnetism on lattice dynamics of SrFe2As2 using high-resolution inelastic x-ray scattering"
    Physical Review B, Phys. Rev. B 93, 020301(R)
  • 8. M. Inui, Y. Kajihara, S. Munejiri, S. Hosokawa, A. Chiba, K. Ohara, S. Tsutsui and A.Q.R. Baron:
    "Anomalous dispersion of the acoustic mode in liquid Bi"
    Physical Review B 95 (2015) 54206
  • 9. D. Ishikawa, D. S. Ellis, H. Uchiyama and A.Q.R. Baron:
    "Inelastic x-ray scattering with 0.75 meV resolution at 25.7 keV using a temperature gradient analyzer."
    Journal of Synchrotron Radiation, 22 (2015) 3
  • 10. H. Fukui, T. Katsura, T. Kuribayashi, T. Matsuzak, A. Yoneda, E. Ito, Y. Kudoh, S. Tsutsui &* A.Q.R. Baron:
    "Precise determination of elastic constants by high-resolution inelastic X-ray scattering"
    Journal of Synchrotron Radiation 15, 618-623 (2008)

Recent Research Results

Related Links

Lab Members

Principal investigator

Alfred Baron
Group Director

Core members

Daisuke Ishikawa
Visiting Scientist


Position Deadline
Seeking a Research Scientist or Postdoctoral Researcher position (C21-0203) Open until filled

Contact Information

1-1-1 Kouto, Sayo-cho
Sayo-gun, Hyogo
679-5148 Japan
Email: baron [at] spring8.or.jp