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Masuda Group

member
Associate Professor MASUDA, Takatsugu
Research Associate ASAI, Shinichiro

Research Subjects

  • Magnetic excitations of quantum magnets, frustrated magnets, and topological magnets
  • Detection of spin wave spin current by neutron
  • Development of neutron spectrometer

Quantum magnets, frustrated magnets, and topological magnets have received significant attention as the forefront of quantum phenomena. The research goal of our group is to discover new quantum phenomena and uncover their mechanisms in magnetic materials. We are conducting experimental research, as illustrated in left figure (a) and (b), primarily using conventional neutron spectrometers. Simultaneously, we have developed a new type of neutron spectrometer, called HOrizontally Defocusing Analyzer Concurrent data Acquisition (HODACA), as shown in right figure (a), to efficiently measure the magnetic excitations. In the fiscal year 2022, we conducted a commissioning experiment using a frustrated magnet CsFeCl3 as the test sample. Bragg peaks were observed at the designated positions shown in right figure (b), and a magnetic excitation consistent with a previous study was observed in right figure (c). It was confirmed that efficiency of the measurement is 24 times improved compared with a conventional neutron spectrometer. Hereafter, we will proceed with our research on new phenomena, including the instability of magnons, topological magnons, spin-wave spin currents, and so on, using the HODACA spectrometer.

fig1
Examples of neutron spectra using a conventional neutron spectrometer. (a) Weakly coupled honeycomb lattice Ni2InSbO6. (b) Equilateral triangular spin tube CsCrF4. Analysis of the spectra leads to the identification of spin Hamiltonian.
fig2
(a) Overview of HODACA spectrometer. (b) Bragg peak profiles measured in a frustrated magnet CsFeCl3 by HODACA. (c) Magnetic excitation measured by HODACA. White curve is a theoretical curve reported in a previous study.

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