Neutron scattering on quantum magnetism

by Prof. Takatsugu Masuda (Institute for Solid State Physics, University of Tokyo)

Monday 6 May 2024, 14:30 → 15:30 Europe/Berlin

PH HS 3 (Physics Department)

Neutron scattering is a unique experimental probe for the correlation functions of the atomic position and spin moment in broad momentum-energy space. Since the neutron scattering technique was applied to the study on antiferromagnetic order in MnO [1], it has made considerable progress and is now widely used in various fields of science. In this seminar, I will first review the status of neutron instruments in research reactor JRR-3. Following a 10-year shutdown due to the great earthquake in East Japan in 2011, JRR-3 restarted in 2021, leading to many publications. I will also discuss recent trend in the inelastic neutron scattering studies on magnetism, including topics such as Kitaev liquid, magnon polarization, topological quasiparticle, etc. 

Secondly, I will present research on quantum magnetism conducted by my group. We observed hybridization of Higgs-amplitude and Goldstone modes in frustrated magnet CsFeCl3 under pressure using a combination of triple-axis and chopper spectrometers [2]. Subsequently, we studied the magnetic field effect on the isostructural compound RbFeCl3. Through the detailed analysis on the spectra, we found that the magnon lifetime was successfully controlled via the magnetic field [3]. 

Finally, I will introduce a newly developed multiplex triple-axis spectrometer, HODACA, located at the C1-1 beam port in JRR-3 [4]. Compared to a conventional triple-axis spectrometer, HODACA improves the measurement efficiency by a factor of 70. 

[1] C. G. Shull and J. S. Smart: Phys. Rev. 76, 1256 (1949).
[2] S. Hayashida et al., Sci. Adv. 5, eaaw5639 (2019).
[3] S. Hasegawa et al., Nat Commun. 15, 125 (2024).
[4] H. Kikuchi et al., J. Phys. Soc. Jpn. (in press). H. Kikuchi et al., arXiv:2310.11463.