Geometrical arrangement of spins and their interaction bonds in magnetic materials is one of the decisive factors for their magnetic states. We are interested in nontrivial magnetic ground states and excitations originating from the crystalline symmetry and its breaking, as well as those in the quasiperiodic magnets where spin arrangement loses apparent translational invariance. Representative examples of our recent findings include observation of nonreciprocal magnons in a magnet without inversion symmetry, confirmation of topological triplon bands in a quantum dimerized antiferromagnet with screw axis, and observation of long-range magnetic order in an icosahedral quasicrystal. Those results have been obtained by maximal utilization of neutron scattering technique, being our primary investigation tool. To further advance this technique, we are also working on the development of novel neutron scattering methods, including inelastic spectrum retrieval using energy-dependent diffuse scattering measurement, and improvement of large curved two-dimensional neutron detector for efficient magnetic structure analysis.

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