Magnetic excitations in chiral-structure phase of Ce₃Ir₄Sn₁₃

In this study, we investigated the electronic states of Ce₃Ir₄Sn₁₃ by neutron and X-ray scattering. Crystal structure refinement analyses based on synchrotron X-ray diffraction revealed chiral symmetry with space group I2₁3. The high-energy inelastic neutron scattering spectra indicate two crystal-electric-field level schemes of Ce³⁺ ions, which are attributed to the inequivalent Wyckoff sites in the chiral structure. The spectrum widths indicate that one of the Ce³⁺ 4f-electron states is hybridized with conduction electrons, which is consistent with the Kondo semimetal feature, while the other state is well-localized. The low-energy spectrum reveals spin fluctuations at approximately 0.1 meV, which emerges below 10 K and far above the weak antiferromagnetic ordering temperature of 0.6 K. Moreover, considering also the large absolute value of the Weiss temperature of −33.1 K, we propose an additional magnetic frustration effect. (author)