Dispersive magnetic resonance mode in the Kondo semiconductor CeFe2Al10

Abstract

The CeT2Al10 family of orthorhombic compounds exhibits a very peculiar evolution from a Kondo-insulator (T: Fe) to an unconventional long-range magnetic order (T: Ru, Os). Inelastic neutron scattering experiments performed on single-crystal CeFe2Al10 reveal that this material develops a spin-gap in its magnetic spectral response below ~ 50 K, with a magnetic excitation dispersing from $E=10.2\pm 0.5$ meV at the Y zone-boundary point [q = (0,1,0)] to $\approx 12$ meV at the top of the branch. The excitation shows a pronounced polarization of the magnetic fluctuations along a, the easy anisotropy axis. Its behavior is contrasted with that of the (magnonlike) modes previously reported for CeRu2Al10, which have transverse character and exist only in the antiferromagnetic state. The present observation is ascribed to a "magnetic exciton" mechanism invoked to explain a similar magnetic response previously discovered in YbB12.

4 figures, 6 pages, submitted to Physical Review Letters

References in corpus (2)

• Long-range order and low-energy magnetic excitations in CeRu2Al10
• Anisotropic spin-dynamics in the Kondo semiconductor CeRu2Al10

Cited by in corpus (6)

• Incomplete Protection of the Surface Weyl Cones of the Kondo Insulator SmB${}_6$: Spin Exciton Scattering
• Quantitative study of valence and configuration interaction parameters of the Kondo semiconductors CeM2Al10 (M = Ru, Os and Fe) by means of bulk-sensitive hard x-ray photoelectron spectroscopy
• Contrasting electron and hole doping effects on the spin gap of the caged type Kondo semimetal CeOs${}_2$Al${}_{10}$: A muon spin relaxation and inelastic neutron scattering investigation
• Contrasting chemical pressure effect on the moment direction in the Kondo semiconductor CeT${}_2$Al${}_{10}$ (T = Ru,Os)
• Effect of Nd and Rh substitution on the spin dynamics of Kondo insulator CeFe2Al10
• A crossover from Kondo semiconductor to metallic antiferromagnet with $5d$-electron doping in CeFe${}_2$Al${}_{10}$