Inelastic neutron scattering investigation of spin dynamics in metallic f-electron systems on the hexagonal lattice

The interplay of spin-orbit coupling and RKKY interactions in metallic f-electron systems introduces anisotropy that leads to phenomena such as reduced dimensionality, multipolar ordering, and magnetic frustration due to long-range interactions. In this talk, I will discuss our inelastic neutron scattering experiments in such systems on the hexagonal lattice. In the 5f system U₂Zn₁₇, we observed a continuum of spin fluctuations within the antiferromagnetic state below T_N​=9.7K with no signatures of coherent magnon modes. This continuum persists in the paramagnetic state up to at least T=2T_N​, showing dominantly transverse and one-dimensional characters. In contrast, the isostructural 4f sibling exhibits no discernible ordered moment but presents sharp, dispersive spin-wave modes. Comparative studies between these two systems—focusing on single-ion states, polarization of collective modes, and distinct energy scales—offer insights into the diverse manifestations of quantum magnetism in strongly correlated metallic systems.