Origin of the Raman-susceptibility slope change at T₂

Determine whether the change in slope of the dynamic Raman susceptibility at the T₂ transition in Gd₅Pb₃ results from changes in phonon excitations or magnon excitations.

Background

Gd₅Pb₃ exhibits several magnetic transitions, including T₁ ≈ 220 K, T₂ ≈ 78 K, and T₃ ≈ 34 K. Temperature-dependent Raman measurements were used to examine both phonon behavior and magnetic fluctuations across these transitions.

The dynamic Raman susceptibility remains nearly constant above T₁ and increases between T₁ and T₂. Although a change in slope is observed at T₂, the measurements do not establish whether this feature originates from changes in lattice phonons or magnetic magnons, leaving its microscopic interpretation unresolved.

References

Interestingly, a change in slope is observed at $T_2$, but further work is needed to determine if this results from changes in the phonons or magnons at this temperature.

— A Strategy Toward Room Temperature Topological Hall Effect via Local Moment Magnetism  (2609.03223 - Rao et al., 2 Sep 2026) in Section “Magnetic Phase Transitions in Gd₅Pb₃,” discussion of the dynamic Raman susceptibility