Abstract
Inelastic neutron scattering at low temperatures from a powder of demonstrates this triangular-lattice antiferromagnet hosts collective magnetic excitations from spin- molecules. Apparently gapless () and extending at least up to 2.5 meV, the low-energy magnetic scattering cross section is surprisingly broad in momentum space and involves one-third of the spins present above 100 K. The data are compatible with the presence of valence bonds involving nearest-neighbor and next-nearest-neighbor spins forming a disordered or dynamic state.
- Received 30 August 2013
DOI:https://doi.org/10.1103/PhysRevLett.112.027202
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