Abstract
We present neutron inelastic-scattering results on the low-temperature magnetic state of the frustrated-hyperkagome compound gadolinium gallium garnet (GGG). Our neutron-scattering studies reveal a remarkable range of time scales. Short-range spatial correlations appear static within the instrumental resolution . Three distinct inelastic modes are found at 0.04(1), 0.12(2), and 0.58(3) meV at 0.06 K. The lowest and highest energy excitations show spatial dependencies indicative of dimerized short-range antiferromagnetic correlations that survive to high temperatures, comparable to the nearest-neighbor exchange interactions. Our results suggest that the ground state of a three-dimensional hyperkagome compound differs distinctly from its frustrated counterparts on a pyrochlore lattice and reveal a juxtaposition of co-operative paramagnetism and strong-dimerized coupling. These results are surprising since GGG is often classified as a strongly frustrated system with a manifold of connected states for which one would expect a continuum of gapless excitations.
- Received 12 October 2010
DOI:https://doi.org/10.1103/PhysRevB.82.174408
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