Abstract
Using muon-spin-relaxation measurements we show that the pyrochlore compound , in its magnetically ordered phase below , displays persistent spin dynamics down to temperatures as low as 20 mK. The characteristics of the induced muon relaxation can be accounted for by a scattering process involving two magnetic excitations, with a density of states characterized by an upturn at low energy and a small gap depending linearly on the temperature. We propose that such a density of states is a generic feature of geometrically frustrated magnetic materials.
- Received 4 February 2005
DOI:https://doi.org/10.1103/PhysRevLett.95.047203
©2005 American Physical Society