Slow inhomogeneous spin dynamics in the frustrated antiferromagnet NiGa2S4

Muon spin relaxation experiments in the geometrically frustrated antiferromagnet NiGa2S4 indicate strong slow spin fluctuations at low temperatures. The muon relaxation rate is strongly field dependent, in contrast with the field independence of the gapless excitations indicated by the observed specific heat. (c) 2006 Elsevier B.V. All rights reserved.