Probing the ground state of through measurements

Abstract: We present data recorded on a newly prepared sample of the geometrically frustrated magnetic material . These data confirm previously published results and clearly show that there is a dynamical component in the ground state. This seems in contrast to the result of the linear spin-wave calculation of A.G. Del Maestro and M.J.P. Gingras which predicts the spin-waves to be gapped over the whole first Brillouin zone with a gap larger than about in temperature scale. The measured high-temperature paramagnetic spin dynamics is understood with a simple model. The conditions for observing a spontaneous magnetic field and a finite relaxation rate at low temperature are discussed in terms of the properties of a function which measures the density of fluctuation modes. [Copyright &y& Elsevier]