MAGNETIC CORRELATIONS IN DEUTERONIUM JAROSITE, A MODEL S=5 2 KAGOME ANTIFERROMAGNET/

Deuteronium jarosite, (D3O)Fe-3(SO4)(2)(OD)(6), contains a Kagome latt ice of Heisenberg spins S = 5/2 with a coverage of 97 +/- 1%. DC and A C susceptibility measurements show strong in-plane antiferromagnetic e xchange (theta(CW) = -700 +/- 5 K) and a spin-glass transition at T-f = 13.8 K, while the magnetic contribution to the specific heat below T -f rises with T as T-2, characteristic of two-dimensional propagating modes. Powder neutron diffraction reveals short-range magnetic correla tions with a correlation length. xi approximate to 19 +/- 2 Angstrom a t 1.9 K.