Spin-1/2 kagome compounds: volborthite vs herbertsmithite
Abstract
Two kagome compounds, volborthite Cu3V2O7(OH)2-2H2O and herbertsmithite ZnCu3(OH)6Cl2, are compared in order to derive information about the intrinsic properties of the spin-1/2 kagome antiferromagnet. Volborthite shows a broad maximum at T ~ J / 4 and the approach at T = 0 to a large finite value of the bulk magnetic susceptibility chibulk as well as the local susceptibility chilocal from NMR measurements. These must be intrinsic properties for the spin-1/2 kagome antiferromagnet, as similar behavior has also been reported in chilocal for herbertsmithite [Olariu A et al. 2008 Phys. Rev. Lett., 100 087202]. Impurity effects that may significantly influence the bulk properties are discussed.
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