Ground State of the Kagomé-LikeS=1/2Antiferromagnet VolborthiteCu3V2O7(OH)2·2H2O

F. Bert, D. Bono, P. Mendels, F. Ladieu, F. Duc, J.-C. Trombe, P. Millet
2005 Physical Review Letters  
Volborthite compound is one of the very few realizations of S=1/2 quantum spins on a highly frustrated kagome-like lattice. Low-T SQUID measurements reveal a broad magnetic transition below 2K which is further confirmed by a peak in the 51V nuclear spin relaxation rate (1/T1) at 1.4K$\pm$0.2K. Through 51V NMR, the ground state (GS) appears to be a mixture of different spin configurations, among which 20% correspond to a well defined short range order, possibly of the $\sqrt{3} \times \sqrt{3}$
more » ... } \times \sqrt{3}$ type. While the freezing involve all the Cu$^{2+}$ spins, only 40% of the copper moment is actually frozen which suggests that quantum fluctuations strongly renormalize the GS.
doi:10.1103/physrevlett.95.087203 pmid:16196896 fatcat:5bfp2tcewnczra7wno55nbv42e