Local Spin Susceptibility of the S=1/2 Kagome Lattice in ZnCu3(OD)6Cl2
  We report single-crystal 2-D NMR investigation of the nearly ideal spin S=1/2 kagome lattice ZnCu3(OD)6Cl2. We successfully identify 2-D NMR signals originating from the nearest-neighbors of Cu2+ defects occupying Zn sites. From the 2-D Knight shift measurements, we demonstrate that weakly interacting Cu2+ spins at these defects cause the large Curie-Weiss enhancement toward T=0 commonly observed in the bulk susceptibility data. We estimate the intrinsic spin susceptibility of the kagome planes by subtracting defect contributions, and explore several scenarios. 
T. Imai, M. Fu, T. H. Han and Y. S. Lee
cond-mat.str-el cond-mat.supr-con