NMR and susceptibility characterization of two oxocuprates with antiferromagnetic Cu-chains:: LiCuO2 and LiCu2O2

The CuO2 compounds LiCuO2 and LiCu2O2 both contain CuO4 squares knit together in linear chains. These chains are all equivalent in LiCuO2 and grouped in pairs in LiCu2O2 From susceptibility measurements the spin interaction in both compounds is seen to be dominated by Heisenberg antiferromagnetic exchange. In LiCuO2 the strongly reduced magnetic moment and chi(T)-behavior are typical for random exchange interactions. The Cu-spins in LiCu2O2 form an antiferromagnetically coupled Heisenberg chain with likely some spread in J-values. The differences in the Li-7 NMR relaxation rates support these models. (C) 1998 Elsevier Science Ltd. All rights reserved.