Effect of Zn doping on the spin gap characteristics of BaCu2V2O8: A 51V NMR study

Abstract Spin gap characteristics of the Zn-substituted quasi-one-dimensional (1D) compounds BaCu 2− x Zn x V 2 O 8 ( x =0, 0.1, 0.2, and 0.5) have been investigated by means of the 51 V NMR measurements. For all studied compositions, two 51 V NMR lines which are associated with two vanadium crystallographic sites have been resolved. Within the present doping level, the temperature-dependent NMR shift of each individual site exhibits a character of spin gap. While the deduced spin gap remains almost unchanged, the entire curve of the NMR shift substantially decreases for the high Zn concentration. Such an observation is interpreted as the reduction of the transferred hyperfine field from Cu 2+ , due to the creation of spin vacancies along the spin chains.