Universal behavior of spinless defects in the Haldane chain Y2Ba(Ni,Zn)O5: a study via bulk (squid) and local (NMR) probes

Abstract Spinless-impurity induced magnetic effects in Y 2 Ba(Ni,Zn)O 5 have been probed via susceptibility and 89 Y NMR. 89 Y NMR spectra of these samples contain multiple peaks, as a consequence of impurity-induced excitations. Here, the T -dependence of the impurity-induced magnetization is consistent with a net “effective” spin S ≈0.4 on either side of the Zn-impurity in the one-dimensional chain. Further, 89 Y NMR experiments with (Y 1− y Ca y ) 2 BaNi 1− x Zn x O 5 , indicate a non-interacting behavior of the hole (introduced due to Ca doping) and S =0 impurity.