NMR study of Zn doping effect in spin ladder system SrCu2O3

Nuclear magnetic resonance spectra of Cu nuclei were measured in a typical spin ladder system, Sr(Cu1-xZnx)(2)O-3 (x = 0%, 0.25%, and 0.5%) at temperatures ranging from room temperature to 20 K. The linewidth of the spectrum peaks drastically increased at temperatures below 100 K with x being only 0.25%. The width Delta W increased with the increase in Zn concentration and the decrease in temperatures (Delta W similar to x/T). These facts prove that a quite minute amount of impurity breaks the singlet ground state and the effect of impurity is observed in the whole system.