MAGNETIC-BEHAVIOR IN LI-DOPED LA2CUO4

We report muon-spin-relaxation studies in the Li-doped cuprates La2Cu1 -xLixO4 for x = 0.01, 0.05, 0.10, 0.45, and 0.50. For low Li concentra tions (x less than or equal to 0.10) we find a rapid suppression of T- N as x increases, but little change in the magnitude and temperature d ependence of the antiferromagnetic order parameter. This indicates tha t Li doping effectively destroys antiferromagnetism (similar to Sr dop ing, but different from Zn doping) without strongly affecting either t he on-site Cu moments or the shape of the spin-wave excitation spectru m. For high Li concentrations we find that the majority of the sample volume is nonmagnetic, suggesting possible singlet-state formation.