Magnetic structure of the frustrated S=1/2 chain magnet LiCu2O2 doped with nonmagnetic Zn

We present the results of magnetization, electron spin resonance (ESR), and nuclear magnetic resonance (NMR) measurements on single-crystal samples of the frustrated S = 1/2 chain cuprate LiCu2O2 doped with nonmagnetic Zn2+. As shown by the x-ray techniques, the crystals of Li(Cu1-xZnx)(2)O-2 with x < 0.12 are single-phase, whereas for higher Zn concentrations the samples were polyphase. ESR spectra for all monophase samples (0 <= x < 0.12) can be explained within the model of a planar spin structure with a uniaxial type anisotropy. The NMR spectra of the highly doped single-crystal sample Li(Cu0.9Zn0.1)(2)O-2 can be described in the frame of a planar spin-glass-like magnetic structure with short-range spiral correlations in the crystal ab planes with strongest exchange bonds. The value of magnetic moments of Cu2+ ions in this structure is close to the value obtained for undoped crystals: (0.8 +/- 0.1) mu(B)