Coexistence of dimerization and long-range magnetic order in the frustrated spin-chain system LiCu2O2:: Inelastic light scattering study -: art. no. 104421

Raman scattering studies of the frustrated spin chain system LiCu2O2 are reported. Two transitions into a magnetically ordered phase (taken place at temperatures similar to9 and similar to24 K) have been confirmed from the analysis of optical properties of the samples. Interestingly, two different magnetic excitations, seen at 100 and 110 cm(-1) in the magnetically ordered phase superimpose each other independently, indicating a coherent coexistence of long-range magnetic order and dimerization. The observed phenomenon is attributed to magnetostructural peculiarities of LiCu2O2 leading to the intrinsic presence of magnetic/nonmagnetic impurities on a nanometer scale. In particular, magnetic impurities play a significant role in driving the transition from an incommensurate state to a Neel ordered one at 9 K.