We investigate the magnetic properties of the multiferroic quantum-spin
system LiCu2βO2β by electron spin resonance (ESR) measurements at X- and
Q-band frequencies in a wide temperature range (TN1ββ€Tβ€300\,K). The observed anisotropies of the g tensor and the ESR linewidth in
untwinned single crystals result from the crystal-electric field and from local
exchange geometries acting on the magnetic Cu2+ ions in the zigzag-ladder
like structure of LiCu2βO2β. Supported by a microscopic analysis of the
exchange paths involved, we show that both the symmetric anisotropic exchange
interaction and the antisymmetric Dzyaloshinskii-Moriya interaction provide the
dominant spin-spin relaxation channels in this material.Comment: 10 pages, 10 Figure