Using electron-spin-resonance (ESR) technique we investigate the magnetic structure of CuCrO2, quasi-two-dimensional antiferromagnet with weakly distorted triangular lattice. Resonance frequencies and the excitation conditions in CuCrO2 at low temper
atures are well described in the frame of cycloidal spin structure, defined by two susceptibilities parallel and perpendicular to the spin plane and by a biaxial crystal-field anisotropy. In agreement with the calculations, the character of the eigenmodes changes drastically at the spin-flop transition. The splitting of the observed modes can be well attributed to the resonances from different domains. The domain structure in CuCrO2 can be controlled by annealing of the sample in magnetic field.
