Using the electron-spin-resonance technique we investigate the magnetic structure of CuCrO${}_2$, a quasi-two-dimensional antiferromagnet with a weakly distorted triangular lattice. Resonance frequencies and the excitation conditions in CuCrO${}_2$ at low temperatures are well described in the frame of cycloidal spin structure, which is defined by two susceptibilities parallel and perpendicular to the spin plane (${\chi }_{\perp }$ and ${\chi }_{\parallel }$) 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 CuCrO${}_2$ can be controlled by annealing of the sample in a magnetic field.

• Received 3 July 2013

DOI:https://doi.org/10.1103/PhysRevB.88.144403