Temperature dependence of the electron paramagnetic resonance linewidth in NaV2O5

The qualitative explanation of the temperature dependence of the linewidth of electron-paramagnetic resonance (EPR) in α'-NaV₂O₅ is proposed. Our simple theory is based on the effectively one-dimensional quantum description of effective spin-spin interactions. We explain the high-temperature increase of the EPR linewidth with increasing temperature by the influence of the effective magnetic anisotropy of spin-spin interactions. The low-temperature upturn of the temperature dependence of the EPR linewidth is explained by the effect of period doubling of the exchange interaction of the effective quasi-one-dimensional spin subsystems. Our theory does not demand the controversial presence of the staggered Dzyaloshinskii-Moriya interactions at high temperatures.