Low-temperature spin dynamics of quasi-one-dimensional systems
Abstract
The processes responsible for the critical broadening of the resonance EPR line in quasione-dimensional antiferromagnetic systems CMC and TMAMC, determined by the temperature behavior of the intersite correlation functions in chains of manganese ions, were studied. It was found that in the range of critical broadening two sections with a crossover point Tcross≈2−3TN can be separated. On the high-temperature section the dynamics of the systems is close to the dynamics of the isotropic classical chain, in spite of the presence of single-ion anisotropy. On the low-temperature section the dynamics of the system is determined by the density of domain walls or solitons in the correlated chain, which gives an exponential temperature dependence of the resonance line width.