Dynamic fields in the partial magnetization plateau of Ca3Co2O6

Fluctuation dynamics in magnetization plateaux are a relatively poorly explored area in frustrated magnetism. Here we use muon spin relaxation to determine the fluctuation timescale and associated field distribution width in the partial magnetization plateau of Ca3Co2O6. The muon spin relaxation rate has a simple and characteristic field dependence which we model and by fitting to the data at 15 K extract a fluctuation timescale tau = 880(30) ps and a field distribution width Delta = 40.6(3) mT. Comparison with previous results on Ca3Co2O6 suggests that this fluctuation timescale can be associated with short-range, slowly fluctuating magnetic order.