Microscopic Magnetic Nature of the Quasi-one-Dimensional Antiferromagnet BaCo2V2O8

The BaCo2V2O8 compound belongs to a wide group of quasi-one-dimensional (Q1D) antiferromagnets (AF) and its Co2+ ions form Q1D screw-chains along the c-axis. We here present the first investigation of the microscopic magnetic nature of a single crystalline BaCo2V2O8 sample using μ+SR. Our data reveal the presence of several clear muon frequencies below TN indicatingthe onsetofa long-range order. Above5K, the μ+SR spectra is well fitted to a simple power-exponential relaxing function. The temperature dependence of the relaxation-rate(λ)as well as the power (n)display a clear anomaly aroundT = 44 K, indicating the onset of short-range 1D correlations.