Anomalous spin dynamics in a two-dimensional magnet induced by anisotropic critical fluctuations

We investigate the temperature dependence of g factor in two-dimensional (2D) ferromagnet CrSiTe(3 )by combining three-dimensional vector-ferromagnetic resonance (FMR) experiments. It is shown from the angular dependence that the dramatic g shift near critical temperature originates from the interplay of enhanced magnetic fluctuations and anisotropic spin interactions in 2D magnetism. The crossover from isotropic to anisotropic g factor for T -> T-c yields anomalously parallel pumped excitations. In the critical regime, the field suppression of critical fluctuations is associated with the field dependence of g shift. Furthermore, the results of FMR g shift are scaled by susceptibilities and spontaneous magnetization obtained from magnetometry measurements, which show good agreement with the universality class of the 2D Ising model.