Dependence of magnetic losses f (20≪f≪1000 Hz) and induction Bm(0.1≪Bm0.75 Tl) of amorphous rapidly quenched alloy Fe81Si4B13C2 at 300 and 77 K was studied. Anomalous growth of magnetic losses per cycle with the frequency decrease from 200 to 20 Hz was revealed. Analysis of the results obtained permits interpreting the fact as a consequence of magnetic after effect pronouncement, resulting in anomalous growth of domain wall motion due to the appearance of the Barkhauser correlated jumps.