Systematic room‐temperature measurements of the aftereffect of the ac magnetic permeability have been performed on a Fe81B13.5Si3.5C2amorphous ribbon in order to get detailed information about the nature of the atomic ordering processes responsible for the magnetic relaxation. The magnetic aftereffect related to 180° domain‐wall motion has been measured by means of a specific technique allowing periodic domain‐wall displacements to be induced between two fixed, neighboring equilibrium positions by applying a square‐wave field of proper amplitude and frequency. In this way, the average direction of the magnetization vector is cyclically modified in all points where the studied directional ordering processes may occur. As a consequence, the kinetics of ordering is modified in a characteristic way, giving rise to relevant variations in the intensity of the magnetic aftereffect measured between fixed times (t1=2×10−3s andt2=10−1s), and in the value of the magnetic induction at the timet2. All measurements have been performed at constant applied field. The degree of reliability of this experimental technique has been analyzed in detail. The magnetic aftereffect, &Dgr;B=B(t1)−B(t2), and the magnetic inductionB(t2) have been measured as functions of the number of domain‐wall cycles, and after removing the square‐wave field for a variable timet*. The results of many independent measurements are reported and discussed.