Rotational hysteresis in an anisotropic Mn-Al-C permanent magnet

Measurements of the torque curves and rotational hysteresis energy of an uniaxial grain-oriented Mn-Al-C permanent magnet have been made on two specimens: one with the preferred axis of magnetization in the plane of rotation of the applied field and the other with the preferred axis perpendicular to the plane of rotation of the applied field. From the values of the rotational hysteresis integrals it has been concluded that magnetization changes occur by an incoherent mechanism, most probably by domain wall nucleation and displacement.