Matteucci effect as exhibited by cylindrical CoP amorphous multilayers

CoP amorphous samples, electrodeposited on copper wires and exhibiting a longitudinal magnetic anisotropy, show a spontaneous Matteucci effect once the substrate has been subjected to torque. This induces an easy axis to allow for magnetization to occur, breaking away from its original longitudinal direction. The magnetic domain structures, as observed by the Bitter technique, revealed that the anisotropy changes direction, rotating gradually from its initial longitudinal position to a 45° helix, as the torque was increased. The reversible part of the circular magnetization switching curves, set against the longitudinal magnetic field, was fitted by assuming a magnetization rotation model in which constant anisotropic magnitude values were hardly modified, while allowing changes in direction.