Reversal of circular magnetization in a thin wall cone by axial translation of a single circumferential domain wall

Reversal of the circular direction of magnetization in a thin wall conical member having a circumferential easy axis is shown to proceed by the axial translation of a single 180° domain wall. The entire cone is first remanently magnetized in one circular direction by a large enough coaxial current. An oppositely polarized circumferential domain is nucleated at the small end of the cone when the circular field from a reverse current reaches a critical amplitude. Radial expansion of this critical field with increasing current extends the reverse domain towards the large end of the cone. The field arising from small axial components of magnetization resulting from applied torsion allows ready detection of the axial position of the 180° wall