Motion of domain walls in helical magnets (abstract)

Abstract

The magnetically ordered structure of many helical magnets takes the form of planes of ferromagnetically ordered atoms for which the direction of ordering alters by rotation through a fixed angle γ on passing from one plane to the next. This ordered state can be characterized by the direction of the normal to the set of planes (the axis of a helix) and the angle γ (the turn angle of the helix). For most helical materials there can exist domains of two chiralities, those with turn-angle +γ and those with turn-angle −γ. The size and structure of the region between two such domains (a domain wall) has been investigated in the static regime. When a magnetic field is applied the direction of the magnetic moments may change. The equations of motion are set up in the continuum approximation and the resulting effects on the magnetic structure of the domains and the domain walls are considered in the two cases when the applied field is within or perpendicular to the easy plane of magnetization.