Circular domain velocity versus force

A simple technique for measuring the velocity versus force curve of a circular magnetic domain has been devised. The technique consists of moving a domain under a straight current conductor which is adjacent to the surface of the wafer. A square-wave current is applied and the amplitude adjusted until the domain jiggles back and forth under the conductor a distance equal to , where is the radius of the domain. The blurred domain is observed using the Faraday effect. The magnitude of the effective driving field for a conductor with a width equal to , spaced above the wafer, is when ( is the wafer thickness). The velocity is equal to .