Magnetic shift tracks or magnetic strips, to which application of a
rotating magnetic field or by rotation of the strip itself allows
accurate determination of domain wall movement. One particular embodiment
is a method of determining a position of a domain wall in a magnetic
strip. The method includes applying a rotating magnetic field to the
magnetic strip, the magnetic field rotating around a longitudinal axis of
the magnetic strip, and after applying the magnetic field, determining a
displacement of the domain wall to a second position.