Dynamics of a magnetic domain wall in magnetic wires with an artificial neck

Magnetization reversal in submicron magnetic wires consisting of a NiFe/Cu/NiFe trilayer with an artificial neck was investigated by utilizing the giant magnetoresistance effect. A magnetic domain wall was injected into the wire by a local magnetic field applied at the end of the wire. Pinning and depinning of the magnetic domain wall were detected as sharp changes in resistance. It was found that the neck works as a pinning site of a domain wall and that the depinning field increases with a decrease of the neck width. (C) 2003 American Institute of Physics.