Temperature dependence of depinning fields in submicron magnetic wires with an artificial neck

Magnetization reversal in a submicron magnetic wire with an artificial neck consisting of a magnetic/nonmagnetic/magnetic trilayered structure was investigated by utilizing the giant magnetoresistance effect. A magnetic domain wall was pinned by the artificial neck introduced into the wire, which indicates that the neck works as a pinning center of the domain wall. The temperature dependence of the depinning field between 4.2 and 300 K was described well by a theoretical model based on thermally assisted magnetization reversal over a single potential barrier. The magnitude of the potential barrier of the artificial neck was estimated.