Direct observation of Barkhausen effect in strip-patterned ferromagnetic Co/Pd multilayer films

The one-dimensional Barkhausen effect was observed in lithographically defined magnetic strips of Co/Pd multilayer films. The magnetic domain expanded stepwise with a constant speed between pinning sites. Both the wall propagation and the pinning were characterized by the thermal activation process based on their exponential dependency on the strength of the applied magnetic field. The Barkhausen volume was determined to be 1.7 10−13 cm3, which was several orders larger than the activation volume of the wall propagation, 6.5 10−18 cm3. © 2006 American Institute of Physics. DOI: 10.1063/1.2199978