DC magnetization of ferromagnetic amorphous wires with local deformation

Experimental DC (VSM) and theoretical hysteresis loops of a ferromagnetic amorphous wire with a deformation in the middle or exposed to local magnetic fields are investigated. Hysteresis loops show two-stage Barkhausen jumps and staircase relaxation. With a local field at the same position, the loop drastically looses its shape and symmetry depending on the magnitude and the direction of the magnetic bias. A model to explain this behavior is proposed. The proposed model is based on the calculation of the magnetic moment distribution of the domain as a result of domain wall motion and nucleation in the inner core of a ferromagnetic wire and is in a good agreement with the experimental results.