Complex pulsed field magnetization behavior and Walker breakdown in a NiFe thin-film

The magnetization behavior of a Permalloy thin-film ( nominally Ni(81)Fe(19)) was investigated as a function of combined quasistatic and pulsed magnetic fields measured using magneto-optic Kerr effect magnetometry. We observed complex field dependent switching behavior that depends on the relative contributions to the total field of the quasistatic and pulsed fields. As the pulsed field amplitude was increased, complex switching behavior occurs for total fields in excess of the coercive field. A simple phenomenological domain wall propagation model suggests a qualitative understanding of this complex behavior based on Walker breakdown of the domain wall motion occurring in the Permalloy thin-film. (C) 2010 American Institute of Physics. [doi:10.1063/1.3490233]