Dynamics of domain wall in rapidly - changing magnetic field

A new experimental method for studying single domain wall (DW) dynamics in bistable microwires is presented. It provides new possibilities to study the dynamics of a domain wall moving in a region of rapidly-changing magnetic field. When the moving DW is forced to change its parameters in a very short time, the corresponding changes in velocity are different for rapid increase and decrease in field strength. Experimental v(x) dependences are compared with theoretical ones which correspond to the case when a DW moves with no inertial effects, or when the DW has enough time to adapt to the field in which it moves. The results obtained support the idea that a DW in bistable microwires is not a solid object, but changes its parameters (e.g. wall velocity) depending on the magnetic field applied.