Dynamic transformations of the internal structure of a moving domain wall in magnetic nanostripes

The magnetic field (or electric current) driven domain-wall motion in magnetic nanostripes is of considerable interest because it is essential to the performance of information-storage and logic devices. One of the current key problems is to understand the complex behaviors of oscillatory domain-wall motions under applied magnetic fields stronger than the so-called Walker field, beyond which the velocity of domain walls markedly drops. In a certain range just above the Walker field, the motions are not chaotic but rather periodic with different periodicities of dynamic transformations of a moving domain wall between the different types of its internal structure. In addition, three different periodicities of the dynamic transformations are calculated, which consist of different types of domain-wall structures that are transformed from one type to another. The transformation periods vary with the field strength and the nanostripe width. This phenomenon can be described by the dynamic motion of a limited number of magnetic topological solitons such as the vortex and antivortex confined in nanostripes. These results provide a considerably better understanding and details of the domain-wall motions in soft magnetic nanostripes.