AC-Driven Breathing Mode of Confined Magnetic Domain Wall

We theoretically clarified the properties of ac-driven breathing modes of a confined magnetic domain wall. By numerically solving equations of motion for the domain wall, we found three characteristic breathing modes: forced harmonic, regular nonharmonic, and irregular nonharmonic modes. The latter two modes are characterized by the commensurability of the oscillation amplitude of the azimuthal angle of magnetization in the domain wall with a period of the magnetic anisotropy potential. They periodically and alternatively appear as ac amplitude increases above a threshold. We also showed that the voltage signal due to the domain wall depends on the mode.