Periodic magnetic domain wall pinning in an ultrathin film with perpendicular anisotropy generated by the stray magnetic field of a ferromagnetic nanodot array

摘要

The stray magnetic field of an array of hard ferromagnetic perpendicularly magnetized [Co/Pt]_4 nanodots is used to nondestructively generate a periodic pinning potential for domain walls in an underlying [Pt/Co]_2/Pt layer with perpendicular anisotropy. Pinning is evidenced using magneto-optical microscopy. The magnetic field (H) dependence of the average wall velocity in the presence of the periodic pinning potential is consistent with thermally activated creep, modified only by the addition of a uniform retarding field H_(ret), whose magnitude depends on the relative alignment of H and the dots' magnetizations.