Wall Motion by Reverse Néel Walls in Thin Films

Néel walls are presumed to exist as domain boundaries in thin films with thicknesses below 500 Å. Low-drive switching with a superimposed transverse field Ht may take place by reverse wall motion (Ht·Mwall<0) or normal wall motion (Ht·Mwall>0). Wall velocities are determined by intrinsic damping rather than eddy current losses, for films in this thickness region. Reverse wall mobilities have been measured by interrupted pulse flux reversal experiments, in agreement with calculations based on the Landau-Lifshitz equation and uniaxial anisotropy. With h=Ht/HK=0.1, normal wall mobility is about 20% greater than reverse wall mobility.