Geometric effect in magnetization reversal studied by spin-polarized secondary electron microscopy

We have studied the magnetic domain structures and reversal processes of Fe thin films on two-dimensionally arranged hexagonal land-and-groove substrates by using spin-polarized secondary electron microscopy (SP-SEM). The coercivity difference between the land and groove was partly due to the difference in surface roughness between these areas. Weak domain wall pinning at the boundary between the land and groove areas occurred in the magnetization reversal process. The magnetic domain structures and reversal processes were found to depend on film geometry. It was also found that the anisotropy induced by film geometry for the hexagonal land-and-groove structure is weaker than that for the rectangular one. These results suggest that symmetry of film geometry and surface roughness play important roles for the magnetic domain structures and reversal processes in thin magnetic films.