Magnetic domain pinning in lithographically patterned amorphous magnetic layer

Artificial pinning sites have been fabricated for the magnetic domain pinning in perpendicular anisotropy magneto-optical (MO) thin film media. The pinning sites were radial hole array made by patterning a layer of radial gold grid on the silicon nitride (SiN) coated silicon (Si) substrate using a standard electron beam lithography. Various magnetization and demagnetization procedures were performed to investigate the magnetic domain pinning behavior. A polar Kerr microscope was used in situ to monitor the magnetic wall motion and a magnetic force microscope was employed to scan the magnetic domain structures. Magnetic domains were found to be pinned inside the hole array and resembled to the geometric shape of the holes. The coercivity in the patterned MO layer is much higher than in thr unpatterned MO layer. Moreover, the coercivity in the larger pinning sites area is higher than in the smaller pinning sites area.