The magnetic anisotropy and domain structure of permalloy antidot arrays

The magnetic properties of antidot arrays in permalloy films were studied using magnetic force microscopy (MFM), the magneto-optical Kerr effect (MOKE), and torque magnetometry. New observations of the magnetic domain structure, magnetization reversal process, and magnetic anisotropy are presented. Magnetic domains were imaged during magnetization reversal to identify the magnetization switching processes with the field applied along the diagonal and the edge of the hole mesh. A four-fold anisotropy related to the confinement of domains by the hole mesh was observed by torque magnetometry at intermediate fields.