Studies of the Magnetization Reversal Processes in Co Dot and Antidot Arrays on a Microscopic Scale

Co dot and antidot arrays with hexagonal symmetry have been prepared by combined electrochemical and sputtering techniques with significantly reduced nanoscale dimensions. Their magnetization reversal process has been analyzed on a macroscopic scale with Vibrating Sample Magnetometry (VSM) and on a microscopic scale by high spatial resolution Magnetic Transmission Soft X-ray Microscopy (MTXM). We observe for the antidot arrays a nucleation and propagation mode driven reversal mechanism induced by the in-plane anisotropy starting with nucleated clusters following the hexagonal configuration, and the magnetic hardness (i.e., coercivity) depending on the geometry parameters. Contrary, for arrays of short dots, a significant longitudinal anisotropy is deduced with large coercivity, where magnetostatic interactions gives rise to a more complex reversal process and significantly reduced remanence and