Physical and magnetic modification of co/pt multilayers by ion irradiation.

The microstructure of Co/Pt multilayers with large perpendicular magnetic anisotropy (PMA) was investigated before and after energetic ion irradiation. No pronounced microstructural changes were detected at ion doses sufficient to completely reduce the PMA and cause a spin reorientation transition to in-plane. Ion-induced displacement of Co and Pt atoms near Co/Pt interfaces lead to local "roughening" and Co layer strain relaxation, reducing the PMA. The magnetic domain confinement induced by ion irradiation and magnetic patterning by selective ion irradiation were also investigated.