Magnetization Switching of 2.5-inch CoCrPt Patterned Media by a Ring Head

The magnetization reversal process of CoCrPt patterned media by a ring head was investigated. The magnetic force microscopy (MFM) was used to investigate the distributions of the coercivity (H c ) and the easy axis as well as the size of each dot. The large distribution for H c causes the magnetization reversal defects. Possible origins of the large H c distribution are the grain boundary observed for each grain and the large distribution of the easy axis of the CoCrPt.