The recording processes of patterned bits with different bit length generat
ed by focused ion beam etching are investigated by spin stand testing, Comp
ared to conventional written transitions, the magnetization switching of pa
tterned bits requires much smaller write fields. Also the write field gradi
ent is no longer critical to the sharpness of the transition of patterned b
its. Experimental results demonstrate that from the standpoint of recording
, patterned media is a good solution for ultra-high density magnetic record
ing.