High density magnetic recording is investigated for a combination of single-layered perpendicular medium and ring-type head. Simulation study shows a possibility of high linear density recording exceeding 400kFCI under a reduced head-medium spacing of less than 40 nm. Experimental results show that the linear recording resolution(D50) increases drastically with decreasing the spacing. D50=173kFCI is confirmed with a highly oriented CoCrPt perpendicular medium and a narrow gap write head under a spacing of 45 nm. Side writing and side erasing can be reduced below 0.2μm by employing a narrow gap write head with trimmed sharp track edge. A new signal processing method is proposed to deal the dipulse reproduced waveforms which result from the combination of single-laryered medium and ring-type head. It is thus shown that the recording areal density can be increased greatly by employing the present recording system.
