Thermal stability of CoCr-alloy perpendicular magnetic recording media

Thermal decay characteristics of CoCr-alloy single-layer perpendicular magn etic recording media have been investigated and compared with those of long itudinal media. Remanent magnetization and 40 kFCI signal output begin to d ecrease when the magnetic layer thickness is decreased to less than 25 nm f or CoCrTa and CoCrPtTa perpendicular media with M-r/M-s < 0.8. On the contr ary, a CoCrPt medium with M-r/M-s = 0.96 indicates signal decay less than 2 % within the measurement time range of 17 h at all the linear densities. A longitudinal CoCrPt medium of 16 nm thickness shows signal decay more than 8% as the linear density increases more than 300 kFCI. A thinner longitudin al medium (8 nm) shows signal decay of greater than 8% even at a lower line ar density (40 kFCI). The CoCrPt perpendicular medium with the M-r/M-s = 0. 96 shows the medium noise comparable to those with smaller M-r/M-s ratio me dia with the same layer thickness. (C) 1999 Published by Elsevier Science B .V. All rights reserved.