CRMN UNDERLAYERS FOR COCRPT THIN-FILM MEDIA

An improved CoCrPt thin film medium for longitudinal magnetic recordin g which has a coercivity significantly greater than prior CoCrPt thin film media was investigated, A CrMn alloy underlayer was used, instead of the conventional Cr underlayer. A coercivity value of 4280 Oe was easily reached in a CoCrPt film on a 50 nm thick CrMn underlayer as co mpared to 2810 Oe with a pure Cr underlayer, It was found that the coe rcivity increase due to the Mn addition was realized if the substrates were preheated before the sputtering, Grain boundary interdiffusion o f Mn from the underlayer to the magnetic layer may be the cause for th e coercivity increase.