Low-Gas-Pressure Sputtering of CoPtCr–$\hbox{SiO}_2$ Granular Films Made by a Sintered Target Without $\hbox{SiO}_2$ Powder

A new low-Ar-gas-pressure (
P
_Ar
) sputtering process is proposed for the preparation of granular metal-oxide films for use as perpendicular magnetic recording media. CoO and CoSi powders were used as the raw materials of the sintered target rather than SiO
₂
powder to obtain the O/Si ratio to 2 in a granular film under low
P
_Ar
process. Strongly exchange-coupled media were obtained at
P
_Ar
= 0.6 Pa using a conventional (Co)-(Pt)-(Cr)-(SiO
₂
) target, while use of the proposed (Co)-(Pt)-(Cr)-(CoSi)-enriched(CoO) target adjusted the oxygen composition in the granular film, which resulted in the successful fabrication of well magnetically decoupled media at
P
_Ar
= 0.6 Pa.