PURPOSE: To obtain a magnetic recording medium having a high S-N ratio at the time of recording a signal, ensuring low noise and excellent in environmental resistance by forming a nonmagnetic layer of an alloy consisting essentially of Cr and Mo and magnetic layers of an alloy consisting essentially of Co and Pt.
CONSTITUTION: An underlayer 2, a 1st magnetic layer 3, a nonmagnetic layer 4, a 2nd magnetic layer 5, a protective layer 6 and a lubricating layer 7 are successively laminated on a glass substrate 1 to obtain the objective magnetic disk. The glass substrate 1 is made of aluminosilicate glass. The underlayer 2 consists of a thin Al film 2a of 50 thickness, a thin Cr film 2b of 400 thickness and a thin CrMo film 2c of 100 thickness from the substrate 1 side. The CrMo film 2c consists of 98at.& Cr and 2at.% Mo. Each of the 1st and 2nd magnetic layers 3, 5 is made of a CoPtCr alloy consisting of 78at.% Co, 11at.% Pt and 11at.% Cr and the thickness is 120. The nonmagnetic layer 4 between the 1st and 2nd magnetic layers 3, 5 is made of a CrMo alloy consisting of 95at.% Cr and 5at.% Mo and the thickness is 50. The protective layer 6 consists of a Cr film of 50 thickness and a silicon oxide film of 160 thickness contg. dispersed hard fine particles as 1st and 2nd protective layers 6a, 6b.
SATO TAKASHI
HORIKAWA JUNICHI
KAWAI HISAO
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