Perpendicular magnetic recording medium, manufacturing process of the same, and magnetic recording/reproducing apparatus using the same

A perpendicular magnetic recording medium including:

• a perpendicular recording layer formed over a substrate with a soft magnetic underlayer therebetween,
• wherein said perpendicular magnetic recording medium further includes an amorphous layer or nano-crystalline layer formed directly above said substrate and directly below said soft magnetic underlayer;
• wherein said soft magnetic underlayer includes first and second amorphous soft magnetic layers, and a nonmagnetic layer formed between said first and second amorphous soft magnetic layers;
• and
• wherein said first and second amorphous soft magnetic layers are coupled with each other antiferromagnetically;
• wherein said amorphous layer or nano-crystalline layer includes an alloy that contains at least two or more metals selected from a group consisting of Al, Ti, Ta, Cr, Zr, Co, Hf, Si, and B.

A perpendicular magnetic recording medium including:

• a perpendicular recording layer formed over a substrate with a soft magnetic underlayer therebetween,
• wherein said perpendicular magnetic recording medium further includes an amorphous layer formed directly on said substrate, said soft magnetic underlayer being formed directly on said amorphous layer with no other intervening layers therebetween;
• wherein said soft magnetic underlayer includes first and second amorphous soft magnetic layers, and a nonmagnetic layer formed between said first and second amorphous soft magnetic layers;
• and
• wherein said first and second amorphous soft magnetic layers are coupled with each other antiferromagnetically;
• wherein said amorphous layer includes an alloy that contains at least two or more metals selected from a group consisting of Al, Ti, Ta, Cr, Zr, Co, Hf, Si, and B.