Magnetic recording medium

A perpendicular magnetic recording medium comprising:

• a substrate;
• a perpendicular magnetic recording layer disposed over the substrate;
• a soft magnetic underlayer disposed between the substrate and the perpendicular magnetic recording layer;
• a magnetic noise shunting layer disposed under the soft magnetic underlayer, having a higher saturation magnetization value than that of the soft magnetic layer and shunting a magnetic flux that results in noise generated by the magnetic domain walls of the soft magnetic underlayer;
• and
• an isolation layer disposed between the soft magnetic underlayer and the shunting layer and preventing exchange coupling between the shunting layer and the soft magnetic underlayer,
• wherein the shunting layer is formed of one selected from the group consisting of CoZrNb, NiFe, CoFe, and CoFeB, and
• the soft magnetic underlayer has a multi-layered structure in which unit soft magnetic underlayers are stacked and a spacer is disposed between adjacent unit soft magnetic underlayers.

A perpendicular magnetic recording medium comprising:

• a substrate;
• a perpendicular magnetic recording layer disposed over the substrate;
• a soft magnetic underlayer disposed between the substrate and the perpendicular magnetic recording layer;
• a magnetic noise shunting layer disposed under the soft magnetic underlayer, having a higher saturation magnetization value than that of the soft magnetic layer and shunting a magnetic flux that results in noise generated by the magnetic domain walls of the soft magnetic underlayer;
• and
• an isolation layer disposed between the soft magnetic underlayer and the shunting layer and preventing exchange coupling between the shunting layer and the soft magnetic underlayer,
• wherein the soft magnetic underlayer has a multi-layered structure in which unit soft magnetic underlayers are stacked and a spacer is disposed between adjacent unit soft magnetic underlayers.

A perpendicular magnetic recording medium comprising:

• a substrate;
• a perpendicular magnetic recording layer disposed over the substrate;
• a soft magnetic underlayer disposed between the substrate and the perpendicular magnetic recording layer;
• a magnetic noise shunting layer disposed under the soft magnetic underlayer, having a higher saturation magnetization value than that of the soft magnetic layer and shunting a magnetic flux that results in noise generated by the magnetic domain walls of the soft magnetic underlayer;
• and
• an isolation layer disposed between the soft magnetic underlayer and the shunting layer and preventing exchange coupling between the shunting layer and the soft magnetic underlayer,
• wherein the shunting layer is formed of one selected from the group consisting of CoZrNb, NiFe, CoFe, and CoFeB, and the soft magnetic underlayer has a multi-layered structure in which unit soft magnetic underlayers are stacked and a spacer is disposed between adjacent unit soft magnetic underlayers.