Magnetic recording medium

A magnetic disk device comprising:

• a magnetic head for recording information;
• and
• a magnetic recording medium for recording the information thereon, the magnetic recording medium including:
• a substrate;
• a soft magnetic underlayer disposed on the substrate;
• a foundation layer on the soft magnetic underlayer, the foundation layer including a plurality of Ru crystal grains isolated from each other at an upper portion of the foundation layer;
• a first magnetic layer including a plurality of magnetic crystal grains on the plurality of the Ru crystal grains of the foundation layer;
• and
• a second magnetic layer disposed on the plurality of magnetic crystal grains of the first magnetic layer, the second magnetic layer including a plurality of magnetic crystal grains having axes of easy magnetization in the direction perpendicular to the major surface of the substrate and nonmagnetic materials interposed between the crystal grains, the magnetic crystal grains of the first magnetic layer having a smaller grain size than those of the second magnetic layer.

A method for manufacturing a magnetic recording medium comprising:

• providing a substrate;
• forming a foundation layer on the substrate, the foundation layer having a plurality of Ru crystal grains isolated from each other at an upper portion of the foundation layer;
• forming a first magnetic layer on the foundation layer, the first magnetic layer including a plurality of magnetic crystal grains;
• and
• forming a second magnetic layer on the first magnetic layer, the second magnetic layer including a plurality of magnetic crystal grains having axes of easy magnetization perpendicular to the substrate surface and nonmagnetic materials interposed between the magnetic crystal grains, the magnetic crystal grains of the first magnetic layer having a smaller grain size than those of the second magnetic layer.