Magnetic recording medium and magnetic storage apparatus

1. A magnetic recording medium comprising:

a substrate;

an underlayer disposed above the substrate; and

a first magnetic layer disposed above the underlayer,

wherein the first magnetic layer has a granular structure including magnetic grains having a L1 0 structure, and grain boundaries,

wherein a content of the grain boundaries is in a range of 25 volume percent to 50 volume percent, and

wherein the grain boundaries include a chalcogenide-based layered material.

2. The magnetic recording medium as claimed in claim 1 , wherein the chalcogenide-based layered material is selected from a group consisting of TiS 2 , ZrS 2 , HfS 2 , VS 2 , NbS 2 , TaS 2 , MoS 2 , WS 2 , GaS, GeS, and SnS 2 .

3. The magnetic recording medium as claimed in claim 2 , further comprising:

a second magnetic layer including boron, disposed between the underlayer and the first magnetic layer.

4. The magnetic recording medium as claimed in claim 1 , further comprising:

a second magnetic layer including boron, disposed between the underlayer and the first magnetic layer.

5. A magnetic storage apparatus comprising:

the magnetic recording medium according to claim 1 ; and

a magnetic head configured to write information to and read information from the magnetic recording medium.

6. A magnetic storage apparatus comprising:

the magnetic recording medium according to claim 2 ; and

a magnetic head configured to write information to and read information from the magnetic recording medium.

7. A magnetic storage apparatus comprising:

the magnetic recording medium according to claim 3 ; and

a magnetic head configured to write information to and read information from the magnetic recording medium.

8. A magnetic storage apparatus comprising:

the magnetic recording medium according to claim 4 ; and

a magnetic head configured to write information to and read information from the magnetic recording medium.