Magnetic recording medium and magnetic recording and reproducing apparatus
The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent, wherein the ferromagnetic powder is selected from the group consisting of hexagonal strontium ferrite powder and ε-iron oxide powder, and has an average particle size of 5 nm or more and 20 nm or less, wherein the magnetic layer has a servo pattern, and wherein an average area Sdc of magnetic clusters of the magnetic recording medium in a DC demagnetization state, measured by a magnetic force microscope is 0.2×10 4 nm 2 or more and less than 5.0×10 4 nm 2 .
1. A magnetic recording medium comprising:
a non-magnetic support; and
a magnetic layer including ferromagnetic powder and a binding agent,
wherein the ferromagnetic powder is selected from the group consisting of hexagonal strontium ferrite powder and ε-iron oxide powder, and has an average particle size of 5 nm or more and 20 nm or less,
wherein the magnetic layer has a servo pattern, and
wherein an average area Sdc of magnetic clusters of the magnetic recording medium in a DC demagnetization state, measured by a magnetic force microscope is 0.2×10 4 nm 2 or more and less than 5.0×10 4 nm 2 .
2. The magnetic recording medium according to claim 1 ,
wherein a ratio Sdc/Sac of the Sdc to an average area Sac of magnetic clusters of the magnetic recording medium in an AC demagnetization state, measured by a magnetic force microscope is 0.8 or more and 2.0 or less.
3. The magnetic recording medium according to claim 1 ,
wherein the magnetic recording medium is a magnetic tape,
wherein the servo pattern is a timing-based servo pattern, and
wherein an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference L 99.9 −L 0.1 between a value L 99.9 of a cumulative distribution function of 99.9% and a value L 0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less.
4. The magnetic recording medium according to claim 2 ,
wherein the magnetic recording medium is a magnetic tape,
wherein the servo pattern is a timing-based servo pattern, and
wherein an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference L 99.9 −L 0.1 between a value L 99.9 of a cumulative distribution function of 99.9% and a value L 0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less.
5. The magnetic recording medium according to claim 1 ,
wherein the Sdc is 0.2×10 4 nm 2 or more and less than 0.3×10 4 nm 2 .
6. The magnetic recording medium according to claim 2 ,
wherein the Sdc is 0.2×10 4 nm 2 or more and less than 0.3×10 4 nm 2 .
7. The magnetic recording medium according to claim 3 ,
wherein the Sdc is 0.2×10 4 nm 2 or more and less than 0.3×10 4 nm 2 .
8. The magnetic recording medium according to claim 4 ,
wherein the Sdc is 0.2×10 4 nm 2 or more and less than 0.3×10 4 nm 2 .
9. A magnetic recording and reproducing apparatus comprising:
the magnetic recording medium according to claim 1 ; and
a magnetic head.
10. The magnetic recording and reproducing apparatus according to claim 9 ,
wherein a ratio Sdc/Sac of the Sdc to an average area Sac of magnetic clusters of the magnetic recording medium in an AC demagnetization state, measured by a magnetic force microscope is 0.8 or more and 2.0 or less.
11. The magnetic recording and reproducing apparatus according to claim 9 ,
wherein the magnetic recording medium is a magnetic tape,
wherein the servo pattern is a timing-based servo pattern, and
wherein an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference L 99.9 −L 0.1 between a value L 99.9 of a cumulative distribution function of 99.9% and a value L 0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less.
12. The magnetic recording and reproducing apparatus according to claim 10 ,
wherein the magnetic recording medium is a magnetic tape,
wherein the servo pattern is a timing-based servo pattern, and
wherein an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference L 99.9 −L 0.1 between a value L 99.9 of a cumulative distribution function of 99.9% and a value L 0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less.
13. The magnetic recording and reproducing apparatus according to claim 9 ,
wherein the Sdc is 0.2×10 4 nm 2 or more and less than 0.3×10 4 nm 2 .
14. The magnetic recording reproducing apparatus according to claim 10 ,
wherein the Sdc is 0.2×10 4 nm 2 or more and less than 0.3×10 4 nm 2 .
15. The magnetic recording and reproducing apparatus according to claim 11 ,
wherein the Sdc is 0.2×10 4 nm 2 or more and less than 0.3×10 4 nm 2 .
16. The magnetic recording and reproducing apparatus according to claim 12 ,
wherein the Sdc is 0.2×10 4 nm 2 or more and less than 0.3×10 4 nm 2 .