Magnetic recording medium
Provided is a magnetic recording medium capable of achieving high reproduction output in a short wavelength region. The magnetic recording medium comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support. The magnetic layer has a squareness ranging from 0.6 to 1.0 in a perpendicular direction, and the magnetic recording medium is employed for recording a magnetic signal on the medium in a longitudinal direction at a linear recording density of equal to or greater than 300 Kbpi using a recording head with a gap length of equal to or less than 0.3 micrometer, and reproducing the magnetic signal using a magnetoresistive head with a shield spacing of equal to or less than 0.2 micrometer.
1 . A magnetic recording medium comprising a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support, wherein
said magnetic layer has a squareness ranging from 0.6 to 1.0 in a perpendicular direction, and
said magnetic recording medium is employed for recording a magnetic signal on the medium in a longitudinal direction at a linear recording density of equal to or greater than 300 Kbpi using a recording head with a gap length of equal to or less than 0.3 micrometer, and reproducing said magnetic signal using a magnetoresistive head with a shield spacing of equal to or less than 0.2 micrometer.
2 . The magnetic recording medium according to claim 1 , wherein said recording head has a saturation magnetic flux density of equal to or greater than 1.5 T.
3 . The magnetic recording medium according to claim 1 , wherein said magnetic layer has a thickness ranging from 0.01 to 0.15 micrometer.
4 . The magnetic recording medium according to claim 1 , wherein said magnetic layer has a coercivity ranging from 2000 to 5000 Oe.
5 . The magnetic recording medium according to claim 1 , wherein said magnetic layer has a magnetization switching volume ranging from 1000 to 15000 nm 3 .
6 . The magnetic recording medium according to claim 1 , which is one formed by coating a coating liquid for forming a nonmagnetic layer on said nonmagnetic support and drying the coating liquid for forming a nonmagnetic layer to form a nonmagnetic layer, and then coating a coating liquid for forming a magnetic layer on said nonmagnetic layer and drying the coating liquid for forming a magnetic layer.
7 . A method of recording a magnetic signal on a magnetic recording medium with a recording head and reproducing the magnetic signal with a magnetoresistive head, wherein
said magnetic recording medium comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support,
said magnetic layer has a squareness ranging from 0.6 to 1.0 in a perpendicular direction,
said recording head has a gap length of equal to or less than 0.3 micrometer,
said magnetoresistive head has a shield spacing of equal to or less than 0.2 micrometer,
said magnetic signal is recorded on the medium in a longitudinal direction at a linear recording density of equal to or greater than 300 Kbpi.
8 . The method according to claim 7 , wherein said recording head has a saturation magnetic flux density of equal to or greater than 1.5 T.
9 . The method according to claim 7 , wherein said magnetic layer has a thickness ranging from 0.01 to 0.15 micrometer.
10 . The method according to claim 7 , wherein said magnetic layer has a coercivity ranging from 2000 to 5000 Oe.
11 . The method according to claim 7 , wherein said magnetic layer has a magnetization switching volume ranging from 1000 to 15000 nm.
12 . The method according to claim 7 , wherein said magnetic recording medium is one formed by coating a coating liquid for forming a nonmagnetic layer on said nonmagnetic support and drying the coating liquid for forming a nonmagnetic layer to form a nonmagnetic layer, and then coating a coating liquid for forming a magnetic layer on said nonmagnetic layer and drying the coating liquid for forming a magnetic layer.
13 . An apparatus comprising a recording head, a magnetoresistive head and a magnetic recording medium, wherein
said recording head has a gap length of equal to or less than 0.3 micrometer and records a magnetic signal on the medium in a longitudinal direction at a linear recording density of equal to or greater than 300 Kbpi,
said magnetoresistive heads has a shield spacing of equal to or less than 0.2 micrometer and reproduces the magnetic signal,
said magnetic recording medium comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support, and
said magnetic layer has a squareness ranging from 0.6 to 1.0 in a perpendicular direction.
14 . The apparatus according to claim 13 , wherein said recording head has a saturation magnetic flux density of equal to or greater than 1.5 T.
15 . The apparatus according to claim 13 , wherein said magnetic layer has a thickness ranging from 0.01 to 0.15 micrometer.
16 . The apparatus according to claim 13 , wherein said magnetic layer has a coercivity ranging from 2000 to 5000 Oe.
17 . The apparatus according to claim 13 , wherein said magnetic layer has a magnetization switching volume ranging from 1000 to 15000 nm 3 .
18 . The apparatus according to claim 13 , wherein said magnetic recording medium is one formed by coating a coating liquid for forming a nonmagnetic layer on said nonmagnetic support and drying the coating liquid for forming a nonmagnetic layer to form a nonmagnetic layer, and then coating a coating liquid for forming a magnetic layer on said nonmagnetic layer and drying the coating liquid for forming a magnetic layer.