MAGNETIC TAPE DEVICE AND MAGNETIC REPRODUCING METHOD

• US 20180240478A1
• Filed: 02/20/2018
• Published: 08/23/2018
• Est. Priority Date: 02/20/2017
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: KASADA, Norihito, OZAWA, Eiki
• Granted Patent: US 10,546,602 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/00813 magnetic tapes
• CPC Class Codes: G11B 5/02 Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/584 for track following on tapes
• CPC Class Codes: G11B 5/59683 for magnetoresistive heads
• CPC Class Codes: G11B 5/68 comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/7013 characterised by the dispersing agent
• CPC Class Codes: G11B 5/70678 Ferrites
• CPC Class Codes: G11B 5/708 characterised by addition of non-magnetic particles to the layer
• CPC Class Codes: G11B 5/73 Base layers , i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
• CPC Class Codes: G11B 5/74 Record carriers characterised by the form, e.g. sheet shaped to wrap around a drum
• CPC Class Codes: G11B 5/78 Tape carriers
• CPC Class Codes: G11B 5/845 in a magnetic field

Abstract

The magnetic tape device includes a TMR head as a reproducing head; and a magnetic tape which includes a non-magnetic support, and a magnetic layer including ferromagnetic hexagonal ferrite powder and a binding agent on the non-magnetic support, an XRD intensity ratio (Int(110)/Int(114)) of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.

Claims

1. A magnetic tape device comprising:

a magnetic tape; and

a reproducing head,

wherein the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

the ferromagnetic powder is ferromagnetic hexagonal ferrite powder,

an intensity ratio Int(110)/Int(114) of a peak intensity Int(110) of a diffraction peak of a (110) plane with respect to a peak intensity Int(114) of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0,

a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and

a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.

2. The magnetic tape device according to claim 1,

wherein the logarithmic decrement is 0.010 to 0.050.

3. The magnetic tape device according to claim 1,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 2.0 nm.

4. The magnetic tape device according to claim 2,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 2.0 nm.

5. The magnetic tape device according to claim 1,

wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

6. The magnetic tape device according to claim 2,

wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

7. The magnetic tape device according to claim 3,

wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

8. The magnetic tape device according to claim 4,

wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

9. The magnetic tape device according to claim 1,

wherein the magnetic tape includes a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.

10. A magnetic reproducing method comprising:

reproducing information recorded on a magnetic tape by a reproducing head,

wherein the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

the ferromagnetic powder is ferromagnetic hexagonal ferrite powder,

an intensity ratio Int(110)/Int(114) of a peak intensity Int(110) of a diffraction peak of a (110) plane with respect to a peak intensity Int(114) of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0,

a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and

a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.

11. The magnetic reproducing method according to claim 10,

wherein the logarithmic decrement is 0.010 to 0.050.

12. The magnetic reproducing method according to claim 10,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 2.0 nm.

13. The magnetic reproducing method according to claim 11,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 2.0 nm.

14. The magnetic reproducing method according to claim 10,

wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

15. The magnetic reproducing method according to claim 11,

wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

16. The magnetic reproducing method according to claim 12,

wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

17. The magnetic reproducing method according to claim 13,

wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

18. The magnetic reproducing method according to claim 10,

wherein the magnetic tape includes a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.