Magnetic tape device and reproducing method employing TMR reproducing head and tape with characterized XRD intensity ratio

Patent metadata

Field	Value
Publication number	US-10546602-B2
Application number	US-201815899587-A
Country	US
Kind code	B2
Filing date	Feb 20, 2018
Priority date	Feb 20, 2017
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

The magnetic tape device includes a Tunneling Magnetoresistive (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.

First claim

What is claimed is:

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 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.

4. The magnetic tape device according to claim 3 ,
wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

5. The magnetic tape device according to claim 2 ,
wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

6. 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.

7. The magnetic tape device according to claim 6 ,
wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

8. The magnetic tape device according to claim 1 ,
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 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.

13. The magnetic reproducing method according to claim 12 ,
wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

14. The magnetic reproducing method according to claim 11 ,
wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

15. 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.

16. The magnetic reproducing method according to claim 15 ,
wherein the vertical direction squareness ratio of the magnetic tape is 0.65 to 0.90.

17. The magnetic reproducing method according to claim 10 ,
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.

Assignees

• Fujifilm Corp

Inventors

• Kasada Norihito
• Ozawa Eiki

Classifications

• G11B5/708

  characterised by addition of non-magnetic particles to the layer · CPC title

• G11B5/00813

  magnetic tapes · CPC title

• G11B5/70

  on a base layer · CPC title

• G11B5/3909

  Arrangements using a magnetic tunnel junction · CPC title

• G11B5/73

  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 title