MAGNETIC TAPE DEVICE AND MAGNETIC REPRODUCING METHOD

• US 20180286442A1
• Filed: 03/14/2018
• Published: 10/04/2018
• Est. Priority Date: 03/29/2017
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: OZAWA, Eiki, KASADA, Norihito
• Granted Patent: US 10,410,665 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/00813 magnetic tapes
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/70615 containing Fe metal or alloys G11B5/70621 takes precedence
• CPC Class Codes: G11B 5/78 Tape carriers

Abstract

The magnetic tape device includes a TMR head (reproducing head); and a magnetic tape including a magnetic layer including ferromagnetic hexagonal ferrite powder, a binding agent, and fatty acid ester, in which an XRD intensity ratio 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 is 0.65 to 1.00, Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, full widths at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and equal to or smaller than 7.0 nm, and a difference between spacings before and after the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm.

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, a binding agent, and fatty acid ester 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,

a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm,

a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm, and

a difference S_after−

S_before between a spacing S_after measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and a spacing S_before measured by optical interferometry regarding the surface of the magnetic layer before performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

2. The magnetic tape device according to claim 1,

wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing the vacuum heating with respect to the magnetic tape is 3.0 nm to 7.0 nm.

3. The magnetic tape device according to claim 1,

wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape is 3.0 nm to 7.0 nm.

4. The magnetic tape device according to claim 1,

wherein the difference S_after−

S_before is 2.0 nm to 8.0 nm.

5. 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.

6. The magnetic tape device according to claim 1,

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

7. 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.

8. 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, a binding agent, and fatty acid ester 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,

a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm,

a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm, and

a difference S_after−

S_before between a spacing S_after measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and a spacing S_before measured by optical interferometry regarding the surface of the magnetic layer before performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

9. The magnetic reproducing method according to claim 8,

wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing the vacuum heating with respect to the magnetic tape is 3.0 nm to 7.0 nm.

10. The magnetic reproducing method according to claim 8,

wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape is 3.0 nm to 7.0 nm.

11. The magnetic reproducing method according to claim 8,

wherein the difference S_after−

S_before is 2.0 nm to 8.0 nm.

12. The magnetic reproducing method according to claim 8,

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 8,

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

14. The magnetic reproducing method according to claim 8,

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.