Magnetic tape having characterized magnetic layer and magnetic recording and reproducing device

Patent metadata

Field	Value
Publication number	US-11501799-B2
Application number	US-202016832788-A
Country	US
Kind code	B2
Filing date	Mar 27, 2020
Priority date	Sep 29, 2017
Publication date	Nov 15, 2022
Grant date	Nov 15, 2022

Abstract

Provided are a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support, in which the magnetic layer contains an oxide abrasive, an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is greater than 0.08 μm and 0.14 μm or smaller, and an absolute value ΔN of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40, and a magnetic recording and reproducing device including the magnetic tape.

First claim

What is claimed is:

1. A magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support,
wherein the magnetic layer contains an oxide abrasive,
an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is greater than 0.08 μm and 0.14 μm or smaller, and
an absolute value ΔN of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40.

2. The magnetic tape according to claim 1 ,
wherein the oxide abrasive is an alumina powder.

3. The magnetic tape according to claim 1 ,
wherein the ferromagnetic powder is a ferromagnetic hexagonal ferrite powder.

4. The magnetic tape according to claim 1 ,
wherein the difference Nxy−Nz between the refractive index Nxy and the refractive index Nz is 0.25 to 0.40.

5. The magnetic tape according to claim 1 , further comprising a non-magnetic layer containing a non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.

6. The magnetic tape according to claim 1 , further comprising a back coating layer containing a non-magnetic powder and a binding agent on a surface of the non-magnetic support opposite to a surface provided with the magnetic layer.

7. A magnetic recording and reproducing device comprising:
the magnetic tape according to claim 1 ; and
a magnetic head.

8. The magnetic recording and reproducing device according to claim 7 ,
wherein the oxide abrasive is an alumina powder.

9. The magnetic recording and reproducing device according to claim 7 ,
wherein the ferromagnetic powder is a ferromagnetic hexagonal ferrite powder.

10. The magnetic recording and reproducing device according to claim 7 ,
wherein the difference Nxy−Nz between the refractive index Nxy and the refractive index Nz is 0.25 to 0.40.

11. The magnetic recording and reproducing device according to claim 7 ,
wherein the magnetic tape further comprises a non-magnetic layer containing a non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.

12. The magnetic recording and reproducing device according to claim 7 ,
wherein the magnetic tape further comprises a back coating layer containing a non-magnetic powder and a binding agent on a surface of the non-magnetic support opposite to a surface provided with the magnetic layer.

Assignees

• Fujifilm Corp

Inventors

• Hosoda Hidemasa
• Kurokawa Takuto
• Kasada Norihito
• Iwamoto Takahiro

Classifications

• G11B5/68

  comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent · CPC title

• G11B5/78

  Tape carriers · CPC title

• G11B5/7085 Primary

  non-magnetic abrasive particles · CPC title

• G11B5/733

  characterised by the addition of non-magnetic particles {(base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739)} · CPC title

• G11B5/70678

  Ferrites · CPC title