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

Patent metadata

Field	Value
Publication number	US-2021287712-A1
Application number	US-202117326458-A
Country	US
Kind code	A1
Filing date	May 21, 2021
Priority date	Sep 29, 2017
Publication date	Sep 16, 2021
Grant date	—

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 0.04 μm to 0.08 μm, 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 on a non-magnetic support,
wherein a thickness of the magnetic layer is 10 to 100 nm, 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 0.04 μm to 0.08 μm, 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 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 on a surface of the non-magnetic support opposite to a surface provided with the magnetic layer.

7 . The magnetic tape according to claim 1 ,
wherein the thickness of the magnetic layer is 10 to 70 nm.

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

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

10 . The magnetic recording and reproducing device according to claim 8 ,
wherein the ferromagnetic powder is a ferromagnetic hexagonal ferrite powder.

11 . The magnetic recording and reproducing device according to claim 8 ,
wherein the difference Nxy−Nz between the refractive index Nxy and the refractive index Nz is 0.25 to 0.40.

12 . The magnetic recording and reproducing device according to claim 8 ,
wherein the magnetic tape further comprises a non-magnetic layer containing a non-magnetic powder between the non-magnetic support and the magnetic layer.

13 . The magnetic recording and reproducing device according to claim 8 ,
wherein the magnetic tape further comprises a back coating layer containing a non-magnetic powder on a surface of the non-magnetic support opposite to a surface provided with the magnetic layer.

14 . The magnetic tape and reproducing device according to claim 8 ,
wherein the thickness of the magnetic laver is 10 to 70 nm.

Assignees

• Fujifilm Corp

Inventors

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

Classifications

• G11B5/78

  Tape carriers · CPC title

• G11B5/68

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

• G11B5/70678 Primary

  Ferrites · CPC title

• G11B5/00817

  on longitudinal tracks only, e.g. for serpentine format recording · CPC title

• G11B5/70 Primary

  on a base layer · CPC title