Magnetic powder for magnetic recording, magnetic recording medium, and method of manufacturing magnetic powder for magnetic recording
US-2015187471-A1 · Jul 2, 2015 · US
Magnetic recording medium using hexagonal ferrite powder
US10043544B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-10043544-B2 |
| Application number | US-201615258292-A |
| Country | US |
| Kind code | B2 |
| Filing date | Sep 7, 2016 |
| Priority date | Sep 8, 2015 |
| Publication date | Aug 7, 2018 |
| Grant date | Aug 7, 2018 |
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Abstract
Official abstract text for this publication.
The magnetic recording medium has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is hexagonal ferrite powder containing, based on number of particles, greater than or equal to 80% isotropic particles that satisfy the relation 1: major axis length/minor axis length <1.2, with an average particle size of the hexagonal ferrite powder being less than or equal to 30 nm, and a squareness in a vertical direction of the magnetic layer being greater than or equal to 0.65 but less than or equal to 1.00.
First claim
Opening claim text (preview).
What is claimed is: 1. A magnetic recording medium, which comprises a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is hexagonal ferrite powder comprising, based on the number of particles, greater than or equal to 80% isotropic particles that satisfy the following relation 1: major axis length/minor axis length <1.2; with an average particle size of the hexagonal ferrite powder being less than or equal to 30 nm, and a squareness in a vertical direction of the magnetic layer being greater than or equal to 0.65 but less than or equal to 1.00. 2. The magnetic recording medium according to claim 1 , wherein the ferromagnetic powder is hexagonal ferrite powder comprising greater than or equal to 90%, based on number of particles, of the isotropic particles. 3. The magnetic recording medium according to claim 1 , wherein a coefficient of variation in a particle size of the isotropic particles is less than or equal to 25%. 4. The magnetic recording medium according to claim 1 , wherein a coefficient of variation in a particle size of the isotropic particles is less than or equal to 20%. 5. The magnetic recording medium according to claim 2 , wherein a coefficient of variation in a particle size of the isotropic particles is less than or equal to 25%. 6. The magnetic recording medium according to claim 2 , wherein a coefficient of variation in a particle size of the isotropic particles is less than or equal to 20%. 7. The magnetic recording medium according to claim 1 , wherein the magnetic layer comprises a compound comprising a polyalkyleneimine chain and a polyester chain. 8. The magnetic recording medium according to claim 2 , wherein the magnetic layer comprises a compound comprising a polyalkyleneimine chain and a polyester chain. 9. The magnetic recording medium according to claim 3 , wherein the magnetic layer comprises a compound comprising a polyalkyleneimine chain and a polyester chain. 10. The magnetic recording medium according to claim 4 , wherein the magnetic layer comprises a compound comprising a polyalkyleneimine chain and a polyester chain. 11. The magnetic recording medium according to claim 5 , wherein the magnetic layer comprises a compound comprising a polyalkyleneimine chain and a polyester chain. 12. The magnetic recording medium according to claim 6 , wherein the magnetic layer comprises a compound comprising a polyalkyleneimine chain and a polyester chain.
Assignees
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Classifications
- G11B5/70678Primary
Ferrites · CPC title
characterised by the dimension of the magnetic particles · CPC title
characterised by the dispersing agent · CPC title
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Frequently asked questions
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- What does patent US10043544B2 cover?
- The magnetic recording medium has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is hexagonal ferrite powder containing, based on number of particles, greater than or equal to 80% isotropic particles that satisfy the relation 1: major axis length/minor axis length <1.2, with an average particle size of the hexagonal ferrite…
- Who is the assignee on this patent?
- Fujifilm Corp
- What technology area does this patent fall under?
- Primary CPC classification G11B5/70678. Mapped technology areas include Physics.
- When was this patent published?
- Publication date Tue Aug 07 2018 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 1 related publication on this page (citations in our corpus or others sharing the same primary CPC).