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US-2024321303-A1 · Sep 26, 2024 · US
Ferrimagnetic particle powder and manufacturing method therefor, and magnetic recording medium and manufacturing method therefor
US9805754B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9805754-B2 |
| Application number | US-201414901884-A |
| Country | US |
| Kind code | B2 |
| Filing date | Jul 17, 2014 |
| Priority date | Aug 23, 2013 |
| Publication date | Oct 31, 2017 |
| Grant date | Oct 31, 2017 |
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Abstract
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A magnetic recording medium includes: a substrate; and a magnetic layer including a ferrimagnetic particle powder. A product (V×SFD) of a particle volume V and a holding force distribution SFD of the ferrimagnetic particle is equal to or less than 2500 nm3.
First claim
Opening claim text (preview).
The invention claimed is: 1. A magnetic recording medium comprising: a substrate; and a magnetic layer including a ferrimagnetic particle powder, wherein a product (V×SFD) of a particle volume V and a holding force distribution SFD of the ferrimagnetic particle is from 451 nm 3 to 2500 nm 3 , and wherein an average particle thickness of the ferrimagnetic particle powder is from 7 nm to 9 nm. 2. The magnetic recording medium according to claim 1 , wherein the ferrimagnetic particle is a hexagonal ferrite particle. 3. The magnetic recording medium according to claim 2 , wherein the hexagonal ferrite particle contains Ba. 4. The magnetic recording medium according to claim 3 , wherein the hexagonal ferrite particle further contains at least one selected from the group consisting of Co, Zn, and Ti. 5. The magnetic recording medium according to claim 1 , wherein the ferrimagnetic particle has an axial ratio of equal to or less than 3.9. 6. The magnetic recording medium according to claim 1 , wherein the ferrimagnetic particle has a particle volume of equal to or less than 6000 nm 3 . 7. The magnetic recording medium according to claim 1 , wherein the ferrimagnetic particle has a holding force distribution of equal to or less than 0.5. 8. The magnetic recording medium according to claim 1 , wherein a ratio (Vact/V) of an activation volume Vact to a particle volume V for the ferrimagnetic particle is equal to or less than 1.5. 9. The magnetic recording medium according to claim 1 , wherein the ferrimagnetic particle has an axial ratio from 1.9 to 3.9. 10. The magnetic recording medium according to claim 1 , wherein the hexagonal ferrite particle includes strontium ferrite as a main component. 11. A ferrimagnetic particle powder, wherein a product (V×SFD) of a particle volume V and a holding force distribution SFD is from 451 nm 3 to 2500 nm 3 , wherein an average particle thickness of the ferrimagnetic particle powder is from 7 nm to 9 nm.
Assignees
Inventors
Classifications
characterised by the dimension of the magnetic particles · CPC title
- G11B5/70678Primary
Ferrites · CPC title
containing one alkaline earth metal, magnesium or lead · CPC title
Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange · CPC title
Processes or apparatus specially adapted for manufacturing record carriers · CPC title
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Frequently asked questions
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- What does patent US9805754B2 cover?
- A magnetic recording medium includes: a substrate; and a magnetic layer including a ferrimagnetic particle powder. A product (V×SFD) of a particle volume V and a holding force distribution SFD of the ferrimagnetic particle is equal to or less than 2500 nm3.
- Who is the assignee on this patent?
- Sony 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 Oct 31 2017 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 8 related publications on this page (citations in our corpus or others sharing the same primary CPC).