Magnetic recording medium
US-10748570-B2 · Aug 18, 2020 · US
Hexagonal strontium ferrite powder, magnetic recording medium, and magnetic recording and reproducing apparatus
US11222661B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-11222661-B2 |
| Application number | US-202016737521-A |
| Country | US |
| Kind code | B2 |
| Filing date | Jan 8, 2020 |
| Priority date | Jan 11, 2019 |
| Publication date | Jan 11, 2022 |
| Grant date | Jan 11, 2022 |
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Abstract
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A hexagonal strontium ferrite powder, in which an average particle size is 10.0 to 25.0 nm, a content of one or more kinds of atom selected from the group consisting of a gallium atom, a scandium atom, an indium atom, and an antimony atom is 1.0 to 15.0 atom % with respect to 100.0 atom % of an iron atom, and a coercivity Hc is greater than 2,000 Oe and smaller than 4,000 Oe. A magnetic recording medium including: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which the ferromagnetic powder is the hexagonal strontium ferrite powder. A magnetic recording and reproducing apparatus including this magnetic recording medium.
First claim
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What is claimed is: 1. A magnetic recording medium comprising: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, wherein the ferromagnetic powder is a hexagonal strontium ferrite powder, wherein the average particle size is 10.0 to 25.0 nm, the content of one or more kinds of atom selected from the group consisting of a gallium atom, a scandium atom, an indium atom, and an antimony atom is 1.0 to 15.0 atom % with respect to 100.0 atom % of an iron atom, and the coercivity Hc is greater than 2,000 Oe and smaller than 4,000 Oe. 2. A magnetic recording and reproducing apparatus comprising: the magnetic recording medium according to claim 1 ; and a magnetic head. 3. The magnetic recording medium according to claim 1 , wherein the mass magnetization σs of the hexagonal strontium ferrite powder is equal to or greater than 41 A·m 2 /kg. 4. The magnetic recording medium according to claim 1 , wherein the content of the one or more kinds of atom selected from the group consisting of a gallium atom, a scandium atom, an indium atom, and an antimony atom in the hexagonal strontium ferrite powder is 1.0 to 12.0 atom % with respect to 100.0 atom % of an iron atom. 5. The magnetic recording medium according to claim 1 , wherein the hexagonal strontium ferrite powder comprises a gallium atom. 6. The magnetic recording medium according to claim 1 , wherein the hexagonal strontium ferrite powder comprises a scandium atom. 7. The magnetic recording medium according to claim 1 , wherein the hexagonal strontium ferrite powder comprises an indium atom. 8. The magnetic recording medium according to claim 1 , wherein the hexagonal strontium ferrite powder comprises an antimony atom. 9. The magnetic recording medium according to claim 1 , wherein the hexagonal strontium ferrite powder further comprises an aluminum atom. 10. The magnetic recording medium according to claim 1 , wherein the hexagonal strontium ferrite powder further comprises a neodymium atom. 11. The magnetic recording medium according to claim 1 , wherein the hexagonal strontium ferrite powder has a magnetoplumbite type crystal structure.
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Classifications
- G11B5/70678Primary
Ferrites · CPC title
Mixed oxides or hydroxides, (C01G49/0009 takes precedence) · CPC title
containing mixtures of polyurethanes or polyisocyanates with other polymers · CPC title
- G11B5/78Primary
Tape carriers · CPC title
containing one rare earth metal, yttrium or scandium · CPC title
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- What does patent US11222661B2 cover?
- A hexagonal strontium ferrite powder, in which an average particle size is 10.0 to 25.0 nm, a content of one or more kinds of atom selected from the group consisting of a gallium atom, a scandium atom, an indium atom, and an antimony atom is 1.0 to 15.0 atom % with respect to 100.0 atom % of an iron atom, and a coercivity Hc is greater than 2,000 Oe and smaller than 4,000 Oe. A magnetic recordi…
- 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 Jan 11 2022 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 4 related publications on this page (citations in our corpus or others sharing the same primary CPC).