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US 10,373,638 B2Granted
Hexagonal ferrite powder and magnetic recording medium
AssigneeFUJIFILM Corporation
InventorsYoichi Hosoya, Masashi Shirata
Life of this patent
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Abstract
Hexagonal ferrite powder has an average particle size falling within a range of 10 nm to 50 nm, a switching field distribution SFD23° C. measured at a temperature of 23° C. that is less than or equal to 0.80, and a ratio of a switching field distribution SFD−190° C. that is measured at a temperature of −190° C. to the SFD23° C. (SFD−190° C./SFD23° C.) that is greater than 0.80.
Claims9
Hexagonal ferrite powder, which has:
- an average particle size falling within a range of 10 nm to 50 nm;
- a switching field distribution SFD23° C. measured at a temperature of 23° C. falls within a range of 0.10 to 0.60;
- and
- a ratio of a switching field distribution SFD−190° C. that is measured at a temperature of −190° C. to the SFD23° C., SFD−190° C./SFD23° C., falls within a range of 0.90 to 1.50.
1 more element
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 which has:
- an average particle size falling within a range of 10 nm to 50 nm;
- a switching field distribution SFD23° C. measured at a temperature of 23° C. falls within a range of 0.10 to 0.60;
- and
- a ratio of a switching field distribution SFD−190° C. that is measured at a temperature of −190° C. to the SFD23° C., SFD−190° C./SFD23° C., falls within a range of 0.90 to 1.50.
3 more elements
Dependencies are inferred from the claim text.