Patent ID: 11894171
Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  C | IPC C  H

Claim 0:
1. Magnetic powder for a magnetic recording medium, which is an Al-containing hexagonal ferrite magnetic powder having an Al/Fe molar ratio of 0.030 to 0.200, and which has a particle size distribution in which the volume ratio of particles having a particle size of 30 μm or more as measured by a laser diffraction particle size distribution analyzer with a dispersion pressure of 100 kPa is 5.0% or less, and an activation volume Vact of 1800 nm3 or less,
wherein a BET specific surface area according to the BET single-point method is from 50 to 130 m2/g,
wherein D90(500) is 7.0 μm or more and 11.4 μm or less,
wherein D90(100) is 7.6 μm or more and 20.0 μm or less, and
wherein D90(100) represents the cumulative 90% particle size (μm) on a volume basis as measured with a dispersion pressure of 100 kPa, and D90(500) represents the cumulative 90% particle size (μm) on a volume basis as measured with a dispersion pressure of 500 kPa.