Magnetic powder, method of producing the same, and magnetic recording medium

A magnetic powder, comprising:

• particles containing ε-iron oxide, wherein
• a coefficient of variation represented by the following formula (1) is not more than 30%, and
• a ratio Y/X of a sub-peak height Y near a zero magnetic field to a main peak height X in an SFD (Switching Field Distribution) curve is not more than 0.5.
• Coefficient of variation [%]=([Standard deviation of particle diameter]/[Average particle diameter])×100 (1)

A magnetic recording medium, comprising:

• a recording layer that includes particles containing ε-iron oxide, wherein
• δ/Mrt satisfies a relationship represented by the following formula (2), and
• a ratio Y/X of a sub-peak height Y near a zero magnetic field to a main peak height X in an SFD (Switching Field Distribution) curve is not more than 0.5.
• 2.0≤δ/Mrt≤120.0 (2)
• (wherein δ [nm] is an average thickness of the recording layer and Mrt [mA] is a product of a residual magnetization amount and a thickness of the recording layer.)