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US 11,574,651 B2Granted
Magnetic recording medium having -iron oxide-containing particles
AssigneeSony Corporation
InventorsMasaru Terakawa, Yoichi Kanemaki, Minoru Yamaga
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Abstract
A magnetic recording medium, which is used in a recording and playback device in which the shortest recording wavelength is 75 nm or less, in which the magnetic recording medium has a recording layer including powder of ε-iron oxide-containing particles, the average particle size of the particles is 22 nm or less, the coercive force He is 220 kA/m or more and 320 kA/m or less, and the non linear transition shift is 20% or less.
Claims9
A magnetic recording medium, which is used in a recording and playback device in which a shortest recording wavelength is 75 nm or less,
- wherein the magnetic recording medium has a recording layer comprising powder of ε-iron oxide-containing particles,
- wherein an average particle size of the particles is 22 nm or less,
- wherein a coercive force Hc is 220 kA/m or more and 320 kA/m or less,
- wherein a non linear transition shift is 20% or less,
- wherein the ε-iron oxide-containing particles have a core-shell structure,
- wherein an average thickness of the recording layer is 30 nm or more and 120 nm or less, and
- wherein an arithmetic average roughness Ra of a surface on a side of the recording layer is 2.5 nm or less.
4 more elements
Dependencies are inferred from the claim text.