Abstract: A magnetic disk 10 for use in perpendicular magnetic recording has at least a magnetic recording layer on a substrate 1. The magnetic recording layer is composed of a ferromagnetic layer 5 of a granular structure containing silicon (Si) or an oxide of silicon (Si) between crystal grains containing cobalt (Co), a stacked layer 7 having a first layer containing cobalt (Co) or a Co alloy and a second layer containing palladium (Pd) or platinum (Pt), and a spacer layer 6 interposed between the ferromagnetic layer 5 and the stacked layer 7. After forming the ferromagnetic layer 5 on the substrate 1 by sputtering in an argon gas atmosphere, the stacked layer 7 is formed by sputtering in the argon gas atmosphere at a gas pressure lower than that used when forming the ferromagnetic layer 5.

Abstract: [Object] To achieve a high coercive force (Hc) and low-noise characteristics (high S/N ratio) through realization of both segregation of SiO2 and high perpendicular magnetic anisotropy by providing a two-layer structure having magnetic recording layers with different properties. [Solution] A magnetic disk for use in perpendicular magnetic recording, having at least an underlayer 5, a first magnetic recording layer 6, and a second magnetic recording layer 7 on a substrate in this order. The first magnetic recording layer 6 and the second magnetic recording layer 7 are each a ferromagnetic layer of a granular structure containing a nonmagnetic substance forming grain boundary portions between crystal grains containing at least Co (cobalt). Given that the content of the nonmagnetic substance in the first magnetic recording layer 6 is A mol % and the content of the nonmagnetic substance in the second magnetic recording layer 7 is B mol %, A>B.

Abstract: [Object] To provide a manufacturing method that can easily enhance a reversed domain nucleation magnetic field of a magnetic recording layer in a perpendicular magnetic recording medium having, over a substrate, a soft magnetic layer, the magnetic recording layer having a granular structure, and a continuous layer having a high perpendicular magnetic anisotropy.

Abstract: To provide a perpendicular magnetic recording disk having a film structure that improves overwrite characteristics (O/W) while maintaining a coercive force (Hc) high enough not to affect heat fluctuation resistance, and a manufacturing method thereof. A magnetic disk for use in perpendicular magnetic recording, having at least an underlayer, a first magnetic recording layer, and a second magnetic recording layer on a substrate in the order named, characterized in that the first magnetic recording layer and the second magnetic recording layer are each a ferromagnetic layer of a granular structure containing a nonmagnetic substance forming grain boundary portions between crystal grains containing at least Co (cobalt) and, given that the content of the nonmagnetic substance in the first magnetic recording layer is A mol % and the content of the nonmagnetic substance in the second magnetic recording layer is B mol %, A<B.

Abstract: A magnetic disk 10 for use in perpendicular magnetic recording has at least a magnetic recording layer on a substrate 1. The magnetic recording layer is composed of a ferromagnetic layer 5 of a granular structure containing silicon (Si) or an oxide of silicon (Si) between crystal grains containing cobalt (Co), a stacked layer 7 having a first layer containing cobalt (Co) or a Co alloy and a second layer containing palladium (Pd) or platinum (Pt), and a spacer layer 6 interposed between the ferromagnetic layer 5 and the stacked layer 7. After forming the ferromagnetic layer 5 on the substrate 1 by sputtering in an argon gas atmosphere, the stacked layer 7 is formed by sputtering in the argon gas atmosphere at a gas pressure lower than that used when forming the ferromagnetic layer 5.