Abstract: Provided is a method of manufacturing a magnetic disk glass substrate, wherein, in a main surface polishing process, main surface polishing is applied to one of main surfaces of a glass substrate so that the one main surface has a predetermined arithmetic mean roughness, and main surface polishing is applied to the other main surface of the glass substrate so that the other main surface has a roughness which is higher than the arithmetic mean roughness (Ra) of the one main surface and which is low enough to prevent a component forming the magnetic disk glass substrate from being eluted from the other main surface.

Abstract: To provide a magnetic-disk glass substrate manufacturing method that can reduce the inner diameter dimensional error.

Abstract: It is an object to manufacture magnetic recording media with the high recording density. Since nonmagnetic portions (8) with a predetermined pattern are formed in a recording auxiliary layer (4) formed on a magnetic recording layer (3), it is possible to actualize a magnetic recording medium where magnetic portions (7) and the magnetic recording layer (3) immediately below the portions (7) are recording units. The nonmagnetic portions (8) are formed by non-magnetization using ion implantation, and it is thereby possible to manufacture magnetic recording media with the high recording density.

Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.

Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.

Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.

Abstract: Provided is a method of manufacturing a magnetic disk glass substrate, wherein, in a main surface polishing process, main surface polishing is applied to one of main surfaces of a glass substrate so that the one main surface has a predetermined arithmetic mean roughness, and main surface polishing is applied to the other main surface of the glass substrate so that the other main surface has a roughness which is higher than the arithmetic mean roughness (Ra) of the one main surface and which is low enough to prevent a component forming the magnetic disk glass substrate from being eluted from the other main surface.

Abstract: It is an object to manufacture magnetic recording media with the high recording density. Since nonmagnetic portions (8) with a predetermined pattern are formed in a recording auxiliary layer (4) formed on a magnetic recording layer (3), it is possible to actualize a magnetic recording medium where magnetic portions (7) and the magnetic recording layer (3) immediately below the portions (7) are recording units. The nonmagnetic portions (8) are formed by non-magnetization using ion implantation, and it is thereby possible to manufacture magnetic recording media with the high recording density.

Abstract: NG surface information obtained in a defect inspecting step of a magnetic disk substrate is depicted on the magnetic disc substrate, so that the information can be discriminated at a succeeding film depositing step.

Abstract: In a magnetic disk substrate being annular and having a first and a second main surface, (1) surface roughness measured by an atomic force microscope having a resolution of 256×256 pixels per 2 ?m square and/or (2) the number of foreign substances detected to have sizes of 0.1 ?m or more and 1.0 ?m or less upon detection of scattered light from the magnetic disk substrate when laser light with a wavelength of 405 nm is irradiated with a spot size of 5 ?m at a laser power of 25 mW differ/differs between the first and the second main surfaces. Only the first main surface has a surface quality usable as a magnetic recording surface. The number of the foreign substances detected to have the sizes of 0.1 ?m or more and 1.0 ?m or less upon detection of the scattered light from the magnetic disk substrate when the laser light with the wavelength of 405 nm is irradiated with the spot size of 5 ?m at the laser power of 25 mW is 400 or less per 30 cm2 on the second main surface.

Abstract: To provide a magnetic-disk glass substrate manufacturing method that can reduce the inner diameter dimensional error.

Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.