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Substrate for magnetic disk and magnetic recording medium

A magnetic recording medium and magnetic disk technology, applied in the direction of the magnetic recording layer, the base layer of the recording layer, different recording carrier forms, etc., can solve the problems that cannot fully meet the high recording density, and achieve the effect of excellent electromagnetic conversion characteristics

Inactive Publication Date: 2008-12-24
SHOWA DENKO KK
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, in the techniques described in Patent Documents 1 and 2, there are cases where the head collides with asperities on the surface of the substrate when the head moves over the surface of the substrate, and these techniques cannot sufficiently satisfy demands for high recording Density requirements above

Method used

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  • Substrate for magnetic disk and magnetic recording medium
  • Substrate for magnetic disk and magnetic recording medium
  • Substrate for magnetic disk and magnetic recording medium

Examples

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Effect test

experiment example 1 to 12

[0047] Preparation mainly consists of 77% SiO 2 , 11% Li 2 O, 4% Al 2 o 3 and 3% MgO raw material glass, as the material for each disk substrate. By using a melting device, the raw material glass was melted at about 1350° C. to 1500° C., and the raw material glass was mixed, pressed, and cooled, thereby obtaining a disk-shaped glass plate having a diameter of 66 mm and a thickness of about 1 mm. The obtained glass plate was then heat-treated at 540° C. for about five hours to form crystal nuclei and at 780° C. for two hours to form crystals, thereby forming a crystallized glass in which the crystalline phases were lithium disilicate and alpha quartz, And aggregated particles of alpha quartz are dispersed on the glass.

[0048] Next, a base was prepared by forming a center hole in the center portion of the crystallized glass plate using a cylindrical grinding stone. Then, by using a polishing device capable of polishing both sides of the substrate and using diamond particl...

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Abstract

The present invention relates to a magnetic disk substrate, in which an amplitude Wa of a waviness on a surface measured by using an interferometer for a versatile disk at a measuring wave-length of 5.0 mm is within the range of 0.1nm to 0.5 nm, an average amplitude Wb of a microwaviness generated on the waviness by using a microscopy for three-dimensional surface-structural analysis at a measuring wave-length of 30 [mu]m to 200 [mu]m is 0.3nm or less, and a value calculated by dividing the average amplitude Wb of the microwaviness by the amplitude Wa of the waviness is 0.6 or more.

Description

technical field [0001] The present invention relates to a magnetic disk substrate and a magnetic recording medium using the magnetic disk substrate. More particularly, the present invention relates to a magnetic disk substrate that can realize a magnetic recording medium capable of reading and writing commensurately with high recording density. [0002] This application claims the benefit of Japanese Patent Application No. 2005-361719, filed December 15, 2005, and US Provisional Application No. 60 / 752,394, filed December 22, 2005, the contents of which are incorporated herein by reference. Background technique [0003] In recent years, higher recording densities are expected in magnetic disks. In order to meet this requirement, extensive research has been conducted on the surface topography of substrates used in magnetic disks. For example, Patent Document 1 proposes conditions in which the amplitude of surface waviness at a wavelength of 0.3 mm to 3.0 mm is 50 nm or less,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B5/73G11B5/82
Inventor 会田克昭町田裕之
Owner SHOWA DENKO KK
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