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Ag alloy thermal diffusion control film used in magnetic recording medium for thermally assisted recording, magnetic recording medium for thermally assisted recording, and sputtering target

A magnetic recording medium and thermal diffusion technology, applied in magnetic recording, data recording, sputtering coating, etc., can solve the problems of high magnetic crystal anisotropy, magnetic field can not be recorded, etc., to achieve high thermal conductivity and heat resistance Improved effect

Inactive Publication Date: 2012-07-25
KOBE STEEL LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is a problem with these materials with high magnetocrystalline anisotropy that they cannot be recorded in the magnetic fields that can be recorded by conventional recording heads.
[0014] As mentioned above, the thermal diffusion control film used in the magnetic recording medium for thermally assisted recording is required to have all the characteristics of high thermal diffusivity, high surface smoothness, and high heat resistance in addition to high thermal conductivity, but Ag alone Bulk films cannot meet such required properties

Method used

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  • Ag alloy thermal diffusion control film used in magnetic recording medium for thermally assisted recording, magnetic recording medium for thermally assisted recording, and sputtering target
  • Ag alloy thermal diffusion control film used in magnetic recording medium for thermally assisted recording, magnetic recording medium for thermally assisted recording, and sputtering target
  • Ag alloy thermal diffusion control film used in magnetic recording medium for thermally assisted recording, magnetic recording medium for thermally assisted recording, and sputtering target

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0069] In this example, the effects of the composition of the Ag alloy thin film on thermal conductivity, thermal diffusivity, and surface smoothness (Ra) were investigated.

[0070] Specifically, various Ag alloy thin films 200 nm described in Table 2 were produced on a glass substrate (CORNING #1737, substrate size: 50 mm in diameter, 1 mm in thickness) using DC magnetron sputtering. Film formation conditions are: substrate temperature: 22°C, Ar pressure: 2mTorr, input power density: 0.025W / cm 2 , Back pressure: -6 Torr.

[0071] In addition, the content of each element in the said Ag alloy was calculated|required by the ICP optical emission analysis (inductively coupled plasma mass spectrometry) method from the sample produced by the film thickness of 100 nm on the glass substrate.

[0072] Using the Ag alloy thin film thus obtained, thermal conductivity, thermal diffusivity, and surface smoothness (Ra) were investigated in the following manner.

[0073] (Measurement of t...

Embodiment 2

[0086] In this example, various Ag alloy thin films were formed on glass substrates, and the surface shapes after film formation and heat treatment were observed with a scanning reflection electron microscope (SEM).

[0087] In detail, the same as the aforementioned embodiment 1, make image 3 (a)~ image 3 (c) and Figure 4 (a)~ Figure 4 (b) Various Ag alloy films shown in 200nm. The content of the Ag alloy thin film was also calculated in the same manner as in Example 1. Also, for comparison, for pure Ag ( figure 2 (a)~ figure 2 (c)) is also produced in the same manner.

[0088] The heat treatment was performed at 400° C. for 1 hour in the air atmosphere. In the heat-assisted recording method, the heating temperature during actual recording is estimated to be about 100 to 300°C, but in this embodiment, it is set to 400°C as an accelerated test.

[0089] The result is shown in the figure 2 (a)~ figure 2 (c), image 3 (a)~ image 3 (c) and Figure 4 (a)~ Fi...

Embodiment 3

[0094] In this example, using an Ag-0.14 at% Bi-0.2 at% Nd thin film satisfying the requirements of the present invention, the influence of the Ar gas pressure and film thickness during film formation on the surface roughness (Ra) was investigated.

[0095] (About Ag gas pressure)

[0096] In the foregoing embodiment 1, the Ar gas pressure is such as Figure 5 As shown, the surface roughness Ra was varied in the range of 2 to 10 mTorr (film thickness of the Ag alloy thin film = 200 nm), and the surface roughness Ra at this time was measured in the same manner as in Example 1 above. The result is shown in the Figure 5 middle.

[0097] Depend on Figure 5 It can be seen that the surface roughness Ra of the Ag alloy thin film increases sharply when the Ar gas pressure exceeds 5 mTorr. This is presumed to be because the metal particles sputtered from the target are scattered by Ar. Therefore, in order to reduce Ra to 1.0 nm or less specified in the present invention, it is p...

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Abstract

Disclosed is an Ag alloy thermal diffusion control film to be used in a magnetic medium for thermally assisted recording, said thermal diffusion control film maintaining a high heat conductivity, and at the same time, having all of a high thermal diffusivity, a smooth surface roughness, and a high heat resistance. The Ag alloy thermal diffusion control film, is composed of an Ag alloy having Ag as a main component, and satisfies a surface roughness (Ra) of 1.0 nm or less, a heat conductivity of 100W / (mK) or more, and a thermal diffusivity of 4.010-5m2 / sec or more.

Description

technical field [0001] The present invention relates to a magnetic recording medium used in a heat-assisted magnetic recording (HAMR) hard disk drive for magnetic recording assisted by localized heating formed by laser light or near-field light during the recording process. An Ag alloy thin film useful as a thermal diffusion control film between a substrate and a recording film or a substrate layer, and a magnetic recording medium composed of the same. Background technique [0002] In recent years, the demand for recording capacity of magnetic recording media has further increased, and therefore the areal recording density of magnetic recording media has further increased. On the other hand, as the recording density of the magnetic recording medium increases, the volume of the magnetic recording medium per 1 bit decreases. Therefore, the problem of recording demagnetization due to thermal agitation becomes prominent. [0003] For this problem, for example, a method of chang...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B5/738C23C14/14C23C14/34
CPCG11B5/7325G11B5/851C23C14/16C23C14/3414Y10T428/12993G11B5/7375G11B5/7368
Inventor 中井淳一田内裕基
Owner KOBE STEEL LTD
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