JP2004030740A - Magnetic recording medium, its manufacturing method, and magnetic recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium, its manufacturing method, and a magnetic recording and reproducing device by which a noise characteristic can be improved and of which productivity is excellent. <P>SOLUTION: When a magnetic recording medium provided with a soft magnetic film 2, an orientation control film 3, a vertical magnetic recording film 5 in which a magnetization easy axis is arranged vertically to a substrate, and a protection film 6 on a non-magnetic substrate 1, is manufactured, the soft magnetic film 2 is formed by using spatter method, film forming gas pressure is controlled to be between 2Pa and 30Pa when the soft magnetic film 2 is formed. <P>COPYRIGHT: (C)2004,JPO

Description

【００４０】
表１より、成膜ガス圧が２Ｐａ未満である比較例では、スパイクノイズが発生したのに対し、成膜ガス圧が２Ｐａ以上３０Ｐａ以下である実施例では、スパイクノイズが発生しなかったことがわかる。
また、成膜ガス圧が３０Ｐａを越える比較例に比べ、成膜ガス圧が２Ｐａ以上３０Ｐａ以下である実施例では、優れたＳＮＲが得られたことがわかる。
【００４１】
（実施例５〜１０）
軟磁性膜２の組成を表２に示すとおりとする以外は、実施例１に準じて磁気記録媒体を作製した。
これらの実施例の磁気記録媒体について、記録再生特性を評価した。試験結果を表２に示す。
【００４２】
【表２】

【００４３】
表２より、ＣｏとＦｅのうちいずれか一方または両方である磁性元素を７０ａｔ％以上含み、Ｚｒ、Ｈｆ、Ｎｂ、Ｔａ、Ｂ、Ｃ、Ａｌ、Ｓｉのうち１種以上を含む軟磁性膜２を備えた磁気記録媒体では、優れたノイズ特性が得られたことがわかる。
【００４４】
（実施例１１〜１８）
軟磁性膜２を形成する際に、表３に示す成膜ガスを用いること以外は、実施例１に準じて磁気記録媒体を作製した。
これらの実施例の磁気記録媒体について、記録再生特性を評価した。試験結果を表３に示す。
なお、表中、１００Ａｒは１００ｖｏｌ％のＡｒを意味し、成膜ガスがＡｒであることを示す。また成膜ガスとして２種以上の物質名が記載されているものは、これら２種以上の物質からなる混合ガスが成膜ガスとして用いられたことを示す。例えば９０Ａｒ−１０Ｏ_２は、９０ｖｏｌ％のＡｒと１０ｖｏｌ％のＯ_２との混合ガスを意味する。
【００４５】
【表３】

【００４６】
表３より、軟磁性膜２を形成する際に、成膜ガスとして、表中に示すものを用いた場合には、スパイクノイズ発生を防ぐことができたことがわかる。
【００４７】
【発明の効果】
以上説明したように、本発明の磁気記録媒体の製造方法にあっては、軟磁性膜をスパッタ法を用いて形成し、軟磁性膜を形成する際の成膜ガス圧を２Ｐａ以上３０Ｐａ以下とするので、軟磁性膜における磁壁の形成を抑え、スパイク状ノイズの発生を防ぐことができる。よって、ＳＮＲなどのノイズ特性を大きく改善することができる。
また、従来の磁気記録媒体に比べ、膜の形成数を抑え、生産性を高めることができる。
従って、生産性を低下させることなく、ノイズ特性を向上させることができる。
【図面の簡単な説明】
【図１】本発明の磁気記録媒体の第１の実施形態を示す一部断面図である。
【図２】Ｍ−Ｈ曲線を示す模式図である。
【図３】Ｍ−Ｈ曲線を示す模式図である。
【図４】本発明の磁気記録媒体の製造方法の一実施形態を実施するために用いられるスパッタ装置を示す概略構成図である。
【図５】試験結果を示す図である。
【図６】試験結果を示す図である。
【図７】本発明の磁気記録再生装置の一例を示す概略図であり、（ａ）は全体構成を示し、（ｂ）は磁気ヘッドを示す。
【符号の説明】
１・・・非磁性基板、２・・・軟磁性膜、３・・・配向制御膜、５・・・垂直磁気記録膜、６・・・保護膜、８・・・磁気記録媒体、９・・・媒体駆動部、１０…磁気ヘッド、１０ａ・・・主磁極、１０ｂ・・・補助磁極、１０ｃ・・・連結部、１０ｄ・・・コイル、１１・・・ヘッド駆動部、１２・・・記録再生信号処理系[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic recording medium, a method for manufacturing the same, and a magnetic recording / reproducing apparatus.
[0002]
[Prior art]
In the conventional longitudinal magnetic recording, there is a problem that thermal fluctuation occurs when an attempt is made to realize a high recording density by miniaturizing recording bits.
In order to solve this problem, in recent years, a perpendicular magnetic recording system using a perpendicular magnetic recording film having perpendicular magnetic anisotropy has been proposed.
As a magnetic recording medium employing the perpendicular magnetic recording method, there is a magnetic recording medium in which a high magnetic permeability soft magnetic film is provided below a perpendicular magnetic recording film.
However, in a magnetic recording medium provided with a soft magnetic film, magnetic domains are easily formed by the soft magnetic film. Since a domain wall is formed at the boundary between the magnetic domains, spike noise occurs in a region where the domain wall exists.
[0003]
[Problems to be solved by the invention]
Japanese Patent Application Laid-Open No. 10-283624 proposes a magnetic recording medium in which a hard magnetic film made of CoSm or the like is provided below a soft magnetic film. In this magnetic recording medium, the hard magnetic film can make it difficult for magnetic domain walls to be formed in the soft magnetic film.
However, in this magnetic recording medium, the total number of films is increased, so that there is a problem that productivity is reduced. Further, as the temperature increases, the coercive force of the hard magnetic film made of CoSm or the like decreases, and there is a problem that a magnetic domain wall is easily formed in the soft magnetic film.
Japanese Patent Application Laid-Open No. Hei 10-214719 proposes a magnetic recording medium in which an antiferromagnetic film is provided below a soft magnetic film. In this magnetic recording medium, it is possible to make it difficult for a magnetic domain wall to be formed in the soft magnetic film by the antiferromagnetic film.
However, since this magnetic recording medium requires a step of forming a film in a magnetic field or a step of annealing (heat treatment) in a magnetic field, it is difficult to increase productivity.
The present invention has been made in view of the above circumstances, and provides a magnetic recording medium which can suppress spike noise, prevent deterioration of noise characteristics, and is excellent in productivity, a method of manufacturing the same, and a magnetic recording / reproducing apparatus. The purpose is to do.
[0004]
[Means for Solving the Problems]
The present invention manufactures a magnetic recording medium in which a soft magnetic film, an orientation control film, a perpendicular magnetic recording film whose easy axis of magnetization is oriented mainly perpendicular to the substrate, and a protective film are provided on a non-magnetic substrate. Wherein the soft magnetic film is formed by a sputtering method, and a film forming gas pressure at the time of forming the soft magnetic film is 2 Pa or more and 30 Pa or less.
The soft magnetic film contains at least 70 at% of a magnetic element that is one or both of Co and Fe, and at least one of Zr, Hf, Nb, Ta, B, C, Al, and Si. can do.
As the deposition gas, one or more of Ne, Ar, Kr, and Xe can be used.
As a film forming gas, one or more of Ne, Ar, Kr, and Xe are used as O. ₂ , N ₂ , CO ₂ Among them, those obtained by adding at least one of them can be used.
By employing the above manufacturing method, the formation of domain walls in the soft magnetic film can be suppressed without lowering productivity and mass productivity.
The magnetic recording medium of the present invention is manufactured by the above manufacturing method.
A magnetic recording / reproducing apparatus according to the present invention includes the magnetic recording medium described above, and a magnetic head for recording / reproducing information on / from the magnetic recording medium.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of the magnetic recording medium according to the present invention. The magnetic recording medium shown here comprises a soft magnetic film 2, an orientation control film 3, an intermediate film 4 on a non-magnetic substrate 1. , A perpendicular magnetic recording film 5, a protective film 6, and a lubricating film 7 are sequentially formed.
As the nonmagnetic substrate 1, a metal substrate made of a metal material such as aluminum or an aluminum alloy may be used, or a nonmetal substrate made of a nonmetal material such as glass, ceramic, silicon, silicon carbide, or carbon may be used. Good.
As the glass substrate, one made of amorphous glass or crystallized glass can be used. As the amorphous glass, general-purpose soda lime glass, aluminosilicate glass, and aluminosilicate glass can be used. As the crystallized glass, a lithium-based crystallized glass can be used.
As the ceramic substrate, a sintered body mainly containing general-purpose aluminum oxide, aluminum nitride, silicon nitride, or the like, or a substrate made of a fiber reinforced material thereof can be used.
[0006]
The soft magnetic film 2 is made of a soft magnetic material. As this material, a material containing a magnetic element such as Fe or Co can be used.
In particular, it is preferable to use a material containing one or more of Zr, Hf, Nb, Ta, B, C, Al, and Si in addition to the magnetic element. Accordingly, it is possible to prevent a domain wall from being formed in the soft magnetic film 2, to reduce noise caused by the soft magnetic film 2, and to further increase the SNR (ratio of a reproduced signal to noise).
Specifically, a material containing 70 at% or more of a magnetic element that is one or both of Co and Fe and containing one or more of Zr, Hf, Nb, Ta, B, C, Al, and Si is It is suitable.
When the content of the magnetic element is less than the above range, the magnetic properties such as the saturation magnetic flux density and the coercive force deteriorate.
[0007]
Examples of the material of the soft magnetic film 2 include Fe-based alloys (FeZr, FeZrO, FeHf, FeHfC, FeB, etc.), FeCo-based alloys (FeCoO, FeCoB, FeCoN, FeCoSi, etc.), FeAl-based alloys (FeAl, FeAlSi, FeAlSiCr, FeAlSiTiRu, FeAlO, etc.), FeCr alloys (FeCr, FeCrTi, FeCrCu, etc.), FeTa alloys (FeTa, FeTaC, FeTaB, etc.), FeMg alloys (FeMgO, etc.), FeC alloys, FeN alloys, FeSi alloys, Co-based alloys (CoZr, CoZrB, CoZrNb, CoZrTa, CoTa, CoTaMo, etc.) can be mentioned as suitable ones.
[0008]
The coercive force Hc of the soft magnetic film 2 is preferably 50 (Oe) or less (preferably 10 (Oe) or less).
If the coercive force Hc exceeds the above range, the soft magnetic properties become insufficient, and the reproduced waveform is not a so-called rectangular wave but a distorted waveform, which is not preferable.
The product Bs · t of the saturation magnetic flux density Bs and the thickness t of the soft magnetic film 2 is preferably 50 T · nm or more (preferably 80 T · nm or more). If Bs · t is less than the above range, the reproduced waveform becomes distorted and the OW characteristics (overwrite characteristics) are undesirably deteriorated.
[0009]
It is preferable that an oxide layer in which the soft magnetic film constituent material is oxidized is formed on the surface portion of the soft magnetic film 2.
Thereby, magnetic fluctuation on the surface of the soft magnetic film 2 can be suppressed, noise due to the magnetic fluctuation can be reduced, and recording / reproducing characteristics can be improved. Further, the crystal grains of the orientation control film 3 formed on the soft magnetic film 2 can be made finer, and the recording / reproducing characteristics can be improved.
[0010]
The orientation control film 3 controls the orientation and the crystal grain size of the intermediate film 4 and the perpendicular magnetic recording film 5 provided immediately above.
The material of the orientation control film 3 is not particularly limited, but a material having an hcp structure, an fcc structure, or an amorphous structure can be used. Among them, Ru alloy, Hf alloy, Ni alloy and Co alloy are particularly preferable.
[0011]
It is preferable that the thickness of the orientation control film 3 is 0.5 to 30 nm (preferably 1 to 20 nm). When the thickness is within this range, the perpendicular orientation of the perpendicular magnetic recording film 5 becomes particularly high, and the distance between the magnetic head and the soft magnetic film 2 during recording can be reduced. The recording / reproducing characteristics can be improved without lowering.
When the thickness is less than the above range, the perpendicular orientation of the perpendicular magnetic recording film 5 is reduced, and the recording / reproducing characteristics and the resistance to thermal fluctuation are deteriorated.
If the thickness exceeds the above range, the perpendicular orientation of the perpendicular magnetic recording film 5 is reduced, and the recording / reproducing characteristics and the resistance to thermal fluctuation are deteriorated. In addition, since the distance between the magnetic head and the soft magnetic film 2 at the time of recording increases, the resolution of the reproduction signal and the reproduction output decrease.
[0012]
Since the surface shape of the orientation control film 3 affects the surface shapes of the perpendicular magnetic recording film 5 and the protective film 6, the surface irregularities of the magnetic recording medium are reduced, and the flying height of the magnetic head during recording and reproduction is reduced. Preferably, the average surface roughness Ra of the alignment control film 3 is 2 nm or less.
As a result, the flying height of the magnetic head can be reduced, and a higher recording density can be achieved.
[0013]
An intermediate film 4 can be provided between the orientation control film 3 and the perpendicular magnetic recording film 5.
It is preferable to use a material having an hcp structure for the intermediate film 4. For the intermediate film 4, a CoCr alloy, CoCrX ₁ Alloy, CoX ₁ Alloy (X ₁ : One or two or more of Pt, Ta, Zr, Ru, Nb, Cu, Re, Ni, Mn, Ge, Si, O, N and B).
The Co content of the intermediate film 4 is preferably 30 to 70 at%.
The thickness of the intermediate film 4 is 30 nm in order to prevent deterioration of recording / reproducing characteristics due to coarsening of magnetic particles in the perpendicular magnetic recording film 5 and decrease in recording resolution due to an increase in the distance between the magnetic head and the soft magnetic film 2. Or less (preferably 20 nm or less).
By providing the intermediate film 4, the perpendicular orientation of the perpendicular magnetic recording film 5 can be enhanced, so that the coercive force of the perpendicular magnetic recording film 5 can be increased, and the recording / reproducing characteristics and the resistance to thermal fluctuation can be improved.
In the present invention, a configuration without the intermediate film 4 is also possible.
[0014]
The perpendicular magnetic recording film 5 has an axis of easy magnetization oriented mainly in a direction perpendicular to the substrate, and is preferably made of a CoCrPt-based alloy containing at least Co, Cr and Pt.
The Cr content is preferably 14 at% or more and 26 at% or less (preferably 16 at% or more and 22 at% or less), and the Pt content is 12 at% or more and 24 at% or less (preferably 14 at% or more and 20 at% or less). Is preferred.
If the Cr content is less than 14 at%, the exchange coupling between the magnetic particles increases, and as a result, the magnetic cluster diameter increases and noise increases, which is not preferable. Further, when the Cr content exceeds 26 at%, the ratio Mr / Ms of the residual magnetization (Mr) to the saturation magnetization (Ms) and the coercive force are undesirably reduced.
If the content of Pt is less than 12 at%, the recording / reproducing characteristics become insufficient, and the ratio of Mr / Ms is reduced, thereby deteriorating the thermal fluctuation. On the other hand, if the content of Pt exceeds 24 at%, noise increases, which is not preferable.
The perpendicular magnetic recording film 5 preferably contains B. Thereby, the magnetic cluster size can be reduced, and the SNR can be improved. It is preferable that the B content is 0.1 at% or more and 5 at% or less.
[0015]
The perpendicular magnetic recording film 5 can be configured to contain any element other than Co, Cr, Pt, and B. Examples of the element include, but are not particularly limited to, Ta, Mo, Nb, Hf, Ir, Cu, and W.
[0016]
The perpendicular magnetic recording film 5 is not limited to a one-layer structure made of a single material, but may have a structure of two or more layers.
When a structure having two or more layers is employed, at least one of these layers is preferably made of the above-mentioned CoCrPt-based alloy (preferably, Cr content: 14 to 26 at%, Pt content: 12 to 24 at%). .
In addition, Co-based alloys (CoCr, CoB, Co-SiO ₂ Etc.) and a Pd-based alloy (PdB, Pd-SiO ₂ Etc.) can be used.
Further, a multilayer structure including a layer made of an amorphous material such as CoTb and CoNd and a layer made of a CoCrPt-based material may be used.
[0017]
The thickness of the perpendicular magnetic recording film 5 is preferably 7 nm or more and 50 nm or less (preferably 13 nm or more and 40 nm or less). If the thickness of the perpendicular magnetic recording film 5 is less than the above range, sufficient magnetic flux cannot be obtained, and the reproduction output decreases. On the other hand, if the thickness of the perpendicular magnetic recording film 5 exceeds the above range, the magnetic particles of the perpendicular magnetic recording film 5 tend to be coarsened, and the recording / reproducing characteristics are deteriorated.
[0018]
The coercive force of the perpendicular magnetic recording film 5 is preferably 3000 (Oe) or more. When the coercive force is less than 3000 (Oe), it is difficult to increase the recording density. In addition, thermal fluctuation resistance is deteriorated, which is not preferable.
[0019]
It is preferable that Mr / Ms of the perpendicular magnetic recording film 5 is 0.9 or more. When Mr / Ms is less than 0.9, thermal fluctuation resistance is deteriorated, which is not preferable.
[0020]
It is preferable that the reverse magnetic domain nucleation magnetic field (-Hn) of the perpendicular magnetic recording film 5 is 0 (Oe) or more and 2500 (Oe) or less. When the reverse magnetic domain nucleation magnetic field (-Hn) is less than 0 (Oe), thermal fluctuation resistance is deteriorated, which is not preferable.
As shown in FIG. 2, in the MH curve, the point at which the external magnetic field becomes 0 in the process of reducing the external magnetic field from the state where the magnetization is saturated is defined as a, and the point at which the magnetization becomes 0 is defined as b. Assuming that an intersection between a tangent of the MH curve at b and a straight line indicating the saturation magnetization is c, the reverse domain nucleation magnetic field (-Hn) can be represented by the distance (Oe) between the points a and c.
Note that the reverse domain nucleation magnetic field (-Hn) takes a positive value when the point c is located in a region where the external magnetic field is negative (see FIG. 2), and conversely, in a region where the external magnetic field is positive. Takes a negative value if point c is present (see FIG. 3).
[0021]
The perpendicular magnetic recording film 5 preferably has an average crystal grain size of 5 to 15 nm.
The average particle diameter can be determined, for example, by observing the crystal grains of the perpendicular magnetic recording film 5 with a TEM (transmission electron microscope) and image-processing the observed image.
[0022]
The protective film 6 serves to prevent corrosion of the perpendicular magnetic recording film 5 and to prevent damage to the medium surface when the magnetic head comes into contact with the medium, and a conventionally known material can be used. For example, C, SiO ₂ , ZrO ₂ A material containing is usable.
It is desirable that the thickness of the protective film 6 be 1 to 10 nm.
As the lubricant 7, it is preferable to use perfluoropolyether, fluorinated alcohol, fluorinated carboxylic acid, or the like.
[0023]
Hereinafter, an embodiment of a method for manufacturing a magnetic recording medium according to the present invention will be described, taking the case of manufacturing the magnetic recording medium as an example.
FIG. 4 shows a sputtering apparatus used in the manufacturing method of the present embodiment. The sputtering apparatus shown in FIG. 4 includes a chamber 20, targets 21 provided on inner surfaces of both side walls of the chamber 20, A flow controller 23 for adjusting the flow rate of the film forming gas, an introduction pipe 24 for introducing the film forming gas into the chamber 20, and a discharge pipe 25 for discharging the gas in the chamber 20 to the outside of the system. .
[0024]
To manufacture the magnetic recording medium having the above configuration, first, a soft magnetic film 2 is formed on a substrate 1 by a sputtering method.
In forming the soft magnetic film 2, the pressure of the film forming gas is set to 2 Pa to 30 Pa (preferably 4 Pa to 20 Pa, more preferably 6 Pa to 15 Pa).
[0025]
In order to set the pressure of the film forming gas within the above range, for example, the following method can be adopted.
The substrate 1 is accommodated in the chamber 20, and the film-forming gas from the film-forming gas source 22 is introduced into the chamber 20 through the introduction pipe 24 and discharged through the discharge pipe 25.
At this time, the flow rate of the film forming gas is set using the flow rate controller 23 so that the film forming gas pressure in the chamber 20 is in the above range (2 Pa or more and 30 Pa or less).
[0026]
As the film forming gas, it is preferable to use one or more of Ne, Ar, Kr, and Xe.
In particular, one or more of Ne, Ar, Kr, and Xe contain O ₂ , N ₂ , CO ₂ By using a gas to which at least one of them is added, the formation of the domain wall in the soft magnetic film 2 can be more effectively suppressed.
O ₂ Is preferably added at 0.1 to 30% by volume.
N ₂ Is preferably added at 0.05 to 50% by volume.
CO ₂ Is preferably added at 0.1 to 20% by volume.
Power is supplied to the target 21 with the film forming gas pressure being in the above range, and the soft magnetic film 2 is formed on the surface of the substrate 1 by sputtering.
[0027]
By setting the pressure of the deposition gas in the above range, the formation of domain walls in the soft magnetic film 2 can be suppressed, and the generation of spike noise can be prevented. Further, the SNR can be greatly improved.
FIG. 5 is an envelope diagram of a magnetic recording medium having a soft magnetic film 2 formed at a film forming gas pressure of 7.5 Pa.
From this figure, it can be seen that spike noise hardly occurred when the deposition gas pressure was in the above range.
It can be assumed that the spike noise was suppressed because the formation of magnetic domains was suppressed by weakening the coupling between the magnetic particles.
[0028]
If the film forming gas pressure at the time of forming the soft magnetic film 2 is less than 2 Pa, domain wall formation cannot be suppressed, and spike noise occurs.
FIG. 6 is an envelope diagram of a magnetic recording medium having a soft magnetic film 2 formed at a film forming gas pressure of 0.6 Pa.
From this figure, it can be seen that spike noise occurred when the deposition gas pressure was less than 2 Pa.
On the other hand, if the film forming gas pressure exceeds 30 Pa, the orientation of the perpendicular magnetic recording film 5 provided thereon is deteriorated, and the SNR is undesirably lowered.
[0029]
The temperature of the substrate 1 when forming the soft magnetic film 2 is not particularly limited, but is preferably 0 to 400 ° C.
[0030]
It is preferable that the soft magnetic film 2 has an oxide layer formed on a surface layer.
In order to form the oxide layer, for example, after forming the soft magnetic film 2, a method of exposing the surface of the soft magnetic film 2 to an oxygen-containing gas can be employed. Further, when forming the surface layer portion of the soft magnetic film 2, a method of including oxygen in the film forming gas may be employed.
When exposing the surface of the soft magnetic film 2 to an oxygen-containing gas, the substrate 1 on which the soft magnetic film 2 is formed may be left in an oxygen-containing gas atmosphere for about 0.3 to 20 seconds.
As the oxygen-containing gas, an oxygen gas may be used, or a mixed gas of oxygen and another gas (eg, argon or nitrogen) may be used. Alternatively, air can be used.
When a mixed gas of oxygen and another gas is used, the degree of oxidation of the soft magnetic film 2 can be easily adjusted by adjusting the mixing ratio thereof.
In the case where oxygen is contained in the film formation gas, a method in which a film formation gas containing oxygen is used for only part of the film formation process can be employed. As the film forming gas, for example, a gas obtained by mixing oxygen with 0.05 to 50 vol% (preferably 0.1 to 20 vol%) in argon is suitably used.
[0031]
Next, an orientation control film 3, an intermediate film 4, and a perpendicular magnetic recording film 5 are sequentially formed by a sputtering method, a vacuum deposition method, an ion plating method, or the like.
Next, the protective film 6 is preferably formed by a plasma CVD method, an ion beam method, or a sputtering method.
In order to form the lubricant 7, a conventionally known method such as a dipping method and a spin coating method can be employed.
[0032]
In the manufacturing method of the present embodiment, the soft magnetic film 2 is formed by sputtering, and the film forming gas pressure when forming the soft magnetic film 2 is set to 2 Pa or more and 30 Pa or less. Formation can be suppressed, and generation of spike noise can be prevented. Therefore, noise characteristics such as SNR can be greatly improved.
Further, compared to a conventional magnetic recording medium provided with a hard magnetic film or an antiferromagnetic film, the number of films to be formed can be reduced and productivity can be increased.
Therefore, the noise characteristics can be improved without lowering the productivity.
[0033]
FIG. 7 shows an example of a magnetic recording / reproducing apparatus using the magnetic recording medium. The magnetic recording / reproducing apparatus shown here includes a magnetic recording medium 8 having the above configuration, a medium driving unit 9 for driving the magnetic recording medium 8 to rotate, a magnetic head 10 for recording / reproducing information on / from the magnetic recording medium 8, and a head driving unit. 11 and a recording / reproducing signal processing system 12.
The recording / reproducing signal processing system 12 can process input data and send a recording signal to the magnetic head 10, or can process a reproducing signal from the magnetic head 10 and output data.
As the magnetic head 10, a single-pole head for perpendicular recording can be exemplified.
As shown in FIG. 7 (b), a single magnetic pole head having a main magnetic pole 10a, an auxiliary magnetic pole 10b, and a coil 10d provided in a connecting portion 10c for connecting these, is preferably used. it can.
[0034]
According to the magnetic recording / reproducing apparatus, since the magnetic recording medium 8 having the above configuration is used, generation of spike noise can be prevented, and a high error rate can be secured.
[0035]
【Example】
Hereinafter, the effects of the present invention will be specifically described with reference to examples. However, the present invention is not limited to the embodiments described below.
(Example 1)
The cleaned glass substrate 1 (manufactured by OHARA, 2.5 inch (65 mm) in outer diameter) is housed in a chamber of a DC magnetron sputtering apparatus (C-3010, manufactured by Anelva), and the ultimate vacuum degree is 1 × 10 ^-5 The inside of the film forming chamber was evacuated until the pressure became Pa.
On this glass substrate 1, a soft magnetic film 2 (thickness: 200 nm) was formed by sputtering using a target made of 85Fe-15Al (85at% Fe-15at% Al) at room temperature. Ar was used as the film forming gas, and the film forming gas pressure was 7.5 Pa.
As a result of measurement by a vibration type magnetic property measuring device (VSM), it was confirmed that Bs · t of the soft magnetic film 2 was 300 T · nm.
[0036]
Next, the substrate 1 on which the soft magnetic film 2 is formed is heated to 300 ° C., and the orientation control film 3 (thickness) is formed on the soft magnetic film 2 by a sputtering method using a NiTa target at a deposition gas pressure of 0.5 Pa. 10 nm).
Next, the intermediate film 4 (thickness: 10 nm) was formed by a sputtering method using a target composed of 65Co-30Cr-5B (65at% Co-30at% Cr-5at% B).
Next, a perpendicular magnetic recording film 5 (thickness: 25 nm) was formed by a sputtering method using a 63Co-20Cr-17Pt (63 at% Co-20 at% Cr-17 at% Pt) target.
When forming the orientation control film 3, the intermediate film 4, and the perpendicular magnetic recording film 5, Ar was used as a film forming gas.
Next, a protective film 6 (thickness: 5 nm) was formed by a CVD method.
Next, a lubricating film 7 made of perfluoropolyether was formed by dipping to obtain a magnetic recording medium. (See Table 1)
[0037]
(Examples 2 to 4, Comparative Examples 1 to 3)
A magnetic recording medium was manufactured according to Example 1, except that the film forming gas pressure when forming the soft magnetic film 2 was changed. (See Table 1)
[0038]
The recording and reproducing characteristics of the magnetic recording media of these examples and comparative examples were evaluated. The evaluation of the recording / reproducing characteristics was performed using a read / write analyzer RWA1632 manufactured by GUZIK and a spin stand S1701MP.
In the evaluation of the recording and reproducing characteristics, the signal So-p was measured at a linear recording density of 50 kFCI using a single pole magnetic pole (single magnetic pole) in the writing section and a head using a GMR element in the reproducing section, and the noise N was measured. Was measured at a linear recording density of 600 kFCI. SNR was calculated using the following formula.
SNR = 20 × log (So-p / N)
Table 1 shows the test results.
[0039]
[Table 1]

[0040]
According to Table 1, spike noise was generated in the comparative example where the film forming gas pressure was less than 2 Pa, whereas no spike noise was generated in the example where the film forming gas pressure was 2 Pa or more and 30 Pa or less. Understand.
Further, it can be seen that in the examples in which the film forming gas pressure is 2 Pa or more and 30 Pa or less, an excellent SNR was obtained as compared with the comparative example in which the film forming gas pressure exceeded 30 Pa.
[0041]
(Examples 5 to 10)
A magnetic recording medium was manufactured according to Example 1, except that the composition of the soft magnetic film 2 was as shown in Table 2.
The recording and reproduction characteristics of the magnetic recording media of these examples were evaluated. Table 2 shows the test results.
[0042]
[Table 2]

[0043]
As shown in Table 2, the soft magnetic film 2 contains at least 70 at% of a magnetic element which is one or both of Co and Fe, and at least one of Zr, Hf, Nb, Ta, B, C, Al and Si. It can be seen that excellent noise characteristics were obtained with the magnetic recording medium provided with.
[0044]
(Examples 11 to 18)
A magnetic recording medium was manufactured in the same manner as in Example 1 except that a film forming gas shown in Table 3 was used when forming the soft magnetic film 2.
The recording and reproduction characteristics of the magnetic recording media of these examples were evaluated. Table 3 shows the test results.
In the table, 100Ar means 100 vol% Ar, and indicates that the film forming gas is Ar. Further, those in which two or more kinds of substance names are described as the film formation gas indicate that a mixed gas composed of these two or more kinds of substances is used as the film formation gas. For example, 90Ar-10O ₂ Are 90 vol% Ar and 10 vol% O ₂ Means a mixed gas.
[0045]
[Table 3]

[0046]
From Table 3, it can be seen that when the soft magnetic film 2 was formed, when the gas shown in the table was used as the film forming gas, generation of spike noise could be prevented.
[0047]
【The invention's effect】
As described above, in the method for manufacturing a magnetic recording medium of the present invention, a soft magnetic film is formed by a sputtering method, and a film forming gas pressure when forming the soft magnetic film is 2 Pa or more and 30 Pa or less. Therefore, formation of domain walls in the soft magnetic film can be suppressed, and generation of spike noise can be prevented. Therefore, noise characteristics such as SNR can be greatly improved.
Further, as compared with a conventional magnetic recording medium, the number of films formed can be suppressed, and productivity can be increased.
Therefore, the noise characteristics can be improved without lowering the productivity.
[Brief description of the drawings]
FIG. 1 is a partial sectional view showing a first embodiment of a magnetic recording medium according to the present invention.
FIG. 2 is a schematic diagram showing an MH curve.
FIG. 3 is a schematic diagram showing an MH curve.
FIG. 4 is a schematic configuration diagram showing a sputtering apparatus used for carrying out one embodiment of a method for manufacturing a magnetic recording medium of the present invention.
FIG. 5 is a diagram showing test results.
FIG. 6 is a diagram showing test results.
FIGS. 7A and 7B are schematic views showing an example of a magnetic recording / reproducing apparatus according to the present invention, wherein FIG. 7A shows the entire configuration, and FIG. 7B shows a magnetic head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Non-magnetic substrate, 2 ... Soft magnetic film, 3 ... Orientation control film, 5 ... Perpendicular magnetic recording film, 6 ... Protective film, 8 ... Magnetic recording medium, 9 ..Medium drive unit, 10 ... magnetic head, 10a ... main magnetic pole, 10b ... auxiliary pole, 10c ... connection unit, 10d ... coil, 11 ... head drive unit, 12 ... Recording / playback signal processing system

Claims (6)

A method for manufacturing a magnetic recording medium provided with a soft magnetic film, an orientation control film, a perpendicular magnetic recording film whose easy axis of magnetization is oriented mainly perpendicular to the substrate, and a protective film on a non-magnetic substrate. hand,
A method for manufacturing a magnetic recording medium, wherein the soft magnetic film is formed by a sputtering method, and a film forming gas pressure for forming the soft magnetic film is 2 Pa or more and 30 Pa or less. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein the soft magnetic film contains at least 70 at% of a magnetic element that is one or both of Co and Fe, and Zr, Hf, Nb, Ta, B, and C. A method for manufacturing a magnetic recording medium, comprising at least one of Al, Si and Al. 3. The method for manufacturing a magnetic recording medium according to claim 1, wherein at least one of Ne, Ar, Kr, and Xe is used as a film forming gas. 3. The method for manufacturing a magnetic recording medium according to claim 1, wherein at least one of O ₂ , N ₂ , and CO ₂ is added to at least one of Ne, Ar, Kr, and Xe as a film forming gas. What is claimed is: 1. A method for manufacturing a magnetic recording medium, comprising: A magnetic recording medium manufactured by the method for manufacturing a magnetic recording medium according to claim 1. 6. A magnetic recording / reproducing apparatus comprising: the magnetic recording medium according to claim 5; and a magnetic head for recording / reproducing information on / from the magnetic recording medium.

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