JP4561348B2 - Magnetic recording medium, magnetic recording apparatus, and method of manufacturing magnetic recording medium - Google Patents

Magnetic recording medium, magnetic recording apparatus, and method of manufacturing magnetic recording medium Download PDF

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JP4561348B2
JP4561348B2 JP2004366714A JP2004366714A JP4561348B2 JP 4561348 B2 JP4561348 B2 JP 4561348B2 JP 2004366714 A JP2004366714 A JP 2004366714A JP 2004366714 A JP2004366714 A JP 2004366714A JP 4561348 B2 JP4561348 B2 JP 4561348B2
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magnetic recording
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JP2006172662A (en
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司 井谷
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本発明は、記録面上を浮上する又は擦動する磁気ヘッドにより磁気記録の書込、読出がなされる磁気記録媒体に関し、とくに記録面の環境耐性及び耐磨耗性に優れかつ潤滑特性の劣化が少ない磁気記録媒体に関する。   The present invention relates to a magnetic recording medium in which magnetic recording is written and read by a magnetic head that floats or rubs on a recording surface, and in particular, the recording surface is excellent in environmental resistance and wear resistance, and has deteriorated lubrication characteristics. The present invention relates to a magnetic recording medium with a small amount.

今日、磁気ディスク装置、例えばハードディスクドライブ（ＨＤＤ）では、高速かつ高密度に記録するために、磁気記録媒体を高速回転させるとともに磁気ヘッドの浮上量を小さくする努力が続けられており、さらには記録面を磁気ヘッドが擦動する磁気記憶装置も検討されている。なお、本明細書において、記録面とは磁気ヘッドにより磁気記録層への磁気記録又は読出がなされる側の磁気記録媒体表面をいう。   Today, in a magnetic disk device such as a hard disk drive (HDD), in order to perform high-speed and high-density recording, efforts are made to rotate the magnetic recording medium at a high speed and reduce the flying height of the magnetic head. A magnetic storage device in which a magnetic head rubs the surface has also been studied. In the present specification, the recording surface refers to the surface of the magnetic recording medium on the side where magnetic recording or reading is performed on the magnetic recording layer by the magnetic head.

しかし、磁気記録媒体の磁気ヘッドの浮上量の減少や擦動は、磁気記録媒体の表面（記録面）への磁気ヘッドの衝突確率を高くする。高速回転時のこのような衝突は重大なクラッシュの引き金になる可能性がある。このため、記録面を、磁気ヘッドの衝突時の磨耗やクラッシュから保護することができる高い耐磨耗性と優れた潤滑特性を有する磁気記録媒体が求められている。   However, a decrease in the flying height or friction of the magnetic head of the magnetic recording medium increases the probability of the magnetic head colliding with the surface (recording surface) of the magnetic recording medium. Such a collision during high speed rotation can trigger a serious crash. For this reason, there is a need for a magnetic recording medium having high wear resistance and excellent lubrication characteristics that can protect the recording surface from wear and crash during collision of the magnetic head.

図７は、従来の磁気記録媒体と磁気ヘッドの関係を表す断面図である。図７を参照して、従来の磁気ディスク装置、例えばハードディスクドライブ（ＨＤＤ）に用いられる磁気記録媒体１０の記録面１０ａの保護は、磁気記録層４上に設けられた保護層２１と、その保護層２１上に塗布された潤滑剤８とでなされていた。保護層２１は、ダイヤモンドライクカーボン（以下「ＤＬＣ」という。）のような耐磨耗性を有する硬質材料から構成され、磁気記録層４を磁気ヘッド７の接触（より正確には磁気ヘッドのスライド面７ｄとの接触）による損傷から保護するとともに、磁気記録層４が雰囲気中の水分及び酸性化学物質により腐食されることを防止する。潤滑剤８は、ＰＦＰＥ（パーフルオロポリエーテル）のような流動性を有する潤滑材料からなり、磁気ヘッド７の接触時の摩擦を軽減する。   FIG. 7 is a cross-sectional view showing the relationship between a conventional magnetic recording medium and a magnetic head. Referring to FIG. 7, the recording surface 10a of a magnetic recording medium 10 used in a conventional magnetic disk device, for example, a hard disk drive (HDD) is protected by a protective layer 21 provided on the magnetic recording layer 4 and the protection thereof. It was made with the lubricant 8 applied on the layer 21. The protective layer 21 is made of a hard material having wear resistance such as diamond-like carbon (hereinafter referred to as “DLC”), and the magnetic recording layer 4 is brought into contact with the magnetic head 7 (more precisely, sliding of the magnetic head). The magnetic recording layer 4 is protected from being damaged by moisture and acidic chemicals in the atmosphere. The lubricant 8 is made of a lubricating material having fluidity such as PFPE (perfluoropolyether), and reduces friction when the magnetic head 7 contacts.

潤滑特性の劣化が少なく、耐磨耗性に優れた磁気記録媒体１０を提供するため、撥水性を有する中空カーボンナノチューブを潤滑剤として用いる技術が公開されている（特許文献１を参照）。図８は従来の改良された潤滑方法の説明図であり、カーボンナノチューブを分散させた潤滑剤を用いたときの磁気記録媒体と磁気ヘッドの状態を断面図により表している。   In order to provide the magnetic recording medium 10 with little deterioration of lubrication characteristics and excellent wear resistance, a technique using hollow carbon nanotubes having water repellency as a lubricant is disclosed (see Patent Document 1). FIG. 8 is an explanatory view of a conventional improved lubrication method, and shows a state of a magnetic recording medium and a magnetic head in a cross-sectional view when a lubricant in which carbon nanotubes are dispersed is used.

図８を参照して、潤滑剤８に分散されたカーボンナノチューブ２２は、保護層２１の表面にカーボンナノチューブ２２の側面を接して吸着し、厚さがほぼカーボンナノチューブ６の直径に等しい層を形成する。従って、磁気ヘッド７は保護層２１上に吸着されたカーボンナノチューブ２２に阻まれ、保護層２１への接触は回避される。このため、保護層２１の磨耗、損傷を防ぐことができる。   Referring to FIG. 8, carbon nanotubes 22 dispersed in lubricant 8 are adsorbed by contacting the side surfaces of carbon nanotubes 22 with the surface of protective layer 21 to form a layer whose thickness is approximately equal to the diameter of carbon nanotubes 6. To do. Accordingly, the magnetic head 7 is blocked by the carbon nanotubes 22 adsorbed on the protective layer 21, and contact with the protective layer 21 is avoided. For this reason, abrasion and damage of the protective layer 21 can be prevented.

一方、磁気ヘッド７がカーボンナノチューブ２２に衝突しても、カーボンナノチューブ２２は強靱で損傷を受けない。また、カーボンナノチューブ２２は転動して衝突の衝撃を逃がすので、高温にならない。このため、この磁気記録媒体１０は耐磨耗性に優れ、かつ潤滑剤８の劣化が少ない。さらに、潤滑剤８を用いず、カーボンナノチューブのみを保護層２１の表面に分散して潤滑層とする方法も開示されている。この方法では、磁気ヘッドと保護層２１の距離をカーボンナノチューブ２２の直径まで短くすることができる。
特開２００１−６７６４４号公報 On the other hand, even if the magnetic head 7 collides with the carbon nanotube 22, the carbon nanotube 22 is strong and not damaged. Further, since the carbon nanotubes 22 roll to release the impact of the collision, the carbon nanotubes 22 do not reach a high temperature. For this reason, the magnetic recording medium 10 is excellent in wear resistance and the lubricant 8 is less deteriorated. Furthermore, a method of dispersing only the carbon nanotubes on the surface of the protective layer 21 without using the lubricant 8 to form a lubricating layer is also disclosed. In this method, the distance between the magnetic head and the protective layer 21 can be reduced to the diameter of the carbon nanotube 22.
JP 2001-67644 A

上述した従来の磁気記録媒体１０では、流動性を有する潤滑剤８が硬質の保護層２１上に塗布されているため、磁気記録媒体１０の回転速度が大きくなると潤滑剤８が飛散して減少し（いわゆるスピンオフ）次第に記録面１０ａの潤滑特性が失わる。とくに、高速回転時に磁気ヘッド７と記録面１０ａとが接触した場合、接触面が瞬間的に高温になり潤滑剤８が変質し、潤滑特性が著しく低下してしまい、場合によってはヘッドクラッシュに至る場合もある。   In the conventional magnetic recording medium 10 described above, since the lubricant 8 having fluidity is applied on the hard protective layer 21, the lubricant 8 scatters and decreases as the rotational speed of the magnetic recording medium 10 increases. (So-called spin-off) Gradually, the lubricating properties of the recording surface 10a are lost. In particular, when the magnetic head 7 and the recording surface 10a come into contact with each other during high-speed rotation, the contact surface instantaneously becomes high temperature, the lubricant 8 is denatured, and the lubrication characteristics are remarkably deteriorated. In some cases.

また、磁気記録層４上に保護層２１を設けるために、磁気ヘッド７のスライド面７ｄと磁気記録層４間の距離（磁気的スペーシング）が磁気ヘッド７の浮上量より保護層２１の厚さだけ長くなり、記録密度の向上の障害となっている。この保護層２１を薄くすると、磁気記録層４の組成成分が保護層２１に被覆されていない部分を通って表面まで拡散して腐食生成物を形成し、この腐食生成物が磁気ヘッド７のスライド面７ｄに衝突するので、保護層２１をあまり薄くすることはできない。   Further, in order to provide the protective layer 21 on the magnetic recording layer 4, the distance (magnetic spacing) between the slide surface 7 d of the magnetic head 7 and the magnetic recording layer 4 is determined by the thickness of the protective layer 21 based on the flying height of the magnetic head 7. Therefore, it becomes longer and becomes an obstacle to improving the recording density. When the protective layer 21 is thinned, the composition component of the magnetic recording layer 4 diffuses to the surface through a portion that is not covered with the protective layer 21 to form a corrosion product, and this corrosion product slides on the magnetic head 7. Since it collides with the surface 7d, the protective layer 21 cannot be made too thin.

このように、保護層と潤滑剤とで磁気記録層を保護する従来の磁気記録媒体では、スピンオフ及び磁気ヘッドの接触により記録面の潤滑特性が劣化する。また、カーボンナノチューブを潤滑剤に分散させる方法では、磁気記録媒体１０の高速回転時のスピンオフを避けられず、潤滑特性の劣化を招く。また、潤滑剤８を用いず、カーボンナノチューブを保護層２１表面に分散して潤滑層を形成する方法では、カーボンナノチューブ２２の層がその直径程度と薄いため、雰囲気中の水分等が凝集して形成された水滴が容易に保護層２１表面に接触し、その下の磁気記録層４を腐食するおそれがある。このため、厚い保護層２１の配設が欠かせず、記録密度の向上が阻害されていた。   As described above, in the conventional magnetic recording medium in which the magnetic recording layer is protected by the protective layer and the lubricant, the lubrication characteristics of the recording surface deteriorate due to the spin-off and the contact of the magnetic head. Further, in the method of dispersing the carbon nanotubes in the lubricant, the spin-off at the time of high speed rotation of the magnetic recording medium 10 cannot be avoided, and the lubrication characteristics are deteriorated. Further, in the method of forming the lubricating layer by dispersing the carbon nanotubes on the surface of the protective layer 21 without using the lubricant 8, the carbon nanotube 22 layer is as thin as its diameter, so that moisture in the atmosphere aggregates. The formed water droplets may easily come into contact with the surface of the protective layer 21 and corrode the magnetic recording layer 4 therebelow. For this reason, the provision of the thick protective layer 21 is indispensable, and the improvement of the recording density is hindered.

本発明は、磁気記録層と磁気ヘッド間の距離が小さく、かつ記録面の潤滑特性の劣化及び磁気記録層の腐食が生じ難い磁気記録媒体、及びその磁気記録媒体を用いた磁気記録装置を提供することを目的としている。   The present invention provides a magnetic recording medium in which the distance between the magnetic recording layer and the magnetic head is small, the lubrication characteristics of the recording surface are hardly deteriorated, and the magnetic recording layer is hardly corroded, and a magnetic recording apparatus using the magnetic recording medium The purpose is to do.

上記課題を解決するために、本発明の第一の構成に係る磁気記録媒体は、その記録面にカーボンナノチューブが根元を固定されて立設されたカーボンナノチューブ層を有する。
In order to solve the above-described problems, the magnetic recording medium according to the first configuration of the present invention has a carbon nanotube layer in which carbon nanotubes are erected with their roots fixed on the recording surface.

カーボンナノチューブは、単層（ＳＷＮＴ）又は多層（ＷＭＮＴ）の円筒構造からなる直径がサブｎｍ〜数十ｎｍ程度の針状物質であり、可撓性を有する。このため、磁気ヘッドが記録面に接近して磁気ヘッドのスライド面がカーボンナノチューブの先端に接触すると、カーボンナノチューブは撓んで磁気ヘッドを受け止めるように作用するので、記録面に垂直方向の衝撃が緩和される。また、磁気ヘッドの衝突時にスライド面と記録面との間に作用するずれ応力は、接触したカーボンナノチューブがスライド面の進行方向にさらに撓むことで緩和される。このように、磁気ヘッドの記録面への衝突の衝撃が緩和されるから、記録面、例えば磁気記録層の表面の損傷を有効に防ぐことができる。   The carbon nanotube is a needle-like substance having a diameter of sub-nm to several tens of nanometers having a single-layer (SWNT) or multi-layer (WMNT) cylindrical structure, and has flexibility. Therefore, when the magnetic head approaches the recording surface and the slide surface of the magnetic head comes into contact with the tip of the carbon nanotube, the carbon nanotube bends and acts to receive the magnetic head, so that the impact in the direction perpendicular to the recording surface is reduced. Is done. Further, the deviation stress acting between the slide surface and the recording surface at the time of the collision of the magnetic head is alleviated by further bending the contacted carbon nanotubes in the traveling direction of the slide surface. Thus, since the impact of the collision with the recording surface of the magnetic head is alleviated, it is possible to effectively prevent damage to the recording surface, for example, the surface of the magnetic recording layer.

さらに、磁気ヘッド衝突時の衝撃が大きい場合は、カーボンナノチューブは根元近くから倒伏し略全長に渡ってその側面を記録面に接触して延在するようになる。磁気ヘッドのスライド面は、この倒伏したカーボンナノチューブの層の上を滑走する。カーボンナノチューブは耐磨耗性に優れるから、倒伏したカーボンナノチューブの層は良好な潤滑層として作用する。またカーボンナノチューブは強靱で、かかる磁気ヘッドの衝突、滑走によってカーボンナノチューブが破損することは少ない。なお、多少の本数のカーボンナノチューブが破損しても、カーボンナノチューブの立設密度は高いから、記録面の耐磨耗性及び潤滑特性が問題とされる程に劣化することは少ない。このように、衝突の衝撃が大きい場合でも、記録面と磁気ヘッドの間に必ずカーボンナノチューブが介在して磁気ヘッドが記録面に直接接触しないから、磁気ヘッド及び磁気記録媒体の損傷が防止される。   Furthermore, when the impact at the time of collision of the magnetic head is large, the carbon nanotubes fall from near the base and extend with their side surfaces in contact with the recording surface over substantially the entire length. The sliding surface of the magnetic head slides over this lying carbon nanotube layer. Since carbon nanotubes are excellent in wear resistance, the lying carbon nanotube layer acts as a good lubricating layer. In addition, carbon nanotubes are strong, and the carbon nanotubes are rarely damaged by the collision and sliding of the magnetic head. Even if a certain number of carbon nanotubes are damaged, the standing density of the carbon nanotubes is high, so that the wear resistance and lubrication characteristics of the recording surface are rarely deteriorated. As described above, even when the impact of the collision is large, the carbon head is always interposed between the recording surface and the magnetic head so that the magnetic head does not directly contact the recording surface, thereby preventing damage to the magnetic head and the magnetic recording medium. .

また、上記本発明の第一の構成では、流動性を有する潤滑剤を必要としないので、潤滑剤の劣化又は減少による潤滑特性の劣化を生ずることがない。このように潤滑剤を使用しない場合には、カーボンナノチューブの表面が撥水性であること、具体的には水との接触角が９０度を超える撥水性処理がされている必要がある。これにより、雰囲気中の水分が凝集して水滴が形成されても、大きな表面張力が働いて、立設するカーボンナノチューブの先端に水滴が球状に保持され、水滴が記録面に接することが阻止される。従って、保護層がなくても記録面から進行する腐食を防止することができる。このため、保護層を設けず、磁気記録層を直接記録面として表出することができる。これにより、磁気ヘッドと記録面との距離を、保護層を設けた場合に較べて小さくすることができ、高い記録密度を実現することができる。勿論、必要ならば保護層を設けてもよい。   Further, in the first configuration of the present invention, since a lubricant having fluidity is not required, there is no occurrence of deterioration of lubrication characteristics due to deterioration or reduction of the lubricant. When the lubricant is not used in this way, the surface of the carbon nanotubes must be water repellent, specifically, a water repellent treatment in which the contact angle with water exceeds 90 degrees is required. As a result, even if moisture in the atmosphere aggregates and water droplets are formed, a large surface tension is applied and the water droplets are held in a spherical shape at the tips of the standing carbon nanotubes, and the water droplets are prevented from coming into contact with the recording surface. The Therefore, corrosion that proceeds from the recording surface can be prevented without a protective layer. For this reason, a magnetic recording layer can be directly exposed as a recording surface without providing a protective layer. Thereby, the distance between the magnetic head and the recording surface can be reduced as compared with the case where the protective layer is provided, and a high recording density can be realized. Of course, a protective layer may be provided if necessary.

本発明のカーボンナノチューブは、その根元を記録面に固定して立設される。固定することで、磁気ヘッドが衝突してもカーボンナノチューブが衝突位置から排除されることを防ぐことができる。このため、カーボンナノチューブに基づく耐磨耗性を長く維持することができる。カーボンナノチューブを立設する角度は、記録面に垂直方向が好ましいが、これに限らず斜めに立設されてもよい。   The carbon nanotube of the present invention is erected with its root fixed to the recording surface. By fixing, it is possible to prevent the carbon nanotube from being excluded from the collision position even if the magnetic head collides. For this reason, the wear resistance based on the carbon nanotube can be maintained for a long time. The angle at which the carbon nanotubes are erected is preferably perpendicular to the recording surface, but is not limited thereto, and may be erected obliquely.

カーボンナノチューブの外径は、可撓性の観点から細いことが好ましい。この点から、カーボンナノチューブの直径は２０ｎｍ以下が好ましく、とくに単層構造のナノチューブ（ＳＷＮＴ）は直径がサブｎｍ〜５ｎｍであるので適している。   The outer diameter of the carbon nanotube is preferably thin from the viewpoint of flexibility. From this point, the diameter of the carbon nanotube is preferably 20 nm or less, and the single-walled nanotube (SWNT) is particularly suitable because the diameter is sub nm to 5 nm.

カーボンナノチューブの長さ及び立設密度は、水分の進入の阻止、カーボンナノチューブの可撓性、及び磁気ヘッドの浮上量を考慮して適切に定められる。即ち、雰囲気から凝集してカーボンナノチューブの先端に付着した水滴が記録面に到達するのを防ぐには、長くかつ高密度の方がよい。なお、このとき考慮すべき水滴は、記録ビットサイズ程度以上の大きさのものである。カーボンナノチューブの可撓性を高めて磁気ヘッドの磨耗、損傷を防ぐには、長くかつ低密度の方がよい。磁気ヘッドの浮上量を小さくするには、短くかつ低密度の方がよい。これらを考慮すると、例えば、数μｍ幅の記録ビットサイズ、数十ｎｍの浮遊量、カーボンナノチューブが直径１０〜２０ｎｍの多層構造のナノチューブ（ＭＷＮＴ）とするとき、カーボンナノチューブの長さ及び密度はそれぞれ７００ｎｍ以下、４×１０12本／ｍ2 以上とすることが好ましい。 The length and standing density of the carbon nanotubes are appropriately determined in consideration of the prevention of moisture entry, the flexibility of the carbon nanotubes, and the flying height of the magnetic head. That is, in order to prevent water droplets aggregated from the atmosphere and adhering to the tip of the carbon nanotube from reaching the recording surface, a longer and higher density is better. Note that the water droplets to be taken into consideration at this time are those having a recording bit size or more. In order to increase the flexibility of the carbon nanotube and prevent the magnetic head from being worn or damaged, a longer and lower density is better. In order to reduce the flying height of the magnetic head, shorter and lower density are better. Considering these, for example, when a recording bit size of several μm width, a floating amount of several tens of nm, and a carbon nanotube having a multi-layered nanotube (MWNT) having a diameter of 10 to 20 nm, the length and density of the carbon nanotube are respectively It is preferably 700 nm or less and 4 × 10 12 pieces / m 2 or more.

本発明の第二の構成では、上記本発明の第一の構成のカーボンナノチューブが立設する記録面に潤滑剤を塗布する。即ち、記録面に塗布された潤滑剤は、立設するカーボンナノチューブの間を埋める層を形成する。本構成では、潤滑剤の塗布により、記録面の潤滑特性をさらに優れたものとすることができる。なお、本構成のカーボンナノチューブは、潤滑剤によりカーボンナノチューブの表面がコーテングされて撥水性となるから、カーボンナノチューブ自体は撥水処理がされていなくてもよい。   In the second configuration of the present invention, a lubricant is applied to the recording surface on which the carbon nanotubes of the first configuration of the present invention are erected. That is, the lubricant applied to the recording surface forms a layer that fills the space between the standing carbon nanotubes. In this configuration, the lubrication characteristics of the recording surface can be further improved by applying the lubricant. In addition, since the surface of the carbon nanotube is coated with a lubricant to be water repellent, the carbon nanotube itself may not be subjected to water repellent treatment.

本構成では、記録面に塗布された潤滑剤は、記録面に高密度に立設されたカーボンナノチューブの根元を浸すように記録面上に広がる。このため、磁気記録媒体、すなわち記録面が高速回転しても、潤滑剤は高密度のカーボンナノチューブに遮られて飛散しないので、潤滑剤のスピンオフが抑制される。従って、記録面の潤滑特性の劣化が少ない。   In this configuration, the lubricant applied to the recording surface spreads on the recording surface so as to immerse the roots of the carbon nanotubes erected at high density on the recording surface. For this reason, even if the magnetic recording medium, that is, the recording surface rotates at high speed, the lubricant is blocked by the high-density carbon nanotubes and is not scattered, so that the spin-off of the lubricant is suppressed. Therefore, there is little deterioration in the lubrication characteristics of the recording surface.

本第二の構成のカーボンナノチューブの立設密度は、潤滑剤の流動を抑制する観点から高いことが望ましい。通常用いられる潤滑剤であるＰＦＰＥ（パーフルオロポリエーテル）系潤滑剤を、２０，０００ｒｐｍで回転する直径１０ｃｍの磁気記録媒体に）用いたとき、カーボンナノチューブの密度が４×１０12本／ｍ2 以上あれば有効にスピンオフを抑制することができる。 It is desirable that the standing density of the carbon nanotube of the second configuration is high from the viewpoint of suppressing the flow of the lubricant. When a PFPE (perfluoropolyether) lubricant, which is a commonly used lubricant, is used (for a magnetic recording medium having a diameter of 10 cm rotating at 20,000 rpm), the density of the carbon nanotubes is 4 × 10 12 / m 2. If it is more, spin-off can be effectively suppressed.

上述した第一及び第二の構成の磁気記録媒体を、磁気ヘッドが記録面に押圧され擦動する擦動型の磁気記録装置に用いることができる。磁気ヘッドを記録面に押圧すると、磁気ヘッドと記録面との間に倒伏したカーボンナノチューブが介在し、磁気ヘッドはそのカーボンナノチューブの層の上を擦動する。カーボンナノチューブは硬質で潤滑性及び耐磨耗性に優れるから、この倒伏したカーボンナノチューブの層は優れた潤滑層及び保護層として機能する。この場合、磁気ヘッドと記録面との距離はカーボンナノチューブの直径程度と短く、記録密度を容易に高くすることができる。   The magnetic recording media having the first and second configurations described above can be used in a sliding type magnetic recording apparatus in which a magnetic head is pressed against a recording surface and rubbed. When the magnetic head is pressed against the recording surface, the lying carbon nanotubes are interposed between the magnetic head and the recording surface, and the magnetic head rubs on the carbon nanotube layer. Since the carbon nanotubes are hard and excellent in lubricity and wear resistance, the layer of carbon nanotubes that has fallen down functions as an excellent lubricating layer and protective layer. In this case, the distance between the magnetic head and the recording surface is as short as the diameter of the carbon nanotube, and the recording density can be easily increased.

上述したように、本発明の磁気記録媒体は、磁気ヘッドの衝突を緩和しかつ水分の進入を阻止するので、保護層を薄く又は除去することができるので磁気ヘッドと磁気記録層間の距離が短く、高密度に記録することができる。   As described above, the magnetic recording medium of the present invention alleviates the collision of the magnetic head and prevents moisture from entering, so that the protective layer can be thinned or removed, so that the distance between the magnetic head and the magnetic recording layer is short. High density recording.

また、潤滑剤を使用する構成では、潤滑剤のスピンオフが抑制されるから、潤滑特性の劣化が少ない磁気記録媒体を提供することができる。   Further, in the configuration using the lubricant, since the spin-off of the lubricant is suppressed, it is possible to provide a magnetic recording medium with little deterioration of the lubrication characteristics.

本発明の第一実施形態は、保護層を設けない磁気記録媒体に関する。図１は本発明の第一実施形態断面図であり、磁気記録媒体とその記録面上を浮上する磁気ヘッドを表している。図２は本発明の第一実施形態の部分拡大断面図であり、表面に水滴が付着した記録媒体を表している。   The first embodiment of the present invention relates to a magnetic recording medium without a protective layer. FIG. 1 is a sectional view of a first embodiment of the present invention, showing a magnetic recording medium and a magnetic head flying above the recording surface. FIG. 2 is a partially enlarged cross-sectional view of the first embodiment of the present invention, showing a recording medium having water droplets attached to the surface.

本発明の第一実施形態に係る磁気記録媒体は、浮上型のハードディスク磁気装置に用いられる磁気ディスクである。この磁気記録媒体は、図１及び図２を参照して、ガラス基板１上に、厚さ５μｍのＮｉ−Ｐ層２、厚さ１５ｎｍのＣｒ系下地層３、厚さ３０ｎｍのＣｏ系磁気記録層４がこの順序でスパッタにより積層され、その磁気記録層４表面（本実施形態では記録面１０ａとなる。）にカーボンナノチューブ６が記録面１０ａにほぼ垂直に立設されたカーボンナノチューブ層５が形成されている。   The magnetic recording medium according to the first embodiment of the present invention is a magnetic disk used in a floating type hard disk magnetic device. 1 and FIG. 2, this magnetic recording medium includes a Ni-P layer 2 having a thickness of 5 μm, a Cr-based underlayer 3 having a thickness of 15 nm, and a Co-based magnetic recording having a thickness of 30 nm on a glass substrate 1. The layers 4 are laminated in this order by sputtering, and a carbon nanotube layer 5 is formed on the surface of the magnetic recording layer 4 (which becomes the recording surface 10a in the present embodiment) with the carbon nanotubes 6 standing substantially perpendicular to the recording surface 10a. Is formed.

なお、カーボンナノチューブ６と記録面１０ａとがなす角度は、磁気ヘッド７をカーボンナノチューブ６が撓んで受け止めることができる程度の角度があれば足りる。また、その角度も全てのカーボンナノチューブ６が同一である必要はなく、全体としてある方向、例えば垂直方向に分布していればよい。さらに、カーボンナノチューブ６が毛髪状に絡み合うものでもよい。   The angle formed between the carbon nanotube 6 and the recording surface 10a only needs to be an angle that allows the carbon nanotube 6 to bend and receive the magnetic head 7. Also, the carbon nanotubes 6 do not have to have the same angle as long as they are distributed in a certain direction, for example, the vertical direction. Further, the carbon nanotubes 6 may be entangled in a hair shape.

かかるカーボンナノチューブ６は、例えば周知のＣＶＤ法を用いて成長させることができる。二瓶瑞久等は、表面化学 ｖｏｌ．２５，Ｎｏ．６，ｐｐ３２６−３３１，２００４に、触媒を含む成長面上に多層構造のカーボンナノチューブ（ＭＷＮＴ）を立設するように成長させるＣＶＤ技術を公開している。また、Ｙｏｉｃｈｉ Ｍｕｒａｋａｍｉ等は、Ｃｈｅｍｉｃａｌ Ｐｈｙｓｉｃｓ Ｌｅｔｔｅｒｓ ３８５ （２００４） ２９８−３０３に、Ｃｏ−Ｍｏ触媒を含む成長面上に立設する単層構造のカーボンナノチューブ（ＳＷＮＴ）を成長するＣＶＤ技術を公開している。本実施形態のカーボンナノチューブ６はこのようなＣＶＤ法を用いて成長することができる。勿論、立設するカーボンナノチューブ６を形成できる他の方法を用いることもできる。   Such carbon nanotubes 6 can be grown using, for example, a well-known CVD method. Mizuhisa Nibe et al., Surface Chemistry vol. 25, no. 6, pp 326-331, 2004 discloses a CVD technique for growing a carbon nanotube (MWNT) having a multi-layer structure on a growth surface including a catalyst. In addition, Yoichi Murakami et al., In Chemical Physics Letters 385 (2004) 298-303, disclosed a CVD technique for growing a single-walled carbon nanotube (SWNT) standing on a growth surface containing a Co-Mo catalyst. Yes. The carbon nanotube 6 of this embodiment can be grown using such a CVD method. Of course, other methods capable of forming the standing carbon nanotubes 6 can also be used.

本第一実施形態のカーボンナノチューブ６は、チャンバ内に外部バイアス電圧を印加することができる電極を備えたプラズマＣＶＤ装置（図示せず）を用い、以下の工程を経て形成された。先ず、表面に磁気記録層４が形成された状態の磁気記録媒体１０を、記録面１０ａを上方に向けて電極上に載置し、３５０℃に加熱し保持する。次いで、チャンバ内にＣＶＤガスを導入した後、プラズマを励起し、電極に４００Ｖの負電圧のバイアス電圧を印加しつつ、磁気記録媒体１０の記録面１０ａにカーボンナノチューブ６を成長した。ＣＶＤガスとして流量１０ｓｃｃｍのメタノールと流量１００ｓｃｃｍの水素ガスを混合してチャンバ内に流入した。チャンバ内の圧力は２５０Ｐａであり、プラズマは２．４ＧＨｚのマイクロ波で励起した。この装置では、チャンバ内の電極には負のバイアス電圧が印加されているため、電極表面にほぼ垂直に電気力線が発生する。この状態で多層構造のカーボンナノチューブ６（ＭＷＮＴ）が、ほぼ電極表面に垂直に、即ち記録面１０ａに垂直に成長した。   The carbon nanotube 6 of the first embodiment was formed through the following steps using a plasma CVD apparatus (not shown) provided with an electrode capable of applying an external bias voltage in the chamber. First, the magnetic recording medium 10 having the magnetic recording layer 4 formed on the surface is placed on the electrode with the recording surface 10a facing upward, and heated to 350 ° C. and held. Next, after introducing a CVD gas into the chamber, plasma was excited, and carbon nanotubes 6 were grown on the recording surface 10 a of the magnetic recording medium 10 while applying a negative bias voltage of 400 V to the electrodes. As a CVD gas, methanol having a flow rate of 10 sccm and hydrogen gas having a flow rate of 100 sccm were mixed and flowed into the chamber. The pressure in the chamber was 250 Pa, and the plasma was excited with 2.4 GHz microwave. In this apparatus, since a negative bias voltage is applied to the electrodes in the chamber, electric lines of force are generated substantially perpendicular to the electrode surfaces. In this state, the multi-layered carbon nanotube 6 (MWNT) grew almost perpendicular to the electrode surface, that is, perpendicular to the recording surface 10a.

ＣＶＤ法を用いたカーボンナノチューブ６の成長には、よく知られているように成長面に触媒が存在する必要がある。本第一実施形態では、記録面１０ａとして表出する面がＣｏを含む磁気記録層の表面なので、成長面となる記録面１０ａにはＣｏが分散して存在する。この記録面１０ａに分散するＣｏが触媒として作用するので、容易にカーボンナノチューブ６が立設するように成長する。   As is well known, the growth of the carbon nanotubes 6 using the CVD method requires the presence of a catalyst on the growth surface. In the first embodiment, since the surface exposed as the recording surface 10a is the surface of the magnetic recording layer containing Co, Co is present in a dispersed manner on the recording surface 10a serving as the growth surface. Since Co dispersed on the recording surface 10a acts as a catalyst, the carbon nanotubes 6 grow easily so as to stand upright.

上述したバイアス電圧を印加したＣＶＤ法により成長したカーボンナノチューブ６は、直径が１０〜２０ｎｍ、長さが１００ｎｍ、立設密度が１×１０14本／ｍ2 であった。 The carbon nanotubes 6 grown by the above-described CVD method applying the bias voltage had a diameter of 10 to 20 nm, a length of 100 nm, and a standing density of 1 × 10 14 / m 2 .

次いで、カーボンナノチューブ６の表面を撥水処理した。撥水処理は、少量のＰＦＰＥ系の潤滑剤を記録面１０ａに塗布し、カーボンナノチューブ６表面に潤滑剤をコートした。また、既述の特許文献１にあるように、カーボンナノチューブ成長後に、メタン等の疎水性官能基を含むガスのプラズマに暴露することで行なうこともできる。これらの撥水処理により、カーボンナノチューブ６に水との接触角が９０°を超える疎水性を付与することができる。   Next, the surface of the carbon nanotube 6 was subjected to water repellent treatment. In the water repellent treatment, a small amount of PFPE-based lubricant was applied to the recording surface 10a, and the surface of the carbon nanotube 6 was coated with the lubricant. Further, as described in Patent Document 1 described above, after carbon nanotube growth, it can be performed by exposing to plasma of a gas containing a hydrophobic functional group such as methane. By these water repellent treatments, the carbon nanotubes 6 can be given hydrophobicity with a contact angle with water exceeding 90 °.

このように、カーボンナノチューブ層５を構成するカーボンナノチューブ６を撥水処理すると、雰囲気から凝集した水がカーボンナノチューブ層５表面に落下しても、図２を参照して、水は表面張力により球形の水滴１１になってカーボンナノチューブ６の先端に保持され、記録面１０ａ（即ち磁気記録層４の表面）まで到達しない。このため、磁気記録層４が雰囲気に表出していても磁気記録層４の腐食は阻止される。このように、カーボンナノチューブ６を撥水性にすると、磁気記録層４を被覆する保護層を設ける必要はないか、あるいは後述する第三実施形態のように極めて薄い保護層とすることができる。   In this way, when the carbon nanotubes 6 constituting the carbon nanotube layer 5 are subjected to water repellent treatment, even if water aggregated from the atmosphere falls on the surface of the carbon nanotube layer 5, the water is spherical due to the surface tension as shown in FIG. The water droplet 11 is held at the tip of the carbon nanotube 6 and does not reach the recording surface 10a (that is, the surface of the magnetic recording layer 4). For this reason, even if the magnetic recording layer 4 is exposed to the atmosphere, corrosion of the magnetic recording layer 4 is prevented. Thus, when the carbon nanotubes 6 are made water-repellent, it is not necessary to provide a protective layer that covers the magnetic recording layer 4, or an extremely thin protective layer can be formed as in the third embodiment described later.

次に、本発明の第一実施形態の磁気記録媒体１０を備えた磁気記録装置の動作を説明する。図３は本発明の第一実施形態の動作説明用断面図（その１）であり、図１の部分拡大図であって記録・書込動作時のカーボンナノチューブの状態を表している。図４は本発明の第一実施形態の動作説明用断面図（その２）であり、磁気ヘッドが記録面へ衝突した状態を表している。   Next, the operation of the magnetic recording apparatus including the magnetic recording medium 10 according to the first embodiment of the present invention will be described. FIG. 3 is a sectional view (No. 1) for explaining the operation of the first embodiment of the present invention, and is a partially enlarged view of FIG. 1, showing the state of the carbon nanotubes during the recording / writing operation. FIG. 4 is a cross-sectional view (part 2) for explaining the operation of the first embodiment of the present invention, showing a state where the magnetic head has collided with the recording surface.

正常な書込・読出状態では、図３を参照して、磁気ヘッド７は記録面１０ａから１０ｎｍ〜数十ｎｍ浮上して飛行する。なお、図１を参照して、磁気ヘッド７及び磁気記録媒体１０は相対的にそれぞれ逆方向の進行方向７ｃ、１０ｃに移動している。再び図３を参照して、カーボンナノチューブ６の長さは１００ｎｍと磁気ヘッド７の浮上量より長いので、磁気ヘッド７のスライド面７ｄにカーボンナノチューブ６が接触し、接触したカーボンナノチューブ６ａは磁気ヘッド７の進行方向へ反るように撓む。即ち、磁気ヘッド７は撓んだカーボンナノチューブ６ａにより支持される。このとき、カーボンナノチューブ６は、スライド面７ｄに接触すると撓んで進行方向７ｃの衝撃を緩和する。また、上下の衝撃は、カーボンナノチューブ６ａの撓みにより吸収される。従って、本実施形態の磁気記録媒体は、衝撃の吸収力に優れている。なお、磁気ヘッド７の後端７ｂが通過した記録面１０ａでは、撓んでいたカーボンナノチューブ６ａが再び立設してもとの状態に戻る。   In a normal writing / reading state, referring to FIG. 3, the magnetic head 7 flies 10 nm to several tens of nm from the recording surface 10a. Referring to FIG. 1, the magnetic head 7 and the magnetic recording medium 10 are relatively moved in the reverse traveling directions 7c and 10c, respectively. Referring again to FIG. 3, since the length of the carbon nanotube 6 is 100 nm, which is longer than the flying height of the magnetic head 7, the carbon nanotube 6 contacts the slide surface 7d of the magnetic head 7, and the contacted carbon nanotube 6a is the magnetic head. 7 to bend in the direction of travel. That is, the magnetic head 7 is supported by the bent carbon nanotube 6a. At this time, the carbon nanotubes 6 bend when they come into contact with the slide surface 7d, and relieve the impact in the traveling direction 7c. The upper and lower impacts are absorbed by the bending of the carbon nanotubes 6a. Therefore, the magnetic recording medium of this embodiment is excellent in shock absorption. Note that, on the recording surface 10a through which the rear end 7b of the magnetic head 7 has passed, the bent carbon nanotube 6a returns to its original state even if it is erected again.

磁気ヘッド７が記録面１０ａへ衝突するほどの大きな力が加わった場合、図４を参照して、磁気ヘッド７直下のカーボンナノチューブ６ａは、スライド面７ｄに押圧されて完全に倒伏し、ほぼ全長が記録面１０ａに接して延在する。その結果、磁気ヘッド７と記録面１０ａとの間に倒伏したカーボンナノチューブ６ａが挟まれ、このカーボンナノチューブ６ａ上を磁気ヘッド７が滑走する。従って、本実施形態の磁気記録媒体１０は、磁気ヘッド７と記録面１０ａとが直接衝突することがなく、保護層がなくても優れた耐衝撃性、耐磨耗性を保持できる。   When a force large enough to cause the magnetic head 7 to collide with the recording surface 10a is applied, referring to FIG. 4, the carbon nanotubes 6a immediately below the magnetic head 7 are pressed down by the slide surface 7d and completely fall down, so that almost the entire length is reached. Extends in contact with the recording surface 10a. As a result, the lying carbon nanotube 6a is sandwiched between the magnetic head 7 and the recording surface 10a, and the magnetic head 7 slides on the carbon nanotube 6a. Therefore, the magnetic recording medium 10 of this embodiment does not directly collide with the magnetic head 7 and the recording surface 10a, and can maintain excellent impact resistance and wear resistance even without a protective layer.

上述した第一実施形態の磁気記録媒体１０を、擦動型の磁気ヘッドに適用することもできる。このとき、磁気ヘッド７は記録面１０ａに押圧され、図４を参照して、磁気ヘッド７と記録面１０ａとの間に倒伏したカーボンナノチューブ６ａを挟み、磁気ヘッド７はこのカーボンナノチューブ６ａ上を擦動する。これにより、磁気ヘッド７と磁気記録層４との距離を、カーボンナノチューブ６ａの直径程度まで小さくすることができる。   The magnetic recording medium 10 of the first embodiment described above can also be applied to a sliding type magnetic head. At this time, the magnetic head 7 is pressed against the recording surface 10a, and referring to FIG. 4, the lying carbon nanotube 6a is sandwiched between the magnetic head 7 and the recording surface 10a, and the magnetic head 7 moves over the carbon nanotube 6a. Rub. Thereby, the distance between the magnetic head 7 and the magnetic recording layer 4 can be reduced to about the diameter of the carbon nanotube 6a.

本発明の第二実施形態は、カーボンナノチューブが立設された記録面上に潤滑剤からなる潤滑層を形成した記録媒体に関する。図５は本発明の第二実施形態断面図であり、磁気記録媒体の表面の構造を表している。   The second embodiment of the present invention relates to a recording medium in which a lubricating layer made of a lubricant is formed on a recording surface on which carbon nanotubes are erected. FIG. 5 is a sectional view of the second embodiment of the present invention, showing the structure of the surface of the magnetic recording medium.

本第二実施形態では、図５を参照して、磁気記録媒体１０の記録面１０ａに、カーボンナノチューブ６が立設され、カーボンナノチューブ層５が形成されている。このカーボンナノチューブ６の成長前の磁気記録媒体１０の構造、及びカーボンナノチューブ６の成長方法は第一実施形態と同様である。次いで、ｄｉｐ法（浸漬法）により、記録面１０ａ上にＰＦＰＥ系の潤滑剤８を塗布する。この潤滑剤８はカーボンナノチューブ６の根元、即ち記録面１０ａ上まで沈降し記録面１０ａを被覆する潤滑剤８の層を形成する。次いで、窒素中で紫外線を照射して、カーボンナノチューブ６と潤滑剤８との付着性を高める。本第二実施形態の磁気記録媒体１０は潤滑剤８があるため第一実施形態のものより潤滑特性が優れている。なお、本実施形態では潤滑剤８が疎水性を有するからカーボンナノチューブ６の撥水化処理を省略することもできる。   In the second embodiment, referring to FIG. 5, carbon nanotubes 6 are erected on the recording surface 10 a of the magnetic recording medium 10 to form the carbon nanotube layer 5. The structure of the magnetic recording medium 10 before the growth of the carbon nanotubes 6 and the growth method of the carbon nanotubes 6 are the same as in the first embodiment. Next, a PFPE-based lubricant 8 is applied on the recording surface 10a by a dip method (dipping method). The lubricant 8 settles down to the base of the carbon nanotube 6, that is, the recording surface 10a, and forms a layer of the lubricant 8 that covers the recording surface 10a. Next, ultraviolet rays are irradiated in nitrogen to enhance the adhesion between the carbon nanotubes 6 and the lubricant 8. Since the magnetic recording medium 10 of the second embodiment has the lubricant 8, the lubricating characteristics are superior to those of the first embodiment. In this embodiment, since the lubricant 8 has hydrophobicity, the water repellency treatment of the carbon nanotubes 6 can be omitted.

本第二実施形態の磁気記録媒体１０のスピンオフ耐性を評価した。第二実施形態の磁気記録媒体１０を２０，０００ｒｐｍで３０分間回転を継続したのち、回転前後の潤滑剤８の量の変化を観測した。潤滑剤８の量は、磁気記録媒体１０の記録面１０ａの反射赤外線吸収スペクトルのうちＣ−Ｆ結合に基づく吸収ピーク（１３００ｃｍ-1）の強度により評価した。その結果、回転前後で潤滑剤８の変化は観測されなかった。この結果は、本第二実施形態の磁気記録媒体１０が、潤滑剤８のスピンオフによる劣化が極めて小さいことを示している。 The spin-off resistance of the magnetic recording medium 10 of the second embodiment was evaluated. After the magnetic recording medium 10 of the second embodiment was continuously rotated at 20,000 rpm for 30 minutes, a change in the amount of the lubricant 8 before and after the rotation was observed. The amount of the lubricant 8 was evaluated by the intensity of the absorption peak (1300 cm −1 ) based on the C—F bond in the reflected infrared absorption spectrum of the recording surface 10 a of the magnetic recording medium 10. As a result, no change in the lubricant 8 was observed before and after the rotation. This result indicates that the magnetic recording medium 10 of the second embodiment is extremely small in deterioration due to the spin-off of the lubricant 8.

さらに、本発明に係る磁気記録媒体１０の耐湿性試験を行ない、従来の磁気記録媒体と比較した。本発明の第一及び第二実施形態の磁気記録媒体１０を、温度６５℃、湿度８０％の環境に２４時間放置した。その後、室温にて希硝酸を磁気記録媒体１０に滴下し、１時間放置したのち滴下した希硝酸に含まれる元素を定量分析した。定量分析には、誘導プラズマ質量分析計（ＩＰＣ−ＭＳ）を用いた。その結果、磁気記録層４の主成分であるＣｏの溶出量は両実施形態とも２．５μｇ／ｍ2 であった。この本発明の実施形態に係る磁気記録媒体１０からのＣｏの溶出量は、ダイヤモンド状カーボン保護層２１及び潤滑剤の層を磁気記録層４上に設けた従来の磁気記録媒体の溶出量と同じであった。このように、本発明に係る磁気記録媒体１０は、保護層２１がなくても保護層がある従来の磁気記録媒体と同程度の耐腐食性を有している。 Further, a moisture resistance test of the magnetic recording medium 10 according to the present invention was performed and compared with a conventional magnetic recording medium. The magnetic recording medium 10 of the first and second embodiments of the present invention was left in an environment of a temperature of 65 ° C. and a humidity of 80% for 24 hours. Thereafter, dilute nitric acid was dropped onto the magnetic recording medium 10 at room temperature, and after standing for 1 hour, the elements contained in the dropped dilute nitric acid were quantitatively analyzed. An induction plasma mass spectrometer (IPC-MS) was used for quantitative analysis. As a result, the elution amount of Co as the main component of the magnetic recording layer 4 was 2.5 μg / m 2 in both the embodiments. The elution amount of Co from the magnetic recording medium 10 according to the embodiment of the present invention is the same as the elution amount of the conventional magnetic recording medium in which the diamond-like carbon protective layer 21 and the lubricant layer are provided on the magnetic recording layer 4. Met. Thus, the magnetic recording medium 10 according to the present invention has the same level of corrosion resistance as a conventional magnetic recording medium having a protective layer without the protective layer 21.

本発明の第三実施形態は、第一及び第二実施形態の磁気記録媒体の記録面に保護層を設けた実施形態に関する。図６は本発明の第三実施形態断面図であり、磁気記録層の表面に保護層が設けられた磁気記録媒体を表している。   The third embodiment of the present invention relates to an embodiment in which a protective layer is provided on the recording surface of the magnetic recording medium of the first and second embodiments. FIG. 6 is a cross-sectional view of a third embodiment of the present invention, showing a magnetic recording medium in which a protective layer is provided on the surface of the magnetic recording layer.

図６を参照して、本第三実施形態の磁気記録媒体１０は、磁気記録層４の表面にダイヤモンド状カーボンからなる保護層９が設けられている点を除き、第一又は第二実施形態と同様である。このように、保護層９を設けることで磁気記録層４の損傷、腐食をより効果的に抑制することができる。   Referring to FIG. 6, the magnetic recording medium 10 of the third embodiment is the first or second embodiment except that a protective layer 9 made of diamond-like carbon is provided on the surface of the magnetic recording layer 4. It is the same. Thus, by providing the protective layer 9, damage and corrosion of the magnetic recording layer 4 can be more effectively suppressed.

この保護層９は、従来の磁気記録媒体の保護層２１に較べて薄く形成することができる。例えば、下層の磁気記録層４からＣｏ等が保護層９表面に拡散するほど薄くすることもできる。さらには、保護層９が例えば２ｎｍ以下と薄くて、磁気記録層４の一部が表出するものでもよい。このように保護層９を薄くすると、保護層９表面に触媒となるＣｏ等が拡散するので、その表面に第一実施形態と同様の方法を用いて立設するカーボンナノチューブを成長することができる。また、保護層９が厚くその表面にＣｏ等が存在しない場合は、保護層９をＣｏ等の触媒となる元素を含むダイヤモンド状カーボンをスパッタ等により形成することで、保護層９表面に第一実施形態と同様にしてカーボンナノチューブ６を成長することができる。他に、保護層９表面に触媒となる元素をスパッタにより分散させたのち、カーボンナノチューブ６を成長してもよい。   The protective layer 9 can be formed thinner than the protective layer 21 of the conventional magnetic recording medium. For example, the thickness can be reduced as Co or the like diffuses from the lower magnetic recording layer 4 to the surface of the protective layer 9. Furthermore, the protective layer 9 may be as thin as 2 nm or less, for example, and a part of the magnetic recording layer 4 may be exposed. When the protective layer 9 is thinned in this manner, Co or the like that becomes a catalyst diffuses on the surface of the protective layer 9, so that carbon nanotubes standing on the surface can be grown using the same method as in the first embodiment. . If the protective layer 9 is thick and Co or the like is not present on the surface thereof, the protective layer 9 is formed on the surface of the protective layer 9 by forming diamond-like carbon containing an element serving as a catalyst such as Co by sputtering or the like. The carbon nanotube 6 can be grown in the same manner as in the embodiment. In addition, the carbon nanotubes 6 may be grown after an element serving as a catalyst is dispersed on the surface of the protective layer 9 by sputtering.

上述した本明細書の記載には、以下の付記記載の発明が開示されている。
（付記１）基板上に記録層を有する磁気記録媒体において、
前記記録層表面にカーボンナノチューブが立設されたカーボンナノチューブ層を有することを特徴とする磁気記録媒体。
（付記２）前記カーボンナノチューブが長さ７００ｎｍ以下、密度４×１０12本／ｍ2 以上で配置された請求項１記載の磁気記録媒体。
（付記３）前記カーボンナノチューブが単層構造である付記１記載の磁気記録媒体。
（付記４）前記カーボンナノチューブの直径が、２０ｎｍ以下である付記１記載の磁気記録媒体。
（付記５）前記カーボンナノチューブ層に潤滑剤が塗布されていることを特徴とする付記１記載の磁気記録媒体。
（付記６）前記潤滑剤の膜厚が、前記カーボンナノチューブの長さよりも薄いことを特徴とする付記５記載の磁気記録媒体。
（付記７）前記カーボンナノチューブの表面が撥水性であることを特徴とする付記１記載の磁気記録媒体。
（付記８）前記記録層上に保護層が設けられていることを特徴とする付記１記載の磁気記録媒体。
（付記９）付記１〜８の何れかに記載の磁気記録媒体を備えた磁気記録装置。 In the description of the present specification described above, the invention described in the following supplementary notes is disclosed.
(Appendix 1) In a magnetic recording medium having a recording layer on a substrate,
A magnetic recording medium comprising a carbon nanotube layer in which carbon nanotubes are erected on the surface of the recording layer.
(Supplementary note 2) The magnetic recording medium according to claim 1, wherein the carbon nanotubes are arranged with a length of 700 nm or less and a density of 4 × 10 12 pieces / m 2 or more.
(Supplementary note 3) The magnetic recording medium according to supplementary note 1, wherein the carbon nanotube has a single-layer structure.
(Additional remark 4) The magnetic recording medium of Additional remark 1 whose diameter of the said carbon nanotube is 20 nm or less.
(Supplementary note 5) The magnetic recording medium according to supplementary note 1, wherein a lubricant is applied to the carbon nanotube layer.
(Additional remark 6) The magnetic recording medium of Additional remark 5 characterized by the film thickness of the said lubricant being thinner than the length of the said carbon nanotube.
(Supplementary note 7) The magnetic recording medium according to supplementary note 1, wherein a surface of the carbon nanotube is water repellent.
(Supplementary note 8) The magnetic recording medium according to supplementary note 1, wherein a protective layer is provided on the recording layer.
(Supplementary note 9) A magnetic recording apparatus including the magnetic recording medium according to any one of supplementary notes 1 to 8.

本発明によれば、耐衝撃性、耐腐食性に優れ、かつ潤滑特性の劣化が少ない磁気記録媒体を提供することができるから、ハードデスク等の磁気記録装置の信頼性を著しく向上することができる。   According to the present invention, it is possible to provide a magnetic recording medium that is excellent in impact resistance and corrosion resistance and has little deterioration in lubrication characteristics, so that the reliability of a magnetic recording apparatus such as a hard disk can be remarkably improved. it can.

本発明の第一実施形態断面図First embodiment cross-sectional view of the present invention 本発明の第一実施形態の部分拡大断面図Partial enlarged sectional view of the first embodiment of the present invention 本発明の第一実施形態の動作説明用断面図（その１）Sectional drawing for demonstrating operation | movement of 1st embodiment of this invention (the 1) 本発明の第一実施形態の動作説明用断面図（その２）Sectional drawing for demonstrating operation | movement of 1st embodiment of this invention (the 2) 本発明の第二実施形態断面図Cross-sectional view of the second embodiment of the present invention 本発明の第三実施形態断面図Cross-sectional view of a third embodiment of the present invention 従来の磁気記録媒体と磁気ヘッドの関係を表す断面図Sectional drawing showing the relationship between a conventional magnetic recording medium and a magnetic head 従来の改良された潤滑方法の説明図Illustration of conventional improved lubrication method

符号の説明Explanation of symbols

１ 基板
２ Ｎｉ−Ｐ層
３ Ｃｒ系下地層
４ 磁気記録層
５ カーボンナノチューブ層
６，６ａ，２２ カーボンナノチューブ
７ 磁気ヘッド
７ａ 先端
７ｂ 後端
７ｃ 磁気ヘッドの進行方向
７ｄ スライド面
８ 潤滑剤
９，２１ 保護層
１０ 磁気記録媒体
１０ａ 記録面
１０ｃ 磁気記録媒体の進行方向
１１ 水滴 DESCRIPTION OF SYMBOLS 1 Substrate 2 Ni-P layer 3 Cr system underlayer 4 Magnetic recording layer 5 Carbon nanotube layer 6, 6a, 22 Carbon nanotube 7 Magnetic head 7a Front end 7b Rear end 7c Magnetic head traveling direction 7d Slide surface 8 Lubricant 9, 21 Protective layer 10 Magnetic recording medium 10a Recording surface 10c Direction of travel of magnetic recording medium 11 Water droplet

Claims (6)

基板上に記録層を有する磁気記録媒体において、
前記記録層表面にカーボンナノチューブが根元を固定されて立設されたカーボンナノチューブ層を有することを特徴とする磁気記録媒体。 In a magnetic recording medium having a recording layer on a substrate,
The magnetic recording medium characterized by having a carbon nanotube layer in which the carbon nanotubes on the recording layer surface is erected and fixed to the base. 前記カーボンナノチューブが長さ７００ｎｍ以下、密度４×１０12本／ｍ2 以上で配置された請求項１記載の磁気記録媒体。 The magnetic recording medium according to claim 1, wherein the carbon nanotubes are arranged with a length of 700 nm or less and a density of 4 × 10 12 / m 2 or more. 前記カーボンナノチューブ層に潤滑剤が塗布されていることを特徴とする請求項１記載の磁気記録媒体。   The magnetic recording medium according to claim 1, wherein a lubricant is applied to the carbon nanotube layer. 前記カーボンナノチューブの表面が撥水性であることを特徴とする請求項１記載の磁気記録媒体。   2. The magnetic recording medium according to claim 1, wherein the surface of the carbon nanotube is water repellent. 請求項１、２、３又は４記載の磁気記録媒体を備えた磁気記録装置。   A magnetic recording apparatus comprising the magnetic recording medium according to claim 1, 2, 3 or 4. 基板上に記録層を有する磁気記録媒体の製造方法において、In a method for manufacturing a magnetic recording medium having a recording layer on a substrate,
基板上に、少なくとも表面に金属触媒を含有する記録層を形成する工程と、Forming a recording layer containing a metal catalyst on at least the surface of the substrate;
前記金属を触媒とする触媒法により前記記録層表面にカーボンナノチューブを形成して、前記記録層表面に立設するカーボンナノチューブ層を形成する工程とを有することを特徴とする磁気記録媒体の製造方法。Forming a carbon nanotube on the surface of the recording layer by a catalytic method using the metal as a catalyst, and forming a carbon nanotube layer standing on the surface of the recording layer. .
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