JP2007080380A

JP2007080380A - Magnetic recording medium

Info

Publication number: JP2007080380A
Application number: JP2005266426A
Authority: JP
Inventors: Tatsuya Hinoue; 竜也檜上; Hiroyuki Suzuki; 博之鈴木; Tomoo Yamamoto; 朋生山本; Yotsuo Yahisa; 四男屋久
Original assignee: Hitachi Global Storage Technologies Netherlands BV
Current assignee: HGST Netherlands BV
Priority date: 2005-09-14
Filing date: 2005-09-14
Publication date: 2007-03-29

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium which has a high medium S/N ratio, an excellent bit error rate and no problem in overwriting characteristics and is stable to thermal fluctuation. <P>SOLUTION: In the magnetic recording medium wherein a base film and a magnetic film are sequentially formed on a substrate 10, the base film has at least three base layers, the base layer 11 of the base layers formed in contact with the substrate 10 is an amorphous alloy layer containing Ti and Cu, the base layer 13 of the base layers formed in contact with the magnetic film is a Cr based alloy layer having a body centered cubic structure and the magnetic film is a Co based alloy having hexagonal dense structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は高密度磁気記録を実現するための磁気記録媒体に関する。 The present invention relates to a magnetic recording medium for realizing high-density magnetic recording.

磁気ディスク装置に代表される磁気記憶装置に対する大容量化の要求が益々高まっている。この要求を満たすため、高感度な磁気ヘッドや、高S/Nな磁気記録媒体の開発が求められている。媒体のS/Nを向上させるには、高密度で記録したときの再生出力を向上させる必要がある。一般に磁気記録媒体は、基板上に形成されたシード層と呼ばれる第１の下地層、クロムを主成分とする合金からなる体心立方構造の第２の下地層、磁性膜、及びカーボンを主成分とする保護膜から構成される。磁性膜には主にコバルトを主成分とする六方稠密構造をとる合金が用いられている。再生出力を向上させるには、磁性膜に（11.0）面、もしくは（10.0）面を基板面と略平行とした結晶配向をとらせて、磁化容易軸である六方稠密構造のc軸を膜面内方向に向けることが有効である。磁性膜の結晶配向はシード層によって制御できることが知られている。また、再生出力は基板表面に機械的なテクスチャ加工を施して、円周方向に磁気的な異方性を導入することによっても向上できることが知られている。 There is an increasing demand for a large capacity of a magnetic storage device represented by a magnetic disk device. In order to satisfy this requirement, development of a high-sensitivity magnetic head and a high S / N magnetic recording medium is required. In order to improve the S / N of the medium, it is necessary to improve the reproduction output when recording at a high density. In general, a magnetic recording medium has a first underlayer called a seed layer formed on a substrate, a second underlayer having a body-centered cubic structure made of an alloy containing chromium as a main component, a magnetic film, and carbon as main components. It consists of a protective film. An alloy having a hexagonal close-packed structure mainly composed of cobalt is used for the magnetic film. In order to improve the reproduction output, the magnetic film is oriented so that the (11.0) plane or (10.0) plane is substantially parallel to the substrate surface, and the c axis of the hexagonal close-packed structure, which is the easy axis of magnetization, is the film plane. It is effective to face inward. It is known that the crystal orientation of the magnetic film can be controlled by the seed layer. It is also known that the reproduction output can be improved by applying mechanical texture processing to the substrate surface and introducing magnetic anisotropy in the circumferential direction.

磁性膜の結晶配向性を制御する技術として、特許文献１には、基板上に第１の下地層、第２の下地層、及び第３の下地層を介して磁性膜が形成されており、第１の下地層が非晶質構造の合金からなり、第２の下地層がW単体もしくはWを含む合金層からなり、第３の下地層が１層以上のCrを主成分とした体心立方構造の合金層からなり、磁性膜が１層以上のCoを主成分とした六方稠密構造の合金層からなる磁気記録媒体が開示されている。特許文献２には、非磁性基板、非磁性下地層、磁性層及び保護膜をこの順で有する磁気記録媒において、非磁性下地層を２層以上の積層構造から構成し、非磁性基板側から、Cr-Ta系合金、Cr-Nb系合金、Cr-Ti系合金、Cr-Zr系合金、Cr-Hf系合金からなる群から選ばれる層と、Co-W系合金、Co-W-B系合金、Co-Mo系合金、Co-Mo-B系合金、Co-W-Mo系合金、Co-W-Mo-B系合金からなる群から選ばれる層とから構成する磁気記録媒体が開示されている。 As a technique for controlling the crystal orientation of the magnetic film, in Patent Document 1, a magnetic film is formed on a substrate through a first underlayer, a second underlayer, and a third underlayer, The first underlayer is made of an alloy having an amorphous structure, the second underlayer is made of W alone or an alloy layer containing W, and the third underlayer is made up of one or more layers of Cr as a main component. There has been disclosed a magnetic recording medium comprising a cubic structure alloy layer, and a magnetic film comprising a hexagonal close-packed alloy layer mainly composed of one or more Co layers. In Patent Document 2, in a magnetic recording medium having a nonmagnetic substrate, a nonmagnetic underlayer, a magnetic layer, and a protective film in this order, the nonmagnetic underlayer is composed of a laminated structure of two or more layers, and from the nonmagnetic substrate side. A layer selected from the group consisting of Cr-Ta alloy, Cr-Nb alloy, Cr-Ti alloy, Cr-Zr alloy, Cr-Hf alloy, Co-W alloy, Co-WB alloy , A magnetic recording medium comprising a layer selected from the group consisting of a Co-Mo alloy, a Co-Mo-B alloy, a Co-W-Mo alloy, and a Co-W-Mo-B alloy is disclosed. Yes.

特開２００５−１９０５１２号公報JP 2005-190512 A 特開２００４−３９１９６号公報JP 2004-39196 A

磁気記録媒体において再生出力の向上は、媒体S/Nを向上させる上で重要な課題である。出力特性の向上には、上記特許文献にあるような技術を用いて結晶配向性を向上する方法がある。しかし、１平方ミリメートル当たり160メガビット以上の面記録密度を実現するには、上記の方法を単純に組み合わせるだけでは不十分である。更なる媒体S/N向上のためには、結晶配向性を向上させるだけでなく、テクスチャ加工が施された基板を用いたときに導入される磁気的な異方性も同時に向上させる必要がある。そのためには、特に基板に接して形成される層の材料や組成、成膜条件等を最適化する必要がある。 Improvement of reproduction output in a magnetic recording medium is an important issue in improving the medium S / N. In order to improve the output characteristics, there is a method of improving the crystal orientation using a technique as described in the above-mentioned patent document. However, a simple combination of the above methods is not sufficient to achieve a surface recording density of 160 megabits per square millimeter or more. In order to further improve the medium S / N, it is necessary not only to improve the crystal orientation but also to simultaneously improve the magnetic anisotropy introduced when using a textured substrate. . For that purpose, it is particularly necessary to optimize the material and composition of the layer formed in contact with the substrate, the film forming conditions, and the like.

本発明の目的は、高い媒体S/Nを有し、オーバーライト特性に問題なく、ビットエラーレートに優れ、かつ熱揺らぎに対しても十分に安定な磁気記録媒体を提供することである。 An object of the present invention is to provide a magnetic recording medium having a high medium S / N, no problem in overwrite characteristics, excellent bit error rate, and sufficiently stable against thermal fluctuation.

上記目的を達成するために、本発明の代表的な磁気記録媒体は、基板上に下地膜と磁性膜が順次形成され、下地膜は少なくとも３層の下地層を有し、これら下地層のうち基板に接して形成される層はTiとCuを含有する非晶質合金層であり、前記下地層のうち前記磁性膜に接して形成される層は体心立方構造のCr基合金層であり、前記磁性膜は六方稠密構造のCo基合金であることを特徴とする。 In order to achieve the above object, in a typical magnetic recording medium of the present invention, a base film and a magnetic film are sequentially formed on a substrate, and the base film has at least three base layers. The layer formed in contact with the substrate is an amorphous alloy layer containing Ti and Cu, and the layer formed in contact with the magnetic film in the underlayer is a body-centered cubic Cr-based alloy layer. The magnetic film is a Co-based alloy having a hexagonal close-packed structure.

前記TiとCuを含有する非晶質合金層に含まれるCuの濃度は25at.%以上であることが望ましい。また、前記基板は表面にテクスチャ加工による溝が概ね基板円周方向に形成されており、磁性膜の残留磁束密度Brと膜厚tの積Brtについて円周方向に測定したBrtθと半径方向に測定したBrtrの比Brtθ/Brtr(BrOR)が1.2以上であることが望ましい。さらに、線源にCuKα1線を用いたX線回折装置を用い、X線の入射方向を媒体円周方向と平行になるようにして測定した媒体円周方向の磁性層(11.0)面のロッキングカーブから求めた半値幅Δθ50が６°以下であることが望ましい。 The concentration of Cu contained in the amorphous alloy layer containing Ti and Cu is preferably 25 at.% Or more. Further, the substrate has textured grooves formed on the surface thereof in the circumferential direction, and the Brtθ measured in the circumferential direction and the radial direction of the product Brt of the residual magnetic flux density Br and the film thickness t of the magnetic film are measured. The Brtr ratio Brtθ / Brtr (BrOR) is preferably 1.2 or more. Furthermore, the rocking curve of the magnetic layer (11.0) surface in the medium circumferential direction was measured using an X-ray diffractometer using CuKα1 as the radiation source and the incident direction of the X-rays being parallel to the circumferential direction of the medium. It is desirable that the half width Δθ50 obtained from the above is 6 ° or less.

本発明によれば、高い媒体S/Nを有し、オーバーライト特性に問題なく、ビットエラーレートに優れ、かつ熱揺らぎに対しても十分に安定な磁気記録媒体を提供することができる。 According to the present invention, it is possible to provide a magnetic recording medium that has a high medium S / N, has no problem in overwrite characteristics, has an excellent bit error rate, and is sufficiently stable against thermal fluctuation.

図１は本発明の実施例による磁気記録媒体（磁気ディスク）の基本構成を示す断面図である。磁気ディスクは基板に対して両面が同じ構成であるので、図１では片面のみ示している。磁気ディスクは、基板10に下地膜（第１の下地層11、第２の下地層12、第３の下地層13）、磁性膜（第１の磁性層14、中間層15、第２の磁性層16）、保護膜17、潤滑膜18が順に堆積された膜構造をとる。基板10として、化学強化されたガラス基板、あるいはリンを含有したニッケル合金をアルミニウム合金にめっきした剛体基板を用いることが好ましい。これらの基板上に概ね円板の周方向に微細なテクスチャ加工を施すことが、磁気的な異方性を付与する上で好ましい。検証の結果、円板の半径方向に測定した表面粗さは、間歇接触型の原子間力顕微鏡で５μｍ角の大きさを観察した結果、最大高さRmaxで1.0nmから5.0nm、平均表面粗さRaで0.15nmから0.60nmの基板を用いれば、磁気ヘッドの浮上信頼性が十分であることが確認できた。 FIG. 1 is a sectional view showing a basic configuration of a magnetic recording medium (magnetic disk) according to an embodiment of the present invention. Since both sides of the magnetic disk have the same configuration with respect to the substrate, only one side is shown in FIG. The magnetic disk has a base film (first base layer 11, second base layer 12, third base layer 13), magnetic film (first magnetic layer 14, intermediate layer 15, second magnetic layer) on a substrate 10. Layer 16), protective film 17, and lubricating film 18 are sequentially deposited. As the substrate 10, it is preferable to use a chemically strengthened glass substrate or a rigid substrate obtained by plating a nickel alloy containing phosphorus on an aluminum alloy. It is preferable to apply fine texture processing on the substrate in the circumferential direction of the disk in order to impart magnetic anisotropy. As a result of the verification, the surface roughness measured in the radial direction of the disk was observed to be 5 μm square with an intermittent contact type atomic force microscope. As a result, the maximum height Rmax was 1.0 nm to 5.0 nm. It was confirmed that the flying reliability of the magnetic head was sufficient when a substrate with a thickness of Ra of 0.15 nm to 0.60 nm was used.

基板10と第１の磁性層14の間に下地膜を形成することにより、磁性膜の結晶配向性を制御し、結晶粒径を微細化することが可能である。ここでは、基板10と第１の磁性層14との間に非晶質構造のTi-Cu合金からなる第１の下地層11と、非晶質構造のW-Co合金からなる第２の下地層12と、体心立方構造のCr-Ti-B合金からなる第３の下地層13を設けた。磁性膜の良好な結晶配向性を得るためには、基板と体心立方構造のCr基合金の間に形成する層を非晶質構造とする必要がある。さらに、基板に接する層にTiとCuを含有することで、テクスチャ加工を施した基板（以下テクスチャ基板）を用いたときの磁気的な異方性と、磁性膜の結晶配向性を同時に高めることができる。磁性膜のCo基合金に11.0配向をとらせてCo基合金のc軸を面内方向に向かせるためには、磁性膜と接する層に体心立方構造のCr基合金を用いる必要がある。ここでは、磁性膜はCo-Cr-Pt合金からなる第１の磁性層14、Ru中間層15、Co-Cr-Pt-B合金からなる第２の磁性層16を積層した。複数の磁性層を積層することによって媒体性能を向上することができる。複数の磁性層を積層する際、磁性層間に非磁性の中間層を形成すると、特に低ノイズ化が可能となり好ましい。磁性層の層数をさらに増やすことも媒体性能向上のためには効果がある。 By forming a base film between the substrate 10 and the first magnetic layer 14, the crystal orientation of the magnetic film can be controlled and the crystal grain size can be reduced. Here, a first underlayer 11 made of an amorphous Ti—Cu alloy and a second lower layer made of an amorphous W—Co alloy are interposed between the substrate 10 and the first magnetic layer 14. A base layer 12 and a third base layer 13 made of a Cr—Ti—B alloy having a body-centered cubic structure were provided. In order to obtain good crystal orientation of the magnetic film, the layer formed between the substrate and the body-centered cubic Cr-based alloy needs to have an amorphous structure. Furthermore, by including Ti and Cu in the layer in contact with the substrate, the magnetic anisotropy and the crystal orientation of the magnetic film are simultaneously improved when using a textured substrate (hereinafter referred to as texture substrate). Can do. In order to make the Co-based alloy of the magnetic film have the 11.0 orientation and to make the c-axis of the Co-based alloy in the in-plane direction, it is necessary to use a Cr-based alloy having a body-centered cubic structure for the layer in contact with the magnetic film. Here, as the magnetic film, a first magnetic layer 14 made of a Co—Cr—Pt alloy, a Ru intermediate layer 15, and a second magnetic layer 16 made of a Co—Cr—Pt—B alloy were laminated. The medium performance can be improved by laminating a plurality of magnetic layers. When laminating a plurality of magnetic layers, it is particularly preferable to form a nonmagnetic intermediate layer between the magnetic layers because noise can be reduced. Increasing the number of magnetic layers is also effective for improving the medium performance.

第１の下地層11に含まれるCuの濃度を25at.%以上とすると、非晶質構造をとりやすくなり磁性膜の結晶配向性を高めることができるため好ましい。
第２の下地層12にWとCoを含むと、磁性膜の結晶配向性をさらに高めることができ好ましい。
Cr基合金である第３の下地層13にTiとBを含有させると、磁性膜の結晶粒径が微細化され低ノイズ化のため好ましい。
第１の磁性層14はCo-Cr合金、Co-Cr-Pt合金、Co-Cr-B合金など、PtとBを同時に含有しないCo基合金を用いることが、磁性膜の11.0配向を得るために好ましい。
第２の磁性層16は低ノイズ化のためCrとBを含有することが好ましい。また、第２の磁性層16は保磁力確保のためPtを含有することが好ましい。 It is preferable that the concentration of Cu contained in the first underlayer 11 is 25 at.% Or more because an amorphous structure is easily formed and the crystal orientation of the magnetic film can be improved.
It is preferable that the second underlayer 12 contains W and Co because the crystal orientation of the magnetic film can be further improved.
It is preferable that Ti and B are contained in the third underlayer 13 which is a Cr-based alloy because the crystal grain size of the magnetic film is reduced and the noise is reduced.
The first magnetic layer 14 is made of a Co-based alloy that does not contain Pt and B, such as a Co—Cr alloy, a Co—Cr—Pt alloy, or a Co—Cr—B alloy, in order to obtain the 11.0 orientation of the magnetic film. Is preferable.
The second magnetic layer 16 preferably contains Cr and B to reduce noise. The second magnetic layer 16 preferably contains Pt in order to ensure coercive force.

上記下地膜、磁性膜は、ターゲットをスパッタすることによって基板上に形成する。物理蒸着法として直流スパッタ法が有効であり、直流スパッタ法の他に、高周波スパッタ法、直流パルススパッタ法等の方法も有効である。直流スパッタ法を用いる場合には、第２の磁性層16以降のプロセスでバイアス電圧を印加すると、保磁力が増加するため好ましい。バイアスが印加される磁性層にTaが含まれると、特にバイアスの効果が大きい。 The base film and the magnetic film are formed on the substrate by sputtering a target. A direct current sputtering method is effective as the physical vapor deposition method, and methods such as a high frequency sputtering method and a direct current pulse sputtering method are also effective in addition to the direct current sputtering method. When the DC sputtering method is used, it is preferable to apply a bias voltage in the process after the second magnetic layer 16 because the coercive force is increased. When Ta is contained in the magnetic layer to which the bias is applied, the effect of the bias is particularly great.

上記の方法で作製した磁気ディスクを、磁気ディスクを駆動する駆動部と、誘導型記録ヘッドと磁気抵抗効果型再生ヘッドからなる高感度な磁気ヘッドと、磁気ヘッドを磁気ディスクに対して相対運動させる手段と、磁気ヘッドへの信号入力手段と磁気ヘッドからの出力信号の処理手段とを有する磁気ディスク装置に採用することにより、１平方ミリメートル当たり160メガビット以上の面記録密度を実現することが可能となる。 The magnetic disk manufactured by the above method is moved relative to the magnetic disk by a drive unit for driving the magnetic disk, a high-sensitivity magnetic head composed of an inductive recording head and a magnetoresistive reproducing head, and the magnetic head. And a magnetic disk device having a signal input means to the magnetic head and an output signal processing means from the magnetic head, it is possible to realize a surface recording density of 160 megabits per square millimeter or more. Become.

以下、各実施例の膜構成、製造方法、磁気特性について詳細に説明する。
〈実施例１〉
実施例１による磁気ディスクの膜構造は図１と同じである。基板10上に第１の下地層11として10.0〜25.0nmのTi-Cu合金層、第２の下地層12として3.0nmのW-30at.%Co合金層を室温で形成した。ランプヒータによって基板の温度を約330℃になるように加熱した後、第３の下地層13として厚さ8.0nmのCr-10at.%Ti-5at.%B合金層を形成した。更に厚さ3.0nmのCo-14at.%Cr-6at.%Pt合金からなる第１の磁性層14、0.6nmのRu中間層15、18.0nmのCo-18at.%Cr-14at.%Pt-8at.%B合金からなる第２の磁性層16を順次形成後、3.0nmのカーボンを主成分とする保護膜17を形成した。保護膜形成後、パーフルオロアルキルポリエーテルを主成分とする潤滑剤を塗布して厚さ1.8nmの潤滑膜18を形成した。 Hereinafter, the film configuration, manufacturing method, and magnetic characteristics of each example will be described in detail.
<Example 1>
The film structure of the magnetic disk according to Example 1 is the same as that shown in FIG. A Ti—Cu alloy layer of 10.0 to 25.0 nm was formed as the first underlayer 11 on the substrate 10, and a W-30 at.% Co alloy layer of 3.0 nm was formed as the second underlayer 12 at room temperature. After heating the substrate to about 330 ° C. with a lamp heater, a Cr-10 at.% Ti-5 at.% B alloy layer having a thickness of 8.0 nm was formed as the third underlayer 13. Furthermore, a first magnetic layer 14 made of a Co-14at.% Cr-6at.% Pt alloy with a thickness of 3.0 nm, a 0.6 nm Ru intermediate layer 15, a 18.0 nm Co-18at.% Cr-14at.% Pt- After sequentially forming the second magnetic layer 16 made of 8 at.% B alloy, a protective film 17 mainly composed of 3.0 nm carbon was formed. After forming the protective film, a lubricant mainly composed of perfluoroalkyl polyether was applied to form a lubricating film 18 having a thickness of 1.8 nm.

第１の下地層11の成膜には以下の組成のTi-Cu合金ターゲットを用いた。
Ti-33at.%Cu、
Ti-50at.%Cu、
Ti-75at.%Cu。
成膜には表面に同心円状のテクスチャ加工が施されたアルミノシリケートガラス基板10を用いた。基板10は成膜前にアルカリ洗浄を行い乾燥させた。上記多層膜の形成は枚葉式スパッタリング装置を用いて行った。このスパッタリング装置のベース真空度は1.0〜1.2×10^-5Paであった。タクトは９秒とした。成膜時のArガス圧力は、第１の下地層11は0.53〜1.73Pa、第２の下地層12は0.53Pa、第３の下地層13から第２の磁性層16までは0.93Paとした。加熱はArに酸素を１%添加した混合ガス雰囲気中で行った。カーボン保護膜17はArに窒素を10％添加した混合ガス雰囲気中で形成した。第１の下地層11および第２の磁性層16の放電時間は4.5秒、第２の下地層12、第１の磁性層14および中間層15の放電時間は2.5秒、第３の下地層13の放電時間は4.0秒とした。 A Ti—Cu alloy target having the following composition was used for forming the first underlayer 11.
Ti-33at.% Cu,
Ti-50at.% Cu,
Ti-75at.% Cu.
For the film formation, an aluminosilicate glass substrate 10 having a concentric texture on the surface was used. The substrate 10 was dried by alkali washing before film formation. The multilayer film was formed using a single wafer sputtering apparatus. The base vacuum degree of this sputtering apparatus was 1.0 to 1.2 × 10 ⁻⁵ Pa. The tact time was 9 seconds. The Ar gas pressure during film formation was 0.53 to 1.73 Pa for the first underlayer 11, 0.53 Pa for the second underlayer 12, and 0.93 Pa from the third underlayer 13 to the second magnetic layer 16. . Heating was performed in a mixed gas atmosphere in which 1% of oxygen was added to Ar. The carbon protective film 17 was formed in a mixed gas atmosphere in which 10% of nitrogen was added to Ar. The discharge time of the first underlayer 11 and the second magnetic layer 16 is 4.5 seconds, the discharge time of the second underlayer 12, the first magnetic layer 14 and the intermediate layer 15 is 2.5 seconds, the third underlayer 13 The discharge time was 4.0 seconds.

作製した磁気ディスクのBrt（Br：磁性膜の残留磁束密度、t：磁性膜の膜厚）と残留保磁力HcrはFast Remanent Moment Magnetometer （FRMM）を用いて評価した。KV/kT（K：結晶磁気異方性定数、V：磁性結晶粒の体積、k：ボルツマン定数、T：絶対温度）は、振動試料型磁力計（VSM）を用いて次の方法で評価した。室温において7.5秒から240秒までの残留保磁力を測定し、その結果をSharrockの式にフィッティングしてKV/kTを求めた。発明者らの検討から、この手法により求めたKV/kTが概ね70以上であれば、熱揺らぎによる出力減衰を抑制でき、信頼性上問題はないという結果を得た。テクスチャ基板によって媒体の円周方向に導入される磁気的な異方性BrORは、VSMによって測定した円周方向のBrtθと半径方向のBrtrの比をとることで求めた。VSMによる評価には、磁気ディスクを8mm角に切り出した試料を用いた。 Brt (Br: residual magnetic flux density of magnetic film, t: thickness of magnetic film) and residual coercive force Hcr of the manufactured magnetic disk were evaluated using a Fast Remanent Moment Magnetometer (FRMM). KV / kT (K: crystal magnetic anisotropy constant, V: volume of magnetic crystal grain, k: Boltzmann constant, T: absolute temperature) was evaluated by the following method using a vibrating sample magnetometer (VSM). . KV / kT was calculated by measuring the residual coercivity from 7.5 to 240 seconds at room temperature and fitting the result to Sharrock's equation. From the inventors' study, it was found that if KV / kT obtained by this method is approximately 70 or more, output attenuation due to thermal fluctuation can be suppressed and there is no problem in reliability. The magnetic anisotropy BrOR introduced in the circumferential direction of the medium by the texture substrate was obtained by taking the ratio of the circumferential direction Brtθ and the radial direction Brtr measured by VSM. For the evaluation by VSM, a sample obtained by cutting a magnetic disk into 8 mm square was used.

作製した磁気ディスクの結晶配向性はCuKα1線を用いたX線回折により評価した。X線源には銅の回転対陰極を用い、印加電圧を50kV、電流を160mAに設定した。光学系は、発散スリットを１°、散乱スリットを１°、受光スリットを0.3mm、湾曲モノクロメータを使用して構成した。X線の入射方向が媒体の円周方向と平行になるように設定した。θ-2θ走査は2θ角度を30°から90°まで４°/分の速さで0.03°間隔で走査して反射強度を測定した。ロッキングカーブ測定は、まずθ-2θ走査によって求めた磁性膜の11.0回折ピーク位置に2θ角度を固定し、θ角度を15°から60°まで２°/分の速さで0.05°間隔で走査して反射強度を測定した。次に、2θ角度を磁性膜の測定時と同じ値に固定し、同様の測定方法によって成膜していないガラス基板のロッキングカーブ測定を行い、これをバックグラウンドデータとした。磁性膜のカーブからバックグラウンドのカーブを差し引くことによって磁性膜(11.0)面のロッキングカーブを求め、このカーブの半値幅をとりΔθ50とした。 The crystal orientation of the produced magnetic disk was evaluated by X-ray diffraction using CuKα1 line. As the X-ray source, a rotating copper cathode was used, the applied voltage was set to 50 kV, and the current was set to 160 mA. The optical system was constructed using a diverging slit of 1 °, a scattering slit of 1 °, a light receiving slit of 0.3 mm, and a curved monochromator. The X-ray incident direction was set to be parallel to the circumferential direction of the medium. In the θ-2θ scan, the reflection intensity was measured by scanning the 2θ angle from 30 ° to 90 ° at a rate of 4 ° / min at intervals of 0.03 °. In the rocking curve measurement, the 2θ angle is fixed at the 11.0 diffraction peak position of the magnetic film obtained by θ-2θ scanning, and the θ angle is scanned from 0.05 ° to 60 ° at 0.05 ° intervals at a speed of 2 ° / min. The reflection intensity was measured. Next, the 2θ angle was fixed to the same value as when the magnetic film was measured, and the rocking curve of a glass substrate not formed was measured by the same measurement method, and this was used as background data. The rocking curve of the magnetic film (11.0) surface was obtained by subtracting the background curve from the curve of the magnetic film, and the half width of this curve was taken as Δθ50.

記録再生特性の評価は記録用の電磁誘導型磁気ヘッドと再生用のスピンバルブ型磁気ヘッドを併せ持つ複合型ヘッドと組み合わせてスピンスタンドで行った。図２に本実施例及び他の実施例で用いられる磁気ヘッドの特性を示す。ヘッドサンプル(HEAD No.1-5)の各々の、最高線記録密度HF（kFC/mm）、記録電流Iw（mA）、センス電流Is（mA）、書込トラック幅Tww（μm）、読出トラック幅Twr（μm）、スキュー角Skew（deg.）、回転数ROTNUM（s^-1）が示されている。本実施例の評価にはヘッドサンプル(HEAD No.1)を用いた。中記録密度MF=HF/2で記録した時の出力と、高記録密度HFにおける媒体ノイズから信号対雑音比(Smf/N)を求めた。低記録密度LF=HF/10で記録後、高記録密度HF信号を重ね書きしてLF信号の減衰比からオーバーライト特性(O/W)を求めた。ビットエラーレート(logBER)はランダムパターンで特定のトラックをほぼ１周記録した直後に読み出しを行った際の、総読み出しバイト数に対するエラーバイト数をカウントすることによって求めた。 The recording / reproducing characteristics were evaluated by a spin stand in combination with a composite type head having both a recording electromagnetic induction type magnetic head and a reproducing spin valve type magnetic head. FIG. 2 shows the characteristics of the magnetic head used in this embodiment and other embodiments. Maximum linear recording density HF (kFC / mm), recording current Iw (mA), sense current Is (mA), write track width Tww (μm), read track for each of the head samples (HEAD No.1-5) The width Twr (μm), the skew angle Skew (deg.), And the rotation speed ROTNUM (s ⁻¹ ) are shown. A head sample (HEAD No. 1) was used for the evaluation of this example. The signal-to-noise ratio (Smf / N) was obtained from the output when recording at medium recording density MF = HF / 2 and the medium noise at high recording density HF. After recording at a low recording density LF = HF / 10, a high recording density HF signal was overwritten and the overwrite characteristic (O / W) was obtained from the attenuation ratio of the LF signal. The bit error rate (logBER) was obtained by counting the number of error bytes relative to the total number of read bytes when reading was performed immediately after recording a specific track almost once in a random pattern.

本実施例（試験例No.101〜112）の評価結果を図３に示す。第１の下地層11にTi-33at.%Cuを用いた試験例No.101〜104は、第１の下地層成膜時のArガス圧力が増加するにつれて、Δθ50が徐々に大きくなり、BrORが徐々に大きくなった。第１の下地層11にTi-50at。%CuおよびTi-75at.%Cuを用いた試験例No.105〜112は、Arガス圧力増加とともにΔθ50が減少し、試験例No.101〜104とは逆の傾向を示した。ただし、Δθ50が最小となったときの値は、どの第１の下地層材料でも5.5°前後となった。各試験例のHcrは約360kA/mでほぼ一定となった。BrtはΔθ50の値が大きくなり結晶配向性が劣化した試験例で減少した。Ti-75at.%Cuを用いた試験例No.109〜112のBrORは他の試験例より小さくなった。第１の下地層に含まれるCu濃度が増加するとBrORが低下することが示唆される。Smf/Nが14dB未満となった試験例No.105、106、109、110はΔθ50の値が他の試験例よりも大きく、結晶配向性の向上が記録再生特性の向上につながることがわかる。Ti-75at.%Cuを用いた媒体のlogBERが他の試験例に比べ若干悪くなったが、これはBrORが小さいことによるものと考えられる。 The evaluation results of this example (Test Examples Nos. 101 to 112) are shown in FIG. In Test Examples Nos. 101 to 104 using Ti-33 at.% Cu for the first underlayer 11, Δθ50 gradually increased as the Ar gas pressure during the formation of the first underlayer increased, and BrOR Gradually increased. Ti-50at for the first underlayer 11. In Test Examples Nos. 105 to 112 using% Cu and Ti-75 at.% Cu, Δθ50 decreased with increasing Ar gas pressure, and showed a tendency opposite to Test Examples No. 101 to 104. However, the value when Δθ50 was minimized was around 5.5 ° for any first underlayer material. The Hcr of each test example was almost constant at about 360 kA / m. Brt decreased in the test example in which the value of Δθ50 increased and the crystal orientation deteriorated. BrOR of test examples Nos. 109 to 112 using Ti-75 at.% Cu was smaller than other test examples. This suggests that BrOR decreases as the Cu concentration in the first underlayer increases. In Test Examples Nos. 105, 106, 109, and 110 in which Smf / N is less than 14 dB, the value of Δθ50 is larger than that of the other test examples, and it can be seen that improvement in crystal orientation leads to improvement in recording and reproduction characteristics. The logBER of the medium using Ti-75at.% Cu was slightly worse than the other test examples. This is probably due to the small BrOR.

〈比較例１〉
第１の下地層11にCo-50at.%Ti合金層を形成した以外、実施例１と同様にして磁気ディスクを作製した。本比較例（試験例No.121〜124）の評価結果を図４に示す。記録再生特性評価にはヘッドサンプル（HEADNo.1）を用いた。第１の下地層成膜時のArガス圧力が増加するにつれてΔθ50が急激に増加した。本比較例のなかで最もΔθ50が小さくなった試験例No.121の値は6.1°となった。実施例１では各第１の下地層とも最小5.5°程度であったことから、Ti-Cu合金を第１の下地層11に用いることで、結晶配向性を高めることができることがわかる。本比較例のSmf/Nは条件によらずすべての試験例で14dB未満となり、実施例１の媒体に比べ低くなった。結晶配向性の差がSmf/Nの差につながっものと考えられる。本比較例のlogBERは最良のもので-4.0桁を示したが、全体としては実施例１の媒体に比べると若干悪くなった。 <Comparative example 1>
A magnetic disk was manufactured in the same manner as in Example 1 except that a Co-50 at.% Ti alloy layer was formed on the first underlayer 11. The evaluation results of this comparative example (Test Examples Nos. 121 to 124) are shown in FIG. A head sample (HEAD No. 1) was used for recording / reproduction characteristics evaluation. As the Ar gas pressure at the time of forming the first underlayer increased, Δθ50 increased rapidly. The value of Test Example No. 121 in which Δθ50 was the smallest among the present comparative examples was 6.1 °. In Example 1, since each first underlayer was at least about 5.5 °, it can be seen that the crystal orientation can be improved by using a Ti—Cu alloy for the first underlayer 11. Smf / N of this comparative example was less than 14 dB in all test examples regardless of conditions, and was lower than that of the medium of Example 1. It is thought that the difference in crystal orientation leads to the difference in Smf / N. The logBER of this comparative example was the best and showed −4.0 digits, but was slightly worse than the medium of Example 1 as a whole.

〈実施例２〉
基板10上に第１の下地層11として5.0〜25.0nmのTi-Cu合金層、第２の下地層12として3.0nmのW-30at.%Co合金層を室温で形成した。ランプヒータによって基板の温度を約390℃になるように加熱した後、第３の下地層13として厚さ10.0nmのCr-10at.%Ti-3at.%B合金層を形成した。更に厚さ3.0nmのCo-14at.%Cr-6at.%Pt合金からなる第１の磁性層14、0.6nmのRu中間層15、12.5nmのCo-22at.%Cr-14at.%Pt-4at.%B-2at.%Ta合金からなる第２の磁性層16、10.0nmのCo-11at.%Cr-13at.%Pt-15at.%B合金からなる第３の磁性層を順次形成後、保護膜17として3.0nmのカーボンを主成分とする膜を形成した。保護膜形成後、パーフルオロアルキルポリエーテルを主成分とする潤滑剤を塗布して厚さ1.8nmの潤滑膜18を形成した。 <Example 2>
On the substrate 10, a Ti—Cu alloy layer of 5.0 to 25.0 nm was formed as the first underlayer 11, and a W-30 at.% Co alloy layer of 3.0 nm was formed as the second underlayer 12 at room temperature. After heating the substrate to about 390 ° C. with a lamp heater, a Cr-10 at.% Ti-3 at.% B alloy layer having a thickness of 10.0 nm was formed as the third underlayer 13. Furthermore, a first magnetic layer 14 made of a Co-14at.% Cr-6at.% Pt alloy with a thickness of 3.0 nm, a 0.6 nm Ru intermediate layer 15, and a 12.5 nm Co-22at.% Cr-14at.% Pt- After sequentially forming the second magnetic layer 16 made of 4at.% B-2at.% Ta alloy and the third magnetic layer made of Co-11at.% Cr-13at.% Pt-15at.% B alloy of 10.0 nm As a protective film 17, a film containing 3.0 nm carbon as a main component was formed. After forming the protective film, a lubricant mainly composed of perfluoroalkyl polyether was applied to form a lubricating film 18 having a thickness of 1.8 nm.

第1の下地層の成膜には以下の組成のTi-Cu合金ターゲットを用いた。
Ti-15at.%Cu、
Ti-25at.%Cu、
Ti-33at.%Cu、
Ti-41at.%Cu。
成膜には表面に同心円状のテクスチャ加工が施されたアルミノシリケートガラス基板10を用いた。基板10は成膜前にアルカリ洗浄を行い乾燥させた。上記多層膜の形成は枚葉式スパッタリング装置を用いて行った。このスパッタリング装置のベース真空度は1.0〜1.2×10^-5Paであった。タクトは９秒とした。成膜時のArガス圧力は、第１の下地層11および第２の下地層12は0.53Pa、第３の下地層13、第１の磁性層14および中間層15は0.93Pa、第２の磁性層16および第３の磁性層は0.67Paとした。加熱はArに酸素を１%添加した混合ガス雰囲気中で行った。カーボン保護膜17はArに窒素を10％添加した混合ガス雰囲気中で形成した。第３の下地層13、第２の磁性層16および第３の磁性層のスパッタ時に-200Vのバイアス電圧を基板に印加した。第１の下地層11、第２の磁性層16および第３の磁性層の放電時間は4.5秒、第２の下地層12、第１の磁性層14および中間層15の放電時間は2.5秒、第３の下地層13の放電時間は4.0秒とした。 A Ti—Cu alloy target having the following composition was used for forming the first underlayer.
Ti-15at.% Cu,
Ti-25at.% Cu,
Ti-33at.% Cu,
Ti-41at.% Cu.
For the film formation, an aluminosilicate glass substrate 10 having a concentric texture on the surface was used. The substrate 10 was dried by alkali washing before film formation. The multilayer film was formed using a single wafer sputtering apparatus. The base vacuum degree of this sputtering apparatus was 1.0 to 1.2 × 10 ⁻⁵ Pa. The tact time was 9 seconds. The Ar gas pressure during film formation is 0.53 Pa for the first underlayer 11 and the second underlayer 12, 0.93 Pa for the third underlayer 13, the first magnetic layer 14 and the intermediate layer 15, and the second The magnetic layer 16 and the third magnetic layer were 0.67 Pa. Heating was performed in a mixed gas atmosphere in which 1% of oxygen was added to Ar. The carbon protective film 17 was formed in a mixed gas atmosphere in which 10% of nitrogen was added to Ar. A bias voltage of -200 V was applied to the substrate during sputtering of the third underlayer 13, the second magnetic layer 16, and the third magnetic layer. The discharge time of the first underlayer 11, the second magnetic layer 16 and the third magnetic layer is 4.5 seconds, the discharge time of the second underlayer 12, the first magnetic layer 14 and the intermediate layer 15 is 2.5 seconds, The discharge time of the third underlayer 13 was 4.0 seconds.

本実施例（試験例No.201〜216）の評価結果を図５に示す。記録再生特性評価にはヘッドサンプル（HEADNo.2）を用いた。第１の下地層11にTi-25at.%Cu、Ti-33at.%Cu、Ti-41at.%Cuを用いた試験例205〜216は、第１の下地層11の膜厚によらずBrtが5.0Tnm程度、Hcrが360kA/m程度でほぼ一定となった。それに対し、第１の下地層11にTi-15at.%Cuを用いた試験例No.201〜204は、第１の下地層11の膜厚が増加するに従って、BrtとHcrが徐々に劣化した。図６〜９に試験例No.203、206、210、214のX線回折プロファイルを示す。第１の下地層11のCu濃度が25at.%以上である試験例No.206、210、214では、磁性層によるCo基合金の11.0回折ピークおよび第３の下地層13によるCr基合金の200回折ピークのみが現れた。一方、Ti-15at.%Cuを第１の下地層11に用いた試験例No.203では、Co基合金11.0回折ピークおよびCr基合金200回折ピーク以外に、Co基合金の00.2回折ピークおよび第１の下地層11によるTi基合金の00.2回折ピークが観測された。 The evaluation results of this example (Test Examples Nos. 201 to 216) are shown in FIG. A head sample (HEAD No. 2) was used for evaluation of recording and reproduction characteristics. Test examples 205 to 216 in which Ti-25at.% Cu, Ti-33at.% Cu, and Ti-41at.% Cu are used for the first underlayer 11 are Brt regardless of the film thickness of the first underlayer 11. Was approximately constant at 5.0 Tnm and Hcr at 360 kA / m. In contrast, in Test Examples Nos. 201 to 204 using Ti-15at.% Cu for the first underlayer 11, Brt and Hcr gradually deteriorated as the thickness of the first underlayer 11 increased. . 6 to 9 show X-ray diffraction profiles of Test Examples Nos. 203, 206, 210, and 214. In Test Examples Nos. 206, 210, and 214 in which the Cu concentration of the first underlayer 11 is 25 at.% Or more, the 11.0 diffraction peak of the Co-based alloy by the magnetic layer and the 200 of the Cr-based alloy by the third underlayer 13 are used. Only diffraction peaks appeared. On the other hand, in Test Example No. 203 in which Ti-15at.% Cu was used for the first underlayer 11, in addition to the Co-based alloy 11.0 diffraction peak and the Cr-based alloy 200 diffraction peak, A 00.2 diffraction peak of the Ti-based alloy due to 1 underlayer 11 was observed.

第１の下地層11のTi-Cu合金のCu濃度が少ない場合、第１の下地層11が結晶構造を持つようになり、そのことが第３の下地層13のCr基合金や磁性層のCo基合金の結晶配向性を乱したのである。また、第１の下地層11が結晶構造を持つ場合、第１の下地層の膜厚が厚くなるに従って第１の下地層の結晶が成長するため、第１の下地層が厚くなるほど第３の下地層13と磁性層の結晶配向性が劣化し媒体性能が劣化する。試験例201〜204おいて、第１の下地層11の膜厚が増加するに従って磁気特性が劣化したのはこのためである。図５よりΔθ50の値で結晶配向性を比較すると、第１の下地層11のCu濃度が25at.%以上である試験例No.205〜216では3.6°程度で差はなかった。それに対し、第１の下地層11のCu濃度が15at.%の試験例201〜204は他の媒体よりΔθ50の値が大きくなり、第１の下地層11の膜厚が厚くなるほどΔθ50の値が大きくなった。 When the Cu concentration of the Ti—Cu alloy of the first underlayer 11 is low, the first underlayer 11 has a crystal structure, which is the result of the Cr-based alloy or magnetic layer of the third underlayer 13. This disturbed the crystal orientation of the Co-based alloy. Further, when the first underlayer 11 has a crystal structure, the crystal of the first underlayer grows as the thickness of the first underlayer increases. Therefore, the third underlayer increases as the first underlayer 11 increases. The crystal orientation of the underlayer 13 and the magnetic layer deteriorates and the medium performance deteriorates. This is the reason why the magnetic characteristics deteriorated in the test examples 201 to 204 as the thickness of the first underlayer 11 increased. When comparing the crystal orientation with the value of Δθ50 as shown in FIG. 5, there was no difference at about 3.6 ° in Test Examples Nos. 205 to 216 in which the Cu concentration of the first underlayer 11 was 25 at. On the other hand, in the test examples 201 to 204 in which the Cu concentration of the first underlayer 11 is 15 at.%, The value of Δθ50 is larger than that of other media, and the value of Δθ50 increases as the film thickness of the first underlayer 11 increases. It became bigger.

図５より、記録再生特性は第１の下地層11にTi-33at.%Cuを用いた試験例209〜212が最も高Smf/Nで最も低logBERとなった。Ti-25at.%CuとTi-41at.%Cuを用いた媒体は、Ti-33at.%Cuを用いた媒体に比べlogBERが最大0.4桁劣化したが、−６桁以上の値を示しており十分に良好な性能を示した。Ti-15at.%Cuを用いた媒体は、第１の下地層11の膜厚が5.0nmの試験例No.201のみ記録再生特性を評価し、他の試験例は磁気特性が大きく劣化しているため記録再生特性は評価しなかった。Ti-33at.%Cuを用いた媒体に比べ、試験例No.201はBERが１桁近く劣化し、Smf/Nは１dB以上劣化した。 As shown in FIG. 5, the recording / reproduction characteristics were the highest Smf / N and the lowest log BER in Test Examples 209 to 212 using Ti-33 at.% Cu for the first underlayer 11. The media using Ti-25at.% Cu and Ti-41at.% Cu deteriorated by a maximum of 0.4 orders of magnitude compared to the media using Ti-33at. The performance was sufficiently good. For the media using Ti-15at.% Cu, only the test example No. 201 in which the film thickness of the first underlayer 11 is 5.0 nm was evaluated for recording / reproducing characteristics, and the magnetic characteristics of the other test examples were greatly deteriorated. Therefore, the recording / reproduction characteristics were not evaluated. Compared to the media using Ti-33at.% Cu, Test Example No. 201 deteriorated BER by almost one digit and Smf / N deteriorated by 1 dB or more.

〈比較例２〉
第１の下地層11に10.0〜20.0nmのCo-50at.%Ti合金層を形成した以外、実施例２と同様にして磁気ディスクを作製した。本比較例（試験例No.221〜223）の評価結果を図１０に示す。記録再生特性評価にはヘッドサンプル（HEADNo.2）を用いた。BrtおよびHcrは実施例２の試験例No.205〜216と同等であった。図１１に試験例No.222のX線回折プロファイルを示す。本比較例のX線回折ピークはCo基合金の11.0回折ピークとCr基合金の200回折ピークのみが現れた。ただし、Δθ50の値は実施例２の試験例No.205〜216に比べ0.8°程度大きくなった。本比較例のlogBERは−６桁程度の値で良好であったが、Smf/Nは実施例２の試験例No.205〜216に比べ0.5〜１dB程度劣化した。このSmf/Nの違いはΔθ50の値の差に現れたような結晶配向性の違いによるものと考えられる。すなわち、Ti-Cu合金を第１の下地層11に用いると結晶配向性を高めることができ、その結果、記録再生特性を改善できることがわかる。 <Comparative example 2>
A magnetic disk was manufactured in the same manner as in Example 2 except that a Co-50 at.% Ti alloy layer of 10.0 to 20.0 nm was formed on the first underlayer 11. The evaluation results of this comparative example (Test Examples No. 221 to 223) are shown in FIG. A head sample (HEAD No. 2) was used for evaluation of recording and reproduction characteristics. Brt and Hcr were equivalent to Test Examples Nos. 205 to 216 in Example 2. FIG. 11 shows the X-ray diffraction profile of Test Example No. 222. As for the X-ray diffraction peak of this comparative example, only the 11.0 diffraction peak of the Co-based alloy and the 200 diffraction peak of the Cr-based alloy appeared. However, the value of Δθ50 was larger by about 0.8 ° than Test Example Nos. 205 to 216 of Example 2. The logBER of this comparative example was good at a value of about -6 digits, but Smf / N was deteriorated by about 0.5 to 1 dB as compared with Test Examples Nos. 205 to 216 of Example 2. This difference in Smf / N is considered to be due to the difference in crystal orientation as shown in the difference in Δθ50. That is, it can be seen that when a Ti—Cu alloy is used for the first underlayer 11, the crystal orientation can be enhanced, and as a result, the recording / reproducing characteristics can be improved.

〈実施例３〉
第１の下地層11の成膜時のArガス圧力を0.53〜2.13Paとし、実施例２と同様に磁気ディスクを作製した。本実施例（No.301〜312）の評価結果を図１２に示す。図１２には実施例２の試験例No.201、206、210、214の結果も併せて示した。記録再生特性評価にはヘッドサンプル（HEADNo.2）を用いた。第１の下地層成膜時のArガス圧力に対し、BrtとHcrはほぼ一定となった。第１の下地層11の組成によらず、Arガス圧力増加とともにΔθ50の値が徐々に大きくなった。ただし、第１の下地層11に含まれるCu濃度が高くなるにつれてΔθ50の増加幅は小さくなった。一方、第１の下地層11の組成によらず、Arガス圧力増加とともにBrORが徐々に増加した。特に第１の下地層11にTi-41at.%Cuを用いた試験例No.214および310〜312では、Arガス圧力増加とともにSmf/NとlogBERが改善した。これは、Δθ50を大きく劣化させずにBrORを向上できたためである。 <Example 3>
The Ar gas pressure during film formation of the first underlayer 11 was 0.53 to 2.13 Pa, and a magnetic disk was manufactured in the same manner as in Example 2. The evaluation results of this example (Nos. 301 to 312) are shown in FIG. FIG. 12 also shows the results of Test Examples Nos. 201, 206, 210, and 214 of Example 2. A head sample (HEAD No. 2) was used for evaluation of recording and reproduction characteristics. Brt and Hcr were almost constant with respect to the Ar gas pressure during the formation of the first underlayer. Regardless of the composition of the first underlayer 11, the value of Δθ50 gradually increased with increasing Ar gas pressure. However, the increase width of Δθ50 became smaller as the Cu concentration contained in the first underlayer 11 increased. On the other hand, regardless of the composition of the first underlayer 11, BrOR gradually increased with increasing Ar gas pressure. In particular, in Test Examples Nos. 214 and 310 to 312 using Ti-41 at.% Cu for the first underlayer 11, Smf / N and logBER improved with increasing Ar gas pressure. This is because BrOR could be improved without significantly degrading Δθ50.

〈比較例３〉
第１の下地層11に15.0nmのCo-50at.%Ti合金層を用い、成膜時のArガス圧力を0.53〜2.13Paとして、実施例３と同様に磁気ディスクを作製した。本比較例（試験例No.321〜323）の評価結果を図１３に示す。図１３には比較例２の試験例No.222の結果も併せて示した。記録再生特性評価にはヘッドサンプル（HEADNo.2）を用いた。第１の下地層成膜時のArガス圧力が増加するに従って、Δθ50の値が急激に大きくなった。このことから、Ti-Cu合金を第１の下地層11に用いた場合、結晶配向性を向上できるだけでなく、成膜時のArガス圧力に対して結晶配向性をより安定化できることがわかる。 <Comparative Example 3>
A magnetic disk was manufactured in the same manner as in Example 3 by using a Co-50 at.% Ti alloy layer of 15.0 nm as the first underlayer 11 and setting the Ar gas pressure during film formation to 0.53 to 2.13 Pa. The evaluation results of this comparative example (Test Examples No. 321 to 323) are shown in FIG. FIG. 13 also shows the results of Test Example No. 222 of Comparative Example 2. A head sample (HEAD No. 2) was used for evaluation of recording and reproduction characteristics. As the Ar gas pressure at the time of forming the first underlayer increased, the value of Δθ50 suddenly increased. From this, it can be seen that when a Ti—Cu alloy is used for the first underlayer 11, not only the crystal orientation can be improved, but also the crystal orientation can be further stabilized against the Ar gas pressure during film formation.

〈実施例４〉
基板10上に第１の下地層11として15.0nmのTi-Cu合金層、第２の下地層12として3.0nmのW-30at.%Co合金層を室温で形成した。ランプヒータによって基板の温度を約310℃になるように加熱した後、第３の下地層13として厚さ8.0nmのCr-10at.%Ti-3at.%B合金層を形成した。更に厚さ3.0nmのCo-14at.%Cr-6at.%Pt合金からなる第１の磁性層14、0.6nmのRu中間層15、15.0nmのCo-18at.%Cr-13at.%Pt-8at.%B合金からなる第２の磁性層16、2.5nmのCo-11at.%Cr-13at.%Pt-15at.%B合金からなる第３の磁性層を順次形成後、保護膜17として3.0nmのカーボンを主成分とする膜を形成した。保護膜形成後、パーフルオロアルキルポリエーテルを主成分とする潤滑剤を塗布して厚さ1.8nmの潤滑膜を形成した。 <Example 4>
A 15.0 nm Ti—Cu alloy layer as a first underlayer 11 and a 3.0 nm W-30 at.% Co alloy layer as a second underlayer 12 were formed on a substrate 10 at room temperature. After heating the substrate to about 310 ° C. with a lamp heater, a Cr-10 at.% Ti-3 at.% B alloy layer having a thickness of 8.0 nm was formed as the third underlayer 13. Furthermore, a first magnetic layer 14 made of a Co-14at.% Cr-6at.% Pt alloy with a thickness of 3.0 nm, a 0.6 nm Ru intermediate layer 15, a 15.0 nm Co-18at.% Cr-13at.% Pt- A second magnetic layer 16 made of 8 at.% B alloy and a third magnetic layer made of 2.5 nm Co-11 at.% Cr-13 at.% Pt-15 at. A film composed mainly of 3.0 nm carbon was formed. After forming the protective film, a lubricant mainly composed of perfluoroalkyl polyether was applied to form a lubricating film having a thickness of 1.8 nm.

第１の下地層11の成膜には以下の組成のTi-Cu合金ターゲットを用いた。
Ti-25at.%Cu、
Ti-33at.%Cu、
Ti-41at.%Cu、
Ti-50at.%Cu。
成膜には表面に同心円状のテクスチャ加工が施されたアルミノシリケートガラス基板10を用いた。基板は成膜前にアルカリ洗浄を行い乾燥させた。上記多層膜の形成は枚葉式スパッタリング装置を用いて行った。このスパッタリング装置のベース真空度は1.0〜1.2×10^-5Paであった。タクトは９秒とした。成膜時のArガス圧力は、第１の下地層11は0.53〜3.72Pa、第２の下地層12は0.53Pa、第３の下地層13から第３の磁性層までは0.93Paとした。加熱はArに酸素を１%添加した混合ガス雰囲気中で行った。カーボン保護膜17はArに窒素を10％添加した混合ガス雰囲気中で形成した。第１の下地層11、第２の磁性層14および第３の磁性層の放電時間は4.5秒、第２の下地層12、第１の磁性層14および中間層15の放電時間は2.5秒、第３の下地層13の放電時間は4.0秒とした。 A Ti—Cu alloy target having the following composition was used for forming the first underlayer 11.
Ti-25at.% Cu,
Ti-33at.% Cu,
Ti-41at.% Cu,
Ti-50at.% Cu.
For the film formation, an aluminosilicate glass substrate 10 having a concentric texture on the surface was used. The substrate was cleaned by alkali washing before film formation. The multilayer film was formed using a single wafer sputtering apparatus. The base vacuum degree of this sputtering apparatus was 1.0 to 1.2 × 10 ⁻⁵ Pa. The tact time was 9 seconds. The Ar gas pressure during film formation was 0.53 to 3.72 Pa for the first underlayer 11, 0.53 Pa for the second underlayer 12, and 0.93 Pa from the third underlayer 13 to the third magnetic layer. Heating was performed in a mixed gas atmosphere in which 1% of oxygen was added to Ar. The carbon protective film 17 was formed in a mixed gas atmosphere in which 10% of nitrogen was added to Ar. The discharge time of the first underlayer 11, the second magnetic layer 14 and the third magnetic layer is 4.5 seconds, the discharge time of the second underlayer 12, the first magnetic layer 14 and the intermediate layer 15 is 2.5 seconds, The discharge time of the third underlayer 13 was 4.0 seconds.

本実施例（試験例No.401〜416）の評価結果を図１４に示す。記録再生特性評価にはヘッドサンプル（HEADNo.3）を用いた。第１の下地層11にTi-25at.%CuおよびTi-33at.%Cuを用いた場合、第１の下地層成膜時のArガス圧力が1.60PaのときΔθ50が最小となりBrORが最大となり、Smf/NおよびlogBERが最良となった。Ti-41at.%CuおよびTi-50at.%Cuを用いた場合、Arガス圧力が0.53PaのときΔθ50が最小となったが、BrORは小さくなった。Ti-41at.%CuおよびTi-50at.%Cuを用いた場合、Δθ50が5.5°程度でBrORが1.3程度の値をとるとき、Smf/NとlogBERが最良となった。以上より、記録再生特性改善のためにはΔθ50とBrORを同時に改善する必要があることがわかる。第１の下地層11に用いるTi-Cu合金の組成と成膜条件を制御することにより、Δθ50とBrORを同時に改善できる。 The evaluation results of this example (Test Examples Nos. 401 to 416) are shown in FIG. A head sample (HEAD No. 3) was used for evaluation of recording and reproduction characteristics. When Ti-25at.% Cu and Ti-33at.% Cu are used for the first underlayer 11, Δθ50 is minimized and BrOR is maximized when the Ar gas pressure during the formation of the first underlayer is 1.60 Pa. , Smf / N and logBER were the best. When Ti-41at.% Cu and Ti-50at.% Cu were used, Δθ50 was minimized when the Ar gas pressure was 0.53 Pa, but BrOR became smaller. When Ti-41at.% Cu and Ti-50at.% Cu were used, Smf / N and logBER were the best when Δθ50 was about 5.5 ° and BrOR was about 1.3. From the above, it can be seen that Δθ50 and BrOR must be improved at the same time in order to improve the recording and reproduction characteristics. By controlling the composition of the Ti—Cu alloy used for the first underlayer 11 and the film forming conditions, Δθ50 and BrOR can be improved simultaneously.

〈比較例４〉
第１の下地層11の材料を変え、成膜時のArガス圧力を0.53〜2.13Paとして、実施例４と同様に磁気ディスクを作製した。第１の下地層11の成膜には以下の合金ターゲットを用いた。
Co-50at.%Ti、
Cr-50at.%Ti、
Cr-44at.%Ti-12at.%Al。
本比較例（試験例No.421〜432）の評価結果を図１５に示す。記録再生特性評価にはヘッドサンプル（HEADNo.3）を用いた。第１の下地層成膜時のArガス圧力増加とともに、Δθ50の値が急激に増加した。Δθ50の値は最良の場合でも６°程度で、実施例４のTi-Cu合金を第１の下地層11に用いた場合に比べ悪くなった。ただし、BrORは最大1.3程度で実施例４の媒体と同程度であった。Δθ50が劣化したため、Smf/Nも実施例４の媒体に比べ若干劣化した。以上より、Δθ50とBrORを同時に改善し記録再生特性を改善するには、第１の下地層11にTi-Cu合金を用いることが有効であることがわかる。 <Comparative example 4>
A magnetic disk was manufactured in the same manner as in Example 4 by changing the material of the first underlayer 11 and setting the Ar gas pressure during film formation to 0.53 to 2.13 Pa. The following alloy target was used for forming the first underlayer 11.
Co-50at.% Ti,
Cr-50at.% Ti,
Cr-44at.% Ti-12at.% Al.
The evaluation results of this comparative example (Test Examples No. 421 to 432) are shown in FIG. A head sample (HEAD No. 3) was used for evaluation of recording and reproduction characteristics. As the Ar gas pressure increased during the formation of the first underlayer, the value of Δθ50 increased rapidly. The value of Δθ50 is about 6 ° at the best, which is worse than when the Ti—Cu alloy of Example 4 is used for the first underlayer 11. However, BrOR was about 1.3 at the maximum, which was about the same as the medium of Example 4. Since Δθ50 was deteriorated, Smf / N was slightly deteriorated as compared with the medium of Example 4. From the above, it can be seen that it is effective to use a Ti—Cu alloy for the first underlayer 11 in order to improve Δθ50 and BrOR at the same time to improve the recording / reproducing characteristics.

〈実施例５〉
基板10上に15.0nmの第１の下地層11を形成後、第２の下地層12として3.0nmのW-30at.%Co合金層を室温で形成した。ランプヒータによって基板の温度を約370℃になるように加熱した後、第３の下地層13として厚さ8.0nmのCr-10at.%Ti-3at.%B合金層を形成した。更に厚さ1.2nmのCo-16at.%Cr-9at.%Pt合金からなる第１の磁性層14、9.0nmのCo-22at.%Cr-14at.%Pt-6at.%B-2at.%Ta合金からなる第２の磁性層16、9.5nmのCo-12at.%Cr-13at.%Pt-12at.%B合金からなる第３の磁性層を順次形成後、保護膜17として3.0nmのカーボンを主成分とする膜を形成した。保護膜形成後、パーフルオロアルキルポリエーテルを主成分とする潤滑剤を塗布して厚さ1.8nmの潤滑膜18を形成した。 <Example 5>
After forming the first underlayer 11 of 15.0 nm on the substrate 10, a W-30 at.% Co alloy layer of 3.0 nm was formed as the second underlayer 12 at room temperature. After heating the substrate to about 370 ° C. with a lamp heater, a Cr-10 at.% Ti-3 at.% B alloy layer having a thickness of 8.0 nm was formed as the third underlayer 13. Further, a first magnetic layer 14 made of a Co-16at.% Cr-9at.% Pt alloy with a thickness of 1.2 nm, Co-22at.% Cr-14at.% Pt-6at.% B-2at.% With a thickness of 9.0 nm The second magnetic layer 16 made of Ta alloy and the third magnetic layer made of Co-12at.% Cr-13at.% Pt-12at.% B alloy of 9.5 nm are sequentially formed, and then a protective film 17 of 3.0 nm A film composed mainly of carbon was formed. After forming the protective film, a lubricant mainly composed of perfluoroalkyl polyether was applied to form a lubricating film 18 having a thickness of 1.8 nm.

第１の下地層11の成膜には以下の合金ターゲットを用いた。
Ti-25at.%Cu、
Ti-40at.%Co-10at.%Ni、
Al-25at.%Cu、
Al-50at.%Cu。
成膜には表面に同心円状のテクスチャ加工が施されたアルミノシリケートガラス基板10を用いた。基板は成膜前にアルカリ洗浄を行い乾燥させた。上記多層膜の形成は枚葉式スパッタリング装置を用いて行った。このスパッタリング装置のベース真空度は1.0〜1.2×10^-5Paであった。タクトは９秒とした。成膜時のArガス圧力は、第１の下地層11と第２の下地層12は0.53Pa、第３の下地層13と第１の磁性層14は0.93Pa、第２の磁性層16と第３の磁性層は0.67Paとした。加熱はArに酸素を１%添加した混合ガス雰囲気中で行った。カーボン保護膜17はArに窒素を10％添加した混合ガス雰囲気中で形成した。第３の下地層13、第２の磁性層16および第３の磁性層のスパッタ時に-200Vのバイアス電圧を基板に印加した。第１の下地層11、第２の磁性層14および第３の磁性層の放電時間は4.5秒、第２の下地層12および第１の磁性層14の放電時間は2.5秒、第３の下地層13の放電時間は4.0秒とした。 The following alloy target was used for forming the first underlayer 11.
Ti-25at.% Cu,
Ti-40at.% Co-10at.% Ni,
Al-25at.% Cu,
Al-50at.% Cu.
For the film formation, an aluminosilicate glass substrate 10 having a concentric texture on the surface was used. The substrate was cleaned by alkali washing before film formation. The multilayer film was formed using a single wafer sputtering apparatus. The base vacuum degree of this sputtering apparatus was 1.0 to 1.2 × 10 ⁻⁵ Pa. The tact time was 9 seconds. The Ar gas pressure during film formation is 0.53 Pa for the first underlayer 11 and the second underlayer 12, 0.93 Pa for the third underlayer 13 and the first magnetic layer 14, and the second magnetic layer 16 The third magnetic layer was 0.67 Pa. Heating was performed in a mixed gas atmosphere in which 1% of oxygen was added to Ar. The carbon protective film 17 was formed in a mixed gas atmosphere in which 10% of nitrogen was added to Ar. A bias voltage of -200 V was applied to the substrate during sputtering of the third underlayer 13, the second magnetic layer 16, and the third magnetic layer. The discharge time of the first underlayer 11, the second magnetic layer 14 and the third magnetic layer is 4.5 seconds, the discharge time of the second underlayer 12 and the first magnetic layer 14 is 2.5 seconds, the third lower layer The discharge time of the formation 13 was 4.0 seconds.

本実施例（試験例No.501〜504）の評価結果を図１６に示す。記録再生特性評価にはヘッドサンプル（HEADNo.4）を用いた。第１の下地層11にTi-25at.%Cuを用いた試験例No.501がΔθ50が最も小さくなりSmf/NとlogBERが最良となった。Ti-40at.%Co-10at.%Niを用いた試験例No.502はBrORは最も大きくなったがΔθ50が試験例No.501に比べ大きくなり、Smf/NとlogBERは試験例No.501に比べ悪くなった。Al-25at.%CuおよびAl-50at.%Cuを用いた試験例No.503、504は、Δθ50が大きくなりBrORも小さくなって、磁気特性と記録再生特性が大きく劣化した。これらの結果から、第１の下地層11にはTiとCuを同時に含むことが媒体性能向上のために重要であることがわかる。 The evaluation results of this example (Test Examples No. 501 to 504) are shown in FIG. A head sample (HEAD No. 4) was used for recording / reproduction characteristics evaluation. In Test Example No. 501 in which Ti-25at.% Cu was used for the first underlayer 11, Δθ50 was the smallest and Smf / N and logBER were the best. In Test Example No. 502 using Ti-40at.% Co-10at.% Ni, BrOR was the largest, but Δθ50 was larger than Test Example No. 501, and Smf / N and logBER were Test Example No. 501. It became worse than. In Test Examples Nos. 503 and 504 using Al-25at.% Cu and Al-50at.% Cu, Δθ50 was increased and BrOR was decreased, so that the magnetic characteristics and the recording / reproducing characteristics were greatly deteriorated. From these results, it is understood that it is important for the first underlayer 11 to simultaneously contain Ti and Cu for improving the medium performance.

〈実施例６〉
基板10上に15.0nmの第１の下地層11を形成後、第２の下地層12として3.0nmのW-30at.%Co合金層を室温で形成した。ランプヒータによって基板の温度を約370℃になるように加熱した後、第３の下地層13として厚さ8.0nmのCr-10at.%Ti-3at.%B合金層を形成した。更に厚さ2.5nmのCo-16at.%Cr-9at.%Pt合金からなる第１の磁性層14、0.6nmのRuからなる第１の中間層15、12.0nmのCo-16at.%Cr-12at.%Pt-8at.%B合金からなる第２の磁性層16、0.7nmのRuからなる第２の中間層、10.0nmのCo-11at.%Cr-13at.%Pt-15at.%B合金からなる第３の磁性層を順次形成後、保護膜17として3.0nmのカーボンを主成分とする膜を形成した。保護膜形成後、パーフルオロアルキルポリエーテルを主成分とする潤滑剤を塗布して厚さ1.8nmの潤滑膜を形成した。 <Example 6>
After forming the first underlayer 11 of 15.0 nm on the substrate 10, a W-30 at.% Co alloy layer of 3.0 nm was formed as the second underlayer 12 at room temperature. After heating the substrate to about 370 ° C. with a lamp heater, a Cr-10 at.% Ti-3 at.% B alloy layer having a thickness of 8.0 nm was formed as the third underlayer 13. Furthermore, a first magnetic layer 14 made of a Co-16at.% Cr-9at.% Pt alloy with a thickness of 2.5 nm, a first intermediate layer 15 made of 0.6 nm with Ru, and a Co-16at.% Cr— with 12.0 nm. 2nd magnetic layer 16 made of 12at.% Pt-8at.% B alloy, 2nd intermediate layer made of 0.7nm Ru, 10.0nm Co-11at.% Cr-13at.% Pt-15at.% B After sequentially forming the third magnetic layer made of an alloy, a film containing 3.0 nm carbon as a main component was formed as the protective film 17. After forming the protective film, a lubricant mainly composed of perfluoroalkyl polyether was applied to form a lubricating film having a thickness of 1.8 nm.

第1の下地層の成膜には以下の合金ターゲットを用いた。
Ti-25at.%Cu、
Ti-50at.%Cu、
Ti-25at.%Cu-25at.%Al、
Ti-33at.%Cu-33at.%Al。
成膜には表面に同心円状のテクスチャ加工が施されたアルミノシリケートガラス基板10を用いた。基板は成膜前にアルカリ洗浄を行い乾燥させた。上記多層膜の形成は枚葉式スパッタリング装置を用いて行った。このスパッタリング装置のベース真空度は1.0〜1.2×10^-5Paであった。タクトは９秒とした。成膜時のArガス圧力は、第１の下地層11は0.53〜1.60Pa、第２の下地層12は0.53Pa、第３の下地層13から第３の磁性層までは0.93Paとした。加熱はArに酸素を１%添加した混合ガス雰囲気中で行った。カーボン保護膜17はArに窒素を10％添加した混合ガス雰囲気中で形成した。第３の下地層13、第２の磁性層16および第３の磁性層のスパッタ時に-200Vのバイアス電圧を基板に印加した。第１の下地層11、第２の磁性層14および第３の磁性層の放電時間は4.5秒、第２の下地層12、第１の磁性層14、第１の中間層15および第２の中間層の放電時間は2.5秒、第３の下地層13の放電時間は4.0秒とした。 The following alloy target was used for forming the first underlayer.
Ti-25at.% Cu,
Ti-50at.% Cu,
Ti-25at.% Cu-25at.% Al,
Ti-33at.% Cu-33at.% Al.
For the film formation, an aluminosilicate glass substrate 10 having a concentric texture on the surface was used. The substrate was cleaned by alkali washing before film formation. The multilayer film was formed using a single wafer sputtering apparatus. The base vacuum degree of this sputtering apparatus was 1.0 to 1.2 × 10 ⁻⁵ Pa. The tact time was 9 seconds. The Ar gas pressure during film formation was 0.53 to 1.60 Pa for the first underlayer 11, 0.53 Pa for the second underlayer 12, and 0.93 Pa from the third underlayer 13 to the third magnetic layer. Heating was performed in a mixed gas atmosphere in which 1% of oxygen was added to Ar. The carbon protective film 17 was formed in a mixed gas atmosphere in which 10% of nitrogen was added to Ar. A bias voltage of -200 V was applied to the substrate during sputtering of the third underlayer 13, the second magnetic layer 16, and the third magnetic layer. The discharge time of the first underlayer 11, the second magnetic layer 14, and the third magnetic layer is 4.5 seconds, the second underlayer 12, the first magnetic layer 14, the first intermediate layer 15, and the second magnetic layer. The discharge time of the intermediate layer was 2.5 seconds, and the discharge time of the third underlayer 13 was 4.0 seconds.

本実施例（試験例No.601〜612）の評価結果を図１７に示す。記録再生特性評価にはヘッドサンプル（HEADNo.5）を用いた。各試験例とも同等のΔθ50の値を示し、Smf/NとlogBERもほぼ同等であった。第１の下地層11にTi-Cu-Al合金を用いた媒体はTi-Cu合金を用いた媒体に比べ、BrORが若干高くなった。Ti-Cu合金にAlなどの第３の材料を加えることで、更なる性能向上を見込めることがわかる。 The evaluation results of this example (Test Examples No. 601 to 612) are shown in FIG. A head sample (HEAD No. 5) was used for evaluation of recording and reproduction characteristics. Each test example showed an equivalent value of Δθ50, and Smf / N and logBER were almost equivalent. The medium using the Ti—Cu—Al alloy for the first underlayer 11 has a slightly higher BrOR than the medium using the Ti—Cu alloy. It can be seen that further performance improvement can be expected by adding a third material such as Al to the Ti-Cu alloy.

以上の説明のとおり本発明の各実施例によれば、高い媒体S/Nを有し、オーバーライト特性に問題なく、ビットエラーレートに優れ、かつ熱揺らぎに対しても十分に安定な磁気ディスクを提供することができる。また、上記磁気ディスクを高感度な磁気ヘッドと組み合わせた磁気ディスク装置においては、１平方ミリメートル当たり160メガビット以上の面記録密度を実現することが可能となる。 As described above, according to each embodiment of the present invention, a magnetic disk having a high medium S / N, no problem in overwrite characteristics, excellent bit error rate, and sufficiently stable against thermal fluctuation. Can be provided. Further, in a magnetic disk device in which the above magnetic disk is combined with a highly sensitive magnetic head, it is possible to realize a surface recording density of 160 megabits or more per square millimeter.

本発明の実施例による磁気ディスクの基本構成を示す断面図である。It is sectional drawing which shows the basic composition of the magnetic disc by the Example of this invention. 磁気ディスクの電磁変換特性の測定に用いられる磁気ヘッドの特性を示す図である。It is a figure which shows the characteristic of the magnetic head used for the measurement of the electromagnetic conversion characteristic of a magnetic disc. 本発明の実施例１による磁気ディスクの媒体諸特性を示す図である。It is a figure which shows the medium characteristics of the magnetic disc by Example 1 of this invention. 比較例１の媒体諸特性を示す図である。FIG. 6 is a diagram showing various media characteristics of Comparative Example 1; 本発明の実施例２による磁気ディスクの媒体諸特性を示す図である。It is a figure which shows the medium characteristics of the magnetic disc by Example 2 of this invention. 本発明の実施例２による磁気ディスクのX線回折プロファイルを示す図である。It is a figure which shows the X-ray-diffraction profile of the magnetic disc by Example 2 of this invention. 本発明の実施例２による磁気ディスクのX線回折プロファイルを示す図である。It is a figure which shows the X-ray-diffraction profile of the magnetic disc by Example 2 of this invention. 本発明の実施例２による磁気ディスクのX線回折プロファイルを示す図である。It is a figure which shows the X-ray-diffraction profile of the magnetic disc by Example 2 of this invention. 本発明の実施例２による磁気ディスクのX線回折プロファイルを示す図である。It is a figure which shows the X-ray-diffraction profile of the magnetic disc by Example 2 of this invention. 比較例２の媒体諸特性を示す図である。FIG. 6 is a diagram showing various media characteristics of Comparative Example 2. 比較例２のX線回折プロファイルを示す図である。6 is a diagram showing an X-ray diffraction profile of Comparative Example 2. FIG. 本発明の実施例３による磁気ディスクの媒体諸特性を示す図である。It is a figure which shows the medium characteristics of the magnetic disc by Example 3 of this invention. 比較例３の媒体諸特性を示す図である。FIG. 6 is a diagram showing various media characteristics of Comparative Example 3. 本発明の実施例４による磁気ディスクの媒体諸特性を示す図である。It is a figure which shows the medium characteristics of the magnetic disc by Example 4 of this invention. 比較例４の媒体諸特性を示す図である。FIG. 6 is a diagram showing various media characteristics of Comparative Example 4. 本発明の実施例５による磁気ディスクの媒体諸特性を示す図である。It is a figure which shows the medium characteristics of the magnetic disc by Example 5 of this invention. 本発明の実施例６による磁気ディスクの媒体諸特性を示す図である。It is a figure which shows the medium characteristics of the magnetic disc by Example 6 of this invention.

符号の説明Explanation of symbols

１０…基板、
１１…第１の下地層、
１２…第２の下地層、
１３…第３の下地層、
１４…第１の磁性層、
１５…中間層、
１６…第２の磁性層、
１７…保護膜、
１８…潤滑膜。
10 ... substrate,
11 ... first underlayer,
12 ... Second underlayer,
13 ... Third underlayer,
14 ... 1st magnetic layer,
15 ... intermediate layer,
16 ... the second magnetic layer,
17 ... Protective film,
18 ... Lubricating film.

Claims

基板上に下地膜と磁性膜が順次形成された磁気記録媒体において、
前記下地膜は少なくとも３層の下地層を有し、
前記下地層のうち前記基板に接して形成される層はTiとCuを含有する非晶質合金層であり、
前記下地層のうち前記磁性膜に接して形成される層は体心立方構造のCr基合金層であり、
前記磁性膜は六方稠密構造のCo基合金であることを特徴とする磁気記録媒体。 In a magnetic recording medium in which a base film and a magnetic film are sequentially formed on a substrate,
The base film has at least three base layers,
Of the underlying layer, the layer formed in contact with the substrate is an amorphous alloy layer containing Ti and Cu,
Of the underlayer, the layer formed in contact with the magnetic film is a body-centered cubic Cr-based alloy layer,
The magnetic recording medium is characterized in that the magnetic film is a Co-based alloy having a hexagonal close-packed structure.

請求項１に記載の磁気記録媒体において、
前記下地膜は第１の下地層と第２の下地層と第３の下地層を有し、
前記第１の下地層はTiとCuを含有する非晶質合金層であり、
前記第２の下地層はWとCoを含有する非晶質合金層であり、
前記第３の下地層はTiとBを含有する体心立方構造のCr基合金層であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 1,
The base film has a first base layer, a second base layer, and a third base layer,
The first underlayer is an amorphous alloy layer containing Ti and Cu,
The second underlayer is an amorphous alloy layer containing W and Co;
3. The magnetic recording medium according to claim 1, wherein the third underlayer is a Cr-based alloy layer having a body-centered cubic structure containing Ti and B.

請求項１に記載の磁気記録媒体において、
前記下地膜は第１の下地層と第２の下地層と第３の下地層を有し、
前記第１の下地層はTiとCuを含有する非晶質合金層であり、
前記第２の下地層はWとCoを含有する非晶質合金層であり、
前記第３の下地層はTiとBを含有する体心立方構造のCr基合金層であり、
前記磁性膜は少なくとも２層の磁性層を有し、
前記磁性層のうち前記下地膜に接して形成される第１の磁性層はCo-Cr合金層、もしくはCo-Cr-Pt合金層、もしくはCo-Cr-B合金層であり、
前記磁性層のうち前記第１の磁性層の上部に形成される磁性層はCrとPtとBを含有するCo基合金層であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 1,
The base film has a first base layer, a second base layer, and a third base layer,
The first underlayer is an amorphous alloy layer containing Ti and Cu,
The second underlayer is an amorphous alloy layer containing W and Co;
The third underlayer is a Cr-based alloy layer having a body-centered cubic structure containing Ti and B,
The magnetic film has at least two magnetic layers;
Of the magnetic layers, the first magnetic layer formed in contact with the base film is a Co—Cr alloy layer, a Co—Cr—Pt alloy layer, or a Co—Cr—B alloy layer,
The magnetic recording medium, wherein the magnetic layer formed on the first magnetic layer of the magnetic layer is a Co-based alloy layer containing Cr, Pt, and B.

請求項３に記載の磁気記録媒体において、
前記第１の磁性層と前記第１の磁性層の上部に形成される磁性との層の間にRu中間層を有することを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 3,
A magnetic recording medium comprising a Ru intermediate layer between the first magnetic layer and the magnetic layer formed on the first magnetic layer.

請求項１に記載の磁気記録媒体において、
前記TiとCuを含有する非晶質合金層に含まれるCuの濃度は25at.%以上であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 1,
A magnetic recording medium, wherein the concentration of Cu contained in the amorphous alloy layer containing Ti and Cu is 25 at.% Or more.

請求項１に記載の磁気記録媒体において、
前記基板は表面にテクスチャ加工による溝が概ね基板円周方向に形成されており、前記磁性膜の残留磁束密度Brと膜厚tの積Brtについて、円周方向に測定したBrtθと半径方向に測定したBrtrの比Brtθ/Brtr(BrOR)が1.2以上であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 1,
The substrate has textured grooves formed on the surface thereof in a generally circumferential direction, and the product Brt of the residual magnetic flux density Br and the film thickness t of the magnetic film is measured in the radial direction with Brtθ measured in the circumferential direction. A magnetic recording medium, wherein the ratio Brrtθ / Brtr (BrOR) of Brtr is 1.2 or more.

請求項１に記載の磁気記録媒体において、
線源にCuKα1線を用いたX線回折装置を用い、X線の入射方向を媒体円周方向と平行になるようにして測定した媒体円周方向の前記磁性膜(11.0)面のロッキングカーブから求めた半値幅Δθ50が６°以下であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 1,
From the rocking curve of the magnetic film (11.0) surface in the medium circumferential direction measured using an X-ray diffractometer using CuKα1 line as the radiation source and the incident direction of the X-ray parallel to the circumferential direction of the medium A magnetic recording medium, wherein the obtained half-value width Δθ50 is 6 ° or less.

請求項１に記載の磁気記録媒体において、
前記基板は表面にテクスチャ加工による溝が概ね基板円周方向に形成されており、前記磁性膜の残留磁束密度Brと膜厚tの積Brtについて、円周方向に測定したBrtθと半径方向に測定したBrtrの比Brtθ/Brtr(BrOR)が1.2以上であり、
線源にCuKα1線を用いたX線回折装置を用い、X線の入射方向を媒体円周方向と平行になるようにして測定した媒体円周方向の前記磁性膜(11.0)面のロッキングカーブから求めた半値幅Δθ50が６°以下であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 1,
The substrate has textured grooves formed on the surface thereof in a generally circumferential direction, and the product Brt of the residual magnetic flux density Br and the film thickness t of the magnetic film is measured in the radial direction with Brtθ measured in the circumferential direction. The Brtr ratio Brtθ / Brtr (BrOR) is 1.2 or more,
From the rocking curve of the magnetic film (11.0) surface in the medium circumferential direction measured using an X-ray diffractometer using CuKα1 line as the radiation source and the incident direction of the X-ray parallel to the circumferential direction of the medium A magnetic recording medium, wherein the obtained half-value width Δθ50 is 6 ° or less.

基板上に下地膜と磁性膜が順次形成された磁気記録媒体において、
前記下地膜は少なくとも３層の下地層を有し、
前記下地層のうち前記基板に接して形成される層は非晶質Ti-Cu合金層、もしくは非晶質Ti-Cu-Al合金層であり、
前記下地層のうち前記磁性膜に接して形成される層は体心立方構造のCr基合金層であり、
前記磁性膜は六方稠密構造のCo基合金であることを特徴とする磁気記録媒体。 In a magnetic recording medium in which a base film and a magnetic film are sequentially formed on a substrate,
The base film has at least three base layers,
Of the underlying layer, the layer formed in contact with the substrate is an amorphous Ti-Cu alloy layer, or an amorphous Ti-Cu-Al alloy layer,
Of the underlayer, the layer formed in contact with the magnetic film is a body-centered cubic Cr-based alloy layer,
The magnetic recording medium is characterized in that the magnetic film is a Co-based alloy having a hexagonal close-packed structure.

請求項９に記載の磁気記録媒体において、
前記下地膜は第１の下地層と第２の下地層と第３の下地層を有し、
前記第１の下地層は非晶質Ti-Cu合金層、もしくは非晶質Ti-Cu-Al合金層であり、
前記第２の下地層は非晶質W-Co合金層であり、
前記第３の下地層は体心立方構造のCr-Ti-B合金層であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 9,
The base film has a first base layer, a second base layer, and a third base layer,
The first underlayer is an amorphous Ti—Cu alloy layer or an amorphous Ti—Cu—Al alloy layer,
The second underlayer is an amorphous W-Co alloy layer;
3. The magnetic recording medium according to claim 1, wherein the third underlayer is a body-centered cubic Cr—Ti—B alloy layer.

請求項９に記載の磁気記録媒体において、
前記下地膜は第１の下地層と第２の下地層と第３の下地層を有し、
前記第１の下地層は非晶質Ti-Cu合金層、もしくは非晶質Ti-Cu-Al合金層であり、
前記第２の下地層は非晶質W-Co合金層であり、
前記第３の下地層は体心立方構造のCr-Ti-B合金層であり、
前記磁性膜は少なくとも２層の磁性層を有し、
前記磁性層のうち前記下地膜に接して形成される第１の磁性層はCo-Cr合金層、もしくはCo-Cr-Pt合金層、もしくはCo-Cr-B合金層であり、
前記磁性層のうち前記第１の磁性層の上部に形成される磁性層はCrとPtとBを含有するCo基合金層であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 9,
The base film has a first base layer, a second base layer, and a third base layer,
The first underlayer is an amorphous Ti—Cu alloy layer or an amorphous Ti—Cu—Al alloy layer,
The second underlayer is an amorphous W-Co alloy layer;
The third underlayer is a body-centered cubic Cr-Ti-B alloy layer;
The magnetic film has at least two magnetic layers;
Of the magnetic layers, the first magnetic layer formed in contact with the base film is a Co—Cr alloy layer, a Co—Cr—Pt alloy layer, or a Co—Cr—B alloy layer,
The magnetic recording medium, wherein the magnetic layer formed on the first magnetic layer of the magnetic layer is a Co-based alloy layer containing Cr, Pt, and B.

請求項１１に記載の磁気記録媒体において、
前記第１の磁性層と前記第１の磁性層の上部に形成される磁性層との間にRu中間層を有することを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 11,
A magnetic recording medium comprising a Ru intermediate layer between the first magnetic layer and a magnetic layer formed on the first magnetic layer.

請求項９に記載の磁気記録媒体において、
前記非晶質Ti-Cu合金層、もしくは前記非晶質Ti-Cu-Al合金層に含まれるCuの濃度は25at.%以上であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 9,
A magnetic recording medium, wherein a concentration of Cu contained in the amorphous Ti—Cu alloy layer or the amorphous Ti—Cu—Al alloy layer is 25 at.% Or more.

請求項９に記載の磁気記録媒体において、
前記基板は表面にテクスチャ加工による溝が概ね基板円周方向に形成されており、前記磁性膜の残留磁束密度Brと膜厚tの積Brtについて、円周方向に測定したBrtθと半径方向に測定したBrtrの比Brtθ/Brtr(BrOR)が1.2以上であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 9,
The substrate has textured grooves formed on the surface thereof in a generally circumferential direction, and the product Brt of the residual magnetic flux density Br and the film thickness t of the magnetic film is measured in the radial direction with Brtθ measured in the circumferential direction. A magnetic recording medium, wherein the ratio Brrtθ / Brtr (BrOR) of Brtr is 1.2 or more.

請求項９に記載の磁気記録媒体において、
線源にCuKα1線を用いたX線回折装置を用い、X線の入射方向を媒体円周方向と平行になるようにして測定した媒体円周方向の前記磁性膜(11.0)面のロッキングカーブから求めた半値幅Δθ50が６°以下であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 9,
From the rocking curve of the magnetic film (11.0) surface in the medium circumferential direction measured using an X-ray diffractometer using CuKα1 line as the radiation source and the incident direction of the X-ray parallel to the circumferential direction of the medium A magnetic recording medium, wherein the obtained half-value width Δθ50 is 6 ° or less.

請求項９に記載の磁気記録媒体において、
前記基板は表面にテクスチャ加工による溝が概ね基板円周方向に形成されており、前記磁性膜の残留磁束密度Brと膜厚tの積Brtについて、円周方向に測定したBrtθと半径方向に測定したBrtrの比Brtθ/Brtr(BrOR)が1.2以上であり、
線源にCuKα1線を用いたX線回折装置を用い、X線の入射方向を媒体円周方向と平行になるようにして測定した媒体円周方向の前記磁性膜(11.0)面のロッキングカーブから求めた半値幅Δθ50が６°以下であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 9,
The substrate has textured grooves formed on the surface thereof in a generally circumferential direction, and the product Brt of the residual magnetic flux density Br and the film thickness t of the magnetic film is measured in the radial direction with Brtθ measured in the circumferential direction. The Brtr ratio Brtθ / Brtr (BrOR) is 1.2 or more,
From the rocking curve of the magnetic film (11.0) surface in the medium circumferential direction measured using an X-ray diffractometer using CuKα1 line as the radiation source and the incident direction of the X-ray parallel to the circumferential direction of the medium A magnetic recording medium, wherein the obtained half-value width Δθ50 is 6 ° or less.

基板上に下地膜と磁性膜が順次形成された磁気記録媒体において、
前記下地膜は少なくとも３層の下地層を有し、
前記下地層のうち基板に接して形成される層はTiとCuを含有する非晶質合金層であり、
前記下地層のうち前記磁性膜に接して形成される層は体心立方構造のCr基合金層であり、
前記磁性膜は少なくとも３層の磁性層を有し、
前記磁性層のうち前記下地膜に接して形成される第１の磁性層はCo-Cr合金層、もしくはCo-Cr-Pt合金層、もしくはCo-Cr-B合金層であり、
前記磁性層のうち前記第１の磁性層の上部に形成される磁性層はCrとPtとBを含有するCo基合金層であり、
前記CrとPtとBを含有するCo基合金層は上層側に向かうほどCr濃度が低くなりB濃度が高くなることを特徴とする磁気記録媒体。 In a magnetic recording medium in which a base film and a magnetic film are sequentially formed on a substrate,
The base film has at least three base layers,
Of the foundation layer, the layer formed in contact with the substrate is an amorphous alloy layer containing Ti and Cu,
Of the underlayer, the layer formed in contact with the magnetic film is a body-centered cubic Cr-based alloy layer,
The magnetic film has at least three magnetic layers,
Of the magnetic layers, the first magnetic layer formed in contact with the base film is a Co—Cr alloy layer, a Co—Cr—Pt alloy layer, or a Co—Cr—B alloy layer,
Of the magnetic layers, the magnetic layer formed on the first magnetic layer is a Co-based alloy layer containing Cr, Pt, and B,
The magnetic recording medium according to claim 1, wherein the Co-based alloy layer containing Cr, Pt, and B has a lower Cr concentration and a higher B concentration toward the upper layer.

請求項１７に記載の磁気記録媒体において、
前記第１の磁性層と前記上部の磁性層の間にRu中間層を有することを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 17,
A magnetic recording medium comprising a Ru intermediate layer between the first magnetic layer and the upper magnetic layer.

請求項１７に記載の磁気記録媒体において、
前記基板は表面にテクスチャ加工による溝が概ね基板円周方向に形成されており、前記磁性膜の残留磁束密度Brと膜厚tの積Brtについて、円周方向に測定したBrtθと半径方向に測定したBrtrの比Brtθ/Brtr(BrOR)が1.2以上であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 17,
The substrate has textured grooves formed on the surface thereof in a generally circumferential direction, and the product Brt of the residual magnetic flux density Br and the film thickness t of the magnetic film is measured in the radial direction with Brtθ measured in the circumferential direction. A magnetic recording medium, wherein the ratio Brrtθ / Brtr (BrOR) of Brtr is 1.2 or more.

請求項１７に記載の磁気記録媒体において、
線源にCuKα1線を用いたX線回折装置を用い、X線の入射方向を媒体円周方向と平行になるようにして測定した媒体円周方向の前記磁性膜(11.0)面のロッキングカーブから求めた半値幅Δθ50が６°以下であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 17,
From the rocking curve of the magnetic film (11.0) surface in the medium circumferential direction measured using an X-ray diffractometer using CuKα1 line as the radiation source and the incident direction of the X-ray parallel to the circumferential direction of the medium A magnetic recording medium, wherein the obtained half-value width Δθ50 is 6 ° or less.

請求項１７に記載の磁気記録媒体において、
前記基板は表面にテクスチャ加工による溝が概ね基板円周方向に形成されており、前記磁性膜の残留磁束密度Brと膜厚tの積Brtについて、円周方向に測定したBrtθと半径方向に測定したBrtrの比Brtθ/Brtr(BrOR)が1.2以上であり、
線源にCuKα1線を用いたX線回折装置を用い、X線の入射方向を媒体円周方向と平行になるようにして測定した媒体円周方向の前記磁性膜(11.0)面のロッキングカーブから求めた半値幅Δθ50が６°以下であることを特徴とする磁気記録媒体。 The magnetic recording medium according to claim 17,
The substrate has textured grooves formed on the surface thereof in a generally circumferential direction, and the product Brt of the residual magnetic flux density Br and the film thickness t of the magnetic film is measured in the radial direction with Brtθ measured in the circumferential direction. The Brtr ratio Brtθ / Brtr (BrOR) is 1.2 or more,
From the rocking curve of the magnetic film (11.0) surface in the medium circumferential direction measured using an X-ray diffractometer using CuKα1 line as the radiation source and the incident direction of the X-ray parallel to the circumferential direction of the medium A magnetic recording medium, wherein the obtained half-value width Δθ50 is 6 ° or less.