JPH0335422A - Production of magnetic recording medium - Google Patents
Production of magnetic recording mediumInfo
- Publication number
- JPH0335422A JPH0335422A JP16890089A JP16890089A JPH0335422A JP H0335422 A JPH0335422 A JP H0335422A JP 16890089 A JP16890089 A JP 16890089A JP 16890089 A JP16890089 A JP 16890089A JP H0335422 A JPH0335422 A JP H0335422A
- Authority
- JP
- Japan
- Prior art keywords
- film
- gas
- recording medium
- magnetic recording
- film formation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 17
- 239000000654 additive Substances 0.000 claims abstract description 16
- 230000000996 additive effect Effects 0.000 claims abstract description 16
- 239000000758 substrate Substances 0.000 claims abstract description 15
- 238000004544 sputter deposition Methods 0.000 claims abstract description 13
- 239000007789 gas Substances 0.000 abstract description 29
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 5
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 5
- 239000001301 oxygen Substances 0.000 abstract description 5
- 229910052760 oxygen Inorganic materials 0.000 abstract description 5
- 238000007599 discharging Methods 0.000 abstract description 2
- 239000010408 film Substances 0.000 description 49
- 230000007423 decrease Effects 0.000 description 10
- 238000000034 method Methods 0.000 description 6
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 5
- 229910001882 dioxygen Inorganic materials 0.000 description 5
- 229910000684 Cobalt-chrome Inorganic materials 0.000 description 4
- 239000010952 cobalt-chrome Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 229910001873 dinitrogen Inorganic materials 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000000956 alloy Substances 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 229920001721 polyimide Polymers 0.000 description 3
- 239000002689 soil Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000009751 slip forming Methods 0.000 description 2
- 229910001020 Au alloy Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000003353 gold alloy Substances 0.000 description 1
- 238000001659 ion-beam spectroscopy Methods 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 238000001552 radio frequency sputter deposition Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Landscapes
- Magnetic Record Carriers (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は磁気テープ、磁気ディスク等の磁気記録媒体の
製造方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing magnetic recording media such as magnetic tapes and magnetic disks.
磁気記録技術において、現在実用化されている長手磁気
記録方式を越える高密度記録技術として垂直磁気記録方
式が提案され、精力的に研究開発が進められている。In magnetic recording technology, a perpendicular magnetic recording system has been proposed as a high-density recording technology that exceeds the longitudinal magnetic recording system that is currently in practical use, and research and development is actively underway.
この垂直磁気記録を実現するには、磁気記録媒体は磁性
膜面に対して垂直方向に記録された磁化を安定に存在さ
せることが必要である。そこで、磁気記録媒体は磁化を
安定に存在させるために垂直磁気異方性を高めると共に
できるだけ垂直方向の保磁力を高めなければならない。In order to realize this perpendicular magnetic recording, it is necessary for the magnetic recording medium to have stable magnetization recorded in the direction perpendicular to the magnetic film surface. Therefore, in order to maintain stable magnetization in a magnetic recording medium, it is necessary to increase perpendicular magnetic anisotropy and to increase coercive force in the perpendicular direction as much as possible.
一方、磁気ヘッドから発生される記録磁界の強度は、磁
気記録媒体の表面から膜厚深さ方向に従い減少する。従
って、従来の磁気記録媒体のように垂直方向の保磁力が
膜厚の方向に−様な場合、その保磁力の増加に従い再生
出力が増加するが、ある一定の保磁力で極大値を示しそ
の後は減少する（金属表面技術、ｐ２８〜３７． ｖｏ
ｌ、３５．１９８４） 。これは、前述したように磁気
ヘッドから発生させる記録磁界の強度が磁気記録媒体の
表面から膜厚方向に従い、減少するので、ある一定の保
磁力までは膜全体が記録されるが、更に高い保磁力にな
ると磁気記録媒体の下層部では記録磁界が低いので十分
記録できなかったことによる。On the other hand, the strength of the recording magnetic field generated by the magnetic head decreases from the surface of the magnetic recording medium in the depth direction of the film thickness. Therefore, when the perpendicular coercive force is negative in the direction of the film thickness as in conventional magnetic recording media, the reproduction output increases as the coercive force increases, but reaches a maximum value at a certain coercive force and then decreases (Metal Surface Technology, p. 28-37. vo
l, 35.1984). As mentioned above, the strength of the recording magnetic field generated by the magnetic head decreases from the surface of the magnetic recording medium in the film thickness direction, so the entire film can be recorded up to a certain coercive force, but even higher When it comes to magnetic force, the recording magnetic field is low in the lower layer of the magnetic recording medium, so sufficient recording could not be achieved.
本発明の目的は、磁気ヘッドにより十分記録できるよう
に磁気記録媒体の垂直方向の保磁力を膜の表面付近で高
く、膜厚の深さ方向に進むに従い低くし、再生出力、記
録密度を改善した磁気記録媒体の製造方法を提供するこ
とにある。The purpose of the present invention is to increase the perpendicular coercive force of a magnetic recording medium near the surface of the film and to decrease it as the film thickness increases so that sufficient recording can be performed by a magnetic head, thereby improving reproduction output and recording density. An object of the present invention is to provide a method for manufacturing a magnetic recording medium.
〔課題を解決するための手段］
上記目的を達成するため、本発明による磁気記録媒体の
製造方法においては、基板上にスパッタ法により垂直磁
気異方性膜を形成する際に、少量の添加ガスを含むＡｒ
ガスで放電させ、その添加ガス分圧を膜の形成初期には
高く、形成末期には低くなるようにして膜を形成するも
のである。[Means for Solving the Problems] In order to achieve the above object, in the method for manufacturing a magnetic recording medium according to the present invention, a small amount of additive gas is used when forming a perpendicular magnetic anisotropic film on a substrate by sputtering. containing Ar
A film is formed by discharging a gas and making the partial pressure of the added gas high at the beginning of film formation and low at the end of film formation.
［作用］
基板上にスパッタ法により垂直磁気異方性膜を形成する
際に、少量の添加ガスを含むＡｒガスで放電させ、その
添加ガス分圧を膜の形成初期には高く、形成末期には低
くなるよう調整することにより、磁気記録媒体の垂直方
向の保磁力が表面付近で高く、膜厚の深さ方向に進むに
従い低くし、磁気ヘッドにより媒体の下層部まで十分記
録できる。[Function] When forming a perpendicular magnetic anisotropic film on a substrate by sputtering, a discharge is made with Ar gas containing a small amount of additive gas, and the partial pressure of the additive gas is high in the early stage of film formation and is increased in the final stage of film formation. By adjusting the perpendicular coercive force to be low, the perpendicular coercive force of the magnetic recording medium is high near the surface and decreases as the film thickness increases, allowing the magnetic head to sufficiently record to the lower layer of the medium.
次に、本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第１図は本発明による磁気記録媒体の製造方法を実施す
る連続成膜用スパッタ装置を示す概略図である。FIG. 1 is a schematic diagram showing a continuous film-forming sputtering apparatus for carrying out the method of manufacturing a magnetic recording medium according to the present invention.
図において、真空チャンバー１内に、基板（ベースフィ
ルム）３を巻付けた繰出リール６と、繰出リール６から
繰出された基板３を巻取る巻取り−ル２とを設けるとと
もに、両リール２．６の中間位置に中間ロール５を設置
し、リール２，６間に張り渡された基板３を中間ロール
５のロール面に沿って巻回する。さらに、中間ロール５
に巻回された基板３に対向させてターゲット９を設置し
、基板３とターゲット９との間にマスク８ａ、 ８ｂを
設け、さらにマスク８ａ、 ８ｂに対向する基板３付近
に添加ガス導入用ノズル７を配設する。In the figure, a vacuum chamber 1 is provided with a feed reel 6 around which a substrate (base film) 3 is wound, and a take-up reel 2 that winds up the substrate 3 fed out from the feed reel 6. An intermediate roll 5 is installed at an intermediate position between the reels 2 and 6, and the substrate 3 stretched between the reels 2 and 6 is wound along the roll surface of the intermediate roll 5. Furthermore, the intermediate roll 5
A target 9 is placed facing the substrate 3 wound around the substrate 3, masks 8a and 8b are provided between the substrate 3 and the target 9, and additional gas introduction nozzles are provided near the substrate 3 facing the masks 8a and 8b. Place 7.
本発明は第１図に示す連続成膜用スパッタ装置を用いて
繰出リール６からの基板３を中間ロール５に巻回してタ
ーゲット９に対向させ、基板３上にスパッタ法により垂
直異方性膜を形成し、その膜形成後の基板３を巻取リー
ル２に巻取り基板３上に連続して成膜を行う。ここで、
本発明は基板３上にスパッタ法により垂直異方性膜を形
成する際に、添加ガス導入用ノズル７から少量の添加ガ
スを導入し、その少量の添加ガスを含むＡｒガスで放電
させ、その添加ガス分圧を膜の形成初期には高く、形成
末期には低くなるように調整することにより、磁気記録
媒体の垂直方向の保磁力が表面付近で高く、膜厚の深さ
方向に進むに従い低くし、磁気ヘッドにより媒体の下層
部まで十分記録可能とするものである。The present invention uses a continuous film forming sputtering apparatus shown in FIG. The substrate 3 after the film formation is wound onto the take-up reel 2 and films are continuously formed on the substrate 3. here,
In the present invention, when forming a vertically anisotropic film on a substrate 3 by sputtering, a small amount of additive gas is introduced from the additive gas introduction nozzle 7, and Ar gas containing the small amount of additive gas is discharged. By adjusting the added gas partial pressure so that it is high at the beginning of film formation and low at the end of film formation, the perpendicular coercive force of the magnetic recording medium is high near the surface and increases as the film thickness increases. This allows the magnetic head to sufficiently record down to the lower layer of the medium.
まず、添加ガス（酸素、窒素）量により種々の垂直方向
の保磁力となる垂直異方性膜の作製条件について述べる
。ここで、ターゲット９にはＣｏＣｒ（Ｃｒ２０ａｔ％
）合金ターゲット上にＴａチップ（２，５ｃ上％）を配
置したものを用い、基板としてのベースフィルム３には
ポリイミドフィルムを用いた。ＣｏＣｒＴａ膜は成膜時
に＾ｒ以外に添加するガス分圧を種々変えて（但し全ガ
ス圧力は１ ｍＴｏｒｒと一定）作製した。First, we will describe the conditions for producing a perpendicularly anisotropic film that exhibits various perpendicular coercive forces depending on the amount of added gas (oxygen, nitrogen). Here, the target 9 is CoCr (Cr20at%
) A Ta chip (2.5c upper %) arranged on an alloy target was used, and a polyimide film was used as the base film 3 as a substrate. CoCrTa films were fabricated by varying the partial pressure of gases added other than ^r during film formation (however, the total gas pressure was kept constant at 1 mTorr).
これらの膜について振動試料型磁力計により磁気特性を
調べた。The magnetic properties of these films were investigated using a vibrating sample magnetometer.
第２図に垂直異方性磁界Ｈｋ及び垂直方向の保磁力Ｈｃ
上の酸素ガス分圧ＰＯｌ依存性を示す。ＨｋはＰＯｌが
ｌ Ｘ １０”−’Ｔｏｒｒ以上で６ ｋｏｅの値から
減少する。Figure 2 shows the perpendicular anisotropic magnetic field Hk and the perpendicular coercive force Hc.
The dependence of the above oxygen gas partial pressure on POl is shown. Hk decreases from a value of 6 koe when POl is greater than l x 10''-'Torr.
また、ｐｏ、の５ Ｘ １０−”ＴｏｒｒからＩ Ｘ
１０−’Ｔｏｒｒの範囲においてＰＯ，の増加に従いＨ
ｃ上の値は１，２０００ｅから４００ｅへと減少する。Also, from 5 x 10-” Torr of po,
In the range of 10-' Torr, as PO increases, H
The value on c decreases from 1,2000e to 400e.
次に、第３図にＨｋ及びＨｅの窒素ガス分圧ＰＮ、依存
性を示す。ＨｋはＰＮ、が２ＸＩＯ−”Ｔｏｒｒ以上で
６ ｋＯｅの値から減少する。また、ＰＮ、の２ Ｘ
１０＝’ Ｔｏｒｒから５ Ｘ １０−’Ｔｏｒｒの範
囲においてＰＮ。Next, FIG. 3 shows the dependence of Hk and He on nitrogen gas partial pressure PN. Hk decreases from the value of 6 kOe when PN is 2XIO-"Torr or more.
PN in the range of 10='Torr to 5 x 10-'Torr.
の増加に従いＨｅ上の値は１，０ＯＯＯｅから４００ｅ
へと減少する。以上のようにＰＯｌ、 ＰＮ、により種
々のｌ−１ｃ上の垂直異方性が得られる。As the value increases, the value on He increases from 1,000e to 400e
decreases to As described above, various perpendicular anisotropies on l-1c can be obtained by POl and PN.
次に上記結果を用い本発明の磁気記録媒体の製造方法に
ついて述べる。まず、添加ガスとして酸素を用いた実施
例について述べる。真空チャンバー１内で中間ロール５
によりベースフィルム３を加熱しながら繰出リール６か
ら繰出した後、Ａｒガスと添加ガス導入用ノズル７を通
して酸素ガスを導入し、投入電力１ｋＷ、全ガス圧力１
ｍＴｏｒｒのスパッタ条件で中間ロール５を回転させ
ベースフィルム３を矢印４の方向に走行させながら連続
的にＣｏＣｒＴａ膜を０．３ｂｍＪｌ［成膜した。ここ
で、ノズル７は一定の酸素ガス流量のもとてその空間的
な配置により、右側マスク８ａの左端（即ち膜の形成初
期）から左側マスク８ｂの右端（即ち形成末期）に進む
に従い酸素ガス分圧ｐｏ、がＩ Ｘ １０−’Ｔｏｒｒ
から５ＸＩＯ−’Ｔｏｒｒへ減少するようにした。なお
、成膜中の中間ロール５の温度は約１００℃と一定にし
た。このように作製したＣｏＣｒＴａ媒体のＨｅ土は膜
の表面の１，２０００ｅの値から深さ方向に進むに従い
減少し、膜の初期層では４００ｅの値となった。また比
較のために従来例としてＡｒガスのみでＣｏＣｒＴａ
（０，３ｐ ｍ厚）媒体も同様に作製した。この場合、
ＣｏＣｒＴａ膜のＨｅ土はほぼ膜厚方向によらず９００
０ｅの値となった。Next, the method for manufacturing the magnetic recording medium of the present invention will be described using the above results. First, an example using oxygen as the additive gas will be described. Intermediate roll 5 in vacuum chamber 1
After feeding the base film 3 from the feeding reel 6 while heating it, oxygen gas was introduced through the nozzle 7 for introducing Ar gas and additive gas, and the input power was 1 kW and the total gas pressure was 1.
A CoCrTa film of 0.3 bJl was continuously formed under sputtering conditions of mTorr while rotating the intermediate roll 5 and running the base film 3 in the direction of the arrow 4. Here, due to the spatial arrangement of the nozzle 7 with a constant flow rate of oxygen gas, the oxygen gas flows as it progresses from the left end of the right mask 8a (i.e., the initial stage of film formation) to the right end of the left mask 8b (i.e., the final stage of film formation). The partial pressure po is I x 10-'Torr
to 5XIO-'Torr. Note that the temperature of the intermediate roll 5 during film formation was kept constant at about 100°C. The He soil in the CoCrTa medium thus prepared decreased from a value of 1,2000e at the surface of the film as it progressed in the depth direction, reaching a value of 400e in the initial layer of the film. For comparison, as a conventional example, CoCrTa was produced using only Ar gas.
A (0.3 pm thick) medium was similarly prepared. in this case,
The He soil of the CoCrTa film is 900% regardless of the film thickness direction.
The value was 0e.
以上のように本発明の製造方法により作製したＣｏＣｒ
Ｔａ膜及び従来と同様な方法で作製したＣｏＣｒＴａ膜
についてそれぞれ記録再生特性を調べた。ここで用いた
ヘッドはギャプ長０．３１Ｌｍのものである。CoCr produced by the production method of the present invention as described above
The recording and reproducing characteristics of a Ta film and a CoCrTa film produced by a conventional method were investigated. The head used here had a gap length of 0.31 Lm.
その結果を第４図に示す。第４図は再生出力Ｖ（相対値
）の記録密度り依存性を示したものである。The results are shown in FIG. FIG. 4 shows the dependence of the reproduction output V (relative value) on the recording density.
本結果から本発明の製造方法により作製したＣｏＣｒＴ
ａ膜が再生出力、記録密度共に従来に比べ改善されるこ
とがわかった。From this result, CoCrT produced by the production method of the present invention
It was found that the a-film has improved both reproduction output and recording density compared to the conventional one.
次に添加ガスとして窒素を用いた実施例について述べる
。窒素の場合、第３図から上記酸素と同様に膜厚方向に
依存したＨｅ土を得るために右側マスク８ａの左端の窒
素ガス分圧ＰＮ、を５ Ｘ １０−’Ｔｏｒｒ。Next, an example using nitrogen as the additive gas will be described. In the case of nitrogen, the nitrogen gas partial pressure PN at the left end of the right mask 8a is set to 5 x 10-' Torr in order to obtain a He soil that depends on the film thickness direction, as in the case of oxygen, as shown in FIG.
左側マスク８ｂの右端のＰＮ、を２ Ｘ １０−”Ｔｏ
ｒｒとなるようにノズル７及び窒素ガス流量を調整し他
のスパッタ条件は同様にして作製した。その結果第４図
と同様に再生出力、記録密度が改善されることがわかっ
た。The right end PN of the left mask 8b is 2 x 10-”To
The nozzle 7 and the nitrogen gas flow rate were adjusted so that the sputtering conditions were rr, and the other sputtering conditions were the same. As a result, it was found that the reproduction output and recording density were improved as shown in FIG.
上記の実施例において、ターゲット９はＣｏＣｒ合金タ
ーゲット上にＴａチップを配置した複合ターゲットを用
いたが、ＣｏＣｒＴａ合金ターゲット等いずれのターゲ
ットでもよく、Ｃｒ組成、Ｔａ組成もそれぞれ２０ａｔ
％、２，５ａｔ％以外のものでもよい。ベースフィルム
３はポリイミドフィルムを用いたが、ポリイアミドフィ
ルム、ポリエステルフィルム等地の有機フィルムでもよ
い、また、スパッタ中において、投入電力及び全ガス圧
はそれぞれ１．ＯｋＷ、 １ｍＴ。In the above embodiment, the target 9 used was a composite target in which Ta chips were placed on a CoCr alloy target, but any target such as a CoCrTa alloy target could be used, and the Cr composition and Ta composition were each 20 at.
%, 2.5at% may be used. Although a polyimide film was used as the base film 3, it may also be an organic film such as a polyimide film or a polyester film.During sputtering, the input power and total gas pressure were each 1. OKW, 1mT.
ｒｒとしたが、他の値でも良く、中間ロール５の温度も
約１００℃と設定したが、他の温度でも良い。rr, but other values may be used, and although the temperature of the intermediate roll 5 is also set at approximately 100°C, other temperatures may be used.
さらに本実施例において、ＣｏＣｒＴａ膜の作製にはＲ
Ｆマグネトロンスパッタ法を用いたが、ＲＦスパッタ法
、ＤＣスパッタ法、イオンビームスパッタ法、電子ビー
ム蒸着法、抵抗加熱蒸着法、ＭＢＥ法、ＣＶＤ法など従
来周知の何れの薄膜形成技術も使用可能である。また、
本実施例では垂直磁気記録媒体としてＣｏＣｒＴａ膜を
用いたが、ＣｏＣｒ膜等他の等地系金合金膜もよい。Furthermore, in this example, R
Although F magnetron sputtering was used, any conventional thin film forming technique such as RF sputtering, DC sputtering, ion beam sputtering, electron beam evaporation, resistance heating evaporation, MBE, or CVD can also be used. be. Also,
In this embodiment, a CoCrTa film is used as the perpendicular magnetic recording medium, but other isochoric gold alloy films such as a CoCr film may also be used.
［発明の効果］
以上説明したように、本発明によれば、添加ガス（窒素
、酸素）の導入により、従来作製が困難であった膜厚の
深さ方向に従い垂直方向の保磁力が減少する媒体の作製
が容易となり、しかも、従来に比べ低い書き込み電流で
再生出力、記録密度を増加することができる効果を有す
る。[Effects of the Invention] As explained above, according to the present invention, by introducing the additive gas (nitrogen, oxygen), the coercive force in the vertical direction decreases along the depth direction of the film thickness, which was difficult to manufacture in the past. It is possible to easily manufacture the medium, and moreover, it has the effect of increasing reproduction output and recording density with a lower write current than conventional ones.
第１図は本発明による磁気記録媒体の製造方法を実施す
る連続成膜用スパッタ装置を示す概略図、第２図は垂直
異方性磁界Ｈｋ及び垂直方向の保磁力Ｈｅ上の酸素ガス
分圧依存性を示す図、第３図は垂直異方性磁界Ｈｋ及び
垂直方向の保磁力Ｈｃ上の窒素ガス分圧依存性を示す図
、第４図は本発明による媒体と比較して従来媒体につい
て再生出力Ｖ（相対値）の記録密度り依存性を示す図で
ある。FIG. 1 is a schematic diagram showing a sputtering apparatus for continuous film formation that implements the method for manufacturing a magnetic recording medium according to the present invention, and FIG. 2 is a partial pressure of oxygen gas in a perpendicular anisotropic magnetic field Hk and a perpendicular coercive force He. FIG. 3 is a diagram showing the dependence of the nitrogen gas partial pressure on the perpendicular anisotropic magnetic field Hk and the perpendicular coercive force Hc. FIG. FIG. 3 is a diagram showing the dependence of reproduction output V (relative value) on recording density.
Claims (1)
成する際に、少量の添加ガスを含むＡｒガスで放電させ
、その添加ガス分圧を膜の形成初期には高く、形成末期
には低くなるようにして膜を形成することを特徴とする
磁気記録媒体の製造方法。(1) When forming a perpendicular magnetic anisotropic film on a substrate by sputtering, a discharge is performed using Ar gas containing a small amount of additive gas, and the partial pressure of the additive gas is high in the early stage of film formation, and at the final stage of film formation. 1. A method of manufacturing a magnetic recording medium, characterized in that a film is formed in such a manner that .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16890089A JPH0335422A (en) | 1989-06-30 | 1989-06-30 | Production of magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16890089A JPH0335422A (en) | 1989-06-30 | 1989-06-30 | Production of magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0335422A true JPH0335422A (en) | 1991-02-15 |
Family
ID=15876646
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16890089A Pending JPH0335422A (en) | 1989-06-30 | 1989-06-30 | Production of magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0335422A (en) |
-
1989
- 1989-06-30 JP JP16890089A patent/JPH0335422A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4868070A (en) | Vertical magnetization type recording medium and manufacturing method therefor | |
| JPH0335422A (en) | Production of magnetic recording medium | |
| JPH0546013B2 (en) | ||
| JPS62185246A (en) | Production of magnetic recording medium | |
| JP2668994B2 (en) | Manufacturing method of magnetic recording medium | |
| JP2946748B2 (en) | Manufacturing method of magnetic recording medium | |
| JP3531679B2 (en) | Magnetic recording media | |
| JPH0473215B2 (en) | ||
| EP0653747A1 (en) | Magnetic recording medium and manufacturing method thereof | |
| JPH1064061A (en) | Production of magnetic recording medium | |
| JPH0656650B2 (en) | Magnetic recording medium | |
| JPH07182644A (en) | Magnetic recording medium | |
| JPS6194240A (en) | Preparation of magnetic recording medium | |
| JPH01303623A (en) | Magnetic recording medium | |
| JPS63152018A (en) | Magnetic recording medium | |
| JPS6353721A (en) | Preparation of thin oxide film | |
| JPH0237525A (en) | Production of magnetic recording medium | |
| JPH10261223A (en) | Production of magnetic recording medium | |
| JPH04176015A (en) | Perpendicular magnetic recording medium | |
| JPS62102414A (en) | Magnetic recording medium | |
| JPH04238109A (en) | Magnetic recording medium | |
| JPS6267728A (en) | Production of magnetic recording medium | |
| JP2000163733A (en) | Magnetic recording medium | |
| JPH04117611A (en) | Magnetic recording medium | |
| JPH07240019A (en) | Magnetic recording medium and its production and apparatus for production |