JPH01102724A - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPH01102724A JPH01102724A JP26095987A JP26095987A JPH01102724A JP H01102724 A JPH01102724 A JP H01102724A JP 26095987 A JP26095987 A JP 26095987A JP 26095987 A JP26095987 A JP 26095987A JP H01102724 A JPH01102724 A JP H01102724A
- Authority
- JP
- Japan
- Prior art keywords
- corrosion resistance
- recording medium
- content
- alloy
- magnetic recording
- 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
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 23
- 239000000956 alloy Substances 0.000 claims abstract description 23
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 12
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 9
- 239000010409 thin film Substances 0.000 claims description 24
- 239000010408 film Substances 0.000 claims description 17
- 239000011651 chromium Substances 0.000 claims description 16
- 239000000758 substrate Substances 0.000 claims description 13
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 6
- 229910000531 Co alloy Inorganic materials 0.000 claims description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims 2
- 230000007797 corrosion Effects 0.000 abstract description 17
- 238000005260 corrosion Methods 0.000 abstract description 17
- 230000005415 magnetization Effects 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 4
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 229910001004 magnetic alloy Inorganic materials 0.000 abstract 2
- 230000000052 comparative effect Effects 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- 229910001096 P alloy Inorganic materials 0.000 description 3
- 238000007772 electroless plating Methods 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910020630 Co Ni Inorganic materials 0.000 description 1
- 229910002440 Co–Ni Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910018104 Ni-P Inorganic materials 0.000 description 1
- 229910018536 Ni—P Inorganic materials 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical group [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 1
- 229940044175 cobalt sulfate Drugs 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- WPUMTJGUQUYPIV-JIZZDEOASA-L disodium (S)-malate Chemical compound [Na+].[Na+].[O-]C(=O)[C@@H](O)CC([O-])=O WPUMTJGUQUYPIV-JIZZDEOASA-L 0.000 description 1
- 238000001659 ion-beam spectroscopy Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical compound O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 235000019265 sodium DL-malate Nutrition 0.000 description 1
- 239000001394 sodium malate Substances 0.000 description 1
- PRWXGRGLHYDWPS-UHFFFAOYSA-L sodium malonate Chemical compound [Na+].[Na+].[O-]C(=O)CC([O-])=O PRWXGRGLHYDWPS-UHFFFAOYSA-L 0.000 description 1
- 229940074404 sodium succinate Drugs 0.000 description 1
- ZDQYSKICYIVCPN-UHFFFAOYSA-L sodium succinate (anhydrous) Chemical compound [Na+].[Na+].[O-]C(=O)CCC([O-])=O ZDQYSKICYIVCPN-UHFFFAOYSA-L 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
Landscapes
- Magnetic Record Carriers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は合金磁性薄膜を有する磁気記録媒体に係るもの
であり、特に、この合金磁性薄膜がジルコニウム（Ｚｒ
）及びクロム（Ｃｒ）を含有するコバルト基合金からな
る磁気記録媒体に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium having an alloy magnetic thin film, and in particular, this alloy magnetic thin film is made of zirconium (Zr
) and a cobalt-based alloy containing chromium (Cr).
記録密度の高い合金磁性薄膜を有する磁気記録媒体の研
究開発が近年大いに推進されているが、その一つとして
無電解メツキ法によるコバルト（Ｃｏ）−ニッケル（Ｎ
ｉ）−リン（Ｐ）合金磁性薄膜を用いたものがある。し
かしながらＣｏ−Ｎ１−Ｐ合金は耐食性に問題があり、
該合金磁性薄膜を用いた記録媒体は、永年使用した際の
記録エラー等信頼性の点で劣っていた。例えば、該合金
磁性薄膜を温度５７°Ｃ９湿度８５％の条件下にて２週
間放置した場合には飽和磁化の劣化が３０％であり、ま
た、純水中に１週間放置した場合のそれは４０％にも達
する。このような特性の劣化は実機使用した際の出力低
下を招き、また腐蝕部の存在はエラーの増大を引き起こ
すという問題がある。Research and development of magnetic recording media with alloy magnetic thin films with high recording density has been greatly promoted in recent years, and one of them is cobalt (Co)-nickel (N) using electroless plating method.
i) There is one using a -phosphorus (P) alloy magnetic thin film. However, Co-N1-P alloy has problems with corrosion resistance.
Recording media using the alloy magnetic thin film were inferior in reliability such as recording errors after long-term use. For example, if the alloy magnetic thin film is left for two weeks at a temperature of 57°C and a humidity of 85%, the saturation magnetization will deteriorate by 30%, and if it is left in pure water for one week, it will deteriorate by 40%. %. Such deterioration of characteristics causes a decrease in output when used in actual equipment, and the presence of corroded parts causes an increase in errors.
〔発明が解決しようとする問題点］
このように、無電解メツキ法によるＣｏ−Ｎ１−Ｐ合金
磁性薄膜は、出力低下やエラーの増大などといった信頼
性の低下に帰結する耐食性・耐候性の問題があった。ま
た、スパッタリングで付けたＣ。[Problems to be Solved by the Invention] As described above, the Co-N1-P alloy magnetic thin film produced by the electroless plating method has problems in corrosion resistance and weather resistance that result in a decrease in reliability such as a decrease in output and an increase in errors. was there. Also, C attached by sputtering.
Ｎｉ合金薄膜においても耐食性・耐候性の問題があった
。Ni alloy thin films also have problems with corrosion resistance and weather resistance.
本発明者らは上記不具合を解決するために様々な観点か
ら検討を加え、Ｚｒ及びＣｒを添加したＣｏ基合金磁性
薄膜が極めて優れた耐食性・耐候性を有することを見い
出した。In order to solve the above problems, the present inventors conducted studies from various viewpoints and found that a Co-based alloy magnetic thin film to which Zr and Cr are added has extremely excellent corrosion resistance and weather resistance.
即ち、本発明は、基板上に順次硬質下地層、合金磁性薄
膜が形成された磁気記録媒体において、上記合金磁性薄
膜をＺｒを２〜１０原子％及びＣｒを２〜１５原子％含
有するＣｏ基合金で構成したことを特徴とするものであ
る。That is, the present invention provides a magnetic recording medium in which a hard underlayer and an alloy magnetic thin film are sequentially formed on a substrate. It is characterized by being made of an alloy.
以下本発明の構成について更に詳細に説明する。The configuration of the present invention will be explained in more detail below.
本発明において用いられる磁性薄膜は、Ｚｒを２〜１０
原子％、 Ｃｒを２〜１５原子％含むＣｏ基合金からな
るものである。The magnetic thin film used in the present invention contains 2 to 10 Zr.
It is made of a Co-based alloy containing 2 to 15 atom % of Cr.
Ｚｒの含有量を２〜１０原子％とした理由は、その含有
量が２原子％未満では耐食性を改善するには至らないか
らである。一方、その含有量が１０原子％を越えるとき
は非晶質的性質が強くなり、記録媒体に必要な保磁力が
得られないためである。The reason why the Zr content is set to 2 to 10 atomic % is that if the Zr content is less than 2 atomic %, corrosion resistance cannot be improved. On the other hand, if the content exceeds 10 at %, the amorphous nature becomes strong and the coercive force necessary for the recording medium cannot be obtained.
Ｃｒの含有量を２〜１５原子％とした理由は、Ｚｒと同
様２原子％未満では耐食性改善の効果がないためであり
、１５原子％を越えるときは飽和磁化が低くなりすぎ、
薄層化という高密度記録に適した合金磁性薄膜の特徴が
活かし得ないためである。The reason why the Cr content is set to 2 to 15 at% is that, like Zr, if it is less than 2 at%, there is no effect of improving corrosion resistance, and if it exceeds 15 at%, the saturation magnetization becomes too low.
This is because the characteristics of alloy magnetic thin films suitable for high-density recording, such as thin layers, cannot be utilized.
また、本発明においては合金磁性薄膜形成に先立ち硬質
下地膜が設けられるが、該下地膜はクロム膜が適当であ
り、５００〜５０００人の厚さに付けることが望ましい
。クロム金属はＣｏ基合金薄膜にある結晶学的方位関係
を与えるためＣｏ基合金の磁化容易軸の面内成分が増し
高保磁力とすることができる。このためには結晶が充分
成長することが必要で５００Å以上付ける必要があり、
厚みの増加とともに保磁力を向上させる。厚さの上限は
特に限定されるものでないが、磁気特性の点から５００
０人あれば十分である。Further, in the present invention, a hard base film is provided prior to forming the alloy magnetic thin film, and the base film is suitably a chromium film, and is desirably applied to a thickness of 500 to 5000 mm. Since chromium metal imparts a certain crystallographic orientation relationship to the Co-based alloy thin film, the in-plane component of the axis of easy magnetization of the Co-based alloy increases, resulting in a high coercive force. For this purpose, it is necessary for the crystal to grow sufficiently, and it is necessary to attach it to a thickness of 500 Å or more.
Coercive force improves as thickness increases. The upper limit of the thickness is not particularly limited, but from the viewpoint of magnetic properties, it is 500 mm.
It is sufficient if there are 0 people.
さらに、本発明においてＺｒ及びＣｒ以外の組成として
は、
（イ） Ｃｏのみ
（ロ） Ｃｏの一部をＮｉで置換したものであっても
よい。（ロ）の組成の場合、ＣＯの一部をＮｉで置換す
るときの置換比率はＣＯの４０原子％以下とするのが好
ましい。置換比率が４０原子％を越えるとり、ｃ、ｐ、
母結晶中に占めるｆ、ｃ、ｃ、相の割合が多くなり磁気
特性の低下をもたらすからである。Further, in the present invention, the composition other than Zr and Cr may be (a) only Co, or (b) a part of Co replaced with Ni. In the case of composition (b), it is preferable that the substitution ratio when replacing a portion of CO with Ni is 40 atomic % or less of CO. If the substitution ratio exceeds 40 atom%, c, p,
This is because the proportion of f, c, c phases in the mother crystal increases, resulting in a decrease in magnetic properties.
本発明の磁気記録媒体は、例えば次のようにして製造す
ることができる。即ち紐面研摩された硬質基板上にＡｒ
ガス雰囲気中でのスパッタリング等の真空蒸着法によっ
て初めにＣｒ下地膜を形成し、次いでＺｒ及びＣｒとＣ
ｏ （及び所望、によりＮｉ）を含む合金薄膜を形成し
て作成する。The magnetic recording medium of the present invention can be manufactured, for example, as follows. That is, Ar is placed on a hard substrate whose surface has been polished.
First, a Cr base film is formed by a vacuum evaporation method such as sputtering in a gas atmosphere, and then Zr and Cr and C are deposited.
A thin alloy film containing Ni (and optionally Ni) is formed.
ここに、本発明に用いられる基板としては、非磁性基板
であるならば従来から用いられている各種のものが採用
でき、アルミニウム合金基板、各種のセラミックスまた
はガラス基板などが用いられる。アルミニウム合金基板
は基板表面にアルマイト、Ｎｉ Ｐ等から成る硬質層
が設けられていてもよい。また、磁性薄膜上に非磁性金
属中間層及び／または炭素、ポリ珪酸等の保護膜を設け
てもよい。さらに、この保護股上に潤滑剤を塗布しても
よい。Here, as the substrate used in the present invention, various conventionally used non-magnetic substrates can be used, such as aluminum alloy substrates, various ceramics or glass substrates, etc. The aluminum alloy substrate may be provided with a hard layer made of alumite, NiP, etc. on the surface of the substrate. Further, a nonmagnetic metal intermediate layer and/or a protective film of carbon, polysilicate, etc. may be provided on the magnetic thin film. Additionally, a lubricant may be applied to this protective crotch.
〔実施例］ 以下、本発明を具体的実施例によって詳細に説明する。〔Example] Hereinafter, the present invention will be explained in detail using specific examples.
なお、以下に述べる実施例はｒ、ｆ、平板マグネトロン
装置によった−が、イオン工学的に同様のことが言える
イオンビームスパッタリング等によっても本発明の効果
を得ることが可能であることは勿論である。Although the embodiments described below are based on r, f, and flat plate magnetron devices, it is of course possible to obtain the effects of the present invention by ion beam sputtering, etc., which can be said to be similar in terms of ion technology. It is.
実施例１
ｒ、ｆ、平板マグネトロンスパッタ装置を用い、下記条
件にてガラス基板上に様々な組成のＣｏ基合金磁性薄膜
を形成した。Example 1 Co-based alloy magnetic thin films having various compositions were formed on glass substrates under the following conditions using an r, f, flat plate magnetron sputtering apparatus.
初期排気 １〜３ Ｘ １Ｏ−６Ｔｏ
ｒｒＡｒ圧力 １２〜２０ ｍ
Ｔｏｒｒ投入電力 ２．５
Ｗ／ｃｍ２膜 厚 Ｃｒ下地膜 ２０００〜４
０００ 人Ｃｏ基合金膜 ７００ ０
薄膜形成速度 ２００〜３００人／ｍｉｎ
基板温度 １５０°Ｃその後耐食性及
び耐候性の検討を行なった。ここに、耐食性の評価は３
ＭΩｃｍの純水中に１週間浸すことにより、また耐候性
の評価は温度５７°Ｃ１湿度８０％の条件下に２週間放
置することにより行なった。この結果を第１表の実施例
サンプルＮｏ。Initial exhaust 1~3 X 1O-6To
rrAr pressure 12-20 m
Torr input power 2.5
W/cm2 film thickness Cr base film 2000~4
000 people Co-based alloy film 700 0 Thin film formation rate 200-300 people/min
After the substrate temperature was 150°C, corrosion resistance and weather resistance were examined. Here, the corrosion resistance rating is 3.
Weather resistance was evaluated by immersing it in MΩcm pure water for one week, and by leaving it for two weeks at a temperature of 57° C. and a humidity of 80%. This result is shown in Example Sample No. of Table 1.
１〜８に示す。1 to 8.
比較例１
実施例１と同様の条件で作成したが、膜組成を特許請求
の範囲外となるよう調整した。この耐食性、耐候性テス
ト後の飽和磁化の減衰率を第１表の比較例サンプルＮα
１〜８に示す。Comparative Example 1 A film was prepared under the same conditions as in Example 1, but the film composition was adjusted to be outside the scope of the claims. The attenuation rate of saturation magnetization after this corrosion resistance and weather resistance test was determined by the comparative example sample Nα in Table 1.
1 to 8.
比較例２
下記条件により、表面にＮ１−Ｐ硬質層が設けられたア
ルミニウム合金基板上にＣｏ−Ｎ１−Ｐ合金磁性膜を作
成し、その後耐食性、耐候性の評価を行なった。その結
果を第１表の比較例２のサンプルＮｏ、 ９に示す。Comparative Example 2 A Co-N1-P alloy magnetic film was created on an aluminum alloy substrate having an N1-P hard layer on the surface under the following conditions, and then its corrosion resistance and weather resistance were evaluated. The results are shown in Sample No. 9 of Comparative Example 2 in Table 1.
メツキ浴 硫酸コバルト ０．０６ ｍｏｌ／
１硫酸ニツケル ０．０４
次亜リン酸 ０．２
硫酸アンモニウム ０．１
マロン酸ナトリウム ０．３
リンゴ酸ナトリウム ０．４
コハク酸ナトリウム ０．５
ρＩ＋＝８．９〜９．３ 温度７５〜８５°Ｃ膜厚７
００人第１表より、本発明による磁気記録媒体は、耐食
性テスト後の飽和磁化減衰率（％）が２．０〜６．８程
度であり比較例のもの（試料Ｎｏ、 １〜２、および７
〜８）に比べて、優れた耐食性を有する。Metsuki bath Cobalt sulfate 0.06 mol/
1 Nickel sulfate 0.04 Hypophosphorous acid 0.2 Ammonium sulfate 0.1 Sodium malonate 0.3 Sodium malate 0.4 Sodium succinate 0.5 ρI+=8.9-9.3 Temperature 75-85°C Film thickness 7
00 people Table 1 shows that the magnetic recording medium according to the present invention has a saturation magnetization decay rate (%) of about 2.0 to 6.8 after the corrosion resistance test, and the magnetic recording medium according to the present invention has a saturation magnetization decay rate (%) of about 2.0 to 6.8. 7
It has excellent corrosion resistance compared to 8).
また本発明の組成範囲外の薄膜の場合は、例えば比較例
３ （Ｚｒ量が１２％）のものでは、保磁力が６００ｅ
ｌ、か得られず、媒体として不充分な保磁力となり、ま
たＣｒ組成が２０％の比較例４のものでは飽和磁化が７
．０ＫＧと著しく劣化してしまい薄層化による記録密度
の拘止の点で不具合なものとなる。また、比較例５はＮ
ｉ含有量が４８％と多いもので保磁力が２５００ｅとす
くない。In addition, in the case of a thin film outside the composition range of the present invention, for example, Comparative Example 3 (Zr content: 12%) has a coercive force of 600e.
However, in Comparative Example 4 with a Cr composition of 20%, the saturation magnetization was 7.
．． This results in significant deterioration of 0 KG, resulting in problems in terms of restricting the recording density due to thinning of the layer. In addition, Comparative Example 5 is N
The i content is as high as 48%, and the coercive force is as low as 2500e.
さらに、膜の組成が適切であっても、例えば比較例９の
ように膜厚が薄い場合には所望の磁気特性（保磁力）が
得られない。Furthermore, even if the composition of the film is appropriate, if the film is thin, as in Comparative Example 9, for example, desired magnetic properties (coercive force) cannot be obtained.
〔発明の効果］
以上述べたように、本発明によるＺｒ及びＣｒを含むＣ
ｏ基合金磁性薄膜は、優れた磁気特性を有し従来のＧｏ
−Ｎｉ−Ｐ無電解メツキ磁性薄膜や、Ｚｒ及びＣｒを含
まないＣｏ、 Ｃｏ−Ｎｉ１性薄膜に比較し、遥かに優
れた耐食性・耐候性を示すことが認められる。[Effect of the invention] As described above, C containing Zr and Cr according to the present invention
O-based alloy magnetic thin film has excellent magnetic properties and is superior to conventional Go
-Ni-P electroless plating magnetic thin films and Co and Co-Ni thin films that do not contain Zr and Cr are found to exhibit far superior corrosion resistance and weather resistance.
Claims (4)
成されて成る磁気記録媒体において、該合金磁性薄膜は
ジルコニウムを２〜１０原子％、クルムを２〜１５原子
％含むコバルト基合金からなることを特徴とする磁気記
録媒体。(1) In a magnetic recording medium in which a hard base film and an alloy magnetic thin film are sequentially formed on a substrate surface, the alloy magnetic thin film is a cobalt-based alloy containing 2 to 10 at.% of zirconium and 2 to 15 at.% of chromium. A magnetic recording medium characterized by comprising:
子％、クロムを２〜１５原子％と、残部が実質的にコバ
ルトとニッケルから成り、ニッケルの含有量は、コバル
トの４０原子％以下を置換した量であることを特徴とす
る特許請求の範囲第１項に記載の磁気記録媒体。(2) The alloy magnetic thin film consists of 2 to 10 atomic percent of zirconium, 2 to 15 at. The magnetic recording medium according to claim 1, characterized in that the amount is replaced.
であることを特徴とする特許請求の範囲第１項及び第２
項に記載の磁気記録媒体。(3) Claims 1 and 2, characterized in that the hard base film applied on the substrate is a nonmagnetic chromium layer.
The magnetic recording medium described in section.
であることを特徴とする特許請求の範囲第３項に記載の
磁気記録媒体。(4) The thickness of the non-magnetic chromium layer is 500 to 5000 Å
The magnetic recording medium according to claim 3, characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26095987A JPH01102724A (en) | 1987-10-16 | 1987-10-16 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26095987A JPH01102724A (en) | 1987-10-16 | 1987-10-16 | Magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01102724A true JPH01102724A (en) | 1989-04-20 |
Family
ID=17355141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26095987A Pending JPH01102724A (en) | 1987-10-16 | 1987-10-16 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01102724A (en) |
-
1987
- 1987-10-16 JP JP26095987A patent/JPH01102724A/en active Pending
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