JPS63255817A - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- JPS63255817A JPS63255817A JP62090241A JP9024187A JPS63255817A JP S63255817 A JPS63255817 A JP S63255817A JP 62090241 A JP62090241 A JP 62090241A JP 9024187 A JP9024187 A JP 9024187A JP S63255817 A JPS63255817 A JP S63255817A
- Authority
- JP
- Japan
- Prior art keywords
- ratio
- recording
- coercive force
- magnetic
- 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
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 39
- 230000005415 magnetization Effects 0.000 claims abstract description 23
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 18
- 239000000843 powder Substances 0.000 claims abstract description 9
- 239000011230 binding agent Substances 0.000 claims abstract description 6
- 239000002245 particle Substances 0.000 claims description 15
- 239000006247 magnetic powder Substances 0.000 claims description 6
- 239000000758 substrate Substances 0.000 claims description 2
- 230000004907 flux Effects 0.000 abstract description 6
- 238000000576 coating method Methods 0.000 abstract description 3
- 239000011248 coating agent Substances 0.000 abstract 1
- 238000000034 method Methods 0.000 description 6
- 239000011651 chromium Substances 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- AJCDFVKYMIUXCR-UHFFFAOYSA-N oxobarium;oxo(oxoferriooxy)iron Chemical compound [Ba]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O AJCDFVKYMIUXCR-UHFFFAOYSA-N 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- 229910000684 Cobalt-chrome Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 239000010952 cobalt-chrome Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- IIZPXYDJLKNOIY-JXPKJXOSSA-N 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine Chemical compound CCCCCCCCCCCCCCCC(=O)OC[C@H](COP([O-])(=O)OCC[N+](C)(C)C)OC(=O)CCC\C=C/C\C=C/C\C=C/C\C=C/CCCCC IIZPXYDJLKNOIY-JXPKJXOSSA-N 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- 229910001289 Manganese-zinc ferrite Inorganic materials 0.000 description 1
- 235000021355 Stearic acid Nutrition 0.000 description 1
- 229920002433 Vinyl chloride-vinyl acetate copolymer Polymers 0.000 description 1
- WAIPAZQMEIHHTJ-UHFFFAOYSA-N [Cr].[Co] Chemical compound [Cr].[Co] WAIPAZQMEIHHTJ-UHFFFAOYSA-N 0.000 description 1
- JIYIUPFAJUGHNL-UHFFFAOYSA-N [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[Mn++].[Mn++].[Mn++].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Zn++].[Zn++] Chemical compound [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[Mn++].[Mn++].[Mn++].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Zn++].[Zn++] JIYIUPFAJUGHNL-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000005347 demagnetization Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229940067606 lecithin Drugs 0.000 description 1
- 235000010445 lecithin Nutrition 0.000 description 1
- 239000000787 lecithin Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 229920001228 polyisocyanate Polymers 0.000 description 1
- 239000005056 polyisocyanate Substances 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 239000008117 stearic acid Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、高密度の垂直磁気記録を可能とする磁気記録
媒体に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording medium that enables high-density perpendicular magnetic recording.
従来の技術
近年磁気記録は、高密度化、ディジタル化の方向へ進み
つつある。磁気記録の方式として従来は磁気記録媒体の
面内に磁化の容易軸を持っているいわゆる面内磁化によ
る磁気記録方式が主であった。しかしながら本方式では
、記録密度を上げれば上げるほど磁気記録媒体内の磁化
方向が互いに反発し合うように並ぶため高密度化を計る
のが困難になってきている。そこで最近磁気記録の新し
い方式として、磁気記録媒体の内面に対して垂直方向に
磁化容易軸を持っているいわゆる垂直磁化による磁気記
録方式が開発され、記録密度が飛躍的に増大することが
可能となった。（例えば、岩崎：垂直磁化を用いた高密
度磁気記録：日経エレクトロニクス １９７８年８月７
日号。Ｐ１００〜１１１）このような垂直磁気記録方式
においては、用いる磁性粉は記録媒体の表面に対して垂
直な方向に磁化容易軸を有していることが必要である。BACKGROUND OF THE INVENTION In recent years, magnetic recording has been moving toward higher density and digitalization. Conventionally, the main magnetic recording method has been a magnetic recording method using so-called in-plane magnetization, which has an easy axis of magnetization within the plane of the magnetic recording medium. However, in this method, as the recording density is increased, the magnetization directions within the magnetic recording medium are arranged so as to repel each other, making it difficult to achieve high density. Recently, a new method of magnetic recording, called perpendicular magnetization, in which the axis of easy magnetization is perpendicular to the inner surface of the magnetic recording medium, has been developed, making it possible to dramatically increase the recording density. became. (For example, Iwasaki: High-density magnetic recording using perpendicular magnetization: Nikkei Electronics August 7, 1978
Day number. P100-111) In such a perpendicular magnetic recording system, the magnetic powder used must have an axis of easy magnetization in a direction perpendicular to the surface of the recording medium.
現在のところ、コバルト−クロム（Ｃｏ −Ｃｒ）合金
膜が支持基体の表面にスパッタ法によって形成されたも
のがある。（例えば、岩崎、山崎：垂直磁気異法性を持
つＧｏ −Ｃｒスパッタ膜について：第７回応用磁気学
会学術講演会、４ＰＡ−７，１９７５年）またＣｏ −
Ｃｒ以外にもバリウムフェライトの塗布型の垂直磁気記
録媒体も開発されつつある。（例えば特開昭６０−６９
８２２号公報）
発明が解決しようとする問題点
しかしこれらの磁気記録媒体の場合、垂直配向性は良好
であるが、Ｃｏ −Ｃｒ合金膜は、Ｃｏ −Ｃｒと磁気
ヘッドとが摺動する際に記録媒体と磁気ヘッド双方の摩
耗が激しくなること及び記録媒体自体が可とう性に劣り
、ヘッドの走行もスムースに行かないという欠点がある
。At present, there are some in which a cobalt-chromium (Co-Cr) alloy film is formed on the surface of a supporting base by sputtering. (For example, Iwasaki, Yamazaki: On Go - Cr sputtered films with perpendicular magnetic anisotropy: 7th Academic Conference of the Japan Society of Applied Magnetics, 4PA-7, 1975) Also, Co -
In addition to Cr, coated perpendicular magnetic recording media made of barium ferrite are also being developed. (For example, JP-A-60-69
(No. 822 Publication) Problems to be Solved by the Invention However, although these magnetic recording media have good perpendicular alignment, the Co--Cr alloy film has problems when the Co--Cr and the magnetic head slide. There are disadvantages in that both the recording medium and the magnetic head are subject to severe wear, the recording medium itself has poor flexibility, and the head does not run smoothly.
又従来から硬質磁性材料として知られている例えばＢａ
Ｆｅ、□０１．（バリウムフェライト）などの六方晶系
フェライトは、六角の平板状をなしており、かつ磁化容
易軸も平板の面に垂直であるから、この大方晶系フェラ
イトを記録媒体用の磁性粉末として用いることができれ
ば、塗布法により記録媒体層を形成することが可能とな
り、Ｃｏ −Ｃｒスパッタ膜の場合のように、ヘッドの
摩耗や、ヘッドの走行性も良好な物が得られると考えら
れる。Also, conventionally known hard magnetic materials such as Ba
Fe, □01. Hexagonal ferrite such as (barium ferrite) has a hexagonal flat plate shape, and the axis of easy magnetization is perpendicular to the plane of the flat plate, so this macrogonal ferrite can be used as magnetic powder for recording media. If this is possible, it will be possible to form a recording medium layer by a coating method, and it is thought that a product with good head wear and head runnability, as in the case of a Co--Cr sputtered film, will be obtained.
しかしながら上記従来例の大方晶系フェライトは、保磁
力Ｈｃが高く、板状比（六角の平板状の最大の対角線の
長さＤと厚みｔの比Ｄ／ｌ）が１５以下であるため、現
在実用化されている安価で耐摩耗性、走行性の優れたＭ
ｎ−Ｚｎ系のヘッド（マンガン−亜鉛フェライトヘッド
）では、十分な記録再生ができないばかりか、高い保磁
力と高い板状比のために塗布法による成膜過程において
、粒子相互が凝集し易く、したがって垂直配向性が悪く
高記録密度が可能な垂直磁気記録媒体を得ることができ
なかった。すなわち磁化曲線における、垂直成分の残留
磁束密度（Ｂｒ上）と面内成分の残留磁束密度（Ｂｒ
’ ）との比ＣＢｒ工／ ３ｒ’ ）が２以下となり垂
直磁化膜となりにくい欠点があった。However, the macrogonal ferrite of the conventional example has a high coercive force Hc and a plate ratio (ratio D/l of the maximum diagonal length D of a hexagonal plate shape to the thickness t) of 15 or less. Practical M that is inexpensive and has excellent wear resistance and running performance.
In the n-Zn type head (manganese-zinc ferrite head), not only is it not possible to perform sufficient recording and reproduction, but due to the high coercive force and high platelet ratio, particles tend to aggregate with each other during the film formation process using the coating method. Therefore, it has been impossible to obtain a perpendicular magnetic recording medium that has poor perpendicular alignment and is capable of high recording density. That is, in the magnetization curve, the residual magnetic flux density of the vertical component (on Br) and the residual magnetic flux density of the in-plane component (on Br
The ratio CBr/3r') was less than 2, which had the disadvantage that it was difficult to form a perpendicularly magnetized film.
問題点を解決するための手段
本発明は、前記問題点を解決するため、従来のスパッタ
法で得られる連続合金膜状の媒体でなく、粒径と厚みの
比が大きくしかも保磁力の低い六方晶系フェライト粉と
有機バインダー系よりなる垂直配向性の良好な塗布型媒
体を用いることにより優れた高密度記録媒体が得られる
ことを見出した。Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a hexagonal medium that has a large grain size to thickness ratio and a low coercive force, instead of using a continuous alloy film-like medium obtained by conventional sputtering methods. It has been found that an excellent high-density recording medium can be obtained by using a coated medium with good vertical alignment made of crystalline ferrite powder and an organic binder system.
作用
発明者らは、保磁力が比較的ちいさく、垂直配向性の優
れた六方晶系フェライト塗布型媒体が優れた高密度記録
媒体になることを見出した。すなわち本発明の磁気記録
媒体は、保磁力がちいさく垂直配向性が優れている（磁
化曲線の垂直成分の残留磁束密度と面内成分の残留磁束
密度の比が大）ため、高密度記録領域（短波長領域）で
の記録再生特性が優れている。これは、従来の長手記録
（面内記録）では、高密度記録を達成しようとすると大
きい反磁界に対抗して高い保磁力の媒体、反磁界を減ら
すために薄くかつ磁化の低い媒体が必要なのに対して、
垂直記録では、高記録密度（短波長記録）程度、磁界が
すくなくなるので保磁力を低くできかつ媒体の厚みを薄
（する必要がないためである。The inventors have discovered that a hexagonal ferrite coated medium with a relatively small coercive force and excellent vertical alignment can be an excellent high-density recording medium. In other words, the magnetic recording medium of the present invention has a small coercive force and excellent vertical alignment (the ratio of the residual magnetic flux density of the perpendicular component to the residual magnetic flux density of the in-plane component of the magnetization curve is large), so it can be used in high-density recording areas ( Excellent recording and reproducing characteristics in the short wavelength region). This is because in conventional longitudinal recording (in-plane recording), in order to achieve high-density recording, a medium with a high coercive force is required to resist a large demagnetizing field, and a thin medium with low magnetization is required to reduce the demagnetizing field. for,
This is because in perpendicular recording, the magnetic field is small at high recording densities (short wavelength recording), so the coercive force can be lowered and there is no need to make the medium thinner.
この高密度記録を達成するためには、垂直配向性の優れ
た媒体が必要であり、本発明の保磁力の低い、しかも垂
直配向性の高い媒体が最も高密度記録に適していると言
える。特に共沈法で得られた六方晶系粒子の粒径が０．
０５〜０．３μｍで粒径と厚みとの比が１５〜２５の粉
体は、塗布した時に垂直配向しやすく優れた磁性粉体と
言える。In order to achieve this high-density recording, a medium with excellent vertical alignment is required, and it can be said that the medium of the present invention with low coercive force and high vertical alignment is most suitable for high-density recording. In particular, the particle size of the hexagonal crystal particles obtained by the coprecipitation method is 0.
Powder having a diameter of 0.05 to 0.3 μm and a ratio of particle size to thickness of 15 to 25 can be said to be an excellent magnetic powder that is easily vertically aligned when applied.
実施例
以下、本発明の一実施例について図面に基づいて説明す
る。図は本発明の一実施例における垂直磁気記録媒体の
概略図を示すものである。EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. The figure shows a schematic diagram of a perpendicular magnetic recording medium in an embodiment of the present invention.
図において１１は支持基体、１２は磁性層、１３は六方
晶フェライト粒子、１４は有機バインダーである。In the figure, 11 is a support substrate, 12 is a magnetic layer, 13 is hexagonal ferrite particles, and 14 is an organic binder.
まずＣｕ −Ｚｒで一部置換し共沈法で得られた平均粒
径０．１μｍ、板状粒子の厚さ０．０５μｍ（板状比２
０）のバリウムフェライト粉１００重量部と、結合剤と
して、塩化ビニル酢酸ビニル共重合体１０重量部、ポリ
ウレタン樹脂１０重量部、ポリイソシアネ−）１．５重
量部、レシチン１重量部、ステアリン酸０．５重量部、
メチルエチルケトン１２５重量部、トルエン１２０重量
部から成る組成物をボールミルで約８０時間混合分散し
て磁性塗料を調製した。この磁性塗料を厚さ１３μｍの
ポリエステルフィルム上に乾燥厚が４μｍとなるように
塗布、乾燥し、表面処理を行なった後、所定の幅に裁断
して磁気テープを作った。First, the average particle diameter was 0.1 μm and the thickness of plate-like particles was 0.05 μm (plate ratio 2
100 parts by weight of the barium ferrite powder of 0), 10 parts by weight of vinyl chloride vinyl acetate copolymer, 10 parts by weight of polyurethane resin, 1.5 parts by weight of polyisocyanate, 1 part by weight of lecithin, and 0.0 parts by weight of stearic acid as a binder. 5 parts by weight,
A magnetic paint was prepared by mixing and dispersing a composition consisting of 125 parts by weight of methyl ethyl ketone and 120 parts by weight in a ball mill for about 80 hours. This magnetic paint was applied onto a 13 μm thick polyester film to a dry thickness of 4 μm, dried, surface treated, and then cut into a predetermined width to produce a magnetic tape.
このテープを媒体面に垂直な方向の磁化曲線と平行な方
向の磁化曲線をＶＳＴ （振動試料型磁力計）によって
磁気的特性（垂直配向度）を測定した。結果は、表１、
試料番号１に示す。次にこのテープの記録、再生試験を
行なった。ただし、媒体・ヘッド相対速度３７．５ｍ／
ｓｅｃ記録再生ヘッドはＭｎ −Ｚｎフェライトヘッド
でギャップ長０．２８ｍトランク幅３５μｍ巻数２０タ
ーン、記録周波数７．５ＭＨｚである。結果は同じく表
１、試料番号１に示す。The magnetic properties (degree of vertical orientation) of this tape were measured using a VST (vibrating sample magnetometer) using a magnetization curve in a direction perpendicular to the medium surface and a magnetization curve in a direction parallel to the medium surface. The results are shown in Table 1.
Shown in sample number 1. Next, this tape was subjected to recording and playback tests. However, the media/head relative speed is 37.5 m/
The sec recording/reproducing head is a Mn-Zn ferrite head with a gap length of 0.28 m, a trunk width of 35 μm, a number of turns of 20 turns, and a recording frequency of 7.5 MHz. The results are also shown in Table 1, sample number 1.
以下同様にして磁性粉の保磁力、粒径と粒径と厚さの比
、および垂直配向性が変化した時の再生出力がどうなる
かを、表１の試料番号２〜２７に示す。また試料番号２
８〜３２は、本願発明以外の比較例である。Sample numbers 2 to 27 in Table 1 show what happens to the reproduction output when the coercive force, particle size to particle size to thickness ratio, and vertical orientation of the magnetic powder are changed in the same manner. Also sample number 2
8 to 32 are comparative examples other than the present invention.
ここで垂直配向性はＶＳＭより媒体の面内と垂直の両ヒ
ステリシス曲線（Ｂ−Ｈカーブ）を求め媒体の垂直方向
の残留磁化ＣＢｒ （ＪＬ ） ）および面内（水平）
方向の残留磁化（Ｂｒ （“）〕を求めこれらの比（Ｂ
ｒ （ＪＬ ） ／Ｂｒ （” ） ）の値を取った。Here, the vertical orientation is determined by calculating both the in-plane and perpendicular hysteresis curves (B-H curves) of the medium using VSM, and the residual magnetization CBr (JL) in the perpendicular direction of the medium and the in-plane (horizontal)
Find the residual magnetization (Br (“)) in the direction and calculate the ratio (B
The value of r(JL)/Br('')) was taken.
＊ ただし、試験番号２８〜３２は比較例〔垂直方向の
残留磁化が水平方向の残留磁化にくらべて大きければ大
きいほど優れた垂直磁化膜といえる、Ｂｒ （１） ／
Ｂｒ （“）〉２〕なお特許請求の範囲において、六方
晶フェライトの保磁力を２００〜６０００ｅに限定した
のは、２０００ｅ以下であると保磁力が低すぎて記録減
磁がおこるためであり、６０００ｅ以上であると保磁力
が高すぎてＭｚ −Ｚｎフェライトヘッドで十分に記録
ができないためである。* However, test numbers 28 to 32 are comparative examples [the larger the residual magnetization in the vertical direction is compared to the residual magnetization in the horizontal direction, the better the perpendicularly magnetized film, Br (1) /
Br (“)〉2] In the claims, the reason why the coercive force of the hexagonal ferrite is limited to 200 to 6000e is because if it is less than 2000e, the coercive force is too low and recording demagnetization occurs. This is because if it is 6000e or more, the coercive force is too high and sufficient recording cannot be performed with the Mz-Zn ferrite head.
また六方晶フェライト粉体の平均粒径を０．０５〜０．
３μｍでかつ粒径と厚みの比が１５〜２５に限定したの
は、平均粒径が０．０５μｍ以下では、飽和磁化が充分
に大きくなく高い再生出力が得にくいこと、又０．３μ
ｍ以上になると記録再生時にノイズの発生が大きくなっ
て好ましくないためである。又粒径と厚みの比が１５以
下であると垂直に配向しに（くなりそのために充分な再
生出力が得にくいこと、２５以上になると、記録再生時
にノイズの発生が大きくなって好ましくないためである
。Further, the average particle size of the hexagonal ferrite powder is 0.05 to 0.
The reason why the grain size and thickness ratio was limited to 3 μm and 15 to 25 was because if the average grain size is 0.05 μm or less, the saturation magnetization is not large enough and it is difficult to obtain high reproduction output.
This is because if it exceeds m, noise will increase during recording and reproduction, which is undesirable. Also, if the ratio of grain size to thickness is less than 15, the particles tend to be vertically oriented (which makes it difficult to obtain sufficient reproduction output), and if the ratio is more than 25, noise will increase during recording and reproduction, which is undesirable. It is.
発明の効果
以上述べてきたように、本発明によれば、六方晶フェラ
イトの保磁力が比較的ちいさく、しかも垂直配向性の良
好な媒体において高密度記録を達成するのにきわめて有
益な発明である。Effects of the Invention As described above, the present invention is extremely useful for achieving high-density recording in a medium in which the hexagonal ferrite has a relatively small coercive force and has good vertical alignment. .
図は本発明の一実施例における六方晶フェライト塗布型
垂直磁気記録媒体の概略図である。
１１・・・・・・支持基体、１２・・・・・・磁性層、
１３・・・・・・六方晶フェライト粒子、１４・・・・
・・有機バインダー。
代理人の氏名 弁理士 中尾敏男 はか１名１１−−一
叉将基体
１２−一羞１The figure is a schematic diagram of a hexagonal ferrite coated perpendicular magnetic recording medium according to an embodiment of the present invention. 11...Supporting base, 12...Magnetic layer,
13... Hexagonal ferrite particles, 14...
...Organic binder. Name of agent: Patent attorney Toshio Nakao Haka 1 person 11--Ichimasho base 12-Ichimi 1
Claims (2)
インダー層とから成る磁気記録媒体であって、磁性粉が
六方晶系フェライト粉からなり、その保磁力で２００〜
６００エールステッドで、かつ垂直成分の残留磁化量と
面内成分の残留磁化量の比が２．０以上であることを特
徴とする磁気記録媒体。(1) A magnetic recording medium consisting of a supporting substrate, magnetic powder coated on the surface thereof, and an organic binder layer, in which the magnetic powder consists of hexagonal ferrite powder, and its coercive force is 200 to 200
600 Oersted, and the ratio of the amount of residual magnetization of the perpendicular component to the amount of residual magnetization of the in-plane component is 2.0 or more.
ｍでかつ粒径と厚みの比が１５〜２５であることを特徴
とする特許請求の範囲第（１）項記載の磁気記録媒体。(2) Particle size of hexagonal ferrite powder is 0.05 to 0.3μ
2. The magnetic recording medium according to claim 1, wherein the magnetic recording medium has a particle diameter of m and a ratio of particle size to thickness of 15 to 25.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62090241A JPS63255817A (en) | 1987-04-13 | 1987-04-13 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62090241A JPS63255817A (en) | 1987-04-13 | 1987-04-13 | Magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63255817A true JPS63255817A (en) | 1988-10-24 |
Family
ID=13992998
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62090241A Pending JPS63255817A (en) | 1987-04-13 | 1987-04-13 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63255817A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6196518A (en) * | 1984-10-18 | 1986-05-15 | Victor Co Of Japan Ltd | Magnetic recording medium |
| JPS621113A (en) * | 1985-06-27 | 1987-01-07 | Toshiba Corp | Magnetic recording medium |
-
1987
- 1987-04-13 JP JP62090241A patent/JPS63255817A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6196518A (en) * | 1984-10-18 | 1986-05-15 | Victor Co Of Japan Ltd | Magnetic recording medium |
| JPS621113A (en) * | 1985-06-27 | 1987-01-07 | Toshiba Corp | Magnetic recording medium |
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