JPH0619809B2 - Perpendicular magnetic recording method - Google Patents
Perpendicular magnetic recording methodInfo
- Publication number
- JPH0619809B2 JPH0619809B2 JP57198159A JP19815982A JPH0619809B2 JP H0619809 B2 JPH0619809 B2 JP H0619809B2 JP 57198159 A JP57198159 A JP 57198159A JP 19815982 A JP19815982 A JP 19815982A JP H0619809 B2 JPH0619809 B2 JP H0619809B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- perpendicular magnetic
- magnetic recording
- recording medium
- 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.)
- Expired - Lifetime
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/1278—Structure or manufacture of heads, e.g. inductive specially adapted for magnetisations perpendicular to the surface of the record carrier
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Magnetic Heads (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、磁気記録媒体の厚み方向の磁化によつて記録
する垂直磁気記録方式に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perpendicular magnetic recording system in which recording is performed by magnetization in the thickness direction of a magnetic recording medium.
背景技術とその問題点 高周波（短波長）信号の記録を行う場合、磁気記録媒体
に磁気ヘッドとの相対的移行方向に沿う方向の磁化によ
つて記録するいわゆる長手方向磁気記録方式によるより
も、磁気記録媒体の厚さ方向の磁化、いわゆる垂直磁気
記録方式による方が有利であることが知られている。こ
れは長手方向磁気記録方式では記録信号が短波長になる
ほど自己減磁界が大きくなるに比し、垂直磁気記録方式
では磁性層内の自己減磁界が小さくなる性質をもつこと
に因る。BACKGROUND ART AND PROBLEMS Therefor, when recording a high frequency (short wavelength) signal, rather than by a so-called longitudinal magnetic recording method in which recording is performed on a magnetic recording medium by magnetization in a direction along a relative transition direction with a magnetic head, It is known that the magnetization in the thickness direction of the magnetic recording medium, that is, the so-called perpendicular magnetic recording method is more advantageous. This is because the self-demagnetizing field becomes larger as the recording signal becomes shorter in the longitudinal magnetic recording system, whereas the self-demagnetizing field in the magnetic layer becomes smaller in the perpendicular magnetic recording system.
この垂直磁気記録方式では磁気記録媒体として、高分子
フイルムなどの非磁性基板上にコバルト・クローム（Co
−Cr合金）などの垂直磁気異方性膜を例えばスパツタリ
ングなどで形成した単層膜垂直磁気記録媒体、または非
磁性基板上にパーマロイなどの高透磁率材層を形成し、
その上にコバルト・クロームなどの垂直磁気異方性膜を
形成した２層膜垂直磁気記録媒体が用いられている。と
ころで従来、このような単層膜垂直磁気記録媒体にリン
グヘツド即ち所要の磁気ギヤツプを有し閉磁路を構成す
るコアからなる磁気ヘツドによつて垂直磁気記録を行う
場合、そのリングヘツドのコア材として飽和磁束密度が
4000ガウス程度のフエライトを用いていた。このリング
ヘツドの場合、良好な垂直磁気記録を行うには、文献に
よれば垂直磁気異方性膜の垂直異方性磁界を５KOe以
上、ヘツドの磁気ギヤツプ長さ0.5μｍ以下にする必要
があつた。しかし、磁気ギヤツプ長が0.5μｍ以下のフ
エライト製リングヘツドは、ヘツドのコアの飽和が起き
易く、もともとリングヘツドの記録磁界が回転磁界であ
る為前記の垂直磁気記録媒体を垂直に飽和記録すること
が困難であつた。従つて波長特性も良好でなく、再生電
圧も垂直磁気記録媒体が本来出し得る値まで取り出すこ
とができないという欠点があつた。特に垂直磁気記録媒
体の異方性磁界が５KOe以下の場合には上記の欠点が顕
著になる為、リングヘツドによつて良好な垂直磁気記録
を行うことが困難であつた。In this perpendicular magnetic recording system, the magnetic recording medium is cobalt chrome (Co) on a non-magnetic substrate such as a polymer film.
-Cr alloy) or other perpendicular magnetic anisotropy film is formed by, for example, sputtering or the like to form a single-layer perpendicular magnetic recording medium, or a high magnetic permeability material layer such as Permalloy on a non-magnetic substrate,
A double-layered perpendicular magnetic recording medium having a perpendicular magnetic anisotropy film such as cobalt chrome formed thereon is used. By the way, conventionally, when such a single-layered perpendicular magnetic recording medium is used for perpendicular magnetic recording by a ring head, that is, a magnetic head composed of a core having a required magnetic gear and forming a closed magnetic path, saturation is performed as the core material of the ring head. Magnetic flux density is
I used 4000 gauss of ferrite. In the case of this ring head, in order to perform good perpendicular magnetic recording, according to the literature, the perpendicular anisotropy magnetic field of the perpendicular magnetic anisotropy film must be 5 KOe or more and the head magnetic gap length should be 0.5 μm or less. . However, in a ferrite head ring head with a magnetic gear length of 0.5 μm or less, saturation of the core of the head is likely to occur, and since the recording magnetic field of the ring head is originally a rotating magnetic field, it is difficult to perform perpendicular saturation recording on the perpendicular magnetic recording medium. It was. Therefore, the wavelength characteristic is not good, and the reproducing voltage cannot be taken out to a value that the perpendicular magnetic recording medium can originally take. In particular, when the anisotropic magnetic field of the perpendicular magnetic recording medium is 5 KOe or less, the above-mentioned drawback becomes remarkable, so that it is difficult to perform good perpendicular magnetic recording by the ring head.
発明の目的 本発明は、上述の点に鑑みリングヘツドを用いて良好な
垂直磁気記録が行える垂直磁気記録方式を提供するもの
である。SUMMARY OF THE INVENTION In view of the above points, the present invention provides a perpendicular magnetic recording system capable of performing good perpendicular magnetic recording by using a ring head.
発明の概要 本発明は、基板上に垂直磁気異方性膜を設けた垂直磁気
記録媒体の一平面に、所要の磁気ギャップを有して閉磁
路を構成するコアと、このコアに巻装されコアの磁気ギ
ャップを挟む各対向先端部に逆極性を与える巻線とから
なるリングヘッドの各対向先端部を対向又は対接して記
録する記録方式において、前記コアを飽和磁束密度が80
00ガウス以上の材料より構成することを特徴とするもの
である。この垂直磁気記録方式によれば、再生電圧、波
長特性ともに大幅に改善され、リングヘッドによる良好
な垂直磁気記録が可能となる。特に、リングヘッドと垂
直磁化膜１層の記録媒体の組合せでも高感度記録が可能
となる。SUMMARY OF THE INVENTION According to the present invention, a core forming a closed magnetic circuit having a required magnetic gap is formed on one plane of a perpendicular magnetic recording medium having a perpendicular magnetic anisotropic film provided on a substrate, and the core is wound around the core. In a recording method of recording by facing or abutting each facing tip portion of a ring head composed of windings giving opposite polarities to each facing tip portion sandwiching a magnetic gap of the core, the core has a saturation magnetic flux density of 80
It is characterized by being composed of a material of 00 gauss or more. According to this perpendicular magnetic recording method, both the reproducing voltage and the wavelength characteristic are significantly improved, and good perpendicular magnetic recording by the ring head becomes possible. In particular, high-sensitivity recording is possible even with a combination of a ring head and a recording medium having a single layer of perpendicular magnetization film.
実施例 以下、本発明の実施例について述べる。Examples Hereinafter, examples of the present invention will be described.
第１図は、高分子フイルムなどの非磁性基板(1)上にコ
バルト・クロームなどの垂直磁気異方性膜(2)をスパツ
タリングなどで被着形成してなる単層膜垂直磁気記録媒
体(3)に、磁気ギヤツプｇを有し閉磁路を構成するコア
(4)からなるリングヘツド(5)によつて垂直磁気記録する
例である。第２図は、高分子フイルムなどの非磁性基板
(1)上にパーマロイなどの高透磁率材層(6)を形成し、そ
の上にコバルト・クロームなどの垂直磁気異方性膜(2)
を被着形成した２層膜垂直磁気記録媒体(7)に、リング
ヘツド(5)によつて垂直磁気記録する例である。本発明
においては、単層膜垂直磁気記録媒体(3)または２層膜
垂直磁気記録媒体(7)のいずれの場合にもコア(4)の飽和
磁束密度が8000ガウス以上のリングヘツド(5)を用いて
垂直磁気記録するものである。FIG. 1 shows a single-layer perpendicular magnetic recording medium in which a perpendicular magnetic anisotropy film (2) such as cobalt chrome is deposited on a non-magnetic substrate (1) such as a polymer film by sputtering or the like ( 3) A core that has a magnetic gear g and forms a closed magnetic circuit
This is an example of perpendicular magnetic recording by a ring head (5) composed of (4). Figure 2 shows a non-magnetic substrate such as polymer film.
High magnetic permeability material layer (6) such as Permalloy is formed on (1), and perpendicular magnetic anisotropy film such as cobalt chrome is formed on it (2)
This is an example of perpendicular magnetic recording by a ring head (5) on a double-layered perpendicular magnetic recording medium (7) on which is deposited. In the present invention, a ring head (5) having a saturation magnetic flux density of 8000 gauss or more is provided for the core (4) in either the single-layer perpendicular magnetic recording medium (3) or the double-layer perpendicular magnetic recording medium (7). It is used for perpendicular magnetic recording.
第３図は本発明による垂直磁気記録と従来のリングヘッ
ドを用いた場合の垂直磁気記録とを比較した波長特性図
である。ここでは、垂直異方性磁界ＨKを異にした２種
の垂直磁気記録媒体Ａ及びＢを使用した。媒体Ａはポリ
イミドの非磁性基板上にCo−Cr合金（Crが20原子％含
有）による厚さ0.5μｍの垂直磁気異方性膜をスパツタ
リングによつて被着して得た磁気テープで、その磁気特
性は飽和磁束密度Bsが5000ガウス、抗磁力Hcが1300Oe、
垂直異方性磁界ＨKが4.2KOeである。媒体Ｂは上記媒体
Ａと同様の構成であつて、スパツタリングのAr圧の条件
を変えて垂直異方性磁界ＨKを5.5KOeとした磁気テープ
である。FIG. 3 is a wavelength characteristic diagram comparing the perpendicular magnetic recording according to the present invention with the perpendicular magnetic recording using the conventional ring head. Here, two types of perpendicular magnetic recording media A and B having different perpendicular anisotropy magnetic fields H K were used. Medium A is a magnetic tape obtained by depositing a 0.5 μm-thick perpendicular magnetic anisotropic film of a Co—Cr alloy (containing 20 atomic% of Cr) on a non-magnetic substrate of polyimide by sputtering. The magnetic characteristics are saturation magnetic flux density Bs of 5000 gauss, coercive force Hc of 1300 Oe,
The perpendicular anisotropy magnetic field H K is 4.2 KOe. The medium B is a magnetic tape having the same structure as that of the medium A, and the perpendicular anisotropic magnetic field H K is set to 5.5 KOe by changing the Ar pressure condition of the sputtering.
第３図中、曲線（Ｉ）はコアの飽和磁束密度Bsが10000
ガウス、磁気ギヤツプ長が0.3μｍのFe−Al−Si系合金
（センダスト）からなるリングヘツドで垂直異方性磁界
4.2KOeの垂直磁気記録媒体Ａに記録した場合（本発明）
の波長特性である。曲線（II）は、コアの飽和磁束密度
Bsが4000ガウス、磁気ギャップ長が0.3μｍのフエライ
ト製リングヘツドで、垂直異方性磁界5.5KOeの垂直磁気
記録媒体Ｂに記録した場合（従来）の波長特性である。
曲線（III）は、同様にコアの飽和磁束密度Bsが4000ガ
ウス、磁気ギヤツプ長が0.3μｍのフエライト製リング
ヘツドで、垂直異方性磁界4.2KOeの垂直磁気記録媒体Ａ
に記録した場合（従来）の波長特性である。但し、再生
ヘッドは共通であり、コアの飽和磁束密度Bsが4000ガウ
ス、磁気ギヤツプ長が0.25μｍのフエライト製リングヘ
ツドである。In Fig. 3, the curve (I) shows that the saturation magnetic flux density Bs of the core is 10,000.
Gaussian, magnetic anisotropy field with a ring head made of Fe-Al-Si alloy (Sendust) with a magnetic gap length of 0.3 μm
4.2 When recording on a perpendicular magnetic recording medium A of KOE (the present invention)
The wavelength characteristics of Curve (II) is the saturation magnetic flux density of the core
This is the wavelength characteristic when recorded on a perpendicular magnetic recording medium B having a perpendicular anisotropy magnetic field of 5.5 KOe and using a ferrite head ring head having a Bs of 4000 gauss and a magnetic gap length of 0.3 μm (conventional).
Curve (III) is a ferrite magnetic head with a saturation magnetic flux density Bs of 4000 gauss and a magnetic gear length of 0.3 μm, and a perpendicular magnetic recording medium A with a perpendicular anisotropic magnetic field of 4.2 KOe.
The wavelength characteristics are those when recorded in (conventional). However, the reproducing head is common, and is a ferrite head head having a saturation magnetic flux density Bs of the core of 4000 gauss and a magnetic gear length of 0.25 μm.
曲線（Ｉ）と曲線（II）（III）とを比較すると、曲線
（Ｉ）は曲線（II）（III）よりも再生電圧が４dB以上
大きく、波長30μｍの再生電圧値から６dB下がつた再生
電圧値を示す波長λ50は曲線（Ｉ）の場合、曲線（II）
のλ50の0.86倍、曲線（III）のλ50の0.73倍である。
したがつてコアの飽和磁束密度が10000ガウスのリング
ヘツドで記録すれば、コアの飽和磁束密度が4000ガウス
のリングヘツドで記録するよりも、再生電圧、波長特性
とも大幅に改善できる。しかも、曲線（II）と（III）
の比較で解かる様に、垂直磁気記録媒体の垂直異方性磁
界が５KOe以下になると、コアの飽和磁束密度が4000ガ
ウスのリングヘツドで記録した場合には波長特性が短波
長側で劣化するにもかかわらず、コアの飽和磁束密度が
10000ガウスのリングヘツドで記録した本発明の場合に
は垂直磁気記録媒体の垂直異方性磁界が５KOe以下でも
極めて良好な垂直磁気記録を実現することができる。Comparing the curves (I) and (II) and (III), the reproduction voltage of the curve (I) is 4 dB or more higher than that of the curves (II) and (III), and the reproduction voltage is 6 dB lower than the reproduction voltage value of the wavelength of 30 μm. The wavelength λ 50 showing the voltage value is the curve (II) in the case of the curve (I).
0.86 times the lambda 50, which is 0.73 times the lambda 50 of the curve (III).
Therefore, recording with a ring head with a saturation magnetic flux density of 10,000 gauss in the core can significantly improve the reproducing voltage and wavelength characteristics as compared with recording with a ring head with a saturation magnetic flux density of 4000 gauss. Moreover, curves (II) and (III)
As can be seen from the comparison, when the perpendicular anisotropy magnetic field of the perpendicular magnetic recording medium becomes 5 KOe or less, the wavelength characteristic is deteriorated on the short wavelength side when the saturation magnetic flux density of the core is recorded with a ring head of 4000 Gauss. Nevertheless, the saturation magnetic flux density of the core
In the case of the present invention in which recording is performed with a ring head of 10,000 gauss, extremely good perpendicular magnetic recording can be realized even when the perpendicular anisotropy magnetic field of the perpendicular magnetic recording medium is 5 KOe or less.
曲線（IV）はコアの飽和磁束密度が8000ガウス、磁気ギ
ヤツプ長が0.2μｍのCo−Fe系のアモルフアス合金製の
リングヘツドで、垂直異方性磁界4.2KOeの垂直磁気記録
媒体Ａに記録した場合（本発明）の波長特性である。こ
の場合も、曲線（Ｉ）とほぼ同等の効果が得られる。Curve (IV) is a ring head made of Co-Fe based amorphous alloy with a saturation magnetic flux density of 8000 gauss and a magnetic gap length of 0.2 μm when recorded on a perpendicular magnetic recording medium A with a perpendicular anisotropy magnetic field of 4.2 KOe. It is a wavelength characteristic of (the present invention). In this case as well, an effect similar to that of the curve (I) is obtained.
尚、垂直磁気記録媒体において、２層膜構造にする場合
はそのコバルト・クロームの垂直磁気異方性膜として異
方性磁界ＨKの大きいものを作りにくいが、本発明の場
合にはこのような異方性磁界ＨKの小さい２層膜垂直磁
気記録媒体でも充分に垂直磁気記録ができる。リングヘ
ッドによる垂直記録において、磁化反転させるためのヘ
ッド磁界の垂直方向（媒体の膜厚方向）の大きさＨ
yhは、Ｈyh≧（記録媒体内の反転磁界）＋Ｈｃ（⊥）が
必要となる。In the perpendicular magnetic recording medium, when a two-layer film structure is used, it is difficult to form a cobalt-chromium perpendicular magnetic anisotropic film having a large anisotropic magnetic field H K. Perpendicular magnetic recording can be sufficiently performed even with a double-layered perpendicular magnetic recording medium having a small anisotropic magnetic field H K. In the perpendicular recording by the ring head, the magnitude H of the head magnetic field for reversing the magnetization in the perpendicular direction (medium film thickness direction)
For yh , H yh ≧ (reversal magnetic field in recording medium) + H c (⊥) is required.
一方、記録磁界は記録媒体の厚み方向に減衰するので、
記録媒体の厚みの約50％が完全に磁化反転することを垂
直記録の目安とされ（即ち、約50％磁化反転すれば記録
が十分できたと見なされる）、少なくとも記録媒体の厚
みの約20％の磁化反転が垂直記録としての実用に供する
下限であり、之より少ない場合には垂直記録の実用に供
し得ない。On the other hand, since the recording magnetic field is attenuated in the thickness direction of the recording medium,
It is assumed that about 50% of the thickness of the recording medium completely reverses the magnetization (that is, it is considered that recording could be sufficiently completed if the magnetization is reversed by about 50%), and at least about 20% of the thickness of the recording medium. The magnetization reversal is the lower limit for practical use as perpendicular recording, and if less than this, it cannot be practically used for perpendicular recording.
上記実施例（飽和磁束密度Ｂｓ5000ガウス、抗磁力Ｈｃ
1300Ｏｅの記録媒体で、ギャップ長0.3μｍ以下の場
合）におけるコアのＢｓが10000 ガウスのリングヘッド
では、記録媒体の厚みの約50％が磁化反転され、コアの
Ｂｓが8000 ガウスのリングヘッドでは磁化反転が記録
媒体の厚みの約22％に達する。コアのＢｓが8000ガウス
より小さくなると磁化反転が記録媒体の厚みの約20％に
達しない。（具体的な計算は省略する）。第３図の特性
図から明らかなように、曲線Ｉ（10000 ガウスの場合）
に比べて曲線IV（8000ガウスの場合）には再生電圧が約
20％下がり出しており、これ以上の再生電圧の低下は垂
直記録として実用化が困難となる。The above embodiment (saturation magnetic flux density Bs 5000 gauss, coercive force Hc
With a recording medium of 1300 Oe and a gap length of 0.3 μm or less), a ring head with a core Bs of 10,000 Gauss has a magnetization reversal of about 50% of the thickness of the recording medium, and a ring head with a Bs of 8,000 Gauss has a magnetization. Inversion reaches about 22% of the thickness of the recording medium. When the Bs of the core is smaller than 8000 gauss, the magnetization reversal does not reach about 20% of the thickness of the recording medium. (Specific calculations are omitted). As is clear from the characteristic diagram of FIG. 3, the curve I (in the case of 10000 Gauss)
Compared with the curve IV (for 8000 gauss), the playback voltage is approx.
It has fallen by 20%, and further reduction of the reproduction voltage makes it difficult to put it into practical use as perpendicular recording.
従って、記録媒体の膜厚全体の約20％以上を磁化反転さ
せるためには、コアの飽和磁束密度Ｂｓを8000ガウス以
上とするのがよい。Therefore, in order to reverse the magnetization of about 20% or more of the entire thickness of the recording medium, the saturation magnetic flux density Bs of the core is preferably set to 8000 gauss or more.
発明の効果 上述の本発明によれば、コアの飽和磁束密度Bsが8000
ガウス以上のリングヘツドを用いることにより、再生電
圧、波長特性ともに大幅に改善され、リングヘツドによ
る良好な垂直磁気記録が可能となる。また本発明は従来
不可能であつた垂直異方性磁界ＨKが５KOe以下の垂直磁
気記録媒体に対してもリングヘツドによつて良好に垂直
磁気記録することを可能にするものである。この為に記
録、再生感度の良いリングヘツドを用いた垂直磁気記録
が可能になり、特に垂直磁化膜一層の記録媒体に対して
も高感度記録が可能になり、さらに垂直磁気記録媒体の
作製条件が緩和され垂直磁気記録媒体の生産性が大幅に
向上する。EFFECTS OF THE INVENTION According to the present invention described above, the saturation magnetic flux density Bs of the core is 8000.
By using a ring head of Gauss or more, the reproducing voltage and the wavelength characteristic are greatly improved, and good perpendicular magnetic recording by the ring head is possible. Further, the present invention enables good perpendicular magnetic recording by a ring head even on a perpendicular magnetic recording medium having a perpendicular anisotropic magnetic field H K of 5 KOe or less, which has been impossible in the past. For this reason, perpendicular magnetic recording using a ring head with good recording and reproducing sensitivity becomes possible, and particularly high-sensitivity recording is possible even for a recording medium with a single layer of perpendicular magnetic film. It is alleviated and the productivity of the perpendicular magnetic recording medium is significantly improved.
第１図及び第２図は夫々本発明の垂直磁気記録方式の例
を示す断面図、第３図は本発明の垂直磁気記録と従来の
リングヘツドを用いた場合の垂直磁気記録を比較して示
した波長特性図である。 (1)は非磁性基板、(2)は垂直磁気異方性膜、(5)はリン
グヘツド、(6)は高透磁率材層である。1 and 2 are sectional views showing examples of the perpendicular magnetic recording system of the present invention, and FIG. 3 shows a comparison between the perpendicular magnetic recording of the present invention and the perpendicular magnetic recording using a conventional ring head. FIG. 6 is a wavelength characteristic diagram. (1) is a non-magnetic substrate, (2) is a perpendicular magnetic anisotropic film, (5) is a ring head, and (6) is a high magnetic permeability material layer.
Claims (1)
気記録媒体の一平面に、所要の磁気ギャップを有して閉
磁路を構成するコアと前記コアに巻装されコアの磁気ギ
ャップを挟む各対向先端部に逆極性を与える巻線とから
なるリングヘッドの前記各対向先端部を対向又は対接し
て記録する記録方式において、前記コアは飽和磁束密度
が8000ガウス以上の材料より成ることを特徴とする垂直
磁気記録方式。1. A core forming a closed magnetic circuit having a required magnetic gap on one plane of a perpendicular magnetic recording medium having a perpendicular magnetic anisotropy film on a substrate, and a magnetic field of the core wound around the core. In a recording method of recording by facing or facing each of the facing tips of a ring head composed of windings that give opposite polarities to the facing tips that sandwich a gap, the core is made of a material having a saturation magnetic flux density of 8000 gauss or more. A perpendicular magnetic recording method characterized by being formed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57198159A JPH0619809B2 (en) | 1982-11-11 | 1982-11-11 | Perpendicular magnetic recording method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57198159A JPH0619809B2 (en) | 1982-11-11 | 1982-11-11 | Perpendicular magnetic recording method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5987612A JPS5987612A (en) | 1984-05-21 |
| JPH0619809B2 true JPH0619809B2 (en) | 1994-03-16 |
Family
ID=16386441
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57198159A Expired - Lifetime JPH0619809B2 (en) | 1982-11-11 | 1982-11-11 | Perpendicular magnetic recording method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0619809B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0640361B2 (en) * | 1985-03-07 | 1994-05-25 | 日本ビクター株式会社 | Perpendicular magnetic recording / reproducing method |
| JPS62126174U (en) * | 1986-01-31 | 1987-08-11 | ||
| US5396391A (en) * | 1990-12-12 | 1995-03-07 | Kabushiki Kaisha Toshiba | Magnetic recording system providing a magnetic head having opposite sides for applying different magnetic field strengths to a magnetic recording medium |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57127908A (en) * | 1981-01-29 | 1982-08-09 | Fuji Photo Film Co Ltd | Magnetic head |
-
1982
- 1982-11-11 JP JP57198159A patent/JPH0619809B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5987612A (en) | 1984-05-21 |
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