JP2004013941A

JP2004013941A - Magnetic head and its manufacturing method

Info

Publication number: JP2004013941A
Application number: JP2002162009A
Authority: JP
Inventors: Koichi Osano; 小佐野　浩一; Akinaga Natsui; 夏井　昭長; Terumasa Sawai; 沢井　瑛昌; Shozo Ninomiya; 二宮　祥三
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-06-03
Filing date: 2002-06-03
Publication date: 2004-01-15

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic head by which a high reproducing output can be obtained at the time of reproduction in the magnetic recording of narrow track width. <P>SOLUTION: The magnetic head is so constituted that a metal magnetic film is formed on a slope inclined with respect to a sliding surface and the bottom surface of a groove forming a track has an inclined surface made to be gradually deep from one side of a magnetic core half body to the other side of the magnetic core half body. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、狭いトラック幅で磁気記録を行なう高密度磁気記録用の磁気ヘッド及びその製造方法に関する。
【０００２】
【従来の技術】
図８及び図９は、それぞれ従来から知られているヘッドコア（コイルを巻いていない状態のもので磁気コアともいう）の、斜視図およびＩＸ−ＩＸ断面図である。図を見易くするため断面にハッチを施していない。これらのヘッドコアにコイルを巻いた完成品の磁気ヘッドは、ビデオテープレコーダ等の回転ドラムに搭載され、回転ドラムの外周に沿って走行する磁気テープに情報を記録再生する。
【０００３】
図８に示すヘッドコア５０は、Ｍｎ−Ｚｎフェライト等の磁性体で作られた２つのヘッドコア半体５１Ａ、５１Ｂを接合して構成されている。接合前の個々のヘッドコア半体５１Ａ、５１Ｂに、接合したとき巻き線用の窓５５となる溝５６Ａ、５６Ｂをそれぞれ形成する。磁気ヘッドになったとき磁気ギャップを形成するギャップ面５２に平行になされた前記ヘッドコアの面５３Ａ、５３Ｂを含む全面に、それぞれスパッタリングにより金属磁性膜５４Ａ、５４Ｂを形成する。前記金属磁性膜５４Ａ、５４Ｂの上の磁気ギャップを形成するためのギャップ面５２に非磁性の薄膜をそれぞれ形成した後、２つの磁気コア半体５１Ａ、５１Ｂを溶融ガラス等で接着する。接着した磁気コアのギャップ面５に垂直な両側面を切削して、磁気記録媒体に接触するトラック形成部６０の幅Ｗ１０を所定の寸法にする。最後に前記切削部に溶融ガラスを流し込んで切削部を埋め、ヘッドコア５０が完成する。
【０００４】
【発明が解決しようとする課題】
近年、磁気記録の記録密度の向上に対する要求が高まり、記録媒体のトラックピッチが益々狭くなされるとともに、前記面６０の幅Ｗ１０にほぼ等しいトラック幅も約１０μｍ以下と狭くなされている。そこでこのような狭いトラック幅の磁気記録媒体に信号を記録し高い再生出力が得られる磁気ヘッドが求められている。
【０００５】
磁気ヘッドの再生出力は、トラック幅が狭くなると共に低下していく。図８に示したような従来の構成の磁気ヘッドにおいては、トラック幅が約１０μｍ以下になると、十分大きな再生出力が得られず、トラックピッチを狭くする上で障害となる。トラック幅が狭くても十分な再生出力を得るためには、磁気ヘッドの磁気効率を向上させる必要がある。
本発明は、狭トラック幅の磁気記録において、再生時に高い再生出力が得られる磁気ヘッドを提供することを目的とする。
【０００６】
【課題を解決するための手段】
本発明の磁気ヘッドは、主面に溝を有する磁性材で形成され、前記溝の少なくとも一方の壁面が前記主面に対して鋭角の斜面である磁気コア半体基材、前記溝の斜面に形成した非磁性体の保護膜、前記保護膜の上に形成した軟磁性体の膜、及び前記軟磁性体の膜の、前記主面に露出する面に形成した磁気ギャップ部形成用の非磁性膜を有する磁気コア半体の２つのものを前記主面で接合した磁気コア、及び接合した２つの磁気コア半体の溝により形成される空間を通って巻回したコイルを備え、前記磁気コアの磁気記録媒体に接する部が、前記磁気ギャップ部の両端部領域を切削することによって所定のトラック幅に形成され、前記切削部の片側が一方の磁気コア半体から他方の磁気コア半体にかけて次第に深くなる傾斜面を有し、磁気ギャップ部を挟んで反対側の前記切削部が前記他方の磁気コア半体から一方の磁気コア半体にかけて次第に深くなる傾斜面を有することを特徴とする。
【０００７】
本発明の磁気ヘッドの製造方法は、磁性材の磁気コア半体基材の主面に、少なくとも一方の壁面が前記主面に対して鋭角の斜面を有する溝を形成するステップ、
前記溝の斜面に非磁性体の保護膜を形成するステップ、前記保護膜の上にスパッタリングにより軟磁性体の膜を形成するステップ、前記軟磁性体の膜の、前記主面に露出する面に磁気ギャップ形成用の非磁性膜を形成するステップ、前記の各ステップで形成した磁気コア半体の２つのものを前記主面で接合して磁気コアを形成するステップ、前記磁気コアに、磁気記録媒体に接する磁気ギャップ部が、磁気ギャップ部の両端部領域を切削することによって所定のトラック幅に形成されるように、前記切削部のうち片側に、一方の磁気コア半体から他方の磁気コア半体にかけて次第に深くなる傾斜面を形成し、前記ギャップ部を挟んで反対側が、他方の磁気コア半体から一方の磁気コア半体にかけて次第に深くなる傾斜面を形成するステップ、及び前記２つの磁気コア半体の溝により形成される空間を通ってコイルを巻回するステップを有する。
【０００８】
【発明の実施の形態】
本発明の好適な実施例について図１から図６を参照して説明する。
《第１実施例》
図１は本発明の第１実施例の磁気コア１０の完成品の斜視図、図２は図１のＩＩ−ＩＩ断面図である。図を見易くするため断面にハッチを施していない。図１及び図２において、単結晶フェライト等で作られた２つの磁気コア半体１Ａ、１Ｂが接着ガラス３ではり合わされ、磁気コア１０が形成される。磁気コア１０は、巻線用の窓５を有している。窓５の内壁面５Ａ、５Ｂには、それぞれ、金属磁性膜２Ａ、２Ｂが形成されている。窓５は、略５角形であり、金属磁性膜２Ａ、２Ｂは窓５の内壁面にほぼ均一な厚みで形成されている。金属磁性膜２Ａ、２Ｂは、磁気記録媒体に按する部分であるトラック形成部１６において、磁気ギャップ１５を保つため所定の厚さのギャップ材を介して接している。トラック形成部１６の幅Ｗｌ（以下、トラック幅Ｗｌという）が所定の寸法になるように、トラック形成部１６の両側部を削り取ることにより切り欠き部４Ａ、４Ｂが形成される。磁気ギャップ１５の長手方向は、磁気コア１０の側面に対して、アジマス角θの分だけ傾けられている。
【０００９】
図３の（ａ）から（ｃ）の斜投影図を参照して、図１の磁気コア半体１Ａ、１Ｂの製造方法の工程（ステップ）について説明する。磁気コア半体１Ａと１Ｂは全く同じ形状であるので、以後磁気コア半体１Ａについて説明する。図３の（ａ）において、複数個の磁気コアを一度に作るための、図の右上に向かって長い単結晶フェライトの板状部材２１に、磁気コア１０の完成時に巻線用の窓となる溝２２を砥石による研削加工で形成する。溝２２の図において左側面２２Ａは斜面になされている。底面２２Ｂは板状部材２１の主面である上面２１Ａとほぼ平行になされている。
図３の（ｂ）において、板状部材２１の上面２１Ａ、及び２１Ｂ、溝２２の左側面２２Ａ及び底面２２Ｂに、厚さ７ｎｍのＡｌ_２Ｏ_３の保護膜２３を形成する。次に、アルゴンガス（Ａｒ）と窒素ガス（Ｎ２）との混合ガス雰囲気中で、Ｆｅ−Ｔａをターゲットとして用いるスパッタリングにより、保護膜２３の上に厚さ１８μｍのＦｅＴａＮの金属磁性膜２４を形成する。成膜の際、板状部材２１を支持する基板ホルダー（図示省略）とターゲットとの間に高周波バイアス用の高周波電圧を印加し、その高周波電圧を調節することにより、磁気異方性の向きを制御する。本実施例では前記の金属磁性膜２４を、面内での磁気異方性が小さくほぼ等方性を有するように成膜する。
【００１０】
図３の（ｃ）において、ラッピングにより、面２１Ａ及び２１Ｂの保護膜２３及び金属磁性膜２４を除去し、溝２２の左側面２２Ａ及び底面２２Ｂにのみ金属磁性膜２４を残す。このとき、図３の（ｄ）に示すように、底面２２Ｂの金属磁性膜２４及び保護膜２３を除去し、左側面２２ＡにのみＦｅＴａＮ膜を残した構造にしてもよい。この構成では、底面２２Ｂの保護膜２３及び金属磁性膜２４の除去工程が増えるが、保護膜２３及び金属磁性膜２４の厚み分だけ窓が広くなるのでコイルの巻回数を増やすことができ、その分再生感度を高くすることができる。図３の（ｃ）の金属磁性膜２４は、図１の金属磁性膜２Ａ又は２Ｂに相当する。
図３の（ｃ）の板状部材２１の上面２１Ｂに非磁性膜のギャップ材１５Ａを形成して長尺の磁気コア半体２６が得られる。
【００１１】
図４の（ａ）は２つの磁気コア半体２６を組み合わせたヘッドブロック３０の斜視図であり、同（ｂ）は上面図である。図４の（ａ）の斜視図に示すように、２つの磁気コア半体２６を、上面２１Ｂが接するように組み合わせ、溝２２によって形成される巻線窓５の一部に接着ガラス３を流し込んで２つの磁気コア半体２６を接着する。次に切削工具を用いて切込３１及び３２を入れる。最後に前記切込３１及び３２に溶融ガラスを流し込み切込３１、３２をガラスで埋めてヘッドブロック３０を形成する。図４の（ｂ）はヘッドブロック３０の上面図である。図４の（ｂ）において、ヘッドブロック３０を、点線３５及び点線３６で示す位置で切断して分離することにより、図５の（ａ）に上面図で示す磁気コア３９が複数個得られる。図５の（ａ）の磁気コア３９の上下の斜めの部分３７を長辺４０に直角な切断線Ｌ１で切断すると、図５の（ｂ）に上面図で示す磁気コア１０が得られる。更に、図６の（ａ）の側面図に示すように曲線切断線Ｌ２及び直線切断線Ｌ３で切断して磁気コア１０の完成品が得られる。図６の上面のトラック形成部１６が磁気記録媒体に対向する面である。
【００１２】
本実施例による磁気コア１０は、２つの磁気コア半体２６を接着してから切込３１及び３２を入れることによって、所定のトラック幅Ｗｌを有する、磁気記録媒体に対向する磁気ギャップ部を形成する。最後に磁気コア１０の巻線窓５にコイルを巻いて磁気ヘッドが完成する。図１及び図２に示す本実施例の磁気コア１０は、図８及び図９に示す従来の磁気コア５０と以下の点で異なっている。
従来の磁気コア５０は、図９に示すように、ヘッドギャップを形成する面５２に平行なヘッドコア面５３Ａ、５３Ｂに金属磁性膜５４Ａ、５４Ｂがそれぞれ形成されている。またヘッドコア５０の図において下部の領域５０Ａにおいて、ヘッドコア半体５１Ａ、５１Ｂの対向面にそれぞれ金属磁性膜５４Ｃ、５４Ｄが形成されている。
これに対して、本実施例の磁気コア１０では、図２に示すように、磁気コア半体１Ａ、１Ｂは、トラック形成部１６の近傍において磁気ギャップ１５を形成する面１５Ｆに平行ではなく鋭角の斜面になされている。またヘッドコア１０の図において下部の領域１０Ａにおいて、ヘッドコア半体１Ａ、１Ｂの対向面に金属磁性膜が設けられていない。この２つの構成上の特徴により、以下に詳細に説明するように再生出力レベルが高くなる。
図１の磁気コア１０において、記録媒体（図示省略）に対向するトラック幅Ｗ１が１５μｍ、１０μｍ及び７μｍの３種の磁気ヘッドを作り、実際に信号を記録再生してその特性を調べた。比較の対象として、磁気ギャップ面５２の両側に厚さ１８μｍのＦｅＴａＮの金属磁性膜５４Ａ、５４Ｂを形成した図８に示す従来の構造の試験用の磁気ヘッドを用いる。この試験用磁気ヘッドのトラック幅Ｗ１０も１５μｍ、１０μｍ、７μｍの３種類である。試験用磁気ヘッドと本実施例の図３及び図４に示す工程で作った磁気コア１０を用いた磁気ヘッドについて、それぞれ磁気テープに２０ＭＨｚの正弦波の同一レベルの信号を記録再生して、再生出力レベルを測定した。その結果、トラック幅Ｗｌが１５μｍの磁気ヘッドでは、本実施例の磁気ヘッドと試験用の磁気ヘッドとでは再生出力レベルにほとんど差がなかった。トラック幅Ｗ１が１０μｍの磁気ヘッドでは、再生出力レベルは本実施例の磁気ヘッドの方が０．５ｄＢ高かった。またトラック幅Ｗ１が７μｍのものでは本実施例のものの方が１ｄＢ高かった。以上の比較試験の結果から、本実施例の工程で製作した磁気ヘッドは、磁気ギャップ１５の近傍において、磁気コア半体１Ａ、１Ｂを磁気ギャップ１５を形成する面１５Ｆに平行でなく鋭角の斜面にしたことにより、トラック幅が小さくなるに従って、従来の磁気ヘッドよりも記録再生時の再生出力レベルが高くなることがわかった。
【００１３】
《第２実施例》
本発明の第２実施例の磁気ヘッドについて以下に説明する。第２実施例の磁気ヘッドの磁気コアは前記の第１実施例の、図３から図６に示す工程と実質的に同様の工程で作られる。本実施例の磁気コアと前記第１実施例の磁気コア１０との違いは、本実施例では、図３の（ａ）における溝２２の左側面２２Ａを回転砥石で研磨し、面の粗さを原子間力顕微鏡（ＡＦＭ）による測定値でＲａ約３０ｎｍ以下にする。前記第１実施例では左側面２２Ａの面の粗さはＲａ約６０ｎｍ以上であった。図３の（ｂ）に示す、板状部材２１の上面２１Ａ及び２１Ｂ、溝２２の左側面２２Ａ及び底面２２Ｂに、厚さ５ｎｍのＡ１_２０_３の保護膜２３を形成する。次にアルゴンガスと窒素ガスとの混合ガス中において、Ｆｅ−Ｔａ−Ｓｉをターゲットとして用いるスバッタリングにより、厚さ１８μｍのＦｅＴａＳｉＮの金属磁性膜２４を形成した。ＦｅＴａＳｉＮ膜２４は、形成された面内での磁気異方性が小さくほば等方性を有するように条件を定めて成膜した。それ以後の工程は前記図３から図６の第１実施例のものと同様である。なおトラック幅Ｗ１は７μｍのもの１種のみを作った。
【００１４】
第２実施例の磁気ヘッドにより、２０ＭＨｚの正弦波を磁気テープに記録再生して、再生出力レベルを調べた。その結果、前記第１実施例のトラック幅Ｗ１が７μｍの磁気ヘッドの場合に比べて再生出力レベルが約１ｄＢ高かった。
本実施例の磁気ヘッドでは、巻線窓となる溝２２の左側面２２Ａの粗さを小さくすることにより、左側面２２Ａの上に形成される金属磁性膜であるＦｅＴａＳｉＮの金属磁性膜２４の微視的な膜構造の乱れが少なくなる。そのため磁気ギャップ１５から金属磁性膜２４に流入する磁束の密度が高くなり、再生出力レベルが上昇する。
【００１５】
《第３実施例》
本発明の第３実施例の磁気ヘッドについて以下に説明する。第３実施例の磁気コアは、前記第１実施例の図３から図６に示す工程と類似の工程で作られ外観上は同様の構成を有する。本実施例の磁気コアと前記第１実施例の磁気コア１０との違いは、本実施例では、第２実施例と同様に、図３の（ａ）における溝２２の左側面２２Ａを回転砥石で研磨し、面の粗さを原子問力顕微鏡（ＡＦＭ）による測定値でＲａ約３０ｎｍ以下にする。次に図３の（ｂ）に示す、板状部材２１の上面２１Ａ及び２１Ｂ、溝２２の左側面２２Ａ及び底面２２Ｂに、厚さ５ｎｍのＡｌ_２Ｏ_３の保護膜２３を形成する。保護膜２３の上に、アルゴンガスと窒素ガスとの混合ガス中においてＦｅ−Ｔａ−Ｓｉをターゲットとして用いるスパッタリングにより、厚さ３μｍのＦｅＴａＳｉＮの金属磁性膜２４を形成する。厚さ３μｍの金属磁性膜２４と厚さ１５ｎｍのＡｌ_２Ｏ_３絶縁膜を交互に形成して、ＦｅＴａＳｉＮの膜とＡｌ_２Ｏ_３の膜の組を６組積層し総厚を約２０μｍにする。金属磁性膜２４は形成された面内での磁気異方性が小さくほぼ等方性を有するように条件を定めて成膜する。それ以後の工程は前記図３から図６の第１実施例のものと同様である。なおトラック幅Ｗ１が７μｍのもの１種のみを作った。
【００１６】
第３実施例の磁気ヘッドにより、２０ＭＨｚの正弦波を磁気テープに記録再生して、再生出力レベルを調べたところ、前記第２実施例のトラック幅７μｍの磁気ヘッドの、ＦｅＴａＳｉＮ膜を厚さ１８μｍの１層の膜にしたものに比ベて、再生出力レベルが約０．５ｄＢ高かった。また４０ＭＨｚの正弦波信号を記録再生して調べたところ、前記第２実施例の磁気ヘッドで同じ４０ＭＨｚの正弦波信号を記録再生した場合に比べて再生出力レベルが１．５ｄＢ高かった。
【００１７】
本実施例の磁気ヘッドでは、巻線窓となる溝２２の左側面２２Ａの粗さを小さくすることにより、左側面２２Ａの上に形成される金属磁性膜であるＦｅＴａＳｉＮ膜２４の微視的な膜構造の乱れが少なくなる。そのため磁気ギャップ１５からＦｅＴａＳｉＮ膜２４に流入する磁束の密度が高くなり再生出力のレベルの増加につながる。更に、ＦｅＴａＳｉＮ膜とＡｌ２Ｏ３膜とを交互に積層することにより、高い周波数におけるＦｅＴａＳｉＮ膜の表皮効果による磁束密度の偏りが改善される。その結果特に高い周波数における再生出力レベルが高くなる。
【００１８】
《第４実施例》
本発明の第４実施例の磁気ヘッドについて以下に説明する。第４実施例の磁気ヘッドの磁気コアは、前記第３実施例の磁気コアと実質的に同様の工程で作られ、同様の構成を有する。本実施例では、第３実施例のＦｅＴａＳｉＮ膜２４の代わりにＦｅＴａＮ膜を用いている。本実施例においては、Ａｌ_２Ｏ_３膜とＦｅＴａＮ膜をスパックリングで成膜して積層するとき、図３の（ａ）に示す単結晶フエライトの板状部材２１とターゲット間に高周波バイアス電圧を印加する。そして高周波バイアス電圧をコントロールして、磁化容易軸が左側面２２Ａの面内で磁気ギャップ１５（図１）を形成する面とほぼ平行になるように条件を定めて成膜する。
【００１９】
本実施例の磁気ヘッドのトラック幅Ｗ１が７μｍのものを作り、第１実施例のトラック幅Ｗ１が７μｍの磁気ヘッドとを比較した。その結果、本実施例のものでは、第１実施例のものに比べて２０ＭＨｚの正弦波信号の記録再生で平均０．５ｄＢ、４０ＭＨｚの正弦波信号の記録再生では１ｄＢ高い再生出力レベルが得られた。
【００２０】
《第５実施例》
本発明の第５実施例の磁気ヘッドについて図７を参照して説明する。第５実施例の磁気コア１０は、前記第３実施例の磁気コア１０と実質的に同様の工程で作られ、同様の構成を有する。本実施例では、第３実施例の金属磁性膜２４にＦｅＴａＳｉＮ膜の代わりにＦｅＴａＮ膜を用いている。
本実施例においては、図７に示すように、Ａ１_２０_３膜とＦｅＴａＮ膜をスパッタリングで成膜して積層するとき、単結晶フェライトの板状部材２１の左側面２２Ａと、ターゲットであるＦｅ−Ｔａ板４０の面４１とを平行にする。本実施例の磁気ヘッドのトラック幅Ｗ１が７μｍのものと、左側面２２ＡとＦｅ−Ｔａ板４０の面４１とを平行にせずに成膜した磁気ヘッドとを、それぞれ２０ＭＨｚの正弦波信号の記録再生をして比較した。その結果、本実施例のものは約１ｄＢだけ再生出力レベルが高かった。
【００２１】
【発明の効果】
以上の各実施例で詳細に説明したように、本発明によれば、狭トラック幅の磁気ヘッドにおいて、磁気コア半体１Ａ、１Ｂを、磁気ギャップの近傍において、磁気ギャップを形成するレベル面に平行でない鋭角の斜面にしたことにより、特に高い周波数の信号の記録再生における再生出力レベルが従来の磁気ヘッドよりも高くなる。また、鋭角の斜面の面の粗さを小さくすることにより、特に高い周波数の信号の再生出力レベルを更に大きくすることができる。
【図面の簡単な説明】
【図１】本発明の各実施例に共通の磁気コアの完成品の斜視図
【図２】図１の磁気コアのＩＩ−ＩＩ断面図
【図３】（ａ）から（ｃ）は、本発明の各実施例の磁気コア半体の製造工程を示す斜投影図
（ｄ）は他の例の磁気コア半体の斜投影図
【図４】（ａ）は本発明の各実施例の磁気コア半体を組み立てて切込みを入れた状態を示す斜視図
（ｂ）は同上面図
【図５】（ａ）は図３の（ｂ）の磁気コアブロックを切り分けた１つの磁気コアの上面図
（ｂ）は前記１つの磁気コアの両端部を切断した磁気コアの上面図
【図６】（ａ）は磁気コアの切断線を示す側面図
（ｂ）は（ａ）の左側面を示す側面図
【図７】本発明の第５実施例における、スバッタリングのターゲットと磁気コア半体２１との位置関係を示す側面図
【図８】従来例の磁気コアの斜投影図
【図９】従来例の磁気コアのＩＸ−ＩＸ断面図
【符号の説明】
１Ａ、１Ｂ　　　　磁性コア半体
２Ａ、２Ｂ　　　　金属磁性膜
３　　　　　　　　接着ガラス
４Ａ、４Ｂ　　　　切り欠き部
５　　　　　　　　巻線用の窓
１０、５０　　　　磁気コア
１５　　　　　　　磁気ギャップ
１６　　　　　　　トラック形成部
２１　　　　　　　板状部材
２１Ａ、２１Ｂ　　上面
２２　　　　　　　溝
２２Ａ　　　　　　左側面
２２Ｂ　　　　　　底面
２３　　　　　　　保護膜
２４　　　　　　　金属磁性膜
２６　　　　　　　磁気コア半体
３０　　　　　　　ヘッドブロック
３１、３２　　　　切込
３５、３６　　　　切断線
Ｌ１、Ｌ２、Ｌ３　切断線
Ｗ１、Ｗ１０　　　トラック幅
６０　　　　　　　トラック形成部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic head for high-density magnetic recording that performs magnetic recording with a narrow track width, and a method of manufacturing the same.
[0002]
[Prior art]
8 and 9 are a perspective view and a IX-IX cross-sectional view of a conventionally known head core (a state in which a coil is not wound and is also referred to as a magnetic core). No hatch is applied to the cross section to make the figure easier to see. A completed magnetic head having a coil wound around these head cores is mounted on a rotating drum such as a video tape recorder, and records and reproduces information on a magnetic tape running along the outer periphery of the rotating drum.
[0003]
The head core 50 shown in FIG. 8 is configured by joining two head core halves 51A and 51B made of a magnetic material such as Mn-Zn ferrite. Grooves 56A, 56B which become windows 55 for winding when joined are formed in the individual head core halves 51A, 51B before joining. Metal magnetic films 54A and 54B are formed by sputtering on the entire surface including the surfaces 53A and 53B of the head core formed parallel to the gap surface 52 forming the magnetic gap when the magnetic head is formed. After a non-magnetic thin film is formed on a gap surface 52 for forming a magnetic gap on the metal magnetic films 54A and 54B, the two magnetic core halves 51A and 51B are bonded with molten glass or the like. Both sides perpendicular to the gap surface 5 of the bonded magnetic core are cut so that the width W10 of the track forming portion 60 that comes into contact with the magnetic recording medium is set to a predetermined size. Finally, molten glass is poured into the cut portion to fill the cut portion, and the head core 50 is completed.
[0004]
[Problems to be solved by the invention]
In recent years, there has been an increasing demand for an improvement in the recording density of magnetic recording, and the track pitch of a recording medium has been further narrowed, and the track width substantially equal to the width W10 of the surface 60 has been narrowed to about 10 μm or less. Therefore, there is a demand for a magnetic head capable of recording a signal on a magnetic recording medium having such a narrow track width and obtaining a high reproduction output.
[0005]
The reproduction output of the magnetic head decreases as the track width decreases. In the conventional magnetic head as shown in FIG. 8, if the track width is less than about 10 μm, a sufficiently large reproduction output cannot be obtained, which is an obstacle to narrowing the track pitch. In order to obtain a sufficient reproduction output even if the track width is narrow, it is necessary to improve the magnetic efficiency of the magnetic head.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic head capable of obtaining a high reproduction output during reproduction in magnetic recording with a narrow track width.
[0006]
[Means for Solving the Problems]
The magnetic head of the present invention is formed of a magnetic material having a groove on a main surface, at least one wall surface of the groove is a magnetic core half base material having an acute slope with respect to the main surface, and a slope of the groove. The formed non-magnetic material protective film, the soft magnetic material film formed on the protective film, and the non-magnetic material for forming a magnetic gap portion formed on the surface of the soft magnetic material film exposed on the main surface. A magnetic core formed by joining two magnetic core halves having a film on the main surface, and a coil wound through a space formed by a groove of the joined two magnetic core halves; The portion in contact with the magnetic recording medium is formed with a predetermined track width by cutting both end regions of the magnetic gap portion, and one side of the cut portion extends from one magnetic core half to the other magnetic core half. It has an inclined surface that gradually deepens, The cutting portion of the opposite side of the flop portion and having an inclined surface gradually deeper toward one magnetic core half body from the other magnetic core halves.
[0007]
In the method of manufacturing a magnetic head of the present invention, a step of forming a groove in which at least one wall surface has a slope inclined at an acute angle with respect to the main surface on the main surface of the magnetic core half base material of the magnetic material,
Forming a nonmagnetic protective film on the slope of the groove, forming a soft magnetic film by sputtering on the protective film, and forming the soft magnetic film on the surface exposed to the main surface. Forming a non-magnetic film for forming a magnetic gap, joining two of the magnetic core halves formed in each of the above steps on the main surface to form a magnetic core, and performing magnetic recording on the magnetic core. On one side of the cut portion, from one magnetic core half to the other magnetic core, so that the magnetic gap portion in contact with the medium is formed with a predetermined track width by cutting both end regions of the magnetic gap portion. Forming an inclined surface that gradually becomes deeper over the half, and forming an inclined surface that gradually becomes deeper from the other magnetic core half to one magnetic core half on the opposite side across the gap portion; Comprising the step of winding the coil through the space formed by the fine said two grooves of magnetic core halves.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
A preferred embodiment of the present invention will be described with reference to FIGS.
<< 1st Example >>
FIG. 1 is a perspective view of a completed product of a magnetic core 10 according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG. No hatch is applied to the cross section to make the figure easier to see. 1 and 2, two magnetic core halves 1A and 1B made of single crystal ferrite or the like are bonded together with an adhesive glass 3 to form a magnetic core 10. The magnetic core 10 has a window 5 for winding. Metal magnetic films 2A and 2B are formed on inner wall surfaces 5A and 5B of window 5, respectively. The window 5 is substantially pentagonal, and the metal magnetic films 2A and 2B are formed on the inner wall surface of the window 5 with a substantially uniform thickness. The metal magnetic films 2A and 2B are in contact with each other via a gap material having a predetermined thickness in order to maintain the magnetic gap 15 in a track forming portion 16 which is a portion corresponding to the magnetic recording medium. The notches 4A and 4B are formed by cutting both sides of the track forming section 16 so that the width Wl of the track forming section 16 (hereinafter, referred to as track width Wl) has a predetermined dimension. The longitudinal direction of the magnetic gap 15 is inclined by the azimuth angle θ with respect to the side surface of the magnetic core 10.
[0009]
The steps (steps) of the method of manufacturing the magnetic core halves 1A and 1B of FIG. 1 will be described with reference to the oblique projection views of FIGS. Since the magnetic core halves 1A and 1B have exactly the same shape, the magnetic core half 1A will be described below. In FIG. 3A, a window for winding when a magnetic core 10 is completed is formed on a plate-like member 21 made of a single crystal ferrite that is long toward the upper right of the figure for forming a plurality of magnetic cores at one time. The groove 22 is formed by grinding using a grindstone. In the drawing of the groove 22, the left side surface 22A is formed as a slope. The bottom surface 22B is substantially parallel to the upper surface 21A, which is the main surface of the plate member 21.
In FIG. 3B, a 7 nm-thick protective film 23 of Al ₂ O ₃ is formed on the upper surfaces 21A and 21B of the plate member 21 and the left side surface 22A and the bottom surface 22B of the groove 22. Next, an 18 μm thick FeTaN metal magnetic film 24 is formed on the protective film 23 by sputtering using Fe—Ta as a target in a mixed gas atmosphere of argon gas (Ar) and nitrogen gas (N 2). I do. At the time of film formation, a high-frequency voltage for high-frequency bias is applied between a target and a substrate holder (not shown) for supporting the plate-like member 21, and the direction of magnetic anisotropy is adjusted by adjusting the high-frequency voltage. Control. In this embodiment, the metal magnetic film 24 is formed so as to have a small in-plane magnetic anisotropy and to be substantially isotropic.
[0010]
In FIG. 3C, the protective film 23 and the metal magnetic film 24 on the surfaces 21A and 21B are removed by lapping, and the metal magnetic film 24 is left only on the left side surface 22A and the bottom surface 22B of the groove 22. At this time, as shown in FIG. 3D, the structure may be such that the metal magnetic film 24 and the protective film 23 on the bottom surface 22B are removed and the FeTaN film is left only on the left side surface 22A. In this configuration, the number of steps of removing the protective film 23 and the metal magnetic film 24 on the bottom surface 22B increases, but the number of turns of the coil can be increased because the window is widened by the thickness of the protective film 23 and the metal magnetic film 24. Minute reproduction sensitivity can be increased. The metal magnetic film 24 in FIG. 3C corresponds to the metal magnetic film 2A or 2B in FIG.
A long magnetic core half 26 is obtained by forming a gap material 15A of a non-magnetic film on the upper surface 21B of the plate-like member 21 of FIG. 3 (c).
[0011]
FIG. 4A is a perspective view of a head block 30 in which two magnetic core halves 26 are combined, and FIG. 4B is a top view. As shown in the perspective view of FIG. 4A, the two magnetic core halves 26 are combined so that the upper surface 21B contacts, and the adhesive glass 3 is poured into a part of the winding window 5 formed by the groove 22. To bond the two magnetic core halves 26 together. Next, cuts 31 and 32 are made using a cutting tool. Finally, molten glass is poured into the cuts 31 and 32, and the cuts 31 and 32 are filled with glass to form the head block 30. FIG. 4B is a top view of the head block 30. In FIG. 4B, the head block 30 is cut and separated at positions indicated by dotted lines 35 and 36, whereby a plurality of magnetic cores 39 shown in a top view in FIG. 5A are obtained. When the upper and lower oblique portions 37 of the magnetic core 39 in FIG. 5A are cut along a cutting line L1 perpendicular to the long side 40, the magnetic core 10 shown in a top view in FIG. 5B is obtained. Further, as shown in the side view of FIG. 6A, the magnetic core 10 is obtained by cutting along a curved cutting line L2 and a straight cutting line L3. The track forming portion 16 on the upper surface in FIG. 6 is the surface facing the magnetic recording medium.
[0012]
The magnetic core 10 according to the present embodiment forms a magnetic gap portion having a predetermined track width Wl and facing the magnetic recording medium by cutting the two magnetic core halves 26 and then making cuts 31 and 32. I do. Finally, a coil is wound around the winding window 5 of the magnetic core 10 to complete the magnetic head. The magnetic core 10 of this embodiment shown in FIGS. 1 and 2 differs from the conventional magnetic core 50 shown in FIGS. 8 and 9 in the following points.
In the conventional magnetic core 50, as shown in FIG. 9, metal magnetic films 54A and 54B are formed on head core surfaces 53A and 53B parallel to a surface 52 forming a head gap, respectively. In a lower region 50A of the head core 50 in the drawing, metal magnetic films 54C and 54D are formed on the opposing surfaces of the head core halves 51A and 51B, respectively.
On the other hand, in the magnetic core 10 of the present embodiment, as shown in FIG. 2, the magnetic core halves 1A and 1B are not parallel to the surface 15F where the magnetic gap 15 is formed in the vicinity of the track forming portion 16 but at an acute angle. The slope has been made. Further, in the lower region 10A in the drawing of the head core 10, the metal magnetic film is not provided on the opposing surfaces of the head core halves 1A and 1B. These two structural features result in higher playback output levels, as described in detail below.
In the magnetic core 10 shown in FIG. 1, three types of magnetic heads having a track width W1 of 15 μm, 10 μm, and 7 μm facing a recording medium (not shown) were manufactured, and signals were actually recorded and reproduced to examine the characteristics. As a comparison target, a test magnetic head having a conventional structure shown in FIG. 8 in which FeTaN metal magnetic films 54A and 54B each having a thickness of 18 μm are formed on both sides of the magnetic gap surface 52 is used. The track width W10 of this test magnetic head is also of three types: 15 μm, 10 μm, and 7 μm. Regarding the test magnetic head and the magnetic head using the magnetic core 10 manufactured in the steps shown in FIGS. 3 and 4 of this embodiment, the same level signal of a 20 MHz sine wave is recorded and reproduced on the magnetic tape, respectively. The output level was measured. As a result, with the magnetic head having the track width Wl of 15 μm, there was almost no difference in the reproduction output level between the magnetic head of this embodiment and the test magnetic head. In the magnetic head having the track width W1 of 10 μm, the reproduction output level was higher by 0.5 dB in the magnetic head of this embodiment. In the case of the track width W1 of 7 μm, that of the present embodiment was higher by 1 dB. From the results of the above comparative test, in the magnetic head manufactured in the process of the present embodiment, in the vicinity of the magnetic gap 15, the magnetic core halves 1A and 1B are not parallel to the surface 15F forming the magnetic gap 15, but have an acute slope. As a result, it has been found that as the track width becomes smaller, the reproduction output level during recording and reproduction becomes higher than that of the conventional magnetic head.
[0013]
<< 2nd Example >>
A magnetic head according to a second embodiment of the present invention will be described below. The magnetic core of the magnetic head according to the second embodiment is manufactured in substantially the same steps as those shown in FIGS. 3 to 6 of the first embodiment. The difference between the magnetic core of the present embodiment and the magnetic core 10 of the first embodiment is that, in the present embodiment, the left side surface 22A of the groove 22 in FIG. Is set to Ra of about 30 nm or less as measured by an atomic force microscope (AFM). In the first embodiment, the surface roughness of the left side surface 22A was Ra of about 60 nm or more. It is shown in (b) of FIG. 3, the upper surface 21A and 21B of the plate-like member 21, the left side surface 22A and the bottom surface 22B of the groove 22, to form the _A1 2 _{0 3} protective film 23 having a thickness of 5 nm. Next, a FeTaSiN metal magnetic film 24 having a thickness of 18 μm was formed by sputtering in a mixed gas of argon gas and nitrogen gas using Fe—Ta—Si as a target. The FeTaSiN film 24 was formed under conditions such that the magnetic anisotropy in the formed plane was small and the film was almost isotropic. The subsequent steps are the same as those in the first embodiment shown in FIGS. Only one track width W1 of 7 μm was prepared.
[0014]
Using the magnetic head of the second embodiment, a sine wave of 20 MHz was recorded and reproduced on a magnetic tape, and the reproduction output level was examined. As a result, the reproduction output level was about 1 dB higher than that of the magnetic head having the track width W1 of 7 μm in the first embodiment.
In the magnetic head of this embodiment, the fineness of the metal magnetic film 24 of FeTaSiN, which is a metal magnetic film formed on the left side surface 22A, is reduced by reducing the roughness of the left side surface 22A of the groove 22 serving as a winding window. Visual disturbance of the film structure is reduced. Therefore, the density of the magnetic flux flowing from the magnetic gap 15 into the metal magnetic film 24 increases, and the reproduction output level increases.
[0015]
<< 3rd Example >>
A magnetic head according to a third embodiment of the present invention will be described below. The magnetic core of the third embodiment is made by processes similar to those shown in FIGS. 3 to 6 of the first embodiment, and has the same external appearance. The difference between the magnetic core of the present embodiment and the magnetic core 10 of the first embodiment is that, in the present embodiment, the left side surface 22A of the groove 22 in FIG. To make the surface roughness Ra of about 30 nm or less as measured by an atomic force microscope (AFM). Next, as shown in FIG. 3B, a protective film 23 of Al ₂ O ₃ having a thickness of 5 nm is formed on the upper surfaces 21A and 21B of the plate member 21, the left side surface 22A and the bottom surface 22B of the groove 22. A 3 μm-thick FeTaSiN metal magnetic film 24 is formed on the protective film 23 by sputtering using Fe—Ta—Si as a target in a mixed gas of argon gas and nitrogen gas. A metal magnetic film 24 having a thickness of 3 μm and an Al ₂ O ₃ insulating film having a thickness of 15 nm are alternately formed, and six sets of a FeTaSiN film and an Al ₂ O ₃ film are stacked to make the total thickness about 20 μm. . The metal magnetic film 24 is formed under predetermined conditions so that the magnetic anisotropy in the formed plane is small and substantially isotropic. The subsequent steps are the same as those in the first embodiment shown in FIGS. Only one type having a track width W1 of 7 μm was prepared.
[0016]
When a sine wave of 20 MHz was recorded and reproduced on a magnetic tape by the magnetic head of the third embodiment, and the reproduction output level was examined, the FeTaSiN film of the magnetic head having a track width of 7 μm of the second embodiment was formed to a thickness of 18 μm. The reproduction output level was about 0.5 dB higher than that of the single-layer film. Further, when a 40 MHz sine wave signal was recorded and reproduced and examined, the reproduced output level was 1.5 dB higher than when the same 40 MHz sine wave signal was recorded and reproduced by the magnetic head of the second embodiment.
[0017]
In the magnetic head of this embodiment, the roughness of the left side surface 22A of the groove 22 serving as a winding window is reduced, so that the FeTaSiN film 24 which is a metal magnetic film formed on the left side surface 22A is microscopically formed. The disorder of the film structure is reduced. Therefore, the density of the magnetic flux flowing from the magnetic gap 15 into the FeTaSiN film 24 increases, which leads to an increase in the level of the reproduction output. Further, by alternately laminating the FeTaSiN film and the Al2O3 film, the bias of the magnetic flux density due to the skin effect of the FeTaSiN film at a high frequency is improved. As a result, the reproduction output level particularly at a high frequency increases.
[0018]
<< 4th Example >>
A magnetic head according to a fourth embodiment of the present invention will be described below. The magnetic core of the magnetic head of the fourth embodiment is manufactured in substantially the same steps as the magnetic core of the third embodiment, and has the same configuration. In this embodiment, an FeTaN film is used instead of the FeTaSiN film 24 of the third embodiment. In this embodiment, when the Al ₂ O ₃ film and the FeTaN film are formed by sputtering and laminated, a high-frequency bias voltage is applied between the single-crystal ferrite plate member 21 and the target shown in FIG. Apply. Then, by controlling the high-frequency bias voltage, the film is formed under conditions such that the axis of easy magnetization is substantially parallel to the plane forming the magnetic gap 15 (FIG. 1) in the plane of the left side surface 22A.
[0019]
The magnetic head of this embodiment having a track width W1 of 7 μm was manufactured and compared with the magnetic head of the first embodiment having a track width W1 of 7 μm. As a result, in the present embodiment, compared with the first embodiment, an average of 0.5 dB is obtained in the recording and reproduction of the sine wave signal of 20 MHz, and in the recording and reproduction of the sine wave signal of 40 MHz, the reproduction output level is higher by 1 dB. Was.
[0020]
<< 5th Example >>
A magnetic head according to a fifth embodiment of the present invention will be described with reference to FIG. The magnetic core 10 of the fifth embodiment is manufactured in substantially the same steps as the magnetic core 10 of the third embodiment, and has the same configuration. In this embodiment, an FeTaN film is used for the metal magnetic film 24 of the third embodiment instead of the FeTaSiN film.
In the present embodiment, as shown in FIG. 7, when stacked deposited by sputtering _A1 2 _{0 3} film and FeTaN film, a left side surface 22A of the single crystal ferrite plate-shaped member 21, a target Fe -Make the surface 41 of the Ta plate 40 parallel. Recording a 20 MHz sine wave signal on each of the magnetic head of this embodiment having a track width W1 of 7 μm and a magnetic head formed by depositing the left side surface 22A and the surface 41 of the Fe-Ta plate 40 without making them parallel. It was reproduced and compared. As a result, the reproducing output level of this embodiment was high by about 1 dB.
[0021]
【The invention's effect】
As described in detail in each of the above embodiments, according to the present invention, in the magnetic head having a narrow track width, the magnetic core halves 1A and 1B are placed near the magnetic gap on the level surface where the magnetic gap is formed. Due to the non-parallel acute slope, the reproduction output level in recording and reproduction of a signal with a high frequency becomes higher than that of the conventional magnetic head. Further, by reducing the roughness of the acute-angled slope, the reproduction output level of a particularly high-frequency signal can be further increased.
[Brief description of the drawings]
1 is a perspective view of a finished product of a magnetic core common to each embodiment of the present invention; FIG. 2 is a cross-sectional view of the magnetic core taken along the line II-II of FIG. 1; FIG. 4 (d) is an oblique projection showing a manufacturing process of a magnetic core half according to each embodiment of the present invention. FIG. 4 (a) is an oblique projection showing a magnetic core half according to another embodiment of the present invention. FIG. 5 (b) is a top view showing a state where the core halves are assembled and cut, and FIG. 5 (a) is a top view of one magnetic core obtained by cutting the magnetic core block of FIG. 3 (b). FIG. 6B is a top view of the magnetic core obtained by cutting both ends of the one magnetic core. FIG. 6A is a side view showing a cutting line of the magnetic core, and FIG. 6B is a side view showing a left side of FIG. FIG. 7 is a side view showing a positional relationship between a sputtering target and a magnetic core half 21 in a fifth embodiment of the present invention. FIG. 8 is a conventional magnetic core. Isometric view 9 IX-IX cross-sectional view of a magnetic core of conventional EXPLANATION OF REFERENCE NUMERALS
1A, 1B Magnetic core half 2A, 2B Metal magnetic film 3 Adhesive glass 4A, 4B Cutout portion 5 Winding window 10, 50 Magnetic core 15 Magnetic gap 16 Track forming portion 21 Plate members 21A, 21B Upper surface 22 Groove 22A Left side surface 22B Bottom surface 23 Protective film 24 Metal magnetic film 26 Magnetic core half 30 Head block 31, 32 Cut 35, 36 Cutting line L1, L2, L3 Cutting line W1, W10 Track width 60 Track forming portion

Claims

A magnetic core half-substrate formed of a magnetic material having a groove on a main surface, wherein at least one wall surface of the groove is a slope inclined at an acute angle to the main surface;
A nonmagnetic protective film formed on the slope of the groove,
A film of a soft magnetic material formed on the protective film, and a non-magnetic film for forming a magnetic gap formed on a surface of the soft magnetic material exposed on the main surface;
A magnetic core formed by joining two magnetic core halves at the main surface, and a coil wound through a space formed by a groove of the joined two magnetic core halves,
A magnetic gap portion of the magnetic core in contact with the magnetic recording medium is formed to have a predetermined track width by cutting both end regions of the magnetic gap portion, and one side of the cut portion is formed from one magnetic core half to the other. It has an inclined surface that becomes gradually deeper toward the magnetic core half, and the cutting portion on the opposite side across the magnetic gap portion has an inclined surface that becomes gradually deeper from the other magnetic core half to one magnetic core half. A magnetic head characterized by the following.

2. The magnetic head according to claim 1, wherein the protective film is a film of aluminum oxide.

2. The magnetic head according to claim 1, wherein the film of the soft magnetic material is one of FeTaN and FeTaSiN.

2. The magnetic head according to claim 1, wherein the soft magnetic film is a multilayer film in which non-magnetic electric insulating films and metal magnetic films are alternately stacked.

2. The magnetic head according to claim 1, wherein the direction of the axis of easy magnetization of the film of the soft magnetic material is parallel to a magnetic gap in a plane where the magnetic film is formed near the main surface.

Forming a groove on the main surface of the magnetic core half-substrate of the magnetic material, at least one wall surface having a slope inclined at an acute angle with respect to the main surface;
Forming a nonmagnetic protective film on the slope of the groove;
Forming a soft magnetic film by sputtering on the protective film,
Forming a non-magnetic film for forming a magnetic gap on a surface of the soft magnetic film exposed on the main surface;
Joining the two magnetic core halves formed in each of the above steps at the main surface to form a magnetic core;
One magnetic core is provided on one side of the cut portion so that a magnetic gap portion in contact with a magnetic recording medium is formed at a predetermined track width by cutting both end regions of the magnetic gap portion. An inclined surface that gradually becomes deeper from the half to the other magnetic core half is formed, and an opposite surface across the gap forms an inclined surface that gradually becomes deeper from the other magnetic core half to one magnetic core half. Winding a coil through a space formed by the grooves of the two magnetic core halves;
A method for manufacturing a magnetic head having:

7. The method according to claim 6, wherein, in the step of forming the soft magnetic film by sputtering, an inclined surface having an acute angle with respect to the main surface is arranged substantially parallel to a surface of a sputtering target.