JPH0370889B2 - - Google Patents
Info
- Publication number
- JPH0370889B2 JPH0370889B2 JP60047439A JP4743985A JPH0370889B2 JP H0370889 B2 JPH0370889 B2 JP H0370889B2 JP 60047439 A JP60047439 A JP 60047439A JP 4743985 A JP4743985 A JP 4743985A JP H0370889 B2 JPH0370889 B2 JP H0370889B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- target
- permalloy
- permalloy thin
- coercive force
- 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
- 229910000889 permalloy Inorganic materials 0.000 claims description 43
- 238000004544 sputter deposition Methods 0.000 claims description 36
- 239000010409 thin film Substances 0.000 claims description 35
- 239000010408 film Substances 0.000 claims description 25
- 239000000758 substrate Substances 0.000 claims description 24
- 230000005415 magnetization Effects 0.000 claims description 18
- 239000013078 crystal Substances 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 229910045601 alloy Inorganic materials 0.000 claims description 7
- 239000000956 alloy Substances 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 40
- 239000007789 gas Substances 0.000 description 8
- 239000011651 chromium Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 239000002355 dual-layer Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 238000011017 operating method Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 239000013077 target material Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/14—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates
- H01F41/30—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates for applying nanostructures, e.g. by molecular beam epitaxy [MBE]
- H01F41/302—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates for applying nanostructures, e.g. by molecular beam epitaxy [MBE] for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices
Description
〔利用分野〕
本発明は、パーマロイ薄膜及び該パーマロイ薄
膜を低保磁力層とすると共に膜面に垂直方向の磁
化容易軸を有する垂直磁化層を磁気記録層とした
垂直磁気記録媒体の製造方法に関する。
〔従来技術〕
上述の低保磁力層と垂直磁化層とからなる二層
膜の磁気記録媒体は、垂直磁気記録方式において
単極型ヘツドによつて効率良く記録できる垂直磁
気記録媒体として特公昭58−91号公報、特公昭58
−10764公報等に提案されている。この提案され
た二層膜構成の垂直磁気記録媒体（以下“二層膜
媒体”という）は、具体的にはRF2極スパツタ法
で作成され、低保磁力層をパーマロイで垂直磁化
層をCo（コバルト）−Cr（クロム）合金膜で構成し
たものであり、高い記録感度と大なる再生出力を
得られる優れたものであるが、記録感度面、再生
出力面等でより一層の改善が望まれている。
〔発明の目的〕
本発明は上述の二層膜媒体の特性が低保磁力層
すなわちNi（ニツケル）、Fe（鉄）を主成分とする
パーマロイ薄膜の特性に左右されることに着目し
なされたもので、電磁変換特性、とくにモジユレ
ーシヨンの小さいパーマロイ薄膜及び垂直磁気記
録媒体の製造方法を目的としたものである。
〔発明の構成、作用効果〕
上述の目的は、以下の本発明により達成され
る。
すなわち本発明は、前述のパーマロイ薄膜をス
パツタリング法により形成するパーマロイ薄膜の
製造方法において、JIS Ｇ 0551又はJIS Ｇ
0552の規定に基いて規定した結晶粒度が３以下の
パーマロイ合金ターゲツトを用いて該パーマロイ
薄膜を形成するパーマロイ薄膜の製造方法を第１
発明とし、パーマロイ薄膜を低保磁力層とした二
層膜構成の垂直磁気記録媒体の製造方法におい
て、低保磁力層のパーマロイ薄膜を第１発明によ
り形成する垂直磁気記録媒体の製造方法を第２発
明とするものである。
上述の本発明は、以下のようにしてなされたも
のである。二層膜媒体の低保磁力層の保磁力は小
さい程記録感度等の面で有利と云われている。そ
こで50e（エルステツド）以下の小さな保磁力のパ
ーマロイ薄膜を低保磁力層とした磁気記録媒体で
デイスクを作成し評価したところ、その再生出力
のエンベロープが変化して、安定な再生という点
からは、結局その最低点に制約され、再生出力は
あまり向上しない問題に遭遇し、種々検討の結
果、その原因が低保磁力層を構成するパーマロイ
薄膜の面内磁気異方性にあることを見出しなされ
たものである。
すなわち、パーマロイ薄膜を低保磁力層とした
上述の磁気記録媒体は、パーマロイ薄膜の磁化困
難軸の方向に走行させて記録・再生した時の方が
磁化容易軸の方向の時に比べて、再生出力が大き
く、特に高密度記録の高周波領域で良好な特性を
示す。
すなわち、面内の再生出力を一様にするために
は、いいかえればモジユレーシヨンを小さくする
ためには低保磁力層全体としての面内磁気異方性
を減少させ、再生出力の最低点を上昇させエンベ
ロープを面内で一様とすることが必要であると考
えられていた。その結果記録密度が高く、記録再
生特性が面内で一様なデイスク方式に適した磁気
記録媒体が得られる。
なお、面内磁気異方性とは膜面に平行な面内で
の磁気異方性のことである。
しかしながら、面内の磁気異方性を一様にする
ことは通常の方法では困難であり、とくに基板を
一方向に移送して低保磁力層を形成するような場
合には異方性が大きく発現するのが普通であつ
た。
本発明者らは以上の知見にもとづき鋭意研究し
た結果、前記パーマロイ薄膜の形成を結晶粒度番
号が３以下のターゲツトを用いて行えば、磁気異
方性が必ずしも一様にならなくてもモジユレーシ
ヨンが小さくなることを見出し本発明に想到し
た。
本発明によるパーマロイ薄膜においては、その
保磁力は結晶粒度番号が大きいターゲツトを用い
た場合に比べて若干大きくなるのが普通である
が、モジユレーシヨンが面内で一様な優れた軟磁
性膜が得られる。
上述の点から本発明の第２発明により得られる
垂直磁気記録媒体は、その低保磁力層が、上述の
結晶粒度番号が３以下と小さいターゲツトを用い
て形成したパーマロイ（Mo（モリブデン）、Cu
（銅）等の第３成分を含んで良い）薄膜であるの
で、保磁力の小さい領域でも面内磁気異方性が小
さく、デイスクの場合にモジユレーシヨンが小さ
く、再生出力が比較的大きいという大きな効果を
奏する。なお、パーマロイ薄膜の透磁率について
は大きいものが記録感度・再生出力面から好まし
く用いられる。
また、磁気記録層としては実施例のCo−Cr合
金膜らなる垂直磁化層は勿論、Ｗ（タングステン）
Ta（タンタル）等の第３元素を添加したCo−Cr
合金、その他公知の垂直磁化層が適用できること
は本発明の趣旨から明らかである。
ここでターゲツトの結晶粒度番号とはJIS Ｇ
0551−1977、Ｇ 0552−1977で規定されている鋼
の結晶粒度試験方法を準用して以下のように測定
したものとする。すなわち、塩酸１重量部に過酸
化水素水４重量部を混合した溶液で測定するパー
マロイターゲツトの表面を腐食させ、露出した新
しい表面を顕微鏡で観察し、前記JIS規定の符図
に示された標準図と比較して、その相当する粒度
番号を判定する方法により行なつた。
またターゲツトの結晶粒度番号は、ターゲツト
作成時の条件、例えば鍛造比、アニール条件（温
度、時間等）、少量の不純物（Ｓ，Mn，…）を
添加することによつて制御できる。
パーマロイターゲツトは組成が同じであれば磁
気特性もほぼ同じであるが、スパツタリングで形
成されたパーマロイ膜の特性は驚くべきことには
ターゲツトの結晶粒度により前述の如くその磁気
特性が異る。
またスパツタリングのパーマロイターゲツトの
表面はほぼ結晶粒度番号の大きさに対応し、粒度
番号の大きいものほど、すなわち結晶粒が細いも
のほど滑らかであり、粒度番号の小さいもの、す
なわち結晶粒の大きいものは粗である。又スパツ
タリングの進行とともにこの差は顕著となり、粒
度番号が小さい（結晶粒が大きい）ターゲツトの
表面はかなりの凹凸を示すようになる。
かかるパーマロイターゲツトの表面の凹凸とス
パツタリングにより得られたパーマロイ膜の磁気
特性は対応するが、スパツタされた粒子がターゲ
ツト時代の記憶を保持したまま膜形成に寄与する
理由については今のところ明らかでない。
以下、上述の本発明の詳細を実施例に基いて説
明する。
なお、この発明は、対向ターゲツト式スパツタ
法によりなされたものであるが、発明の主旨から
して、明らかに他のスパツタリング法にも適用で
きることは明らかである。
なお、上述の対向ターゲツト式スパツタ法は、
特開昭57−158380号公報等で公知のスパツタ法
で、一対の対向配置されたターゲツトの側方に基
板を配し、ターゲツト間に垂直方向にプラズマ捕
促用の磁界を印加してスパツタし、基板上に膜を
形成するスパツタ法を云う。
第１図は本発明の実施に用いた対向ターゲツト
式スパツタ装置の構造図である。
図から明らかな通り、本装置は前述の特開昭57
−158380号公報で公知の対向ターゲツト式スパツ
タ装置と基本的に同じ構成となつている。
すなわち、図において１０は真空槽、２０は真
空槽１０を排気する真空ポンプ等からなる排気
系、３０は真空槽１０内に所定のガスを導入して
真空槽１０内の圧力を１０-1〜１０-4TOrr程度
の所定のガス圧力に設定するガス導入系である。
そして、真空槽１０内には、図示の如く真空槽
１０の側板１１，１２に絶縁部材１３，１４を介
して固着されたターゲツトホルダー１５，１６に
より１対のターゲツトT1，T2が、そのスパツタ
される面T1S，T2Sを空間を隔てて平行に対面す
るように配設してある。そして、ターゲツトT1，
T2を取着するターゲツトホルダー１５，１６は、
冷水パイプ１５１，１６１を介して冷却水が循環
し、ターゲツトT1，T2、永久磁石１５２，１６
２が冷却される。磁石１５２，１６２はターゲツ
トT1，T2を介してＮ極、Ｓ極が対向するように
設けてあり、従つて磁界はターゲツトT1，T2に
垂直な方向に、かつターゲツト間のみに形成され
る。なお、１７，１８は、絶縁部材１３，１４及
びターゲツトホルダー１５，１６をスパツタリン
グ時のプラズマ粒子から保護するためとターゲツ
ト表面以外の部分の異常放電を防止するためとタ
ーゲツト表面以外の部分の異常放電を防止するた
めのシールドである。
また、磁性薄膜が形成される基板４０を保持す
る基板保持手段４１は、真空槽１０内のターゲツ
トT1，T2の側方に設けてある。基板保持手段４
１は、図示省略した支持ブラケツトにより夫々回
転自在かつ互いに軸平行に支持された繰り出しロ
ール４１ａ、支持ロール４１ｂ、巻取ロール４１
ｃの３個のロールからなり、基板４０をターゲツ
トT1，T2間の空間に対面するようにスパツタ面
T1S，T2Sに対して略直角方向に保持するように
配置してある。従つて基板４０は基板保持手段４
１によりスパツタ面T1S，T2Sに対して直角方向
に移動可能である。なお、支持ロール４１ｂはそ
の表面温度が調節可能となつている。
一方、スパツタ電力を供給する直流電源からな
る電力供給手段５０はプラス側をアースに、マイ
ナス側をターゲツトT1，T2に夫々接続する。従
つて電力供給手段５０からのスパツタ電力は、ア
ースをアノードとし、ターゲツトT1，T2をカソ
ードとして、アノード，カソード間に供給され
る。
なお、プレスパツタ時基板４０を保護するた
め、基板４０とターゲツトT1，T2との間に出入
するシヤツター（図示省略）が設けてある。
以上の通り、前述の特開昭57−158380号公報の
ものと基本的には同じ構成であり、公知の通り高
速低温スパツタが可能となる。すなわち、ターゲ
ツトT1，T2間の空間に、磁界の作用によりスパ
ツタガスイオン、スパツタにより放出されたγ電
子等が束縛され高密度プラズマが形成される。従
つて、ターゲツトT1，T2のスパツタが促進され
て前記空間より析出量が増大し、基板４０上への
堆積速度が増し高度スパツタが出来る上、基板４
０がターゲツトT1，T2の側方にあるので低温ス
パツタも出来る。
なお、本発明の対向ターゲツト式スパツタ法
は、前述の装置のものに限定されるものではな
く、前述の通り一対の対面させたターゲツトの側
方に基板を配し、ターゲツト間に垂直方向の磁界
を印加しスパツタし、基板上に膜を形成するスパ
ツタ法を云う。従つて、磁界発生手段も永久磁石
でなく、電磁石を用いても良い。また、磁界もタ
ーゲツト間の空間にγ電子等を閉じ込めるもので
あれば良く、従つてターゲツト全面でなく、ター
ゲツト周囲のみに発生させた場合も含む。
次に上述の対向ターゲツト式スパツタ装置によ
り実施した本発明に係わるパーマロイ薄膜及び垂
直磁気記録媒体の実施例を説明する。
なお、得られた合金膜の結晶構造は理学電機製
計数Ｘ線回析装置を用いて同定し、垂直配向性は
六方最密構造かつ（002）面ピークのロツキング
カーブを前記Ｘ線回析装置で求め、その半値幅△
θ50で評価した。
膜厚及び組成については、螢光Ｘ線装置を用い
て予め較正した曲線から求めた。
媒体の磁気特性は振動試料型磁力計で測定して
求めた。
二層膜媒体の記録・再生特性は、前述の特開昭
58−91号公報で公知のものと同様な垂直型磁気ヘ
ツドを用いて評価した。
〔実施例１〜４および比較例１，２〕
下記条件により基板上にパーマロイ薄膜をター
ゲツトの結晶粒度番号を変えて作成し、その磁気
異方性を評価すると共に、夫々のパーマロイ薄膜
上にCo−Crからなる垂直磁化層を順次形成して
二層膜媒体を作成し、その再生特性を評価した。
Ａ 装置条件
Ａ−１ 低保磁力層
ａ ターゲツトT1，T2材：T1，T2共Mo−
4wt％、Ni−78wt％、Fe−18wt％のパー
マロイ（但、結晶粒度番号は各例で異る）
ｂ 基板４０：50μm厚のポリエチレンテレ
フタレート（PET）フイルム
ｃ ターゲツトT1，T2間隔：120mm
ｄ ターゲツト表面の磁界：100〜200ガウス
ｅ ターゲツトT1，T2形状
：100mmＬ×150mmＷ×12mmｔの矩形
ｆ 基板４０とターゲツトT1，T2端部の距
離：20mm
Ａ−２ Co−Cr垂直磁化層
ａ ターゲツト材：T1，T2共にCo−80wt
％、
Cr−20wt％の合金ターゲツト
ｂ ターゲツトT1，T2間隔：160mm
ｃ ターゲツト表面の磁界：100〜200ガウス
ｄ ターゲツトT1，T2形状
：100mmＬ×150mmＷ×12mmｔの矩形
ｅ 基板４０とターゲツトT1，T2端部の距
離：20mm
Ｂ 操作手順
Ａ−１，Ａ−２の条件のもとで順次次の如く
行なつた。
ａ 基板を設置後、真空槽１０内を到達真空
度が１×10-6Torr以下まで排気する。
ｂ ガスの所定の圧力まで導入し、３〜５分
間のプレスバツタを行ない、シヤツターを
開き、基板４０を図示の通りターゲツト
T1，T2の対向方向に移送しつつ膜形成を
行なつた。なお、スパツタ時のガス圧は４
×10-3Torrとした。
ガスはAr（アルゴン）100％を用いた。
ｃ スパツタ時投入電力はＡ−１，Ａ−２と
もに3KWで行なつた。
Ｃ 実施結果
第２図に比較例のパーマロイ薄膜の特徴的な
磁化特性を示す。基板の走行方向（MD方向）
と基板の幅方向（TD方向）それぞれの磁化特
性が異なり、面内で磁気異方性が生じており、
MD方向は磁化容易軸、TD方向は磁化困難軸
であつた。なお、第２図でＨは印加磁界の強さ
を示し、Ｂは低保磁力層の磁化を示す。
得られた各パーマロイ薄膜の保磁力の測定結
果を表−１に示す。
なお、表−１でHCE，HCHは磁化容易軸、
磁化困難軸方向のそれぞれの保磁力である。
又、垂直磁気記録媒体を得るために表−１の
特性を有するパーマロイ薄膜上にＡ−２の条件
で形成されたCo−Cr層からなる垂直磁化層の
特性を表−２に示す。
[Field of Application] The present invention relates to a permalloy thin film and a method for manufacturing a perpendicular magnetic recording medium in which the permalloy thin film is used as a low coercive force layer and a perpendicular magnetic layer having an axis of easy magnetization perpendicular to the film surface is used as a magnetic recording layer. . [Prior Art] The above-mentioned two-layer magnetic recording medium consisting of a low coercive force layer and a perpendicular magnetization layer was developed as a perpendicular magnetic recording medium that can be efficiently recorded by a unipolar head in the perpendicular magnetic recording system. −91 Publication, Special Publication 1987
-Proposed in Publication No. 10764, etc. This proposed perpendicular magnetic recording medium with a two-layer film structure (hereinafter referred to as a "dual-layer film medium") is specifically created by the RF bipolar sputtering method, with a low coercive force layer of permalloy and a perpendicular magnetic layer of Co ( It is composed of a cobalt (cobalt)-Cr (chromium) alloy film, and is excellent in that it can obtain high recording sensitivity and large playback output, but further improvements are desired in terms of recording sensitivity, playback output, etc. ing. [Object of the Invention] The present invention was made based on the fact that the characteristics of the above-mentioned two-layer film medium are influenced by the characteristics of the low coercive force layer, that is, the permalloy thin film whose main components are Ni (nickel) and Fe (iron). The purpose is to provide a method for manufacturing permalloy thin films and perpendicular magnetic recording media with electromagnetic conversion characteristics, particularly small modulation. [Structure, operation and effect of the invention] The above-mentioned objects are achieved by the present invention as described below. That is, the present invention provides a permalloy thin film manufacturing method in which the permalloy thin film described above is formed by a sputtering method, which complies with JIS G 0551 or JIS G
The first method for producing a permalloy thin film includes forming the permalloy thin film using a permalloy alloy target having a crystal grain size of 3 or less as defined in accordance with the provisions of 0552.
In a method for manufacturing a perpendicular magnetic recording medium having a two-layer structure in which a permalloy thin film is a low coercive force layer, a second invention provides a method for manufacturing a perpendicular magnetic recording medium in which a permalloy thin film as a low coercive force layer is formed according to the first invention. It is considered an invention. The above-mentioned present invention was made as follows. It is said that the smaller the coercive force of the low coercive force layer of a two-layer film medium, the more advantageous it is in terms of recording sensitivity and the like. Therefore, when we created and evaluated a magnetic recording medium using a permalloy thin film with a low coercive force of 50e (Oersted) or less as a low coercive force layer, we found that the envelope of the playback output changed, and from the point of view of stable playback, In the end, they encountered the problem that they were restricted to the lowest point and the reproduction output did not improve much. After various studies, they discovered that the cause of this problem was the in-plane magnetic anisotropy of the permalloy thin film that constitutes the low coercive force layer. It is something. In other words, the above-mentioned magnetic recording medium with a permalloy thin film as a low coercive force layer has a higher reproduction output when recording and reproducing by running the permalloy thin film in the direction of the axis of hard magnetization than when running in the direction of the axis of easy magnetization. is large, and exhibits good characteristics especially in the high frequency range of high density recording. In other words, in order to make the in-plane reproduction output uniform, or in other words, to reduce the modulation, the in-plane magnetic anisotropy of the low coercive force layer as a whole must be reduced, and the lowest point of the reproduction output must be raised. It was considered necessary to make the envelope uniform within the plane. As a result, a magnetic recording medium suitable for a disk system with high recording density and uniform recording and reproducing characteristics in the plane can be obtained. Note that in-plane magnetic anisotropy refers to magnetic anisotropy in a plane parallel to the film surface. However, it is difficult to make the in-plane magnetic anisotropy uniform using normal methods, and especially when the substrate is transferred in one direction to form a low coercive force layer, the anisotropy is large. It was common for this to occur. As a result of intensive research based on the above knowledge, the present inventors found that if the permalloy thin film is formed using a target with a crystal grain size number of 3 or less, the modulation can be achieved even if the magnetic anisotropy is not necessarily uniform. They found that it can be made smaller and came up with the present invention. In the permalloy thin film according to the present invention, the coercive force is normally slightly larger than when a target with a large grain size number is used, but an excellent soft magnetic film with uniform modulation in the plane can be obtained. It will be done. In view of the above, the perpendicular magnetic recording medium obtained according to the second aspect of the present invention has a low coercive force layer made of permalloy (Mo (molybdenum), Cu) formed using the above-mentioned target with a small crystal grain size number of 3 or less.
Since it is a thin film (which may contain a third component such as copper), the in-plane magnetic anisotropy is small even in a region with a small coercive force, and in the case of a disk, the modulation is small and the playback output is relatively large. play. It should be noted that a permalloy thin film with a high magnetic permeability is preferably used from the viewpoint of recording sensitivity and reproduction output. In addition, as a magnetic recording layer, of course the perpendicular magnetic layer made of the Co-Cr alloy film of the embodiment, but also the perpendicular magnetization layer made of W (tungsten).
Co-Cr added with a third element such as Ta (tantalum)
It is clear from the spirit of the present invention that alloys and other known perpendicular magnetization layers can be applied. Here, the target grain size number is JIS G
0551-1977, G 0552-1977, and the following measurements were taken. That is, the surface of the permalloiter target to be measured is corroded with a solution of 1 part by weight of hydrochloric acid and 4 parts by weight of hydrogen peroxide solution, the exposed new surface is observed under a microscope, and the standard shown in the above-mentioned JIS standard map is corroded. This was done by comparing it with the figure and determining the corresponding particle size number. Further, the grain size number of the target can be controlled by controlling the conditions during target preparation, such as the forging ratio, annealing conditions (temperature, time, etc.), and adding small amounts of impurities (S, Mn, . . . ). Permalloy targets have almost the same magnetic properties if they have the same composition, but surprisingly, the magnetic properties of a permalloy film formed by sputtering differ depending on the crystal grain size of the target, as described above. In addition, the surface of the sputtering permalite target roughly corresponds to the size of the grain size number; the larger the grain size number, that is, the thinner the crystal grains, the smoother the surface, and the smaller the grain size number, that is, the larger the crystal grains, the smoother the surface. It's rough. Moreover, as sputtering progresses, this difference becomes more noticeable, and the surface of targets with smaller grain size numbers (larger crystal grains) begins to exhibit considerable irregularities. Although the surface irregularities of such permalloy targets correspond to the magnetic properties of permalloy films obtained by sputtering, it is currently unclear why the sputtered particles contribute to film formation while retaining the memory of the target era. Hereinafter, the details of the above-mentioned present invention will be explained based on examples. Although this invention was made using a facing target sputtering method, it is obvious that it can be applied to other sputtering methods in view of the gist of the invention. In addition, the above-mentioned facing target sputtering method is
According to the sputtering method known in Japanese Patent Application Laid-open No. 57-158380, etc., a substrate is placed on the side of a pair of targets arranged facing each other, and a magnetic field for plasma trapping is applied vertically between the targets to perform sputtering. , refers to the sputtering method for forming a film on a substrate. FIG. 1 is a structural diagram of a facing target sputtering apparatus used in the practice of the present invention. As is clear from the figure, this device was developed in the above-mentioned JP
It has basically the same structure as the opposed target sputtering device known in Japanese Patent No. 158380. That is, in the figure, 10 is a vacuum chamber, 20 is an exhaust system consisting of a vacuum pump etc. for evacuating the vacuum chamber 10, and 30 is a system for introducing a predetermined gas into the vacuum chamber 10 to increase the pressure inside the vacuum chamber 10 to 10 -1 ~ This is a gas introduction system that is set to a predetermined gas pressure of about 10 -4 TOrr. In the vacuum chamber 10, a pair of targets T 1 and T 2 are held by target holders 15 and 16 fixed to the side plates 11 and 12 of the vacuum chamber 10 via insulating members 13 and 14 as shown in the figure. The surfaces T 1S and T 2S to be sputtered are arranged so as to face each other in parallel with a space in between. And target T 1 ,
The target holders 15 and 16 that attach T2 are
Cooling water circulates through cold water pipes 151 and 161, and targets T 1 and T 2 and permanent magnets 152 and 16.
2 is cooled. The magnets 152 and 162 are provided so that their N and S poles face each other with the targets T 1 and T 2 in between, so that a magnetic field is formed in a direction perpendicular to the targets T 1 and T 2 and only between the targets. be done. Note that 17 and 18 are used to protect the insulating members 13 and 14 and the target holders 15 and 16 from plasma particles during sputtering, to prevent abnormal discharge in parts other than the target surface, and to prevent abnormal discharge in parts other than the target surface. It is a shield to prevent. Further, a substrate holding means 41 for holding a substrate 40 on which a magnetic thin film is formed is provided in the vacuum chamber 10 on the side of the targets T 1 and T 2 . Substrate holding means 4
Reference numeral 1 denotes a feed roll 41a, a support roll 41b, and a take-up roll 41, which are supported rotatably and parallel to each other by support brackets (not shown).
It consists of three rolls of c, and the sputtering surface is placed so that the substrate 40 faces the space between targets T1 and T2 .
It is arranged so as to be held in a direction substantially perpendicular to T 1S and T 2S . Therefore, the substrate 40 is the substrate holding means 4
1, it is possible to move in a direction perpendicular to the sputter surfaces T 1S and T 2S . Note that the surface temperature of the support roll 41b can be adjusted. On the other hand, a power supply means 50 consisting of a DC power source for supplying sputtering power has its positive side connected to the ground and its negative side connected to the targets T 1 and T 2 , respectively. Therefore, the sputter power from the power supply means 50 is supplied between the anode and the cathode, with the ground as the anode and the targets T 1 and T 2 as the cathodes. In order to protect the substrate 40 during press sputtering, a shutter (not shown) is provided between the substrate 40 and the targets T 1 and T 2 to move in and out. As mentioned above, the structure is basically the same as that of the above-mentioned Japanese Patent Application Laid-open No. 57-158380, and as is known, high-speed low-temperature sputtering is possible. That is, in the space between the targets T 1 and T 2 , sputter gas ions, γ electrons emitted by the sputter, etc. are bound by the action of the magnetic field, and a high-density plasma is formed. Therefore, sputtering of the targets T 1 and T 2 is promoted, the amount of deposition increases from the space, the deposition rate on the substrate 40 increases, high sputtering occurs, and the substrate 40
0 is on the side of the targets T 1 and T 2 , low-temperature sputtering is also possible. Note that the facing target sputtering method of the present invention is not limited to the above-mentioned apparatus; as mentioned above, a substrate is placed on the side of a pair of facing targets, and a vertical magnetic field is applied between the targets. This is a sputtering method in which a film is formed on a substrate by sputtering. Therefore, the magnetic field generating means may also be an electromagnet instead of a permanent magnet. Further, the magnetic field may be of any type as long as it confines γ electrons etc. in the space between the targets, and therefore it also includes the case where it is generated not over the entire surface of the target but only around the target. Next, an example of a permalloy thin film and a perpendicular magnetic recording medium according to the present invention, which were produced using the above-mentioned facing target type sputtering apparatus, will be described. The crystal structure of the obtained alloy film was identified using a counting X-ray diffraction device manufactured by Rigaku Corporation, and the vertical orientation was determined by the hexagonal close-packed structure and the rocking curve of the (002) plane peak using the X-ray diffraction method described above. Obtained using the device, its half width △
Evaluation was performed at θ 50 . The film thickness and composition were determined from a curve calibrated in advance using a fluorescent X-ray device. The magnetic properties of the medium were determined using a vibrating sample magnetometer. The recording and playback characteristics of double-layer film media were described in the aforementioned Japanese Patent Application Publication No.
The evaluation was carried out using a vertical magnetic head similar to the one known in Japanese Patent No. 58-91. [Examples 1 to 4 and Comparative Examples 1 and 2] Permalloy thin films were created on substrates under the following conditions with different target crystal grain size numbers, and their magnetic anisotropy was evaluated. A two-layer film medium was prepared by sequentially forming perpendicular magnetization layers made of -Cr, and its reproduction characteristics were evaluated. A Apparatus conditions A-1 Low coercive force layer a Target T 1 and T 2 materials: Both T 1 and T 2 are Mo-
Permalloy of 4wt%, Ni-78wt%, Fe-18wt% (however, the grain size number is different for each example) b Substrate 40: 50μm thick polyethylene terephthalate (PET) film c Target T 1 , T 2 interval: 120mm d Magnetic field on target surface: 100 to 200 Gauss e Target T 1 , T 2 shape: 100 mm L x 150 mm W x 12 mm T rectangle f Distance between substrate 40 and target T 1 , T 2 end: 20 mm A-2 Co-Cr perpendicular magnetization Layer a Target material: Both T1 and T2 are Co-80wt
%, Cr-20wt% alloy target b Target T1 , T2 spacing: 160mm c Target surface magnetic field: 100 to 200 Gauss d Target T1 , T2 shape: 100mmL x 150mmW x 12mmt rectangle e Substrate 40 and target Distance between T 1 and T 2 ends: 20 mm B. Operating procedure The following operations were carried out under the conditions of A-1 and A-2. a After installing the substrate, evacuate the inside of the vacuum chamber 10 until the ultimate vacuum level is 1×10 -6 Torr or less. b) Introduce the gas to a predetermined pressure, press the shutter for 3 to 5 minutes, open the shutter, and place the substrate 40 on the target as shown.
Film formation was performed while transferring in opposite directions of T 1 and T 2 . In addition, the gas pressure during sputtering is 4
×10 -3 Torr. The gas used was 100% Ar (argon). c The power input during sputtering was 3KW for both A-1 and A-2. C. Results of implementation Figure 2 shows the characteristic magnetization characteristics of the permalloy thin film of the comparative example. Board running direction (MD direction)
The magnetization characteristics are different in the width direction (TD direction) of the substrate and in the TD direction, and magnetic anisotropy occurs in the plane.
The MD direction was the axis of easy magnetization, and the TD direction was the axis of difficult magnetization. In FIG. 2, H indicates the strength of the applied magnetic field, and B indicates the magnetization of the low coercive force layer. Table 1 shows the measurement results of the coercive force of each permalloy thin film obtained. In addition, in Table 1, HCE and HCH are easy magnetization axes,
These are the respective coercive forces in the direction of the hard magnetization axis. Further, Table 2 shows the characteristics of a perpendicular magnetic layer consisting of a Co--Cr layer formed under conditions A-2 on a permalloy thin film having the characteristics shown in Table 1 to obtain a perpendicular magnetic recording medium.
【表】【table】
【表】
表−２において保磁力の垂直とは媒体膜面と垂
直方向の保磁力を、水平とは媒体膜面と平行方
向の保磁力を示す。なお、保磁力の測定は二層
膜媒体の低保磁力層を分離して行つた。半値幅
Δθ50は、二層膜媒体のまま測定した。
Ｄ 電磁変換特性
表−１の特性を有する各パーマロイ薄膜を低
保磁力層とする前述の二層膜媒体について、第
３図に示すように、MD方向、TD方向に長方
形のサンプルを切り出して、記録密度
50KFRPIにおいてそれぞれの電磁変換特性を
評価した。
表−３及び第４図に測定結果を示す。
なお、電磁変換特性は記録時にはテープ走行
を4.75cm／秒、再生時には9.5cm／秒で行なつ
た。
又、測定値は実施例１を基準とした相対値で
示してある。
表−３及び第４図の実施例１〜４に示したよ
うに結晶粒度番号が小さいターゲツトを用いて
スパツタして形成したパーマロイ薄膜を低保磁
力層としてもう二層媒体は磁化容易軸方向およ
び磁化困難軸方向の再生出力の大きさの比が１
に近く、したがつてフロツピーデイスク形状に
したときにモジユレーシヨンが比較例に比べて
大巾に改良されていることが判る。[Table] In Table 2, vertical coercive force refers to the coercive force perpendicular to the medium film surface, and horizontal refers to the coercive force parallel to the medium film surface. Note that the coercive force was measured by separating the low coercive force layer of the two-layer film medium. The half-width Δθ 50 was measured as a double-layered film medium. D Electromagnetic Conversion Characteristics As shown in Figure 3, rectangular samples were cut out in the MD direction and the TD direction for the above-mentioned two-layer media in which each permalloy thin film having the characteristics shown in Table 1 is used as a low coercive force layer. Recording density
The electromagnetic conversion characteristics of each were evaluated at 50KFRPI. The measurement results are shown in Table 3 and Figure 4. The electromagnetic conversion characteristics were determined by running the tape at 4.75 cm/sec during recording and at 9.5 cm/sec during playback. Moreover, the measured values are shown as relative values based on Example 1. As shown in Examples 1 to 4 in Table 3 and Figure 4, a permalloy thin film formed by sputtering using a target with a small grain size number was used as a low coercive force layer, and the other two-layer medium was arranged in the direction of the easy axis of magnetization and The ratio of the magnitude of the reproduction output in the direction of the hard magnetization axis is 1
Therefore, it can be seen that when the floppy disk shape is formed, the modulation is greatly improved compared to the comparative example.
【表】
また、表−１，表−３よりパーマロイ薄膜形成
時のターゲツトの結晶粒度番号の増加に伴ない再
生出力比が低下することがわかる。従つて、前記
結晶粒度番号は再生出力比が大巾に低下しない範
囲、実用的には３以下であることが好ましく、更
には、再生出力比が0.95以上となり、モジユレー
シヨンのJIS規格を十分満足する２以下とするこ
とが好ましい。[Table] Furthermore, from Tables 1 and 3, it can be seen that the reproduction output ratio decreases as the crystal grain size number of the target increases when forming a permalloy thin film. Therefore, the crystal grain size number is preferably within a range where the reproduction output ratio does not decrease significantly, practically 3 or less, and furthermore, the reproduction output ratio is 0.95 or more and satisfies the JIS standard for modulation. It is preferable to set it to 2 or less.
第１図は本発明の実施に用いた対向ターゲツト
式スパツタ装置の説明図、第２図は比較例の磁気
特性の説明図、第３図はサンプル切り出しの説明
図、第４図はパーマロイターゲツトの結晶粒度番
号と再生出力のMD方向、TD方向の比を示すグ
ラフである。
T1，T2：ターゲツト、１０：真空槽、２０：
排気系、３０：ガス導入系、４０：基板、５０：
スパツタ電源。
Fig. 1 is an explanatory diagram of the opposed target sputtering device used in the implementation of the present invention, Fig. 2 is an explanatory diagram of the magnetic properties of a comparative example, Fig. 3 is an explanatory diagram of sample cutting, and Fig. 4 is an explanatory diagram of the permalloist target. It is a graph showing the ratio of the crystal grain size number and the reproduced output in the MD direction and the TD direction. T 1 , T 2 : Target, 10: Vacuum chamber, 20:
Exhaust system, 30: Gas introduction system, 40: Substrate, 50:
Spatuta power supply.
Claims (1)
パツタリング法により形成するパーマロイ薄膜の
製造方法において、JIS Ｇ 0551又はJIS Ｇ
0552の規定に基いて規定した結晶粒度番号が３以
下のパーマロイ合金ターゲツトを用いてパーマロ
イ薄膜を形成することを特徴とするパーマロイ薄
膜の製造方法。 ２ 前記スパツタリング法が対向ターゲツト式ス
パツタリング法である特許請求の範囲第１項記載
のパーマロイ薄膜の製造方法。 ３ 非磁性の基板上にパーマロイ薄膜からなる低
保磁力層と膜面に垂直方向の磁化容易軸を有する
磁気記録層を有する垂直磁気記録媒体の製造方法
において、前記低保磁力層のパーマロイ薄膜を、
JIS Ｇ 0551又はJIS Ｇ 0552の規定に基いて測
定した結晶粒度番号３以下のパーマロイ合金ター
ゲツトを用いたスパツタリング法により形成する
ことを特徴とする垂直磁気記録媒体の製造方法。 ４ 前記パーマロイ薄膜を形成するスパツタリン
グ法が対向ターゲツト式スパツタリング法である
特許請求の範囲第３項記載の垂直磁気記録媒体の
製造方法。[Claims] 1. A permalloy thin film manufacturing method in which a permalloy thin film containing Ni and Fe as main components is formed by a sputtering method, which complies with JIS G 0551 or JIS G
A method for producing a permalloy thin film, comprising forming a permalloy thin film using a permalloy alloy target having a crystal grain size number of 3 or less as defined in accordance with the provisions of 0552. 2. The method for producing a permalloy thin film according to claim 1, wherein the sputtering method is a facing target sputtering method. 3. In a method for producing a perpendicular magnetic recording medium having a low coercive force layer made of a permalloy thin film on a nonmagnetic substrate and a magnetic recording layer having an axis of easy magnetization perpendicular to the film surface, the permalloy thin film of the low coercive force layer is ,
1. A method for manufacturing a perpendicular magnetic recording medium, characterized in that it is formed by a sputtering method using a permalloy alloy target having a grain size number of 3 or less measured in accordance with the provisions of JIS G 0551 or JIS G 0552. 4. The method of manufacturing a perpendicular magnetic recording medium according to claim 3, wherein the sputtering method for forming the permalloy thin film is a facing target sputtering method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4743985A JPS61207006A (en) | 1985-03-12 | 1985-03-12 | Permalloy thin film and vertical magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4743985A JPS61207006A (en) | 1985-03-12 | 1985-03-12 | Permalloy thin film and vertical magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61207006A JPS61207006A (en) | 1986-09-13 |
| JPH0370889B2 true JPH0370889B2 (en) | 1991-11-11 |
Family
ID=12775181
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4743985A Granted JPS61207006A (en) | 1985-03-12 | 1985-03-12 | Permalloy thin film and vertical magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61207006A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06104893B2 (en) * | 1985-10-16 | 1994-12-21 | 日立金属株式会社 | Target member for sputter and method for manufacturing the same |
| WO2004001779A1 (en) * | 2002-06-21 | 2003-12-31 | Seagate Technology Llc | Method of producing nife alloy films having magnetic anisotropy and magnetic storage media including such films |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5933629A (en) * | 1982-08-17 | 1984-02-23 | Matsushita Electric Ind Co Ltd | Manufacture of vertical magnetic recording medium |
-
1985
- 1985-03-12 JP JP4743985A patent/JPS61207006A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5933629A (en) * | 1982-08-17 | 1984-02-23 | Matsushita Electric Ind Co Ltd | Manufacture of vertical magnetic recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61207006A (en) | 1986-09-13 |
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