JPH0315245B2 - - Google Patents
Info
- Publication number
- JPH0315245B2 JPH0315245B2 JP58031932A JP3193283A JPH0315245B2 JP H0315245 B2 JPH0315245 B2 JP H0315245B2 JP 58031932 A JP58031932 A JP 58031932A JP 3193283 A JP3193283 A JP 3193283A JP H0315245 B2 JPH0315245 B2 JP H0315245B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- layer
- magnetic layer
- magnetization
- 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
- 230000005415 magnetization Effects 0.000 claims description 52
- 239000000463 material Substances 0.000 claims description 30
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 27
- 230000035699 permeability Effects 0.000 claims description 20
- 238000004544 sputter deposition Methods 0.000 claims description 17
- 239000011651 chromium Substances 0.000 claims description 10
- 239000010409 thin film Substances 0.000 claims description 10
- 229910052742 iron Inorganic materials 0.000 claims description 9
- 239000011701 zinc Substances 0.000 claims description 8
- 229910052725 zinc Inorganic materials 0.000 claims description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- 239000013077 target material Substances 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 239000010936 titanium Substances 0.000 claims description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 4
- 239000000654 additive Substances 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 229910017052 cobalt Inorganic materials 0.000 claims description 4
- 239000010941 cobalt Substances 0.000 claims description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 claims description 4
- 229910052749 magnesium Inorganic materials 0.000 claims description 4
- 239000011777 magnesium Substances 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- NPXOKRUENSOPAO-UHFFFAOYSA-N Raney nickel Chemical compound [Al].[Ni] NPXOKRUENSOPAO-UHFFFAOYSA-N 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- HSSJULAPNNGXFW-UHFFFAOYSA-N [Co].[Zn] Chemical compound [Co].[Zn] HSSJULAPNNGXFW-UHFFFAOYSA-N 0.000 claims description 2
- SWFPCDJSMKKRFW-UHFFFAOYSA-N [Cr].[Li] Chemical compound [Cr].[Li] SWFPCDJSMKKRFW-UHFFFAOYSA-N 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- MZZUATUOLXMCEY-UHFFFAOYSA-N cobalt manganese Chemical compound [Mn].[Co] MZZUATUOLXMCEY-UHFFFAOYSA-N 0.000 claims description 2
- HPDFFVBPXCTEDN-UHFFFAOYSA-N copper manganese Chemical compound [Mn].[Cu] HPDFFVBPXCTEDN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052744 lithium Inorganic materials 0.000 claims description 2
- ATTFYOXEMHAYAX-UHFFFAOYSA-N magnesium nickel Chemical compound [Mg].[Ni] ATTFYOXEMHAYAX-UHFFFAOYSA-N 0.000 claims description 2
- QELJHCBNGDEXLD-UHFFFAOYSA-N nickel zinc Chemical compound [Ni].[Zn] QELJHCBNGDEXLD-UHFFFAOYSA-N 0.000 claims description 2
- WJZHMLNIAZSFDO-UHFFFAOYSA-N manganese zinc Chemical compound [Mn].[Zn] WJZHMLNIAZSFDO-UHFFFAOYSA-N 0.000 claims 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 40
- 239000000758 substrate Substances 0.000 description 28
- 239000010408 film Substances 0.000 description 26
- 235000013980 iron oxide Nutrition 0.000 description 22
- 229910000859 α-Fe Inorganic materials 0.000 description 18
- 230000004907 flux Effects 0.000 description 15
- 230000000694 effects Effects 0.000 description 11
- 239000007789 gas Substances 0.000 description 10
- 238000000034 method Methods 0.000 description 9
- 239000000696 magnetic material Substances 0.000 description 8
- 239000013078 crystal Substances 0.000 description 7
- 239000004642 Polyimide Substances 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 229920001721 polyimide Polymers 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229910052596 spinel Inorganic materials 0.000 description 5
- 239000011029 spinel Substances 0.000 description 5
- -1 Fe 3 O 4 Chemical compound 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
- 230000005347 demagnetization Effects 0.000 description 4
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000001747 exhibiting effect Effects 0.000 description 3
- 239000002223 garnet Substances 0.000 description 3
- 239000006247 magnetic powder Substances 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 238000001771 vacuum deposition Methods 0.000 description 3
- 229910000599 Cr alloy Inorganic materials 0.000 description 2
- 229910017518 Cu Zn Inorganic materials 0.000 description 2
- 229910017752 Cu-Zn Inorganic materials 0.000 description 2
- 229910017943 Cu—Zn Inorganic materials 0.000 description 2
- 229910018605 Ni—Zn Inorganic materials 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000005389 magnetism Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 229910052755 nonmetal Inorganic materials 0.000 description 2
- 150000002843 nonmetals Chemical class 0.000 description 2
- 229910000889 permalloy Inorganic materials 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 239000010948 rhodium Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 229910001017 Alperm Inorganic materials 0.000 description 1
- 229920002284 Cellulose triacetate Polymers 0.000 description 1
- 229910020632 Co Mn Inorganic materials 0.000 description 1
- 229910020641 Co Zr Inorganic materials 0.000 description 1
- 229910020678 Co—Mn Inorganic materials 0.000 description 1
- 229910020520 Co—Zr Inorganic materials 0.000 description 1
- 229910017566 Cu-Mn Inorganic materials 0.000 description 1
- 229910017871 Cu—Mn Inorganic materials 0.000 description 1
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 229910017061 Fe Co Inorganic materials 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- 229910006559 Li—Cr Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910019083 Mg-Ni Inorganic materials 0.000 description 1
- 229910019403 Mg—Ni Inorganic materials 0.000 description 1
- 229910016629 MnBi Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910003310 Ni-Al Inorganic materials 0.000 description 1
- 229910000929 Ru alloy Inorganic materials 0.000 description 1
- 229910000756 V alloy Inorganic materials 0.000 description 1
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 1
- 229910000808 amorphous metal alloy Inorganic materials 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- VLWBWEUXNYUQKJ-UHFFFAOYSA-N cobalt ruthenium Chemical compound [Co].[Ru] VLWBWEUXNYUQKJ-UHFFFAOYSA-N 0.000 description 1
- LLESOAREQXNYOK-UHFFFAOYSA-N cobalt vanadium Chemical compound [V].[Co] LLESOAREQXNYOK-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000005308 ferrimagnetism Effects 0.000 description 1
- 230000005307 ferromagnetism Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000006249 magnetic particle Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- AJCDFVKYMIUXCR-UHFFFAOYSA-N oxobarium;oxo(oxoferriooxy)iron Chemical compound [Ba]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O AJCDFVKYMIUXCR-UHFFFAOYSA-N 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910000702 sendust Inorganic materials 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 229910000815 supermalloy Inorganic materials 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910000687 transition metal group alloy Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
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
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
- G11B5/66—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers
- G11B5/667—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers including a soft magnetic layer
-
- 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
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/7368—Non-polymeric layer under the lowermost magnetic recording layer
Description
１ 産業上の利用分野
本発明は磁気テープ、磁気デイスク等の磁気記
録媒体に関するもである。
２ 従来技術
従来、この種の磁気記録媒体は、ビデオ、オー
デイオ、デイジタル等の各種電気信号の記録に幅
広く利用されている。これらは、基体上に被着形
成された磁性層（磁気記録層）の面内長手方向に
おける磁化を用いる方式として発達してきた。と
ころが、近年、磁気記録の高密度化に伴ない、面
内長手方向の磁化を用いる記録方式では、記録信
号が短波長になるにつれ、媒体内の反磁界が増し
て残留磁化の減衰と回転が生じ、再生出力が著し
く減少する。このため記録波長をサブミクロン以
下にすることは極めて困難である。
一方、磁気記録媒体の磁性層の厚さ方向の磁化
（いわゆる垂直磁化）を用いる垂直磁化記録方式
が、最近になつて提案されている（例えば、「日
経エレクトロニクス」1978年８月７日、No.192）。
この記録方式によれば、記録波長が短かくなるに
伴なつて媒体内の残留磁化に作用する反磁界が減
少するので、高密度化にとつて好ましい特性を有
し、本質的に高密度記録に適した方式であると考
えられる。
ところで、このような垂直記録を能率良く行な
うには、磁気記録媒体の記録層が垂直方向（磁性
層の厚さ方向）に磁化容易軸を有していなければ
ならない。こうした磁気記録媒体としては、基体
（支持体）上に、磁性粉末とバインダーとを主成
分とする磁性塗料を塗布し、磁性層の垂直方向に
磁化容易軸が向くように配向させた塗布型の媒体
が知られている。この塗布型媒体には、Co，
Fe3O4、γ−Fe2O3、Co添加Fe3O4、Co添加γ−
Fe2O3、六方晶フエライト（例えばバリウムフエ
ライト）、MnBi等が磁性粉末として用いられて
いる（特開昭52−46803号、同53−67406号、同52
−78403号、同55−86103号、同52−78403号、同
54−87202号各公報）。しかしながら、これらの塗
布型媒体は、磁性層中に非磁性のバインダーが存
在しているために、磁性粉末の充填密度を高める
ことには限界があり、従つてＳ／Ｎ比を充分高く
することができない。しかも、記録される信号の
大きさは磁性粒子の寸法で制約される等、磁性塗
膜からなる磁性層を有する媒体は垂直磁化記録用
としては不適当である。
そこで、垂直磁化する磁性層を、例えばバイン
ダーを用いることなく磁性体を支持体上に連続的
に被着したもので形成した連続薄膜型磁気記録媒
体が、高密度記録に適したものとして注目されて
いる。
この連続薄膜型の垂直磁化記録用記録媒体は、
例えば特公昭57−17282号に開示されているよう
に、コバルトとクロムとの合金膜からなる磁気記
録層を有していて、特にクロム含有量は５〜25重
量％のCo−Cr合金膜が優れているとしている。
また、Co−Cr合金膜に30重量％以下のロジウム
を添加してなる磁性層を有する磁気記録媒体が特
開昭55−111110号公報に開示され、更にコバルト
−バナジウム合金膜（例えば米国電気電信通信学
会：略称IEEE刊行の学会誌、“Transaction on
Magnetism”1982年第18巻No.６、1116頁）やコ
バルト−ルテニウム合金膜（例えば1982年３月開
催の第18回東北大通研シンポジウム「垂直磁気記
録」論文集）を用いた磁気記録媒体が知られてい
る。
一方、例えば上記のCo−Cr系垂直磁化膜と基
体との間にFe−Ni系の軟磁性（低保磁力）下地
層を設けることが、特開昭54−51804号公報に開
示されている。この場合には、軟磁性下地層の存
在によつて、補助磁極からの磁束を対向した主磁
極に集中させることができると共に、記録後の残
留磁化状態における減磁作用が少なくなるという
効果が期待できる。
ところが、本発明者が検討を加えた結果、上記
の如き構造の磁気記録媒体は、Co−Cr系垂直磁
化膜が次に示す欠点を有しているために、実用化
する上で不充分であることを見出した。
(1) 磁性層の面に垂垂直に磁化容易軸を配向させ
るには、特に10-7Torr以上の高真空中で磁性
層を作成する必要があり、かつ基板の高度な洗
浄処理、低スパツタ速度等の如き条件を要し垂
直配向の制御要因が非常に複雑となる。
(2) 信号の記録、再生においては、磁気記録媒体
と垂直記録／再生用ヘツドとを相対的に摺動さ
せるために、ヘツドと媒体との間の界面状態が
悪く、媒体にきずが発生し易く、ヘツドも破損
等を生じる。
(3) 磁性層が硬いために、可撓性のある基体上に
磁性層を設けた場合に亀裂が入り易い。
(4) 磁気記録媒体としての耐蝕性が充分でなく、
従つて表面に保護膜を設ける必要がある。
(5) 原料のコバルトは安定に入手しがたく、コス
トが高くつく。
しかも、本発明者は、上記の軟磁性下地層上に
垂直磁化膜を直接形成すると、垂直磁化膜が軟磁
性下地層の結晶状態に左右され、垂直磁化に要求
される特性を満足しない膜質となつてしまう場合
があることに注目した。即ち、垂直磁化膜が垂直
磁化特性を充たすには特定方向に結晶成長しなけ
ればならないが、これを左右する軟磁性下地層の
結晶状態をコントロールすることがその作製条件
において極めて困難なためである。
３ 発明の目的
本発明者は、上記の如き実情に鑑み、鋭意検討
した結果、高密度の垂直磁気記録に適し、機械的
強度や化学的安定性等に優れ、記録／再生特性に
優れた磁気記録媒体を得ることに成功したもので
ある。
４ 発明の構成及び作用効果
即ち、本発明は、厚さ0.05〜5μmの高透磁率材
料層と厚さ100Å〜5μmの非磁性層と磁性層との
積層構造を有し、これらの各層のうち前記磁性層
が最上層として設けられ、かつ前記磁性層が、
(a) アルミニウム、コバルト、コバルト−マンガ
ン、亜鉛、コバルト−亜鉛、リチウム、クロ
ム、チタン、リチウム−クロム、マグネシウ
ム、マグネシウム−ニツケル、マンガン−亜
鉛、ニツケル、ニツケル−アルミニウム、ニツ
ケル−亜鉛、銅、銅−マンガン、銅−亜鉛及び
バナジウムからなる群より選ばれた添加物質を
含む鉄をターゲツト材として用いた対向ターゲ
ツトスパツタ法により、形成されたものであ
り、
(b) 面内方向での残留磁化（MH）と、その面に
対し垂直方向での残留磁化（MV）との比
（MV／MH）が0.5以上であり、
(c) 前記添加物質を含み、Fe3O4、γ−Fe2O3又
はこれらの中間組成の酸化鉄を主成分とする
連続磁性薄膜からなつている磁気記録媒体に係る
ものである。
本発明によれば、磁性層が酸化鉄を主成分とし
ているから、酸化物に由来する特有の優れた特性
（即ち機械的強度及び化学的安定性等）が得られ、
従来の合金薄膜に必要であつた表面保護膜は不要
となる。この結果、磁気ヘツドと媒体との間隔を
小さくし得て高密度記録が可能になると共に、材
料面から見ても低コスト化が可能となる。
しかも、酸化鉄を主成分とする磁性層の面内方
向と垂直方向とでの残留磁化比（MV／MH）を
0.5以上としているので、酸化鉄磁性体の磁気モ
ーメントは面内方向に対し30度以上垂直方向側へ
立ち上つており、垂直磁化を充分に実現できる構
造になつている。上記磁化量MV，MHは、例え
ば試料振動型磁力計（東英工業社製）で測定可能
である。即ち、MV／MHが0.5未満であれば垂直
磁化に適した磁気モーメントが得られ難い。
また、本発明の磁気記録媒体は、上記の酸化鉄
系磁性層に加えて、上記の高透磁率材料層を設け
ているために、磁性層単独のものに比べて記録時
に磁束を集中させ、かつ記録後の減磁作用を少な
くして記録保持性を向上させることができる。つ
まり、高透磁率材料層が磁束（フラツクス）を通
し易い性質があるために、磁極からの磁束を磁性
層に集中させると共に、後述の磁気還流効果によ
つて残留磁化を充分に保持させる効果があり、記
録密度を損うことなく記録／再生の感度を向上さ
せることができる。
更に重要なことは、上記の磁性層が最上層とし
て設けられ、下地の影響を少なくして、所望の垂
直磁化特性を示す結晶として成長した構造となつ
ていることである。即ち、例えば、上記の高透磁
率材料層上に非磁性層を設け、この上に磁性層を
設けることによつて、高透磁率層の結晶状態の影
響を非磁性層で遮断できるから、非磁性層上の磁
性層は常に所望の方向に結晶軸を有しながら成長
させることができる。また、非磁性層上に高透磁
率層を設け、この上に磁性層を設ける場合も、非
磁性層の存在によつてその上に成長する高透磁率
材料層の結晶状態が良好となり、従つて高透磁率
材料層上の磁性層は目的とする方向に成長し易く
なり、垂直磁化特性を満足したものとなる。
本発明の磁気記録媒体の各層は、次の如くに構
成される。
まず、磁性層は、従来の塗布型磁性層とは根本
的に異なり、バインダーを使用せずに酸化鉄（即
ちFe3O4、γ−Fe2O3、又はこれらの中間組成の
非化学量論的組成からなるベルトライド化合物）
自体が連続的に連なつた薄膜（飽和磁化量が大き
く、保磁力（Hc）が100〜5000Oe）からなつて
いる。この磁性層においては、鉄と酸素の両元素
の総和は磁性層の50重量％以上であるのがよく、
70重量％以上であるのが更に望ましい。また、鉄
と酸素との比は、酸素の原子数／鉄の原子数＝１
〜３であるのがよく、４／３〜２であるのが更に
よく、上記に例示した酸化鉄が適当である。上記
酸化鉄がスピネル型の結晶構造を有していると、
飽和磁化量が大きく、記録信号の再生時に残留磁
束密度が大きくて再生感度が極めて良好となる。
一般に、磁性を示す酸化鉄には、菱面体晶形の寄
生強磁性を有するα−Fe2O3；スピネル構造でフ
エリ磁性を示すFe3O4、γ−Fe2O3又はこれらの
ベルトライド化合物；六方晶型の酸化物である
Ba系フエライト又はSrフエライト、Pbフエライ
ト又はその誘導体；ガーネツト構造の希土類ガー
ネツト型フエライトがある。これらの酸化鉄のう
ち、その磁気特性の重要な１つである飽和磁化量
は、α−Fe2O3では2.0Gauss、Baフエライト、
Srフエライト、Pbフエライトでは最大でも
380Ga−uss程度、更にガーネツト型フエライト
では最大でも140Gaussである。これに対し、本
発明で好ましく使用するスピネル型フエライトの
飽和磁化量は480Gaussを示し、酸化鉄の中で最
も大きい。このような大きな飽和磁化量は、記録
した信号を再生する場合、残留磁束密度の大きさ
を充分にし、再生感度が良好となるために、極め
て有効なものである。一方、スピネル型フエライ
トに類似した飽和磁束密度を示すものとしてBa
フエライト、Srフエライトがあるが、これらの
連続薄膜型の磁性層を形成するには、例えば後述
のスパツタ装置において基体の温度を500℃と高
温に保持しなければならず、このために基体の種
類等が制約される（例えば耐熱性の乏しいプラス
チツクス基体は使用不可能）等、作成条件に問題
があり、不適当である。本発明の好ましく使用さ
れるスピネル型酸化鉄では室温〜300℃と低温で
製膜が可能であり、基体材料の制約を受けること
がない。但、磁性層には、鉄及び酸素以外の金属
又はその酸化物、或いは非金属、半金属又はその
化合物等を添加し、これによつて磁性層の磁気特
性（例えば保磁力、飽和磁化量、残留磁化量）及
びその結晶性、結晶の特定軸方向への配向性の向
上等を図ることができる。こうした添加元素又は
化合物としては、Al，Co，Co−Mn，Zn，Co−
Zn，Li，Cr，Ti，Li−Cr，Mg，Mg−Ni，Mn
−Zn，Ni，Ni−Al，Ni−Zn，Cu，Cu−Mn，
Cu−Zn，Ｖ等が挙げられる。
また、上記高透磁率材料層は一般に、磁性層と
基体との間に設けられるが、基体自体を高透磁率
材料で形成してもよい。高透磁率材料層はフラツ
クスを通し易い性質（特に、初透磁率μiは102以
上、望ましくは2000以上、Hcは特に10Oe以下、
例えば1Oe）を有していて、主として磁性層の面
内方向に磁化容易軸を有するものが好適である。
このような高透磁率材料は軟磁性材料であればよ
く、例えば、純鉄、ケイ素鋼、パーマロイ、スー
パーマロイ、Cu−Znフエライト、アルパーム、
Ni−Znフエライト、Mn−Znフエライト、セン
ダスト、ミユーメタル等からなる合金及び酸化
物；Fe−Co、Co−Zr、CoとTi、Ｙ、Hf、Nb、
Ta又はＷとの合金、Co−Zr−Nd、Fe、Co、Ni
等の遷移金属とSi、Ｂ、Ｐ、Ｃ等の半金属との合
金からなる非晶質が挙げられる。また、高透磁率
材料層の厚みは0.05〜5μmでとすべきであり、0.1
〜3μmが望ましい。即ち、0.05μm未満では、薄
すぎるために効果に乏しくなり、また5μmを越え
ると効果が飽和状態となつて再生出力がそれ程向
上しないからである。
また、上記非磁性層は垂直磁化膜（磁性層）の
配向性を向上させるために基体上に設けられる
が、場合によつては基体自体を非磁性材料で形成
してもよい。この非磁性材料としては、ポリエチ
レンテレフタレート、ポリイミド、ポリアミド等
の有機高分子化合物；Ｃ、Mg、Al、Be、Si、
Ti、Ｖ、Cr、Mn、Cu、Zn、Ga、Ge、As、Se、
Rb、Zr、Nb、Mo、Ag、Cd、In、Sn、Ir、Sb、
Pb、Te、Ta、Ｗ、Rh、Au等の金属又は非金
属、或いはその化合物、酸化物が使用可能であ
る。非磁性層の厚みは、100Å〜5μmとすべきで
あり、0.03μm〜2μmが望ましいが、100Å未満で
は連続した磁性層を形成しがたく、5μmを越える
と下地に高透磁率材料層を設ける場合にその高透
磁率材料層の効果（磁束集中効果、減磁の防止）
が劣化するからである。
また、本発明の磁気記録媒体に使用可能な基体
材料は種々のものが採用可能である。例えば、望
ましい表面平滑性を示す基体として、ポリエチレ
ンテレフタレート、ポリ塩化ビニル、三酢酸セル
ロース、ポリカーボネート、ポリイミド、ポリア
ミド、ポリメチルメタクリレートの如きプラスチ
ツクス、ガラス等のセラミツクス等からなる基本
が使用可能である。或いは金属基体も使用しても
よい。基体の形状はシート、カード、デイスク、
ドラムの他、長尺テープ状でもよい。
この磁気記録媒体を作成するには、基体を固定
板に密着支持し、或いは基体を走行させつつ所定
の材料を被着させることができる。このために
は、真空ポンプ等の真空排気系に接続した処理室
内で、高透磁率材料、非磁性材料及び磁性材料の
ターゲツトを夫々対向ターゲツト方式でスパツタ
することができる。この場合、高透磁率材料層、
非磁性層、磁性層を構成する元素を飛翔させて、
基体上にその連続薄膜を形成することができる。
５ 実施例
以下、本発明の磁気記録媒体を図面参照下に更
に詳細に説明する。
第１図は、磁気記録媒体の一例を示すものであ
つて、ポリイミド等の基体６上に、厚さ約0.1μm
のパーマロイからなる軟磁性層１１が形成され、
この上に厚さ約1000ÅのAlからなる非磁性層１
２が形成され、更にこの上に約1μmの酸化鉄から
なる垂直磁化膜１０が積層されている。
軟磁性層１１は、公知の真空蒸着法で形成され
るもの（蒸発速度200Å／秒、電子ビーム加熱）
であり、非磁性層も、公知の真空蒸着法で形成さ
れるもの（蒸発速度60Å／秒、電子ビーム加熱）
であるため、その形成方法はここでは特に説明し
ない。なお、非磁性層１２としてポリイミドを用
いる場合には、ポリイミドをスプレー塗布、スピ
ン塗布法で厚さ2000Åに形成できる。
垂直磁化膜（磁性層）１０を形成するために、
磁性材料を基体上に被着させる手段として、対向
ターゲツトスパツタ法を用いる。
第２図は、対向ターゲツトスパツタ装置を示す
ものである。
図面において、１は真空槽、２は真空槽１を排
気する真空ポンプ等からなる排気系、３は真空槽
１内に所定のガスを導入してガス圧力を10-1〜
10-4Torr程度に設定するガス導入系である。タ
ーゲツト電極は、ターゲツトホルダー４により一
対のターゲツトT1，T2を互いに隔てて平行に対
向配置した対向ターゲツト電極として構成されて
いる。これらのターゲツト間には、磁界発生手段
（図示せず）による磁界が形成される。一方、磁
性薄膜を形成すべき基体６は、基体ホルダー５に
よつて、上記対向ターゲツト間の側方に垂直に配
置される。
このように構成されたスパツタ装置において、
平行に対向し合つた両ターゲツトT1，T2の各表
面と垂直方向に磁界を形成し、この磁界により陰
極降下部（即ち、ターゲツトT1−T2間に発生し
たプラズマ雰囲気と各ターゲツトT1及びT2との
間の領域）での電界で加速されたスパツタガスイ
オンのターゲツト表面に対する衝撃で放出された
γ電子をターゲツト間の空間に閉じ込め、対向し
た他方のターゲツト方向へ移動させる。他方のタ
ーゲツト表面へ移動したγ電子は、その近傍の陰
極降下部で反射される。こうして、γ電子はター
ゲツトT1−T2間において磁界に束縛されながら
往復運動を繰返すことになる。この往復運動の間
に、γ電子は中性の雰囲気ガスと衝突して雰囲気
ガスのイオンと電子とを生成させ、これらの生成
物がターゲツトからのγ電子の放出と雰囲気ガス
のイオン化を促進させる。従つて、ターゲツト
T1−T2間の空間には高密度のプラズマが形成さ
れ、これに伴なつてターゲツト物質が充分にスパ
ツタされ、側方の基体６上に磁性材料として堆積
してゆくことになる。
この対向ターゲツトスパツタ装置は、他の飛翔
手段に比べて、高速スパツタによる高堆積速度の
製膜が可能であり、また基体がプラズマに直接曝
されることがなく、低い基体温度での製膜が可能
である等のことから、垂直磁化膜を形成するのに
有利である。しかも、対向ターゲツトスパツタ装
置によつて飛翔した磁性膜材料の基板へ入射エネ
ルギーは、通常のスパツタ装置のものよりも小さ
いので、材料が所望の方向へ方向性を以つて堆積
し易く、垂直磁化記録に適した構造の膜を得易く
なる。
次に、上記のスパツタ装置を用いて磁気記録媒
体を作成する具体例を説明する。
この作成条件は以下の通りであつた。
ターゲツト材 鉄（Coを１原子％含有）
基 体 ガラス
対向ターゲツト間隔 100mm
スパツタ空間の磁界 100Oe
ターゲツト形状 100mm直径の円盤（５mm厚）
基体とターゲツト端との間隔 30mm
真空槽内の背圧 10-6Torr
導入ガス Ar＋O2
導入ガス圧 ４×10-3Torr
スパツタ投入電力 420W
このようにして第１図に示す如く、ベースフイ
ルム６上の軟磁性層１１上に酸化鉄系の磁性層１
０を有する磁気記録媒体が得られた。この媒体に
ついて、磁性層の特性評価は、Ｘ線マイクロアナ
ライザー（XMA）による組成の同定、Ｘ線回析
法による酸化鉄の状態、試料振動型磁力計による
磁気特性によつて行なつた。得られた磁気記録媒
体の特性は次の如くであつた。
まず、両内方向での残留磁化量（MH）と面に
垂直方向での残留磁化量（MV）との比はMV／
MH≧0.5であつた。即ち、第３図に例示するよ
うに、破線で示す面内方向での磁化時のヒステリ
シス曲線と、実線で示す垂直方向での磁化時のヒ
ステリシス曲線とが夫々得られたが、印加磁界が
ゼロのときの各磁化量をMH，MVとした。これ
によれば、前者のヒステリシス曲線は後者のヒス
テリシス曲線よりも小さく、MV≧0.5MHとなつ
ていることが明らかであり、垂直磁化にとつて好
適な磁性層が形成されていることが分る。また、
保磁力は垂直方向では920エルステツド、面内方
向では750エルステツドであつた。これは、酸化
鉄系の磁性層においては驚くべき事実である。
また、この磁気記録媒体の組成をXMA（Ｘ線
マイクロアナライザ：日立製作所製「Ｘ−556」
KEVEX−7000型）で測定したところ、Feが主ピ
ークであり、Coが少量含まれていることが分つ
た。更に、酸化鉄の状態を調べるために、Ｘ線回
折装置（日本電子社製「JDX−10RA：Cu Kα管
球使用）を用いて測定したところ、下記表に示す
ように、磁性層が酸化鉄を主成分とするものであ
ることが分つた。しかも、この磁性層は、面内方
向に対して垂直方向に秩序正しい構造を有してい
ることが電子顕微鏡で観察された。
1. Field of Industrial Application The present invention relates to magnetic recording media such as magnetic tapes and magnetic disks. 2. Prior Art Conventionally, this type of magnetic recording medium has been widely used for recording various electrical signals such as video, audio, and digital signals. These have been developed as a system that uses magnetization in the in-plane longitudinal direction of a magnetic layer (magnetic recording layer) formed on a substrate. However, in recent years, with the increase in the density of magnetic recording, recording methods that use magnetization in the longitudinal direction in the plane have a tendency to increase the demagnetizing field within the medium as the recording signal becomes shorter in wavelength, resulting in attenuation and rotation of the residual magnetization. This causes a significant decrease in playback output. For this reason, it is extremely difficult to reduce the recording wavelength to submicron or less. On the other hand, a perpendicular magnetization recording method that uses magnetization in the thickness direction of the magnetic layer of a magnetic recording medium (so-called perpendicular magnetization) has recently been proposed (for example, "Nikkei Electronics" August 7, 1978, No. .192).
According to this recording method, as the recording wavelength becomes shorter, the demagnetizing field that acts on the residual magnetization in the medium decreases, so it has favorable characteristics for increasing density, and is essentially suitable for high-density recording. This method is considered to be suitable for Incidentally, in order to perform such perpendicular recording efficiently, the recording layer of a magnetic recording medium must have an axis of easy magnetization in the perpendicular direction (thickness direction of the magnetic layer). Such a magnetic recording medium is a coated type in which a magnetic coating mainly composed of magnetic powder and a binder is coated on a substrate (support), and the axis of easy magnetization is oriented in the perpendicular direction of the magnetic layer. The medium is known. This coated medium contains Co,
Fe 3 O 4 , γ-Fe 2 O 3 , Co-added Fe 3 O 4 , Co-added γ-
Fe 2 O 3 , hexagonal ferrite (e.g. barium ferrite), MnBi, etc. are used as magnetic powders (Japanese Patent Application Laid-open Nos. 52-46803, 53-67406, 52
-78403, 55-86103, 52-78403, same
54-87202). However, in these coated media, there is a limit to increasing the packing density of magnetic powder due to the presence of a non-magnetic binder in the magnetic layer, and therefore it is difficult to increase the S/N ratio sufficiently. I can't. Moreover, the magnitude of the recorded signal is limited by the size of the magnetic particles, and thus a medium having a magnetic layer made of a magnetic coating is unsuitable for perpendicular magnetization recording. Therefore, continuous thin film magnetic recording media, in which a perpendicularly magnetized magnetic layer is formed by continuously depositing a magnetic material on a support without using a binder, are attracting attention as suitable for high-density recording. ing. This continuous thin film type perpendicular magnetization recording medium is
For example, as disclosed in Japanese Patent Publication No. 57-17282, it has a magnetic recording layer made of an alloy film of cobalt and chromium, and in particular, a Co-Cr alloy film with a chromium content of 5 to 25% by weight is used. It is said to be excellent.
Further, a magnetic recording medium having a magnetic layer formed by adding 30% by weight or less of rhodium to a Co-Cr alloy film is disclosed in JP-A-55-111110, and furthermore, a cobalt-vanadium alloy film (for example, Communication Society: Abbreviation: An academic journal published by IEEE, “Transaction on
Magnetism" 1982 Vol. 18 No. 6, p. 1116) and cobalt-ruthenium alloy films (for example, the 18th Tohoku University Research Symposium "Perpendicular Magnetic Recording" Paper Collection held in March 1982). Are known. On the other hand, for example, JP-A-54-51804 discloses that a Fe-Ni soft magnetic (low coercive force) underlayer is provided between the Co-Cr perpendicular magnetization film and the substrate. . In this case, the presence of the soft magnetic underlayer allows the magnetic flux from the auxiliary magnetic pole to be concentrated on the opposing main magnetic pole, and is expected to have the effect of reducing the demagnetization effect in the residual magnetization state after recording. can. However, as a result of studies conducted by the present inventor, it was found that the magnetic recording medium having the above structure is insufficient for practical use because the Co-Cr-based perpendicularly magnetized film has the following drawbacks. I discovered something. (1) In order to orient the axis of easy magnetization perpendicular to the surface of the magnetic layer, it is necessary to create the magnetic layer in a high vacuum of 10 -7 Torr or higher, and the substrate must be processed with advanced cleaning treatment and low spatter. Conditions such as speed are required, and the control factors for vertical alignment become very complicated. (2) When recording and reproducing signals, the magnetic recording medium and the perpendicular recording/reproducing head slide relative to each other, so the interface between the head and the medium is poor and scratches may occur on the medium. This can easily cause damage to the head. (3) Since the magnetic layer is hard, cracks tend to occur when the magnetic layer is provided on a flexible substrate. (4) Corrosion resistance as a magnetic recording medium is insufficient;
Therefore, it is necessary to provide a protective film on the surface. (5) Cobalt, a raw material, is difficult to obtain stably and is expensive. Furthermore, the present inventor discovered that if a perpendicularly magnetized film is directly formed on the soft magnetic underlayer, the perpendicularly magnetized film will be affected by the crystalline state of the soft magnetic underlayer, resulting in film quality that does not satisfy the characteristics required for perpendicular magnetization. We focused on the fact that there are cases where people get used to it. In other words, in order for a perpendicularly magnetized film to satisfy perpendicular magnetization characteristics, crystals must grow in a specific direction, but it is extremely difficult to control the crystalline state of the soft magnetic underlayer, which affects this, under the manufacturing conditions. . 3. Purpose of the Invention In view of the above-mentioned circumstances, the present inventor has made extensive studies and has developed a magnetic material that is suitable for high-density perpendicular magnetic recording, has excellent mechanical strength and chemical stability, and has excellent recording/reproducing characteristics. We succeeded in obtaining a recording medium. 4. Structure and effects of the invention That is, the present invention has a laminated structure of a high magnetic permeability material layer with a thickness of 0.05 to 5 μm, a nonmagnetic layer and a magnetic layer with a thickness of 100 Å to 5 μm, and among these layers, The magnetic layer is provided as a top layer, and the magnetic layer is (a) aluminum, cobalt, cobalt-manganese, zinc, cobalt-zinc, lithium, chromium, titanium, lithium-chromium, magnesium, magnesium-nickel, manganese. - Formed by a facing target sputtering method using iron containing an additive selected from the group consisting of zinc, nickel, nickel-aluminum, nickel-zinc, copper, copper-manganese, copper-zinc and vanadium as a target material. (b) The ratio of the residual magnetization (MH) in the in-plane direction to the residual magnetization (MV) in the perpendicular direction to the plane (MV/MH) is 0.5 or more, and (c ) The present invention relates to a magnetic recording medium comprising a continuous magnetic thin film containing the above-mentioned additive substance and having iron oxide as a main component of Fe 3 O 4 , γ-Fe 2 O 3 , or an intermediate composition thereof. According to the present invention, since the magnetic layer contains iron oxide as a main component, excellent characteristics unique to oxides (i.e., mechanical strength, chemical stability, etc.) can be obtained,
The surface protective film required for conventional alloy thin films is no longer necessary. As a result, the distance between the magnetic head and the medium can be reduced, making it possible to perform high-density recording, and also to reduce costs in terms of materials. Moreover, the residual magnetization ratio (MV/MH) in the in-plane direction and perpendicular direction of the magnetic layer whose main component is iron oxide is
Since it is set to 0.5 or more, the magnetic moment of the iron oxide magnetic material rises in the perpendicular direction by 30 degrees or more with respect to the in-plane direction, and the structure is such that perpendicular magnetization can be sufficiently realized. The magnetization amounts MV and MH can be measured, for example, with a sample vibrating magnetometer (manufactured by Toei Kogyo Co., Ltd.). That is, if MV/MH is less than 0.5, it is difficult to obtain a magnetic moment suitable for perpendicular magnetization. Furthermore, since the magnetic recording medium of the present invention is provided with the above-mentioned high magnetic permeability material layer in addition to the above-mentioned iron oxide-based magnetic layer, magnetic flux is concentrated during recording compared to a magnetic layer alone. Moreover, the demagnetization effect after recording can be reduced to improve recording retention. In other words, since the high magnetic permeability material layer has the property of easily passing magnetic flux, it is effective in concentrating the magnetic flux from the magnetic pole in the magnetic layer and retaining residual magnetization sufficiently through the magnetic reflux effect, which will be described later. Therefore, recording/reproducing sensitivity can be improved without impairing recording density. What is more important is that the above magnetic layer is provided as the uppermost layer and has a structure grown as a crystal exhibiting desired perpendicular magnetization characteristics while reducing the influence of the underlying layer. That is, for example, by providing a nonmagnetic layer on the high magnetic permeability material layer and providing a magnetic layer on top of the nonmagnetic layer, the influence of the crystalline state of the high magnetic permeability layer can be blocked by the nonmagnetic layer. The magnetic layer on the magnetic layer can be grown while always having the crystal axis in a desired direction. In addition, when a high magnetic permeability layer is provided on a nonmagnetic layer and a magnetic layer is provided on this layer, the presence of the nonmagnetic layer improves the crystalline state of the high magnetic permeability material layer grown thereon. As a result, the magnetic layer on the high magnetic permeability material layer grows easily in the desired direction, and satisfies perpendicular magnetization characteristics. Each layer of the magnetic recording medium of the present invention is constructed as follows. First, the magnetic layer is fundamentally different from conventional coated magnetic layers in that it is made from non-stoichiometric amounts of iron oxide (i.e. Fe 3 O 4 , γ-Fe 2 O 3 , or intermediate compositions thereof) without the use of a binder. (Bertolide compound with theoretical composition)
It consists of a continuous thin film (with a large saturation magnetization and a coercive force (Hc) of 100 to 5000 Oe). In this magnetic layer, the sum of both elements iron and oxygen is preferably 50% by weight or more of the magnetic layer.
More preferably, the content is 70% by weight or more. Also, the ratio of iron and oxygen is: number of oxygen atoms/number of iron atoms = 1
-3 is preferable, and 4/3 - 2 is even better, and the iron oxides exemplified above are suitable. When the iron oxide has a spinel crystal structure,
The amount of saturation magnetization is large, and the residual magnetic flux density is large during reproduction of recorded signals, resulting in extremely good reproduction sensitivity.
In general, iron oxides exhibiting magnetism include α-Fe 2 O 3 which has rhombohedral parasitic ferromagnetism; Fe 3 O 4 and γ-Fe 2 O 3 which have a spinel structure and ferrimagnetism, or their bertolide compounds. ;It is a hexagonal oxide
Ba-based ferrite, Sr ferrite, Pb ferrite or derivatives thereof; rare earth garnet type ferrite with garnet structure. Among these iron oxides, the saturation magnetization, which is one of the important magnetic properties, is 2.0 Gauss for α-Fe 2 O 3 , Ba ferrite,
For Sr ferrite and Pb ferrite, the maximum
It is about 380Gauss, and the maximum for garnet type ferrite is 140Gauss. On the other hand, the saturation magnetization of spinel ferrite preferably used in the present invention is 480 Gauss, which is the largest among iron oxides. Such a large amount of saturation magnetization is extremely effective when reproducing a recorded signal because it ensures a sufficient residual magnetic flux density and improves reproduction sensitivity. On the other hand, Ba has a saturation magnetic flux density similar to spinel ferrite.
There are ferrite and Sr ferrite, but in order to form these continuous thin-film magnetic layers, the temperature of the substrate must be maintained at a high temperature of 500°C, for example in the sputtering equipment described below, and for this reason, the type of substrate must be There are problems with the manufacturing conditions, such as restrictions on the production conditions (for example, the use of plastic substrates with poor heat resistance cannot be used), and the method is inappropriate. The spinel type iron oxide preferably used in the present invention can be formed into a film at a low temperature of room temperature to 300° C., and is not subject to limitations of the substrate material. However, metals other than iron and oxygen or their oxides, nonmetals, semimetals, or compounds thereof are added to the magnetic layer, thereby improving the magnetic properties of the magnetic layer (e.g. coercive force, saturation magnetization, etc.). It is possible to improve the amount of residual magnetization), its crystallinity, and the orientation of the crystal in a specific axis direction. These additive elements or compounds include Al, Co, Co-Mn, Zn, Co-
Zn, Li, Cr, Ti, Li-Cr, Mg, Mg-Ni, Mn
−Zn, Ni, Ni−Al, Ni−Zn, Cu, Cu−Mn,
Examples include Cu-Zn and V. Further, although the high magnetic permeability material layer is generally provided between the magnetic layer and the base, the base itself may be formed of a high magnetic permeability material. The high magnetic permeability material layer has the property of easily passing flux (in particular, the initial magnetic permeability μi is 10 2 or more, preferably 2000 or more, Hc is especially 10 Oe or less,
For example, 1 Oe) and having an axis of easy magnetization mainly in the in-plane direction of the magnetic layer are suitable.
Such high magnetic permeability materials may be soft magnetic materials, such as pure iron, silicon steel, permalloy, supermalloy, Cu-Zn ferrite, alperm,
Alloys and oxides consisting of Ni-Zn ferrite, Mn-Zn ferrite, sendust, miu metal, etc.; Fe-Co, Co-Zr, Co and Ti, Y, Hf, Nb,
Alloy with Ta or W, Co-Zr-Nd, Fe, Co, Ni
Examples include amorphous materials made of alloys of transition metals, such as, and semimetals, such as Si, B, P, and C. In addition, the thickness of the high magnetic permeability material layer should be 0.05-5μm, and 0.1
~3μm is desirable. That is, if the thickness is less than 0.05 μm, the effect will be poor because it is too thin, and if it exceeds 5 μm, the effect will be saturated and the reproduction output will not improve much. Further, the nonmagnetic layer is provided on the substrate in order to improve the orientation of the perpendicularly magnetized film (magnetic layer), but depending on the case, the substrate itself may be formed of a nonmagnetic material. Examples of this nonmagnetic material include organic polymer compounds such as polyethylene terephthalate, polyimide, and polyamide; C, Mg, Al, Be, Si,
Ti, V, Cr, Mn, Cu, Zn, Ga, Ge, As, Se,
Rb, Zr, Nb, Mo, Ag, Cd, In, Sn, Ir, Sb,
Metals or nonmetals such as Pb, Te, Ta, W, Rh, and Au, or their compounds and oxides can be used. The thickness of the nonmagnetic layer should be 100 Å to 5 μm, preferably 0.03 μm to 2 μm, but if it is less than 100 Å, it will be difficult to form a continuous magnetic layer, and if it exceeds 5 μm, a high magnetic permeability material layer will be provided as an underlying layer. In this case, the effect of the high magnetic permeability material layer (magnetic flux concentration effect, prevention of demagnetization)
This is because it deteriorates. Furthermore, various substrate materials can be used for the magnetic recording medium of the present invention. For example, as a substrate exhibiting desirable surface smoothness, base materials such as plastics such as polyethylene terephthalate, polyvinyl chloride, cellulose triacetate, polycarbonate, polyimide, polyamide, polymethyl methacrylate, ceramics such as glass, etc. can be used. Alternatively, metal substrates may also be used. The shape of the base is sheet, card, disk,
In addition to a drum, it may be in the form of a long tape. To produce this magnetic recording medium, the substrate can be closely supported on a fixed plate, or a predetermined material can be applied while the substrate is traveling. For this purpose, targets of a high magnetic permeability material, a non-magnetic material, and a magnetic material can be sputtered in a facing target manner in a processing chamber connected to an evacuation system such as a vacuum pump. In this case, a high permeability material layer,
By flying the elements that make up the non-magnetic layer and the magnetic layer,
A continuous thin film thereof can be formed on a substrate. 5 Examples The magnetic recording medium of the present invention will be explained in more detail below with reference to the drawings. FIG. 1 shows an example of a magnetic recording medium, in which a magnetic recording medium with a thickness of about 0.1 μm is coated on a base 6 made of polyimide or the like.
A soft magnetic layer 11 made of permalloy is formed,
On top of this is a nonmagnetic layer 1 made of Al with a thickness of about 1000 Å.
2 is formed, and a perpendicular magnetization film 10 made of iron oxide with a thickness of about 1 μm is further laminated thereon. The soft magnetic layer 11 is formed by a known vacuum evaporation method (evaporation rate 200 Å/sec, electron beam heating)
The nonmagnetic layer is also formed by a known vacuum evaporation method (evaporation rate 60 Å/sec, electron beam heating).
Therefore, the method for forming it will not be particularly explained here. Note that when polyimide is used as the nonmagnetic layer 12, the polyimide can be formed to a thickness of 2000 Å by spray coating or spin coating. In order to form the perpendicular magnetization film (magnetic layer) 10,
A facing target sputtering method is used as a means for depositing the magnetic material onto the substrate. FIG. 2 shows a facing target sputtering device. In the drawing, 1 is a vacuum chamber, 2 is an evacuation system consisting of a vacuum pump etc. for evacuating the vacuum chamber 1, and 3 is an exhaust system that introduces a predetermined gas into the vacuum chamber 1 to raise the gas pressure to 10 -1 ~
This is a gas introduction system set at approximately 10 -4 Torr. The target electrodes are constructed as opposed target electrodes in which a pair of targets T 1 and T 2 are separated from each other by a target holder 4 and are placed facing each other in parallel. A magnetic field is formed between these targets by magnetic field generating means (not shown). On the other hand, the substrate 6 on which the magnetic thin film is to be formed is placed by the substrate holder 5 perpendicularly to the side between the opposing targets. In the sputtering device configured in this way,
A magnetic field is formed in a direction perpendicular to the surfaces of both targets T 1 and T 2 facing each other in parallel, and this magnetic field creates a gap between the plasma atmosphere generated between the targets T 1 and T 2 and the cathode fall area (i.e., the plasma atmosphere generated between the targets T 1 and T 2 ) . The γ electrons emitted by the impact of the sputtering gas ions accelerated by the electric field on the target surface in the region between T1 and T2 ) are confined in the space between the targets and moved toward the other opposing target. The γ electrons that have moved to the other target surface are reflected by the cathode fall section nearby. In this way, the γ electrons repeatedly move back and forth between the targets T 1 and T 2 while being constrained by the magnetic field. During this reciprocating motion, the γ electrons collide with the neutral atmospheric gas to generate ions and electrons of the atmospheric gas, and these products promote the release of γ electrons from the target and the ionization of the atmospheric gas. . Therefore, the target
A high-density plasma is formed in the space between T 1 and T 2 , and the target material is sufficiently sputtered and deposited as a magnetic material on the side substrate 6 . Compared to other flying methods, this facing target sputtering device enables film formation at a high deposition rate using high-speed sputtering, and the substrate is not directly exposed to plasma, allowing film formation at low substrate temperatures. This method is advantageous for forming a perpendicularly magnetized film. Moreover, since the energy incident on the substrate of the magnetic film material that is ejected by the facing target sputtering device is smaller than that of a normal sputtering device, the material is easily deposited directionally in the desired direction, resulting in perpendicular magnetization. It becomes easier to obtain a film with a structure suitable for recording. Next, a specific example of producing a magnetic recording medium using the above sputtering apparatus will be described. The preparation conditions were as follows. Target material Iron (contains 1 atomic % Co) Substrate Glass spacing between opposing targets 100 mm Magnetic field in sputtering space 100 Oe Target shape 100 mm diameter disk (5 mm thickness) Distance between substrate and target end 30 mm Back pressure in vacuum chamber 10 -6 Torr Introduced gas Ar + O 2 Introduced gas pressure 4×10 -3 Torr Sputter input power 420W In this way, as shown in FIG.
0 was obtained. Regarding this medium, the characteristics of the magnetic layer were evaluated by identifying the composition using an X-ray microanalyzer (XMA), the state of iron oxide using an X-ray diffraction method, and the magnetic properties using a sample vibrating magnetometer. The characteristics of the obtained magnetic recording medium were as follows. First, the ratio of the residual magnetization in both inward directions (MH) and the residual magnetization in the direction perpendicular to the plane (MV) is MV/
MH≧0.5. That is, as illustrated in FIG. 3, a hysteresis curve during magnetization in the in-plane direction shown by the broken line and a hysteresis curve during magnetization in the perpendicular direction shown by the solid line were obtained, but when the applied magnetic field is zero The amount of magnetization at that time was defined as MH and MV. According to this, it is clear that the former hysteresis curve is smaller than the latter hysteresis curve and MV≧0.5MH, indicating that a magnetic layer suitable for perpendicular magnetization is formed. . Also,
The coercive force was 920 Oersted in the vertical direction and 750 Oersted in the in-plane direction. This is a surprising fact for iron oxide-based magnetic layers. In addition, the composition of this magnetic recording medium was measured using an XMA (X-ray microanalyzer: "X-556" manufactured by Hitachi, Ltd.).
When measured with a KEVEX-7000 model, it was found that Fe was the main peak and a small amount of Co was included. Furthermore, in order to investigate the state of iron oxide, measurements were taken using an X-ray diffraction device (JDX-10RA manufactured by JEOL Ltd., using a Cu Kα tube), and as shown in the table below, the magnetic layer was found to be iron oxide. Furthermore, it was observed using an electron microscope that this magnetic layer had an ordered structure in the direction perpendicular to the in-plane direction.
【表】
なお、上記のスパツタ法による製膜前に、基体
上の表面を同一スパツタ装置内でAr+によりボン
バードして表面清浄化処理したり、或いはベーキ
ングを施すか、高周波をかけて表面処理しておく
のが望ましい。
上記した実験と比較するために、上記作成条件
において、ターゲツト材を純鉄（Co含有せず）
として同様にスパツタした結果、得られた磁性薄
膜のMV／MHは0.5未満、保磁力は垂直方向で
600エルステツド、面内方向で500エルステツドで
あつた。
上記の如くに得られる磁気記録媒体は、磁性層
１０の磁化容易軸をその面内方向に対しほぼ垂直
にすることができると共に、磁性層１０下に高透
磁率材料層の軟磁性層１１を設け、かつこの上に
磁性層１０との間に非磁性層１２を設けているこ
とが重要である。
第４図は、非磁性層１２（Al又はポリイミド）
を設けた本発明による磁気記録媒体と非磁性層の
ない磁気記録媒体とについての垂直磁化率（試料
振動型磁力計で測定）と磁性層（Fe3O4）の
（111）面回折反射強度（CuK〓の管球使用）とを
比較して示すものである。これによれば、非磁性
層を設ける場合、明らかに垂直磁化特性がよく、
磁性層の垂直配向度が向上していることが分る。
また、第４図において実線で示す垂直磁化特性
は第１図の構成（軟磁性層１１上に非磁性層１２
を形成したもの）のデータであり、軟磁性層１１
の結晶状態の影響が非磁性層１２によつて効果的
に遮断されていることが分る。一方、第５図の如
くに、非磁性層１２上に軟磁性層１１を設け、こ
の上に磁性層１０を設けても、第４図に一点鎖線
で示す如くに垂直磁化特性が向上することが確認
された。これは、軟磁性層１１が結晶性のよい非
磁性層１２上に形成されるために結晶状態が良く
なり、これに伴なつて軟磁性層１１上には配向性
良く磁性層１０が成長するからである。
また、第５図の如き層構成の媒体において、非
磁性層１２に真空蒸着法で厚さ0.2μmに形成した
Ｃ層を、軟磁性層１１にスパツタ法で厚さ0.5μm
に形成したFe−Ｂアモルフアス合金層を使用し
たものを７種類作成した。そして、上記のＣ層１
２を設けない比較例によるサンプルも７種類作成
したところ、第６図に示すようなデータが得られ
た。この結果から明らかなように、Ｃ層１２を設
けない場合には垂直磁化特性のばらつきがサンプ
ル間で大きいのに対し、本実施例によればサンプ
ル間の特性のばらつきが少なくなり、垂直磁化率
も大きくなることが分る。
なお、第５図において、軟磁性層１１は結晶で
あつても或いは非晶質であつてもその形成時の膜
面の温度分布は重要な条件であると推定される。
再現性のある均一な特性を得るためには、軟磁性
層１１の形成時に温度分布を均一にすることが必
要であり、このために非磁性層１２として熱伝導
率が大きいものに適している。従つて、非磁性層
としては熱伝導率の大きい物質、例えばAlをは
じめとする非磁性金属が望ましいと考えられる。
次に、第１図の軟磁性層１１及び非磁性層１２
について各厚さを変化させたところ、次の結果が
得られた。この結果から、各層の厚さが本発明の
範囲外になると特性が著しく低下することが分
る。[Table] Before forming a film using the sputtering method described above, the surface of the substrate may be cleaned by bombarding it with Ar + in the same sputtering device, baking, or surface treatment using high frequency. It is desirable to keep it. In order to compare with the experiment described above, the target material was pure iron (without Co) under the above production conditions.
The MV/MH of the obtained magnetic thin film was less than 0.5, and the coercive force was in the vertical direction.
It was 600 oersted and 500 oersted in the in-plane direction. The magnetic recording medium obtained as described above can make the axis of easy magnetization of the magnetic layer 10 almost perpendicular to its in-plane direction, and has a soft magnetic layer 11 made of a high magnetic permeability material layer under the magnetic layer 10. It is important to provide a non-magnetic layer 12 between the magnetic layer 10 and the magnetic layer 10. FIG. 4 shows the non-magnetic layer 12 (Al or polyimide)
Perpendicular magnetic susceptibility (measured with a sample vibrating magnetometer) and (111) plane diffraction reflection intensity of the magnetic layer (Fe 3 O 4 ) for the magnetic recording medium according to the present invention provided with a magnetic recording medium and a magnetic recording medium without a nonmagnetic layer. (CuK〓 tube used) is shown in comparison. According to this, when a nonmagnetic layer is provided, the perpendicular magnetization characteristics are clearly good;
It can be seen that the degree of vertical orientation of the magnetic layer is improved. In addition, the perpendicular magnetization characteristics shown by the solid line in FIG. 4 correspond to the structure shown in FIG.
This is the data for the soft magnetic layer 11
It can be seen that the influence of the crystal state is effectively blocked by the nonmagnetic layer 12. On the other hand, even if the soft magnetic layer 11 is provided on the non-magnetic layer 12 and the magnetic layer 10 is provided on top of the soft magnetic layer 11 as shown in FIG. 5, the perpendicular magnetization characteristics can be improved as shown by the dashed line in FIG. was confirmed. This is because the soft magnetic layer 11 is formed on the non-magnetic layer 12 with good crystallinity, so the crystal state is improved, and along with this, the magnetic layer 10 grows on the soft magnetic layer 11 with good orientation. It is from. In addition, in a medium having a layer structure as shown in FIG. 5, a C layer is formed on the nonmagnetic layer 12 to a thickness of 0.2 μm using a vacuum evaporation method, and a C layer is formed on the soft magnetic layer 11 to a thickness of 0.5 μm using a sputtering method.
Seven types were created using the Fe-B amorphous alloy layer formed in . And the above C layer 1
Seven types of samples were also prepared according to comparative examples in which No. 2 was not provided, and data as shown in FIG. 6 were obtained. As is clear from this result, when the C layer 12 is not provided, the variation in perpendicular magnetic properties is large between samples, whereas according to this example, the variation in properties between samples is reduced, and the perpendicular magnetic susceptibility is It turns out that it also gets bigger. In FIG. 5, whether the soft magnetic layer 11 is crystalline or amorphous, it is presumed that the temperature distribution on the film surface at the time of its formation is an important condition.
In order to obtain reproducible and uniform characteristics, it is necessary to make the temperature distribution uniform when forming the soft magnetic layer 11, and for this reason, a material with high thermal conductivity is suitable as the nonmagnetic layer 12. . Therefore, it is considered desirable for the nonmagnetic layer to be made of a material with high thermal conductivity, such as a nonmagnetic metal such as Al. Next, the soft magnetic layer 11 and the nonmagnetic layer 12 in FIG.
The following results were obtained by varying the thickness of the material. This result shows that the characteristics deteriorate significantly when the thickness of each layer falls outside the range of the present invention.
【表】
第７図ａは、磁気記録時の状態を示すものであ
つて、図中の２２は補助磁極であつて記録信号に
より励磁され、そこから媒体側へ磁界１３が発生
している。軟磁性層１１中では、面内方向に主磁
極１４へ向けてフラツクス１５が集中し、磁性層
１０に主磁極１４に対応した磁気記録が高感度に
行なえる。また、第７図ｂは磁気記録後の残留磁
化状態を示すが、軟磁性層１１の存在により、磁
性層１０の記録部分１６と１７との間で軟磁性層
１１中をフラツクス１８が流れ、この磁気還流効
果（馬蹄形磁化モード）で磁化を保持し、その減
磁作用を少なくすることができる。このために、
垂直方向の磁気記録に基づく再生出力を安定にか
つ高レベルで得ることができる。
第８図は、軟磁性層１１上に磁性層１０を直接
設けた磁気記録媒体の再生出力の経時変化を曲線
ａで表わし、かつ上記軟磁性層を設けずに基体上
に磁化膜を直接設けた磁気記録媒体の再生出力の
経時変化を曲線ｂで示し、更に軟磁性層１１上の
非磁性層１２上に磁性層１０を設けた本発明によ
る磁気記録媒体の再生出力の経時変化が曲線ｃで
示した実験データである。この結果から明らかな
ように、曲線ａによる媒体では再生出力が大きく
て経時変化が小さく、これが更に本発明では向上
しているのに対し、軟磁性層を設けない場合には
特性が低下することが分る。但、この強制劣化試
験は、記録密度30キロビツト／インチの媒体（磁
性層の膜厚は5000Å）に対して80℃、85％RHの
条件で出力測定することによつて行なつた。媒体
の記録／再生は、実効ギヤツプ0.4μm、トラツク
幅100μmのリング型ヘツドを用いて行なつた。
次に、本発明による磁気記録媒体は、磁性層と
して酸化鉄を主成分とするものを用いているの
で、従来のCo−Cr系磁性層に比べて化学的、機
械的安定性等に著しく優れている。第９図は、上
記と同様の強制劣化試験を行なつた場合に得られ
た、酸化鉄系磁性層を用いた本発明による媒体
の、試料振動型磁力計（東英工業社製）で測定し
た残留磁束密度Brの経時変化ｃと、Co−Cr系磁
性層を用いた媒体の残留磁束密度Brの経時変化
ｄとを示すものである（ΔBrは残留磁束密度の変
化量）。これによれば、酸化鉄系磁性層では、Co
−Cr系磁性層よりBrの劣化が大副に小さくなる
ことが分る。なお、酸化鉄系磁性層でΔBr／Br
が幾分低下しているのは、膜の組成であるFe3O4
の一部がγ−Fe2O3に移行したからであると考え
られる。また、１カ月（30日）後の観察結果にお
いて、Co−Cr系磁性層の表面に斑点、くもり、
サビ等が生じていたが、酸化鉄系磁性層では表面
状態に変化はみられなかつた。[Table] FIG. 7a shows the state during magnetic recording, and 22 in the figure is an auxiliary magnetic pole, which is excited by a recording signal, and a magnetic field 13 is generated from there toward the medium side. In the soft magnetic layer 11, the flux 15 is concentrated in the in-plane direction toward the main magnetic pole 14, and magnetic recording corresponding to the main magnetic pole 14 can be performed in the magnetic layer 10 with high sensitivity. Further, FIG. 7b shows the state of residual magnetization after magnetic recording, and due to the existence of the soft magnetic layer 11, a flux 18 flows through the soft magnetic layer 11 between the recording portions 16 and 17 of the magnetic layer 10. This magnetic reflux effect (horseshoe magnetization mode) can maintain magnetization and reduce its demagnetization effect. For this,
It is possible to stably obtain high-level reproduction output based on vertical magnetic recording. FIG. 8 shows a curve a representing the change over time in the reproduction output of a magnetic recording medium in which the magnetic layer 10 is directly provided on the soft magnetic layer 11, and in which a magnetized film is provided directly on the substrate without providing the soft magnetic layer. Curve b shows the change over time in the reproduction output of the magnetic recording medium according to the present invention, and curve c shows the change over time in the reproduction output of the magnetic recording medium according to the present invention in which the magnetic layer 10 is provided on the nonmagnetic layer 12 on the soft magnetic layer 11. This is the experimental data shown in . As is clear from this result, the reproduction output of the medium according to curve a is large and the change over time is small, and this is further improved in the present invention, whereas when the soft magnetic layer is not provided, the characteristics deteriorate. I understand. However, this forced deterioration test was conducted by measuring the output on a medium with a recording density of 30 kilobits/inch (the thickness of the magnetic layer was 5000 Å) under conditions of 80° C. and 85% RH. Recording/reproduction of the medium was performed using a ring-type head with an effective gap of 0.4 μm and a track width of 100 μm. Next, since the magnetic recording medium according to the present invention uses a magnetic layer containing iron oxide as the main component, it has significantly superior chemical and mechanical stability compared to conventional Co-Cr magnetic layers. ing. Figure 9 shows measurements of a medium according to the present invention using an iron oxide magnetic layer obtained when a forced deterioration test similar to the above was conducted using a sample vibrating magnetometer (manufactured by Toei Kogyo Co., Ltd.). Fig. 3 shows the change over time c in the residual magnetic flux density Br and the change d over time in the residual magnetic flux density Br of the medium using the Co--Cr magnetic layer (ΔBr is the amount of change in the residual magnetic flux density). According to this, in the iron oxide magnetic layer, Co
-It can be seen that the deterioration of Br is significantly smaller than that of the Cr-based magnetic layer. Note that ΔBr/Br in the iron oxide magnetic layer
The reason for the slight decrease in Fe 3 O 4 is the film composition.
This is considered to be because a part of the γ-Fe 2 O 3 was transferred to γ-Fe 2 O 3 . In addition, the observation results after one month (30 days) showed that there were spots, cloudiness, and
Although rust etc. had occurred, no change was observed in the surface condition of the iron oxide magnetic layer.
図面は本発明を例示するものであつて、第１図
は磁気記録媒体の断面図、第２図は対向ターゲツ
トスパツタ装置の概略断面図、第３図は磁気記録
媒体のヒステリシス曲線図、第４図は磁気記録媒
体の磁性層の垂直配向度及び垂直磁化率を比較し
て示すグラフ、第５図は他の磁気記録媒体の断面
図、第６図は各媒体間での垂直磁化率の変化を示
すグラフ、第７図ａは磁気記録時の概略図、第７
図ｂは残留磁化状態の概略図、第８図は磁気記録
媒体の再生特性の経時変化を比較して示すグラ
フ、第９図は磁気記録媒体の残留磁束密度の経時
変化を比較して示すグラフである。
なお、図面に示された符号において、１……真
空槽、２……排気系、３……ガス導入系、４，５
……ホルダー、６……基体、１０……磁性層、１
１……軟磁性層、１２……非磁性層、１４……主
磁極、２２……補助磁極、T1，T2……ターゲツ
トである。
The drawings illustrate the present invention; FIG. 1 is a sectional view of a magnetic recording medium, FIG. 2 is a schematic sectional view of a facing target sputtering device, FIG. 3 is a hysteresis curve diagram of the magnetic recording medium, and FIG. Figure 4 is a graph comparing the perpendicular orientation degree and perpendicular magnetic susceptibility of the magnetic layers of magnetic recording media, Figure 5 is a cross-sectional view of other magnetic recording media, and Figure 6 is a graph showing the perpendicular magnetic susceptibility between each medium. Graph showing changes, Figure 7a is a schematic diagram during magnetic recording, Figure 7
Figure b is a schematic diagram of the state of residual magnetization, Figure 8 is a graph comparing and showing changes over time in the reproduction characteristics of magnetic recording media, and Figure 9 is a graph comparing and showing changes over time in the residual magnetic flux density of magnetic recording media. It is. In addition, in the symbols shown in the drawings, 1...vacuum chamber, 2...exhaust system, 3...gas introduction system, 4, 5
...Holder, 6...Base, 10...Magnetic layer, 1
1...soft magnetic layer, 12...nonmagnetic layer, 14...main magnetic pole, 22...auxiliary magnetic pole, T1 , T2 ...target.
Claims (1)
Å〜5μmの非磁性層と磁性層との積層構造を有
し、これらの各層のうち前記磁性層が最上層とし
て設けられ、かつ前記磁性層が、 (a) アルミニウム、コバルト、コバルト−マンガ
ン、亜鉛、コバルト−亜鉛、リチウム、クロ
ム、チタン、リチウム−クロム、マグネシウ
ム、マグネシウム−ニツケル、マンガン−亜
鉛、ニツケル、ニツケル−アルミニウム、ニツ
ケル−亜鉛、銅、銅−マンガン、銅−亜鉛及び
バナジウムからなる群より選ばれた添加物質を
含む鉄をターゲツト材として用いた対向ターゲ
ツトスパツタ法により、形成されたものであ
り、 (b) 内面方向での残留磁化（MH）と、その面に
対し垂直方向での残留磁化（MV）との比
（MV／MH）が0.5以上であり、 (c) 前記添加物質を含み、Fe3O4、γ−Fe2O3又
はこれらの中間組成の酸化鉄を主成分とする 連続磁性薄膜からなつている磁気記録媒体。[Claims] 1. A high magnetic permeability material layer with a thickness of 0.05 to 5 μm and a thickness of 100 μm.
It has a laminated structure of a non-magnetic layer and a magnetic layer with a thickness of Å to 5 μm, the magnetic layer is provided as the uppermost layer among these layers, and the magnetic layer is made of (a) aluminum, cobalt, cobalt-manganese, The group consisting of zinc, cobalt-zinc, lithium, chromium, titanium, lithium-chromium, magnesium, magnesium-nickel, manganese-zinc, nickel, nickel-aluminum, nickel-zinc, copper, copper-manganese, copper-zinc and vanadium. It was formed by the facing target sputtering method using iron containing selected additives as the target material, and (b) residual magnetization (MH) in the inner direction and perpendicular to the surface. The ratio ( MV/ MH ) to the residual magnetization (MV ) of A magnetic recording medium consisting of a continuous magnetic thin film as a component.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58031932A JPS59157828A (en) | 1983-02-28 | 1983-02-28 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58031932A JPS59157828A (en) | 1983-02-28 | 1983-02-28 | Magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59157828A JPS59157828A (en) | 1984-09-07 |
| JPH0315245B2 true JPH0315245B2 (en) | 1991-02-28 |
Family
ID=12344740
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58031932A Granted JPS59157828A (en) | 1983-02-28 | 1983-02-28 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59157828A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003203324A (en) * | 2001-10-24 | 2003-07-18 | Toda Kogyo Corp | Perpendicular magnetic recording medium |
| SG108872A1 (en) * | 2001-10-24 | 2005-02-28 | Toda Kogyo Corp | Perpendicular magnetic recording medium |
| US7736767B2 (en) | 2007-03-02 | 2010-06-15 | Hitachi Global Storage Technologies Netherlands, B.V. | Perpendicular magnetic recording medium having an interlayer formed from a NiWCr alloy |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52134706A (en) * | 1976-05-06 | 1977-11-11 | Univ Tohoku | Vertical magnetic recorder reproducer and system therefor |
| JPS5434205A (en) * | 1977-08-22 | 1979-03-13 | Canon Inc | Magnetic recording medium |
| JPS5451810A (en) * | 1977-09-30 | 1979-04-24 | Shiyunichi Iwasaki | Magnetic recording regenerative apparatus |
| JPS57158380A (en) * | 1981-03-26 | 1982-09-30 | Teijin Ltd | Counter target type sputtering device |
-
1983
- 1983-02-28 JP JP58031932A patent/JPS59157828A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52134706A (en) * | 1976-05-06 | 1977-11-11 | Univ Tohoku | Vertical magnetic recorder reproducer and system therefor |
| JPS5434205A (en) * | 1977-08-22 | 1979-03-13 | Canon Inc | Magnetic recording medium |
| JPS5451810A (en) * | 1977-09-30 | 1979-04-24 | Shiyunichi Iwasaki | Magnetic recording regenerative apparatus |
| JPS57158380A (en) * | 1981-03-26 | 1982-09-30 | Teijin Ltd | Counter target type sputtering device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59157828A (en) | 1984-09-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3809418B2 (en) | Magnetic recording medium and magnetic recording apparatus | |
| US4743491A (en) | Perpendicular magnetic recording medium and fabrication method therefor | |
| CA1315612C (en) | Perpendicular magnetic storage medium | |
| JPS63119209A (en) | Soft magnetic thin-film | |
| US4609593A (en) | Magnetic recording medium | |
| JP2508489B2 (en) | Soft magnetic thin film | |
| JPH0315245B2 (en) | ||
| US5244751A (en) | Perpendicular magnetic recording medium, its fabrication method and read-write machine using it | |
| JP3663289B2 (en) | Magnetic recording medium and magnetic storage device | |
| JPH0512765B2 (en) | ||
| JPH0315246B2 (en) | ||
| JPS59157827A (en) | Magnetic recording medium | |
| JPS59157830A (en) | Magnetic recording medium | |
| JPH0315244B2 (en) | ||
| EP0169928A1 (en) | Magnetic recording medium | |
| JPH0573877A (en) | Magnetic recording medium | |
| JPH0311531B2 (en) | ||
| JPS59157833A (en) | Magnetic recording medium | |
| JPH0316690B2 (en) | ||
| JPH01175707A (en) | Laminated soft thin magnetic film | |
| JPS59148120A (en) | Magnetic recording medium | |
| JPH0315248B2 (en) | ||
| JPS59148318A (en) | Formation of magnetic layer | |
| JPH0823929B2 (en) | Perpendicular magnetic recording media | |
| NAKAGAWA et al. | Fabrication and Recording Characteristics of Sputter-Deposited Ba-Ferrite Thin Films Deposited on Pt-Ta Underlayers for Perpendicular Magnetic Recording Media |