JP2003217108A - Magnetic material for magnetic recording medium - Google Patents
Magnetic material for magnetic recording mediumInfo
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- JP2003217108A JP2003217108A JP2002012413A JP2002012413A JP2003217108A JP 2003217108 A JP2003217108 A JP 2003217108A JP 2002012413 A JP2002012413 A JP 2002012413A JP 2002012413 A JP2002012413 A JP 2002012413A JP 2003217108 A JP2003217108 A JP 2003217108A
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- magnetic
- nanoparticles
- recording medium
- fept
- alloy
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は，高密度記録に適し
た磁気記録媒体用磁性材料に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic material for a magnetic recording medium suitable for high density recording.
【０００２】[0002]
【従来の技術】オーディオ用，ビデオ用，コンピュータ
用などの磁気テープや磁気ディスク等の磁気記録媒体
は，記録容量の高密度化による小型化，高性能化が一段
と進み，それに伴って磁気記録媒体用の磁性粉も微粒子
化が進んでいる。2. Description of the Related Art Magnetic recording media such as magnetic tapes and magnetic disks for audio, video and computer use have been further miniaturized and improved in performance due to higher recording capacity. The magnetic powder for use is also becoming finer.
【０００３】記録密度の上昇のためには記録単位のサイ
ズ低下が必要であるが，従来型の磁性粉を用いた媒体で
は高記録密度化の限界に近づいている。このようなこと
から，近年では，高密度磁気記録媒体として，高い結晶
磁気異方性を有し且つ大きな保磁力を示す磁性金属ナノ
粒子が注目されている。To increase the recording density, it is necessary to reduce the size of the recording unit, but in the medium using the conventional magnetic powder, the limit of high recording density is approaching. Therefore, in recent years, magnetic metal nanoparticles having high crystal magnetic anisotropy and large coercive force have been attracting attention as a high-density magnetic recording medium.
【０００４】遷移金属と白金族金属の一部の合金は高温
熱処理による規則格子化により高い磁気異方性を発現す
ることが知られており，特にＦｅＰｔ規則合金はＫu ＝
７×107erg/ccと大きな結晶磁気異方性エネルギーを有
し，熱揺らぎの問題を解決する有力な磁性材料として注
目を集めている。ＦｅＰｔナノ粒子の合成に関する技術
として，例えば以下のものが報告された。It is known that some alloys of transition metals and platinum group metals exhibit high magnetic anisotropy due to ordered lattice formation by high temperature heat treatment, and in particular FePt ordered alloys have Ku =
It has a large crystal magnetic anisotropy energy of 7 × 10 7 erg / cc and is attracting attention as a powerful magnetic material that solves the problem of thermal fluctuation. The following techniques, for example, have been reported as techniques for synthesizing FePt nanoparticles.
【０００５】（１）ショウヘン・スンらにより，化学的
手法を用いたＦｅＰｔナノ粒子の合成法がScience, 200
0, Vol.287, p.1989に報告された。この方法によると，
非親水性溶媒であるジオクチルエーテル中において, Pt
(acac)2をアルコールにより還元し，Fe(CO)5を熱分解す
ることにより，ＦｅＰｔナノ粒子が合成される。作製さ
れたＦｅＰｔナノ粒子は組成制御が可能で，そのサイズ
も３〜１０ｎｍの間で制御できるとされている。(1) Shouhen Seung et al. Have described a method of synthesizing FePt nanoparticles using a chemical method, Science, 200
0, Vol.287, p.1989. According to this method,
In dioctyl ether, a non-hydrophilic solvent, Pt
FePt nanoparticles are synthesized by reducing (acac) 2 with alcohol and thermally decomposing Fe (CO) 5 . It is said that the composition of the produced FePt nanoparticles can be controlled, and the size thereof can be controlled within the range of 3 to 10 nm.
【０００６】（２）城後らは，２００１年度第２５回応
用磁気学会学術講演会において，逆ミセル法を用いたＦ
ｅＰｔナノ粒子の合成法を発表した（該講演概要集200
1, 26aC-6, P.155)。この方法によると，非親水性溶媒
であるイソオクタンを溶媒に使用し，界面活性剤にビス
（2-エチルヘキシル）スルホコハク酸ナトリウムを使用
してミセル場を形成し，このミセル内の水溶液中におい
てＦｅおよびＰｔの塩化物をＮａＢＨ4により還元する
ことによりＦｅＰｔナノ粒子を合成している。この方法
では，反応場に逆ミセルを使用することにより分散性の
良いナノ粒子が得られる。(2) Jogo et al., At the 25th Annual Meeting of the Applied Magnetics Society of Japan, used the F method using the reverse micelle method.
Announced a method for synthesizing ePt nanoparticles.
1, 26aC-6, P.155). According to this method, a non-hydrophilic solvent, isooctane, is used as a solvent, and sodium bis (2-ethylhexyl) sulfosuccinate is used as a surfactant to form a micellar field. FePt nanoparticles are synthesized by reducing Pt chloride with NaBH 4 . In this method, nanoparticles with good dispersibility can be obtained by using reverse micelles in the reaction field.
【０００７】（３）黒部らは，同じく２００１年度第２
５回応用磁気学会学術講演会において，アルコール還元
法によるＦｅＰｔナノ粒子の合成法を発表した（該講演
概要集2001, 26aC-5, P.154)。この方法によると，Ｆｅ
供給源にFe(acac)3を，Ｐｔ供給源にPt(acac)2を使用
し，粒子表面を保護する保護高分子としてポリ（N-ビニ
ル-2-ピロリドン）を使用し，溶媒と還元剤の作用を併
せ持つエチレングリコールによるアルコール還元法によ
りＦｅＰｔナノ粒子を合成している。(3) Kurobe et al.
At the 5th Annual Meeting of the Magnetic Society of Japan, we presented a method for synthesizing FePt nanoparticles by the alcohol reduction method (Summary of the lecture 2001, 26aC-5, P.154). According to this method, Fe
Fe (acac) 3 is used as a source, Pt (acac) 2 is used as a Pt source, poly (N-vinyl-2-pyrrolidone) is used as a protective polymer for protecting the particle surface, and a solvent and a reducing agent are used. FePt nanoparticles are synthesized by an alcohol reduction method using ethylene glycol, which also has the above-mentioned action.
【０００８】このようにして得られるナノ粒子（ＦｅＰ
ｔ）を基盤上に自己配列させた記録媒体では，Ｔbit/in
2オーダーまで記録密度を上げられるポテンシャルを有
することが知られている (前掲のScience, 2000, Vol.2
87, p.1989，およびJournalof the Magnetics Society
of Japan, 2001, V.25, No.8, p.1434)。The nanoparticles thus obtained (FeP
In the recording medium in which t) is self-aligned on the substrate, Tbit / in
It is known to have the potential to increase the recording density up to 2 orders (Science, 2000, Vol. 2 above).
87, p.1989, and Journal of the Magnetics Society
of Japan, 2001, V.25, No.8, p.1434).
【０００９】[0009]
【発明が解決しようとする課題】前記のようなナノ粒子
からなる強磁性合金で記録媒体を作成する場合には，ナ
ノ粒子を規則格子化させるための熱処理が必要である。
そのさい，規則格子化を基盤上で行う場合には，その熱
処理温度に耐える基盤が必要となる。従来のハードディ
スクの基盤は主にガラス基盤やＡｌ基盤が用いられてい
るが，これらを用いたのでは，該熱処理温度で変形する
おそれがある。When a recording medium is made of a ferromagnetic alloy composed of nanoparticles as described above, it is necessary to perform heat treatment for forming nanoparticles into a regular lattice.
At that time, when the ordered lattice is formed on the substrate, a substrate that can withstand the heat treatment temperature is required. A conventional hard disk base is mainly a glass base or an Al base, but if these are used, there is a risk of deformation at the heat treatment temperature.
【００１０】他方，基盤を用いずに熱処理すると，すな
わち，基盤上に塗布することなく分離・乾燥した粒子の
状態で熱処理する場合には，前述の基盤変形の問題はな
いものの，粒子同士の焼結（ランダムに粒子が融着し合
う現象）が起こり，ナノスケールサイズが保持できなく
なって，高密度記録媒体用の磁性粉としては不適当なも
のになりかねない。On the other hand, when the heat treatment is performed without using the base, that is, when the heat treatment is performed in the state of separated and dried particles without coating on the base, there is no problem of the base deformation described above, but the particles are burned together. Cohesion (a phenomenon in which particles are fused at random) occurs, making it impossible to maintain the nanoscale size, which may result in unsuitable magnetic powder for high-density recording media.
【００１１】したがって，本発明の課題は，このような
ナノ粒子を粉状のままで熱処理しても粒子同士の焼結が
起きがたいものに変性することにある。[0011] Therefore, an object of the present invention is to modify such nanoparticles into particles which are hard to sinter even if they are heat-treated in a powder state.
【００１２】[0012]
【課題を解決するための手段】本発明によれば，成分組
成がＦxＭ100-xで表される合金に，元素Ａが，Ａ／（Ｆ
＋Ｍ）の原子百分率で１〜２００（at.%）の範囲で含ま
れている磁気記録媒体用磁性材料を提供する。ただし，
ＦはＦｅまたはＣｏの１種または２種の遷移金属，Ｍは
ＰｔまたはＰｄの１種または２種の白金族金属，３０≦
ｘ≦７０であり，元素ＡはＳｉ，ＡｌおよびＲ（ＲはＹ
を含む希土類元素の１種または２種以上を表す）からな
る群から選ばれた少なくとも１種の元素を表す。この磁
性材料は平均粒子径が１〜１００ｎｍの範囲にあり，そ
の粒子のコア部がＦxＭ100-xの合金（ただし３０≦ｘ≦
７０）からなり，この合金粒子の表面部に元素Ａが偏在
している粒子であるのが好ましい。According to the present invention, the element A is added to the alloy represented by F x M 100-x by adding A / (F
A magnetic material for a magnetic recording medium is contained in the range of 1 to 200 (at.%) In terms of atomic percentage of (+ M). However,
F is one or two transition metals of Fe or Co, M is one or two platinum group metals of Pt or Pd, 30 ≦
x ≦ 70, the element A is Si, Al and R (R is Y
It represents at least one element selected from the group consisting of one or two or more rare earth elements including. This magnetic material has an average particle size in the range of 1 to 100 nm, and the core portion of the particle is an alloy of F x M 100-x (where 30 ≦ x ≦
70) and the element A is unevenly distributed on the surface of the alloy particles.
【００１３】[0013]
【発明の実施の形態】成分組成がＦxＭ100-xで表される
合金のナノ粒子それ自身（ただし，ＦはＦｅまたはＣｏ
の１種以上，ＭはＰｔまたはＰｄの１種以上で，３０≦
ｘ≦７０）は，前述(1) 〜(3) の製法やその他の製法に
よって得ることができるが，このものをＣｕＡｕ型構造
の規則格子をもつ強磁性合金とするには前記のように熱
処理するのが好ましい。適正な熱処理温度は，ナノ粒子
の粒径，形状，成分組成等によって異なるが少なくとも
４５０℃以上を必要とする。そのさい，ＦxＭ100-x合金
ナノ粒子の表面部に適正な元素Ａが適量存在している
と，粒子同士が融着（焼結）する現象を抑制することが
でき，ナノスケールサイズを保持したまま規則格子化を
達成しやすくなる。BEST MODE FOR CARRYING OUT THE INVENTION The nanoparticles of the alloy represented by the composition F x M 100-x itself (where F is Fe or Co)
1 or more, M is one or more of Pt or Pd, and 30 ≦
x ≦ 70) can be obtained by the above-mentioned manufacturing methods (1) to (3) and other manufacturing methods. In order to make this into a ferromagnetic alloy having an ordered lattice of CuAu type structure, heat treatment is performed as described above. Preferably. The appropriate heat treatment temperature depends on the particle size, shape, composition of the nanoparticles, etc., but at least 450 ° C. or higher is required. At that time, if an appropriate amount of the element A is present on the surface of the F x M 100-x alloy nanoparticles, the phenomenon of fusion (sintering) between particles can be suppressed, and the nanoscale size can be reduced. It becomes easy to achieve regular lattice formation while keeping it.
【００１４】元素Ａとしては，Ｓｉ，ＡｌおよびＲ（Ｒ
はＹを含む希土類元素の１種または２種以上を表す）か
らなる群から選ばれた少なくとも１種であるのがよい。
Ｒのうちで，好ましいのはＹまたはＮｄである。As the element A, Si, Al and R (R
Is at least one selected from the group consisting of one or two or more rare earth elements including Y).
Of R, preferred is Y or Nd.
【００１５】本発明に従う磁性材料を得るには，まずＦ
xＭ100-x合金ナノ粒子を製造してから，このナノ粒子に
元素Ａを含有させる処理を施すのがよい。ＦxＭ100-x合
金ナノ粒子の製造には，非親水性溶媒中で有機金属を熱
分解・還元する方法（前記(1) の方法），非親水性溶媒
中で界面活性剤を用いてミセルを成形して還元する逆ミ
セル法（前記(2) の方法），親水性のアルコール溶媒中
で還元を行うアルコール還元法（前記(3) の方法），親
水性溶媒中でＦの塩化物，硫酸塩等とＭの塩化物とを溶
存させて還元剤で還元する方法（同一出願人に係る特願
２００１−４００２１６号に記載の方法），そのほかの
湿式還元法，気相法などあらゆる製法が適用できるが，
非親水性溶媒を用いてＦxＭ100-x合金ナノ粒子を製造し
た場合には，その合金ナノ粒子が生成している非親水性
溶媒に，元素Ａのアルコシド類，例えばテトラエチルオ
ルトシリケート，アルミニウムトリイソプロポキシドな
ど添加して，該合金ナノ粒子表面部に元素Ａを含有させ
るのがよい。他方，親水性溶媒を用いてＦxＭ100-x合金
ナノ粒子を製造した場合には，その合金ナノ粒子が生成
している親水性溶媒に，元素Ａの硫酸塩や，ケイ酸塩，
アルミン酸塩などの金属塩を添加して，該合金ナノ粒子
表面部に元素Ａを含有させるのがよい。To obtain the magnetic material according to the present invention, first, F
After producing the xM100 -x alloy nanoparticles, the nanoparticles may be subjected to a treatment for containing the element A. For the production of F x M 100-x alloy nanoparticles, a method of thermally decomposing / reducing an organic metal in a non-hydrophilic solvent (the method of (1) above) and a surfactant in a non-hydrophilic solvent are used. Reverse micelle method of forming and reducing micelles (method of (2) above), alcohol reduction method of reducing in hydrophilic alcohol solvent (method of (3) above), chloride of F in hydrophilic solvent , A method of dissolving a sulfate or the like and a chloride of M and reducing with a reducing agent (method described in Japanese Patent Application No. 2001-400216 of the same applicant), other wet reduction methods, vapor phase methods Is applicable,
When F x M 100-x alloy nanoparticles are produced using a non-hydrophilic solvent, the non-hydrophilic solvent in which the alloy nanoparticles are produced contains the alcosides of element A, such as tetraethylorthosilicate and aluminum. It is preferable that the element A is contained in the surface portion of the alloy nanoparticles by adding triisopropoxide or the like. On the other hand, when F x M 100-x alloy nanoparticles are produced by using a hydrophilic solvent, the hydrophilic solvent in which the alloy nanoparticles are produced contains the sulfate of element A, silicate,
It is preferable to add a metal salt such as an aluminate so that the surface of the alloy nanoparticles contains the element A.
【００１６】ＦxＭ100-x合金ナノ粒子に元素Ａを含有さ
せる量としては，Ａ／（Ｆ＋Ｍ）の原子百分率が１〜２
００（at.%），好ましくは１〜１５０（at.%），さらに
好ましくは１〜１００（at.%）となる量とするのがよ
い。この原子百分率が１未満では焼結を抑制する効果が
現れず，２００を超える場合には，ナノ粒子の分散性が
低下するようになる。As for the amount of the element A contained in the F x M 100-x alloy nanoparticles, the atomic percentage of A / (F + M) is 1 to 2
The amount is 00 (at.%), Preferably 1 to 150 (at.%), And more preferably 1 to 100 (at.%). If this atomic percentage is less than 1, the effect of suppressing sintering does not appear, and if it exceeds 200, the dispersibility of the nanoparticles decreases.
【００１７】[0017]
【実施例】〔実施例１〕４０ミリＬ（Ｌはリットルを表
す）のジオクチルエーテル中に１ミリモルのＰｔ(acac)
2を混合し，エチレングリコールを３ミリモル添加し
た。次いで，この混合液を１００℃で３０分間保持した
後，オレイン酸を１ミリモル，オレイルアミンを１ミリ
モルおよびＦｅ(ＣＯ)5を１.６ミリモル添加し，２５０
℃に昇温して３０分保持することにより，ＦｅＰｔ微粒
子を合成した。Example 1 1 mmol of Pt (acac) in 40 ml of dioctyl ether (L represents liter).
2 was mixed and 3 mmol of ethylene glycol was added. Then, this mixture was kept at 100 ° C. for 30 minutes, and then 1 mmol of oleic acid, 1 mmol of oleylamine and 1.6 mmol of Fe (CO) 5 were added, and
FePt fine particles were synthesized by raising the temperature to 0 ° C. and holding for 30 minutes.
【００１８】このＦｅＰｔ微粒子を含有したままの液を
ヘキサンで１０倍に希釈し，この希釈液に対し，アルミ
ニウムトリイソプロポシキドを２−プロパノールに溶解
した含アルミニウム溶液を，Ａｌ／（Ｆｅ＋Ｐｔ）の原
子百分率が４６.５at.%に相当する割合で添加し，３０
℃で６０分攪拌した。次いで，液から粒子を分離し，２
−プロパノールで洗浄し，窒素ガス中で乾燥して微粉を
得た。得られた微粉の平均粒径はほぼ４ｎｍであった。The solution containing the FePt fine particles was diluted 10 times with hexane, and an aluminum-containing solution in which aluminum triisopropoxide was dissolved in 2-propanol was added to the diluted solution to obtain Al / (Fe + Pt). The atomic percentage of 46.5at.
The mixture was stirred at 0 ° C for 60 minutes. Then separate the particles from the liquid, 2
-Washed with propanol and dried in nitrogen gas to obtain a fine powder. The average particle size of the obtained fine powder was about 4 nm.
【００１９】この微粉をＮ2雰囲気中で５５０℃に３０
分間保持する熱処理を施し，焼結が殆んど起きていない
平均粒径がほぼ４ｎｍのＦｅＰｔ強磁性粒子を得た。こ
の粒子の電子顕微鏡写真を図１に示した。また，このＦ
ｅＰｔ強磁性粒子から，保磁力（Ｈｃ）＝２９２７（Ｏ
e ），飽和磁化（σｓ）＝３０.９（emu/g ）の磁気特
性が得られた。This fine powder was heated to 550 ° C. in an N 2 atmosphere at 30 ° C.
A heat treatment of holding for a minute was performed to obtain FePt ferromagnetic particles having an average particle diameter of about 4 nm in which almost no sintering occurred. An electron micrograph of the particles is shown in FIG. Also, this F
From ePt ferromagnetic particles, coercive force (Hc) = 2927 (O
e) and saturation magnetization (σs) = 30.9 (emu / g) magnetic properties were obtained.
【００２０】〔実施例２〕４０ミリＬのジオクチルエー
テル中に１ミリモルのＰｔ(acac)2を混合し，エチレン
グリコールを３ミリモル添加した。次いで，この混合液
を１００℃で３０分間保持した後，オレイン酸を１ミリ
モル，オレイルアミンを１ミリモルおよびＦｅ(ＣＯ)5
を１.６ミリモル添加し，２５０℃に昇温して３０分保
持することにより，ＦｅＰｔ微粒子を合成した。Example 2 1 mmol of Pt (acac) 2 was mixed in 40 ml of dioctyl ether, and 3 mmol of ethylene glycol was added. Then, the mixture was kept at 100 ° C. for 30 minutes, and then 1 mmol of oleic acid, 1 mmol of oleylamine and Fe (CO) 5
Was added and the temperature was raised to 250 ° C. and kept for 30 minutes to synthesize FePt fine particles.
【００２１】このＦｅＰｔ微粒子を含有したままの液を
ヘキサンで１０倍に希釈し，この希釈液に対し，テトラ
エチルオルトシリケートをエタノールに溶解した含Ｓｉ
溶液を，Ｓｉ／（Ｆｅ＋Ｐｔ）の原子百分率が１００a
t.%に相当する割合で添加した。次いで，この混合液に
ナトリウムエチラートをｐＨ１２となるまで添加した
後，水蒸気を含む Airでバブリングしながら３０℃で１
８０分攪拌した。次いで，液から粒子を分離し，エタノ
ールで洗浄し，窒素ガス中で乾燥して微粉を得た。得ら
れた微粉の平均粒径はほぼ４ｎｍであった。The solution containing the FePt fine particles was diluted 10 times with hexane, and tetraethyl orthosilicate was dissolved in ethanol to this diluted solution.
The solution has a Si / (Fe + Pt) atomic percentage of 100a
It was added at a rate corresponding to t.%. Next, sodium ethylate was added to this mixed solution until the pH reached 12, and the mixture was stirred at 30 ° C for 1 hour while bubbling with Air containing steam.
Stir for 80 minutes. Then, the particles were separated from the liquid, washed with ethanol, and dried in nitrogen gas to obtain fine powder. The average particle size of the obtained fine powder was about 4 nm.
【００２２】この微粉をＮ2雰囲気中で５５０℃に３０
分間保持する熱処理を施し，焼結が殆んど起きていない
平均粒径がほぼ４ｎｍのＦｅＰｔ強磁性粒子を得た。こ
のＦｅＰｔ強磁性粒子から，保磁力（Ｈｃ）＝２５６６
（Ｏe ），飽和磁化（σｓ）＝２３.０（emu/g ）の磁
気特性が得られた。This fine powder was heated to 550 ° C. in an N 2 atmosphere at 30 ° C.
A heat treatment of holding for a minute was performed to obtain FePt ferromagnetic particles having an average particle diameter of about 4 nm in which almost no sintering occurred. From this FePt ferromagnetic particle, coercive force (Hc) = 2566
Magnetic properties of (Oe) and saturation magnetization (σs) = 23.0 (emu / g) were obtained.
【００２３】〔実施例３〕４０ミリＬのジオクチルエー
テル中に１ミリモルのＰｔ(acac)2を混合し，エチレン
グリコールを３ミリモル添加した。次いで，この混合液
を１００℃で３０分間保持した後，オレイン酸を１ミリ
モル，オレイルアミンを１ミリモルおよびＦｅ(ＣＯ)5
を１.６ミリモル添加し，２５０℃に昇温して３０分保
持することにより，ＦｅＰｔ微粒子を合成した。Example 3 1 mmol of Pt (acac) 2 was mixed in 40 ml of dioctyl ether, and 3 mmol of ethylene glycol was added. Then, the mixture was kept at 100 ° C. for 30 minutes, and then 1 mmol of oleic acid, 1 mmol of oleylamine and Fe (CO) 5
Was added and the temperature was raised to 250 ° C. and kept for 30 minutes to synthesize FePt fine particles.
【００２４】このＦｅＰｔ微粒子を含有したままの液を
ヘキサンで１０倍に希釈し，この希釈液に対し，イット
リウムイソプロポキシドをトルエンに溶解した含Ｙ溶液
を，Ｙ／（Ｆｅ＋Ｐｔ）の原子百分率が２０at.%に相当
する割合で添加し，３０℃で６０分攪拌した。次いで，
液から粒子を分離し，トルエンで洗浄し，窒素ガス中で
乾燥して微粉を得た。得られた微粉の平均粒径はほぼ４
ｎｍであった。The solution containing the FePt fine particles was diluted 10-fold with hexane, and a Y-containing solution in which yttrium isopropoxide was dissolved in toluene was added to the diluted solution to obtain a Y / (Fe + Pt) atomic percentage. The mixture was added at a rate corresponding to 20 at.% And stirred at 30 ° C for 60 minutes. Then,
The particles were separated from the liquid, washed with toluene, and dried in nitrogen gas to obtain fine powder. The average particle size of the obtained fine powder is about 4
was nm.
【００２５】この微粉をＮ2雰囲気中で５５０℃に３０
分間保持する熱処理を施し，焼結が殆んど起きていない
平均粒径がほぼ４ｎｍのＦｅＰｔ強磁性粒子を得た。こ
のＦｅＰｔ強磁性粒子から，保磁力（Ｈｃ）＝２７３２
（Ｏe ），飽和磁化（σｓ）＝２７.３（emu/g ）の磁
気特性が得られた。This fine powder was heated to 550 ° C. in an N 2 atmosphere at 30 ° C.
A heat treatment of holding for a minute was performed to obtain FePt ferromagnetic particles having an average particle diameter of about 4 nm in which almost no sintering occurred. From this FePt ferromagnetic particle, coercive force (Hc) = 2732
Magnetic properties of (Oe) and saturation magnetization (σs) = 27.3 (emu / g) were obtained.
【００２６】〔比較例〕４０ミリＬのジオクチルエーテ
ル中に１ミリモルのＰｔ(acac)2を混合し，エチレング
リコールを３ミリモル添加した。次いで，この混合液を
１００℃で３０分間保持した後，オレイン酸を１ミリモ
ル，オレイルアミンを１ミリモルおよびＦｅ(ＣＯ)5を
１.６ミリモル添加し，２５０℃に昇温して３０分保持
することにより，ＦｅＰｔ微粒子を合成した。Comparative Example 1 mmol of Pt (acac) 2 was mixed in 40 ml of dioctyl ether, and 3 mmol of ethylene glycol was added. Then, this mixture was kept at 100 ° C. for 30 minutes, then 1 mmol of oleic acid, 1 mmol of oleylamine and 1.6 mmol of Fe (CO) 5 were added, and the temperature was raised to 250 ° C. and kept for 30 minutes. As a result, FePt fine particles were synthesized.
【００２７】このＦｅＰｔ微粒子を含有する液にエタノ
ールを添加してＦｅＰｔ微粒子を凝集させたあと，遠心
分離によって液から粒子を分離し，窒素ガス中で乾燥し
て微粉を得た。得られた微粉の平均粒径はほぼ４ｎｍで
あった。Ethanol was added to the liquid containing the FePt fine particles to agglomerate the FePt fine particles, the particles were separated from the liquid by centrifugation, and dried in nitrogen gas to obtain fine powder. The average particle size of the obtained fine powder was about 4 nm.
【００２８】この微粉をＮ2雰囲気中で５５０℃に３０
分間保持する熱処理を施したところ，１０〜２５０ｎｍ
の大きさに焼結したＦｅＰｔ強磁性粒子を得た。このＦ
ｅＰｔ強磁性粒子から，保磁力（Ｈｃ）＝３４０９（Ｏ
e ），飽和磁化（σｓ）＝３６.５（emu/g ）の磁気特
性が得られた。This fine powder was heated to 550 ° C. in an N 2 atmosphere at 30 ° C.
When heat-treated for holding for 10 minutes, 10-250 nm
FePt ferromagnetic particles sintered to have the size of This F
From ePt ferromagnetic particles, coercive force (Hc) = 3409 (O
e) and saturation magnetization (σs) = 36.5 (emu / g) magnetic properties were obtained.
【００２９】[0029]
【発明の効果】以上説明したように，本発明によると，
ＦxＭ100-x合金ナノ粒子を規則格子化して強磁性材料と
する場合の熱処理において，ナノ粒子同士のランダムな
焼結の進行を抑制することができる。したがって，Ｆx
Ｍ100-x合金ナノ粒子を用いた磁気記録媒体用の強磁性
材料を歩留りよく製造することができる。As described above, according to the present invention,
It is possible to suppress the progress of random sintering between nanoparticles in the heat treatment when the F x M 100-x alloy nanoparticles are formed into a regular lattice to form a ferromagnetic material. Therefore, F x
A ferromagnetic material for a magnetic recording medium using M 100-x alloy nanoparticles can be manufactured with high yield.
【図１】本発明に従うＦｅＰｔ合金強磁性ナノ粒子の透
過電子顕微鏡写真である。FIG. 1 is a transmission electron micrograph of FePt alloy ferromagnetic nanoparticles according to the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 間舩 修一 東京都千代田区丸の内１丁目８番２号 同 和鉱業株式会社内 Ｆターム(参考） 5D006 BA01 BA08 DA03 EA01 5E040 AA01 AA03 CA06 HB15 NN01 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Shuichi Mafune 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Within Wa Mining Co., Ltd. F-term (reference) 5D006 BA01 BA08 DA03 EA01 5E040 AA01 AA03 CA06 HB15 NN01
Claims (3)
に，元素Ａが，Ａ／（Ｆ＋Ｍ）の原子百分率で１〜２０
０（at.%）の範囲で含まれている磁気記録媒体用磁性材
料。ただし，Ｆは，ＦｅまたはＣｏの１種または２種の
遷移金属，Ｍは，ＰｔまたはＰｄの１種または２種の白
金族金属， ３０≦ｘ≦７０， 元素Ａは，Ｓｉ，ＡｌおよびＲ（ＲはＹを含む希土類元
素の１種または２種以上を表す）からなる群から選ばれ
た少なくとも１種の元素，を表す。1. An alloy having a component composition of F x M 100-x , wherein the element A is 1 to 20 in atomic percentage of A / (F + M).
A magnetic material for a magnetic recording medium, which is included in the range of 0 (at.%). However, F is one or two kinds of transition metals of Fe or Co, M is one or two kinds of platinum group metals of Pt or Pd, 30 ≦ x ≦ 70, element A is Si, Al and R (R represents one or more rare earth elements including Y) and at least one element selected from the group consisting of
に元素Ａが偏在している請求項１に記載の磁気記録媒体
用磁性材料。2. The magnetic material for a magnetic recording medium according to claim 1, wherein the element A is unevenly distributed on the surface portion of the particles made of an alloy of F x M 100-x .
項２に記載の磁気記録媒体用磁性材料。3. The magnetic material for a magnetic recording medium according to claim 2, which has an average particle diameter of 1 to 100 nm.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008231577A (en) * | 2008-04-09 | 2008-10-02 | National Institute For Materials Science | TERNARY ALLOY OF FePtP |
| US7592042B1 (en) | 2005-12-19 | 2009-09-22 | Fujifilm Corporation | Reverse micelle method of producing core/shell particles |
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|---|---|---|---|---|
| CN108060391B (en) * | 2017-12-15 | 2019-12-27 | 桂林电子科技大学 | Method for accelerating phase transition of FePd thin film |
| CN110560704B (en) * | 2019-10-11 | 2021-10-22 | 东北大学 | Method for inductively synthesizing fct-FePt nano particles by doping low-melting-point elements |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7592042B1 (en) | 2005-12-19 | 2009-09-22 | Fujifilm Corporation | Reverse micelle method of producing core/shell particles |
| JP2008231577A (en) * | 2008-04-09 | 2008-10-02 | National Institute For Materials Science | TERNARY ALLOY OF FePtP |
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