JP5136751B2 - Method for producing FePt nanoparticles and method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles - Google Patents
Method for producing FePt nanoparticles and method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles Download PDFInfo
- Publication number
- JP5136751B2 JP5136751B2 JP2007200589A JP2007200589A JP5136751B2 JP 5136751 B2 JP5136751 B2 JP 5136751B2 JP 2007200589 A JP2007200589 A JP 2007200589A JP 2007200589 A JP2007200589 A JP 2007200589A JP 5136751 B2 JP5136751 B2 JP 5136751B2
- Authority
- JP
- Japan
- Prior art keywords
- fept
- nanoparticles
- functional group
- coating agent
- organic coating
- 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.)
- Active
Links
- 229910005335 FePt Inorganic materials 0.000 title claims description 249
- 239000002105 nanoparticle Substances 0.000 title claims description 184
- 239000002122 magnetic nanoparticle Substances 0.000 title claims description 65
- 238000004519 manufacturing process Methods 0.000 title claims description 42
- 239000011248 coating agent Substances 0.000 claims description 82
- 239000000758 substrate Substances 0.000 claims description 74
- 239000002245 particle Substances 0.000 claims description 68
- 125000000524 functional group Chemical group 0.000 claims description 65
- 239000002270 dispersing agent Substances 0.000 claims description 33
- 238000000137 annealing Methods 0.000 claims description 26
- 239000002904 solvent Substances 0.000 claims description 25
- 150000001875 compounds Chemical class 0.000 claims description 24
- 239000002184 metal Substances 0.000 claims description 24
- 229910052751 metal Inorganic materials 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 24
- 125000004429 atom Chemical group 0.000 claims description 18
- 125000004432 carbon atom Chemical group C* 0.000 claims description 14
- 239000007771 core particle Substances 0.000 claims description 13
- 239000003638 chemical reducing agent Substances 0.000 claims description 12
- 229910052742 iron Inorganic materials 0.000 claims description 12
- 230000007704 transition Effects 0.000 claims description 12
- 230000032683 aging Effects 0.000 claims description 11
- 229910052697 platinum Inorganic materials 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 8
- 238000006722 reduction reaction Methods 0.000 claims description 7
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 6
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 claims description 5
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 claims description 5
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 claims description 5
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 claims description 5
- 239000005642 Oleic acid Substances 0.000 claims description 5
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 claims description 5
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 claims description 5
- 229930195734 saturated hydrocarbon Natural products 0.000 claims description 5
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical class OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 claims description 4
- 150000002009 diols Chemical class 0.000 claims description 4
- 235000021122 unsaturated fatty acids Nutrition 0.000 claims description 4
- 150000004670 unsaturated fatty acids Chemical class 0.000 claims description 4
- 229930195735 unsaturated hydrocarbon Natural products 0.000 claims description 3
- 239000012044 organic layer Substances 0.000 claims description 2
- 239000002356 single layer Substances 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 49
- 239000010408 film Substances 0.000 description 21
- 239000010410 layer Substances 0.000 description 14
- 230000005389 magnetism Effects 0.000 description 13
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 12
- 238000004220 aggregation Methods 0.000 description 12
- 230000002776 aggregation Effects 0.000 description 12
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 12
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 239000006185 dispersion Substances 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 238000002441 X-ray diffraction Methods 0.000 description 5
- 239000012298 atmosphere Substances 0.000 description 5
- 238000005275 alloying Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 239000006249 magnetic particle Substances 0.000 description 4
- 230000005415 magnetization Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- CCCMONHAUSKTEQ-UHFFFAOYSA-N octadec-1-ene Chemical compound CCCCCCCCCCCCCCCCC=C CCCMONHAUSKTEQ-UHFFFAOYSA-N 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 229910001873 dinitrogen Inorganic materials 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 229940087654 iron carbonyl Drugs 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000004528 spin coating Methods 0.000 description 3
- 125000003396 thiol group Chemical group [H]S* 0.000 description 3
- POILWHVDKZOXJZ-ARJAWSKDSA-M (z)-4-oxopent-2-en-2-olate Chemical compound C\C([O-])=C\C(C)=O POILWHVDKZOXJZ-ARJAWSKDSA-M 0.000 description 2
- QGLWBTPVKHMVHM-KTKRTIGZSA-N (z)-octadec-9-en-1-amine Chemical compound CCCCCCCC\C=C/CCCCCCCCN QGLWBTPVKHMVHM-KTKRTIGZSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 125000003277 amino group Chemical group 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- MHDVGSVTJDSBDK-UHFFFAOYSA-N dibenzyl ether Chemical compound C=1C=CC=CC=1COCC1=CC=CC=C1 MHDVGSVTJDSBDK-UHFFFAOYSA-N 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000002003 electron diffraction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 239000000696 magnetic material Substances 0.000 description 2
- -1 methoxysilanyl group Chemical group 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- LQERIDTXQFOHKA-UHFFFAOYSA-N nonadecane Chemical compound CCCCCCCCCCCCCCCCCCC LQERIDTXQFOHKA-UHFFFAOYSA-N 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- NKJOXAZJBOMXID-UHFFFAOYSA-N 1,1'-Oxybisoctane Chemical compound CCCCCCCCOCCCCCCCC NKJOXAZJBOMXID-UHFFFAOYSA-N 0.000 description 1
- SRZXCOWFGPICGA-UHFFFAOYSA-N 1,6-Hexanedithiol Chemical group SCCCCCCS SRZXCOWFGPICGA-UHFFFAOYSA-N 0.000 description 1
- GJRCLMJHPWCJEI-UHFFFAOYSA-N 1,9-Nonanedithiol Chemical compound SCCCCCCCCCS GJRCLMJHPWCJEI-UHFFFAOYSA-N 0.000 description 1
- NQTSTBMCCAVWOS-UHFFFAOYSA-N 1-dimethoxyphosphoryl-3-phenoxypropan-2-one Chemical compound COP(=O)(OC)CC(=O)COC1=CC=CC=C1 NQTSTBMCCAVWOS-UHFFFAOYSA-N 0.000 description 1
- 241000238366 Cephalopoda Species 0.000 description 1
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- UWHCKJMYHZGTIT-UHFFFAOYSA-N Tetraethylene glycol, Natural products OCCOCCOCCOCCO UWHCKJMYHZGTIT-UHFFFAOYSA-N 0.000 description 1
- CUJRVFIICFDLGR-UHFFFAOYSA-N acetylacetonate Chemical compound CC(=O)[CH-]C(C)=O CUJRVFIICFDLGR-UHFFFAOYSA-N 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 125000004093 cyano group Chemical group *C#N 0.000 description 1
- UOQACRNTVQWTFF-UHFFFAOYSA-N decane-1,10-dithiol Chemical compound SCCCCCCCCCCS UOQACRNTVQWTFF-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- VZLNSPSVSKXECI-UHFFFAOYSA-N ethanol;iron Chemical compound [Fe].CCO.CCO VZLNSPSVSKXECI-UHFFFAOYSA-N 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- HHFAWKCIHAUFRX-UHFFFAOYSA-N ethoxide Chemical compound CC[O-] HHFAWKCIHAUFRX-UHFFFAOYSA-N 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 150000002334 glycols Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- LZKLAOYSENRNKR-LNTINUHCSA-N iron;(z)-4-oxoniumylidenepent-2-en-2-olate Chemical compound [Fe].C\C(O)=C\C(C)=O.C\C(O)=C\C(C)=O.C\C(O)=C\C(C)=O LZKLAOYSENRNKR-LNTINUHCSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000005070 ripening Effects 0.000 description 1
- 125000005372 silanol group Chemical group 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000000101 transmission high energy electron diffraction Methods 0.000 description 1
Description
本発明は、超高密度磁気記録システムの実現を可能とするＦｅＰｔナノ粒子及びＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体の製造方法に関する。 The present invention relates to a method of manufacturing a magnetic recording medium having FePt nanoparticles and an FePt magnetic nanoparticle array that can realize an ultra-high density magnetic recording system.
磁気記録による情報ストレージ分野は近年の高度情報化社会を支える基盤技術である。磁気記録密度の向上は大容量の情報処理や社会に散在する知の財産の利用を可能とするだけでなく、記録デバイスの小型化及び軽量化によるユピキタスコンピューティング、更には省電力、省材料の点から低環境負荷を促すことになる。現行のハードディスクドライブ（ＨＤＤ）の磁気記録媒体はスパッタリング法により作製された磁性薄膜が用いられている。更なる記録媒体の高記録密度化のためには、記録ビット面積の縮小化及び記録ビットの経時に対する記録安定性が求められる。ここで、記録ビット面積の縮小化とは、薄膜を構成する磁性粒子の微細化により実現される技術を示す。 The information storage field using magnetic recording is a fundamental technology that supports the advanced information society in recent years. Increasing magnetic recording density not only enables large-capacity information processing and the use of intellectual property scattered throughout society, but also makes it possible to reduce the size and weight of recording devices, as well as ubiquitous computing, power savings, and material savings. This will promote a low environmental load. The magnetic recording medium of the current hard disk drive (HDD) uses a magnetic thin film produced by a sputtering method. In order to further increase the recording density of the recording medium, a reduction in recording bit area and recording stability over time of the recording bit are required. Here, the reduction of the recording bit area indicates a technique realized by miniaturization of magnetic particles constituting the thin film.
磁性粒子の微細化に伴い、体積に比例する粒子内の磁化方向を保つＫuＶ（Ｋu：一軸結晶磁気異方性エネルギー、Ｖ：磁性粒子体積）は、熱エネルギーｋＢＴを下回るために記録情報の熱安定性がボトルネックになっている（熱擾乱）。熱擾乱を低減させる解決策の一つとして記録ビットの安定性に優れた高い結晶磁気異方性エネルギー（Ｋu）を備えた材料の磁気記録媒体材料への適用が求められている。 As the magnetic particles become finer, K u V (K u : uniaxial crystal magnetic anisotropy energy, V: magnetic particle volume), which maintains the magnetization direction in the particles in proportion to the volume, falls below the thermal energy kBT. The thermal stability of information is a bottleneck (thermal disturbance). As one of the solutions for reducing thermal disturbance, application of a material having high crystal magnetic anisotropy energy (K u ) excellent in recording bit stability to a magnetic recording medium material is required.
そこで、ＦｅＰｔ合金は、そのＬ１0（ｆｃｔ）−ＦｅＰｔ結晶（図１参照）が、熱化学的に安定で高い結晶磁気異方性エネルギー（Ｋu）を有することから、新規超高密度磁気記録システムの実現に向けたキーマテリアルとして注目されている。特にＳｕｎらが報告した化学的合成によって得られる大きさの数ナノメートルのＦｅＰｔナノ粒子は、予め規格化された構造体を基板上に配列させる方法を用いるため、現行の薄膜記録媒体の課題とされている磁性粒子間の磁気的な結合に対しての優位性があると言われている。 Therefore, since the L1 0 (fct) -FePt crystal (see FIG. 1) of the FePt alloy is thermochemically stable and has a high magnetocrystalline anisotropy energy (K u ), a novel ultrahigh density magnetic recording is possible. It is attracting attention as a key material for realizing the system. In particular, FePt nanoparticles having a size of several nanometers obtained by chemical synthesis reported by Sun et al. Use a method of arranging a standardized structure on a substrate. It is said that there is an advantage over the magnetic coupling between magnetic particles.
しかしながら、ナノ粒子の特性を最大に発揮させた磁気記録媒体を実現するためには、均一な形状、粒径及び磁気特性を有するＦｅＰｔナノ粒子の作製、更に、この粒子をその磁化容易軸の向きを垂直に揃えて基板上に並べる技術の確立が不可欠である。 However, in order to realize a magnetic recording medium that maximizes the properties of the nanoparticles, the preparation of FePt nanoparticles having a uniform shape, particle size, and magnetic properties, and the orientation of the easy magnetization axis of the particles. It is indispensable to establish a technology that aligns the substrates vertically on the substrate.
本発明は上記事情に鑑みなされたもので、均一な形状及び粒径を有し、均一な磁気特性を与えるＦｅＰｔナノ粒子を製造する方法、及びこの粒子をその磁化容易軸の向きを垂直に揃えて基板上に並べたＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体を製造する方法を提供することを目的とする。 The present invention has been made in view of the above circumstances, a method for producing FePt nanoparticles having a uniform shape and particle size and giving uniform magnetic properties, and the orientation of the easy axis of magnetization of these particles aligned vertically. Another object of the present invention is to provide a method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles arranged on a substrate.
本発明は、上記目的を達成するため、以下のＦｅＰｔナノ粒子の製造方法を提供する。
［１］ 平均粒子径が３〜２０ｎｍのＦｅＰｔナノ粒子を製造する方法であって、Ｐｔ化合物と還元剤と第１の粒子分散剤とを含む溶媒溶液から還元反応により金属Ｐｔ核粒子を生成させ、更に、上記溶媒溶液にＦｅ化合物及び第２の粒子分散剤を添加して、上記Ｐｔ核粒子上に金属Ｆｅを析出させることによりＦｅとＰｔとを含むナノ粒子を生成させ、次いで、１８５〜３２０℃の温度で熟成してＰｔ原子とＦｅ原子とを相互拡散させて合金化することを特徴とするＦｅＰｔナノ粒子の製造方法。
［２］ 上記ＦｅＰｔナノ粒子が面心直方（ｆｃｔ）構造及び／又は面心立方（ｆｃｃ）構造を含むことを特徴とする［１］記載のＦｅＰｔナノ粒子の製造方法。
［３］ 上記ＦｅＰｔナノ粒子が面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子であることを特徴とする［２］記載のＦｅＰｔナノ粒子の製造方法。
［４］ 上記ＦｅＰｔナノ粒子が面心立方（ｆｃｃ）構造を含み、熟成処理の後に、更に、ＦｅＰｔナノ粒子に４００℃以上でアニール処理を施すことにより、面心立方（ｆｃｃ）構造を面心直方（ｆｃｔ）構造に相転移させてＦｅＰｔ磁性ナノ粒子とすることを特徴とする［２］記載のＦｅＰｔナノ粒子の製造方法。
［５］ 上記ＦｅＰｔ磁性ナノ粒子の保磁力が３ｋＯｅ以上、角型比が０．５以上であることを特徴とする［３］又は［４］記載のＦｅＰｔナノ粒子の製造方法。
［６］ 上記ＦｅＰｔナノ粒子の平均粒子径が３〜１０ｎｍであることを特徴とする［１］乃至［５］のいずれかに記載のＦｅＰｔナノ粒子の製造方法。
［７］ 上記第１の粒子分散剤として炭素数３〜１７の直鎖不飽和脂肪酸又はＮ−２−ビニルピロリドンを用いることを特徴とする［１］乃至［６］のいずれかに記載のＦｅＰｔナノ粒子の製造方法。
［８］ 上記第１の粒子分散剤としてオレイン酸を用いることを特徴とする［１］乃至［６］のいずれかに記載のＦｅＰｔナノ粒子の製造方法。
［９］ 上記第２の粒子分散剤として炭素数１６〜１８の直鎖不飽和脂肪族アミンを用いることを特徴とする［１］乃至［８］のいずれかに記載のＦｅＰｔナノ粒子の製造方法。
［１０］ 上記還元剤として炭素数１６〜１８の不飽和炭化水素又は炭素数１６〜１８の飽和炭化水素ジオールを用いることを特徴とする［１］乃至［９］のいずれかに記載のＦｅＰｔナノ粒子の製造方法。
In order to achieve the above object, the present invention provides the following method for producing FePt nanoparticles.
[1] A method for producing FePt nanoparticles having an average particle diameter of 3 to 20 nm, wherein metal Pt core particles are generated by a reduction reaction from a solvent solution containing a Pt compound, a reducing agent, and a first particle dispersant. Further, an Fe compound and a second particle dispersant are added to the solvent solution to precipitate metal Fe on the Pt core particles, thereby generating nanoparticles containing Fe and Pt. A method for producing FePt nanoparticles, characterized by aging at a temperature of 320 ° C. and interdiffusing Pt atoms and Fe atoms to form an alloy.
[2] The method for producing FePt nanoparticles according to [1], wherein the FePt nanoparticles include a face-centered rectangular (fct) structure and / or a face-centered cubic (fcc) structure.
[ 3 ] The method for producing FePt nanoparticles according to [ 2 ], wherein the FePt nanoparticles are FePt magnetic nanoparticles including a face-centered rectangular (fct) structure.
[ 4 ] The FePt nanoparticle includes a face-centered cubic (fcc) structure, and after the aging treatment, the FePt nanoparticle is further annealed at 400 ° C. or higher to make the face-centered cubic (fcc) structure face-centered. [ 2 ] The method for producing FePt nanoparticles according to [ 2 ], wherein a phase transition to a rectangular (fct) structure is performed to form FePt magnetic nanoparticles.
[5] The method for producing FePt nanoparticles according to [3] or [4], wherein the FePt magnetic nanoparticles have a coercive force of 3 kOe or more and a squareness ratio of 0.5 or more.
[ 6 ] The method for producing FePt nanoparticles according to any one of [1] to [5], wherein the average particle diameter of the FePt nanoparticles is 3 to 10 nm.
[ 7 ] FePt according to any one of [1] to [ 6 ], wherein a linear unsaturated fatty acid having 3 to 17 carbon atoms or N-2-vinylpyrrolidone is used as the first particle dispersant. A method for producing nanoparticles.
[8] The method for producing FePt nanoparticles according to any one of [1] to [6], wherein oleic acid is used as the first particle dispersant.
[ 9 ] The method for producing FePt nanoparticles according to any one of [1] to [ 8 ], wherein a linear unsaturated aliphatic amine having 16 to 18 carbon atoms is used as the second particle dispersant. .
[10] The FePt nano of any one of [1] to [9], wherein an unsaturated hydrocarbon having 16 to 18 carbon atoms or a saturated hydrocarbon diol having 16 to 18 carbon atoms is used as the reducing agent. Particle production method.
本発明においては、まず、Ｐｔ化合物と還元剤と第１の粒子分散剤とを含む溶媒溶液から還元反応により金属Ｐｔ核粒子を生成させるが、まず、炭素数３〜１７の直鎖不飽和脂肪酸などの金属Ｐｔの凝集を抑制する第１の粒子分散剤を用いて、金属Ｐｔ核粒子を生成させて、微細な金属Ｐｔ核粒子を高分散状態とし、ここに、Ｆｅ化合物、及び炭素数３〜１７の直鎖不飽和脂肪族アミンなどの金属Ｆｅの凝集を抑制する第２の粒子分散剤を添加し、上記Ｐｔ核粒子上に金属Ｆｅを析出させることにより、ＦｅとＰｔとを含む小径で、かつ形状と粒子径が揃った均一なナノ粒子を得ることができる。 In the present invention, first, metal Pt core particles are generated by a reduction reaction from a solvent solution containing a Pt compound, a reducing agent, and a first particle dispersant. First, a linear unsaturated fatty acid having 3 to 17 carbon atoms. A metal Pt core particle is generated using a first particle dispersant that suppresses aggregation of metal Pt, such as a fine metal Pt core particle, and an Fe compound and a carbon number of 3 A small particle size containing Fe and Pt is obtained by adding a second particle dispersant that suppresses aggregation of metal Fe such as a linear unsaturated aliphatic amine of ˜17 and precipitating metal Fe on the Pt core particles. In addition, uniform nanoparticles having a uniform shape and particle diameter can be obtained.
そして、この粒子を１８５〜３２０℃の温度で、溶媒中で熟成（エイジング）することにより、ナノ粒子中でＰｔ原子とＦｅ原子とを相互拡散して合金化するが、この際も、金属Ｐｔの凝集を抑制する第１の粒子分散剤と、金属Ｆｅの凝集を抑制する第２の粒子分散剤と共存下で熟成させることにより、ナノ粒子同士の凝集が抑制され、形状と粒子径が揃った均一な粒子の状態を保持することができる。 Then, the particles are aged in a solvent at a temperature of 185 to 320 ° C. to cause mutual diffusion of Pt atoms and Fe atoms in the nanoparticles to form an alloy. Is aged in the presence of the first particle dispersant that suppresses the aggregation of the metal and the second particle dispersant that suppresses the aggregation of the metal Fe, so that the aggregation of the nanoparticles is suppressed and the shape and the particle diameter are uniform. And uniform particle state can be maintained.
特に、合金化によって得られた上記ＦｅＰｔナノ粒子は、面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子であることが好ましい。ＦｅＰｔナノ粒子が、面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子である場合、磁気異方性を有する強い磁性を与える面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子を、そのまま（即ち、磁性を有する面心直方（ｆｃｔ）構造への相転移のためのアニール処理を施すことなく）磁性体材料として用いることが可能である。 In particular, the FePt nanoparticles obtained by alloying are preferably FePt magnetic nanoparticles including a face-centered rectangular (fct) structure. When the FePt nanoparticles are FePt magnetic nanoparticles including a face-centered rectangular (fct) structure, the FePt magnetic nanoparticles including a face-centered rectangular (fct) structure that gives strong magnetism having magnetic anisotropy are directly (ie, It can be used as a magnetic material (without annealing for phase transition to a face-centered rectangular (fct) structure having magnetism).
一方、上記ＦｅＰｔナノ粒子が面心立方（ｆｃｃ）構造を含むものである場合、合金化後（熟成処理後）のＦｅＰｔナノ粒子に、更に、４００℃以上でアニール処理を施すことにより、面心立方（ｆｃｃ）構造を面心直方（ｆｃｔ）構造に相転移させてＦｅＰｔ磁性ナノ粒子とすることも可能である。ＦｅＰｔナノ粒子が面心立方（ｆｃｃ）構造を含むものである場合、これを強い磁性を与える面心直方（ｆｃｔ）構造に相転移させることが可能であり、ＦｅＰｔナノ粒子に４００℃以上でアニール処理を施すことにより、ＦｅＰｔナノ粒子をより強い磁性を有するＦｅＰｔ磁性ナノ粒子とすることが可能である。 On the other hand, when the FePt nanoparticles include a face-centered cubic (fcc) structure, the FePt nanoparticles after alloying (after aging treatment) are further subjected to annealing treatment at 400 ° C. or more to obtain face-centered cubic ( It is also possible to transform the (fcc) structure into a face-centered rectangular (fct) structure to form FePt magnetic nanoparticles. When the FePt nanoparticle includes a face-centered cubic (fcc) structure, it can be phase-shifted to a face-centered rectangular (fct) structure that gives strong magnetism, and the FePt nanoparticle is annealed at 400 ° C. or higher. By applying, the FePt nanoparticles can be made into FePt magnetic nanoparticles having stronger magnetism.
また、本発明は、基板上にＦｅＰｔ磁性ナノ粒子が配列した配列体を有する磁気記録媒体を製造する方法として、以下のＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体の製造方法を提供する。
［１１］ 基板上にＦｅＰｔ磁性ナノ粒子の配列体を有する磁気記録媒体を製造する方法であって、
［１］乃至［１０］のいずれかに記載の方法により得られたＦｅＰｔナノ粒子であり、面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子であるＦｅＰｔナノ粒子の表面に、分子鎖の一端側に上記ＦｅＰｔナノ粒子の表面と化学結合し得る第１の官能基、他端側に上記ＦｅＰｔナノ粒子の表面と化学結合しない第２の官能基を有する第１の有機コーティング剤を接触させ、上記第１の有機コーティング剤分子を上記第１の官能基を介して上記ＦｅＰｔナノ粒子の表面に化学結合させることにより、上記ＦｅＰｔナノ粒子の表面上に上記第１の有機コーティング剤分子の単分子膜を形成する工程、
上記基板の表面に、分子鎖の一端側に上記基板の表面と化学結合し得る第３の官能基、他端側に上記基板の表面と化学結合せず、上記第２の官能基と反応して結合を形成し得る第４の官能基を有する第２の有機コーティング剤を接触させ、上記第２の有機コーティング剤分子を上記第３の官能基を介して上記基板の表面に化学結合させることにより、上記基板の表面上に上記第２の有機コーティング剤の単分子膜を形成する工程、及び
上記第１の有機コーティング剤の単分子膜を備えるＦｅＰｔナノ粒子と、上記第２の有機コーティング剤の単分子膜を備える基板とを接触させ、上記第２の官能基と上記第４の官能基とを反応させて結合を形成させることにより、上記基板上に、上記第１及び第２の有機コーティング剤を介してＦｅＰｔナノ粒子が結合して配列したＦｅＰｔナノ粒子の配列体を形成する工程
を含むことを特徴とするＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体の製造方法。
［１２］ 基板上にＦｅＰｔ磁性ナノ粒子の配列体を有する磁気記録媒体を製造する方法であって、
［１］乃至［１０］のいずれかに記載の方法により得られたＦｅＰｔナノ粒子であり、面心立方（ｆｃｃ）構造を含むＦｅＰｔナノ粒子の表面に、分子鎖の一端側に上記ＦｅＰｔナノ粒子の表面と化学結合し得る第１の官能基、他端側に上記ＦｅＰｔナノ粒子の表面と化学結合しない第２の官能基を有する第１の有機コーティング剤を接触させ、上記第１の有機コーティング剤分子を上記第１の官能基を介して上記ＦｅＰｔナノ粒子の表面に化学結合させることにより、上記ＦｅＰｔナノ粒子の表面上に上記第１の有機コーティング剤分子の単分子膜を形成する工程、
上記基板の表面に、分子鎖の一端側に上記基板の表面と化学結合し得る第３の官能基、他端側に上記基板の表面と化学結合せず、上記第２の官能基と反応して結合を形成し得る第４の官能基を有する第２の有機コーティング剤を接触させ、上記第２の有機コーティング剤分子を上記第３の官能基を介して上記基板の表面に化学結合させることにより、上記基板の表面上に上記第２の有機コーティング剤の単分子膜を形成する工程、
上記第１の有機コーティング剤の単分子膜を備えるＦｅＰｔナノ粒子と、上記第２の有機コーティング剤の単分子膜を備える基板とを接触させ、上記第２の官能基と上記第４の官能基とを反応させて結合を形成させることにより、上記基板上に、上記第１及び第２の有機コーティング剤を介してＦｅＰｔナノ粒子が結合して配列したＦｅＰｔナノ粒子の配列体を形成する工程、及び
上記配列したＦｅＰｔナノ粒子に４００℃以上でアニール処理を施すことにより、面心立方（ｆｃｃ）構造を面心直方（ｆｃｔ）構造に相転移させてＦｅＰｔ磁性ナノ粒子とする工程
を含むことを特徴とするＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体の製造方法。
The present invention also provides the following method for producing a magnetic recording medium having an FePt magnetic nanoparticle array as a method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles arranged on a substrate.
[ 11 ] A method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles on a substrate,
The FePt nanoparticles obtained by the method according to any one of [1] to [10] , wherein one end of a molecular chain is formed on the surface of the FePt nanoparticles, which are FePt magnetic nanoparticles including a face-centered rectangular (fct) structure. A first organic coating agent having a first functional group capable of being chemically bonded to the surface of the FePt nanoparticle on the side and a second functional group not chemically bonded to the surface of the FePt nanoparticle on the other side; A single molecule of the first organic coating agent molecule is formed on the surface of the FePt nanoparticle by chemically bonding the first organic coating agent molecule to the surface of the FePt nanoparticle through the first functional group. Forming a film;
A third functional group capable of chemically bonding to the surface of the substrate on one end side of the molecular chain on the surface of the substrate and reacting with the second functional group without chemically bonding to the surface of the substrate on the other end side. Contacting a second organic coating agent having a fourth functional group capable of forming a bond to chemically bond the second organic coating agent molecule to the surface of the substrate via the third functional group. Forming a monomolecular film of the second organic coating agent on the surface of the substrate, FePt nanoparticles comprising the monomolecular film of the first organic coating agent, and the second organic coating agent The first and second organic layers are formed on the substrate by contacting the second functional group and the fourth functional group to form a bond. FePt nano through coating agent Method of manufacturing a magnetic recording medium having a FePt magnetic nanoparticle array which comprises a step of forming an array of FePt nanoparticles child arranged bound to.
[ 12 ] A method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles on a substrate,
The FePt nanoparticle obtained by the method according to any one of [1] to [10], wherein the FePt nanoparticle is formed on the surface of the FePt nanoparticle including a face-centered cubic (fcc) structure on one end side of the molecular chain. A first organic coating agent having a first functional group that can be chemically bonded to the surface of the FePt nanoparticle, and a second functional group that is not chemically bonded to the surface of the FePt nanoparticle on the other end, and contacting the first organic coating Forming a monomolecular film of the first organic coating agent molecule on the surface of the FePt nanoparticle by chemically bonding an agent molecule to the surface of the FePt nanoparticle via the first functional group;
A third functional group capable of chemically bonding to the surface of the substrate on one end side of the molecular chain on the surface of the substrate and reacting with the second functional group without chemically bonding to the surface of the substrate on the other end side. Contacting a second organic coating agent having a fourth functional group capable of forming a bond to chemically bond the second organic coating agent molecule to the surface of the substrate via the third functional group. A step of forming a monomolecular film of the second organic coating agent on the surface of the substrate,
An FePt nanoparticle having a monomolecular film of the first organic coating agent and a substrate having a monomolecular film of the second organic coating agent are brought into contact with each other, and the second functional group and the fourth functional group are brought into contact with each other. Forming an array of FePt nanoparticles in which FePt nanoparticles are combined and arranged on the substrate via the first and second organic coating agents, And a step of subjecting the FePt nanoparticles arranged above to an annealing treatment at 400 ° C. or more to cause a face-centered cubic (fcc) structure to undergo phase transition to a face-centered rectangular (fct) structure to form FePt magnetic nanoparticles. A method of manufacturing a magnetic recording medium having a FePt magnetic nanoparticle array characterized.
［１１］の方法は、面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子を基板上に配列してＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体を製造する方法であり、この場合、ＦｅＰｔナノ粒子は、既に、強い磁性を与える面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子であることから、このＦｅＰｔ磁性ナノ粒子を基板上に配列すれば、磁性を有する面心直方（ｆｃｔ）構造への相転移のためのアニール処理を施すことなく、配列体を磁気記録媒体の磁気記録層として適用することが可能である。 The method [ 11 ] is a method of manufacturing a magnetic recording medium having an FePt magnetic nanoparticle array by arranging FePt magnetic nanoparticles including a face-centered rectangular (fct) structure on a substrate. Since the particles are already FePt magnetic nanoparticles including a face-centered rectangular (fct) structure that gives strong magnetism, if these FePt magnetic nanoparticles are arranged on a substrate, a magnetic face-centered rectangular (fct) structure is provided. It is possible to apply the array as a magnetic recording layer of a magnetic recording medium without performing an annealing process for phase transition into the magnetic recording medium.
また、［１２］の方法は、面心立方（ｆｃｃ）構造を含むＦｅＰｔナノ粒子を基板上に配列してＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体を製造する方法であり、この場合、面心立方（ｆｃｃ）構造を、磁気異方性を有する強い磁性を与える面心直方（ｆｃｔ）構造に相転移させることが可能である。ＦｅＰｔナノ粒子にアニール処理を施さずに基板上に配列させた後に、ＦｅＰｔナノ粒子の配列体に４００℃以上でアニール処理を施して、面心立方（ｆｃｃ）構造を面心直方（ｆｃｔ）構造に相転移させることにより、配列前にアニール処理する場合とは異なり、ＦｅＰｔナノ粒子の凝集などによる大粒径化を避けて、小粒径の均一な粒子が配列した配列体を有する磁気記録媒体を得ることができる。 The method [ 12 ] is a method for manufacturing a magnetic recording medium having an FePt magnetic nanoparticle array by arranging FePt nanoparticles containing a face-centered cubic (fcc) structure on a substrate. The center cubic (fcc) structure can be phase-shifted to a face-centered rectangular (fct) structure that provides strong magnetism with magnetic anisotropy. After the FePt nanoparticles are arranged on the substrate without being annealed, the array of FePt nanoparticles is annealed at 400 ° C. or more to convert the face-centered cubic (fcc) structure into the face-centered rectangular (fct) structure. Magnetic recording medium having an array in which uniform particles of small particle size are arranged by avoiding an increase in particle size due to aggregation of FePt nanoparticles, etc. Can be obtained.
本発明によれば、均一な形状、粒径及び磁気特性を有するＦｅＰｔナノ粒子、特に、面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子を提供することができ、更に、この粒子をその磁化容易軸の向きを垂直に揃えて基板上に並べたＦｅＰｔ磁性ナノ粒子配列体を製造することができる。このようなＦｅＰｔ磁性ナノ粒子及びその配列体を磁気記録媒体に適用することにより、超高密度磁気記録システムの提供が可能となる。 According to the present invention, it is possible to provide FePt nanoparticles having a uniform shape, particle size, and magnetic properties, in particular, FePt magnetic nanoparticles including a face-centered rectangular (fct) structure. An FePt magnetic nanoparticle array in which easy axis directions are aligned vertically and arranged on a substrate can be manufactured. By applying such FePt magnetic nanoparticles and an array thereof to a magnetic recording medium, it is possible to provide an ultra-high density magnetic recording system.
以下、本発明について、更に詳しく説明する。
本発明のＦｅＰｔナノ粒子の製造方法では、まず、Ｐｔ化合物と還元剤と第１の粒子分散剤とを含む溶媒溶液から還元反応により金属Ｐｔ核粒子を生成させる（工程ａ）。Ｐｔ化合物としては、例えばＰｔアセチルアセトナート、Ｐｔエトキシド（Ｐｔ（ＯＥｔ）2）などを用いることができる。また、還元剤としては、１−オクタデセン等の炭素数１６〜１８の不飽和炭化水素（直鎖状のものが好ましく、また片末端に二重結合を有するものが好ましい）、１，２−ヘキサデカンジオール等の炭素数１６〜１８の飽和炭化水素ジオール（飽和炭化水素基が直鎖状のものが好ましく、また１，２−位に各々ヒドロキシル基を有するものが好ましい）などを用いることができる。
Hereinafter, the present invention will be described in more detail.
In the method for producing FePt nanoparticles of the present invention, first, metal Pt core particles are generated by a reduction reaction from a solvent solution containing a Pt compound, a reducing agent, and a first particle dispersant (step a). As the Pt compound, for example, Pt acetylacetonate, Pt ethoxide (Pt (OEt) 2 ) and the like can be used. Further, as the reducing agent, unsaturated hydrocarbons having 16 to 18 carbon atoms such as 1-octadecene (preferably linear hydrocarbons and those having a double bond at one end), 1,2-hexadecane. Saturated hydrocarbon diols having 16 to 18 carbon atoms such as diol (saturated hydrocarbon groups are preferably linear and those having a hydroxyl group at the 1,2-position are preferred) and the like can be used.
一方、第１の粒子分散剤は、生成した金属Ｐｔの凝集を抑制する作用を有するものが好ましく、例えば、オレイン酸等の炭素数３〜１７の直鎖不飽和脂肪酸、Ｎ−２−ビニルピロリドンなどを用いることができる。 On the other hand, the first particle dispersant preferably has an action of suppressing aggregation of the produced metal Pt. For example, a linear unsaturated fatty acid having 3 to 17 carbon atoms such as oleic acid, N-2-vinylpyrrolidone, etc. Etc. can be used.
Ｐｔ化合物、還元剤及び第１の粒子分散剤は、溶媒に溶解させた溶液として用いられる。この溶媒としては、ベンジルエーテル、オクチルエーテル等のエーテル類、テトラエチレングリコール等のグリコール類、ノナデカン等の炭素数１８〜２０の飽和炭化水素などの有機溶媒を用いることが好ましい。 The Pt compound, the reducing agent, and the first particle dispersant are used as a solution dissolved in a solvent. As the solvent, it is preferable to use an organic solvent such as ethers such as benzyl ether and octyl ether, glycols such as tetraethylene glycol, and saturated hydrocarbons having 18 to 20 carbon atoms such as nonadecane.
なお、溶媒溶液に溶解させるＰｔ化合物の濃度はＰｔ基準で０．４５〜０．６５ｍｍｏｌ／ｄｍ3、特に０．５０〜０．５５ｍｍｏｌ／ｄｍ3とすることが好ましい。また、溶媒溶液に溶解させる還元剤の濃度は１．２〜１．８ｍｍｏｌ／ｄｍ3、特に１．５〜１．６ｍｍｏｌ／ｄｍ3とすることが好ましい。一方、溶媒溶液に溶解させる第１の粒子分散剤の濃度は０．９０〜１．５ｍｍｏｌ／ｄｍ3、特に１．０〜１．２ｍｍｏｌ／ｄｍ3とすることが好ましい。 The concentration of the Pt compound to be dissolved in a solvent solution 0.45~0.65mmol / dm 3 in Pt standard, it is particularly preferable to 0.50~0.55mmol / dm 3. The concentration of the reducing agent dissolved in the solvent solution is preferably 1.2 to 1.8 mmol / dm 3 , particularly preferably 1.5 to 1.6 mmol / dm 3 . On the other hand, the concentration of the first particle dispersant dissolved in the solvent solution is preferably 0.90 to 1.5 mmol / dm 3 , particularly 1.0 to 1.2 mmol / dm 3 .
このＰｔ化合物、還元剤及び第１の粒子分散剤を溶解させた溶媒溶液を、例えば６０〜２７５℃、特に８０〜１００℃にして、必要に応じて攪拌しながら加熱することにより、Ｐｔ化合物（Ｐｔイオン）が還元剤により還元されて、金属Ｐｔ核粒子が生成する。この反応時間は、通常５〜１０分間とすることが好ましい。なお、この工程で、金属Ｐｔ核粒子が生成するが、この段階でＰｔ化合物（Ｐｔイオン）の全てが金属Ｐｔ核粒子として生成する必要はなく、一部は残っていてもよい。残留したＰｔ化合物（Ｐｔイオン）は、後の工程において更に金属Ｐｔとして析出させることができる。 The solvent solution in which the Pt compound, the reducing agent, and the first particle dispersant are dissolved is, for example, 60 to 275 ° C., particularly 80 to 100 ° C. Pt ions) are reduced by a reducing agent, and metal Pt core particles are generated. This reaction time is usually preferably 5 to 10 minutes. In this step, metal Pt nucleus particles are generated, but it is not necessary that all of the Pt compounds (Pt ions) are generated as metal Pt nucleus particles at this stage, and some of them may remain. The remaining Pt compound (Pt ion) can be further deposited as metal Pt in a later step.
次に、金属Ｐｔ核粒子を生成させた後の溶媒溶液に、Ｆｅ化合物及び第２の粒子分散剤を添加、好ましくはＦｅ化合物を添加してＦｅ化合物を溶解させた後に第２の粒子分散剤を添加して、金属Ｐｔ核粒子上に金属Ｆｅを析出させる（工程ｂ）。Ｆｅ化合物としては、例えば鉄カルボニル、鉄アセチルアセトナート、鉄エトキシドなどを用いることができる。 Next, the Fe compound and the second particle dispersant are added to the solvent solution after generating the metal Pt core particles, preferably the Fe compound is added to dissolve the Fe compound, and then the second particle dispersant is added. Is added to deposit metal Fe on the metal Pt core particles (step b). As the Fe compound, for example, iron carbonyl, iron acetylacetonate, iron ethoxide and the like can be used.
一方、第２の粒子分散剤は、生成した金属Ｆｅの凝集を抑制する作用を有するものが好ましく、例えば、オレイルアミン等の炭素数１６〜１８の直鎖不飽和脂肪族アミンなどを用いることができる。 On the other hand, the second particle dispersant preferably has an action of suppressing aggregation of the produced metallic Fe, and for example, a linear unsaturated aliphatic amine having 16 to 18 carbon atoms such as oleylamine can be used. .
溶媒溶液に添加するＦｅ化合物の濃度はＦｅ基準で０．９５〜１．１５ｍｍｏｌ／ｄｍ3、特に０．９９〜１．０９ｍｍｏｌ／ｄｍ3とすることが好ましい。一方、溶媒溶液に添加する第２の粒子分散剤の濃度は０．９０〜１．５ｍｍｏｌ／ｄｍ3、特に１．０〜１．２ｍｍｏｌ／ｄｍ3とすることが好ましい。 Fe concentration of the compound 0.95~1.15mmol / dm 3 in Fe criteria to be added to the solvent solution, particularly preferably a 0.99~1.09mmol / dm 3. On the other hand, the concentration of the second particle dispersant added to the solvent solution is preferably 0.90 to 1.5 mmol / dm 3 , particularly preferably 1.0 to 1.2 mmol / dm 3 .
このＦｅ化合物及び第２の粒子分散剤を溶解させた溶媒溶液を、例えば１００〜１４０℃、特に１１５〜１２５℃で必要に応じて攪拌することにより、金属Ｐｔ核粒子上に金属Ｆｅが析出する。この反応時間は、通常５〜１５分間とすることが好ましい。なお、この工程で、金属Ｆｅが析出するが、この段階でＦｅ化合物の全てが金属Ｆｅとして析出する必要はなく、一部は残っていてもよい。残留したＦｅ化合物は、後の工程において更に、金属Ｆｅとして析出させることができる。 By stirring the solvent solution in which the Fe compound and the second particle dispersant are dissolved, for example, at 100 to 140 ° C., particularly 115 to 125 ° C. as necessary, metal Fe is deposited on the metal Pt core particles. . This reaction time is usually preferably 5 to 15 minutes. In this step, metal Fe is precipitated. At this stage, not all of the Fe compound needs to be precipitated as metal Fe, and a part of the Fe compound may remain. The remaining Fe compound can be further precipitated as metallic Fe in a later step.
次に、金属Ｆｅが析出して生成したＦｅとＰｔとを含むナノ粒子を、反応液中で１８５〜３２０℃、好ましくは２２５〜２７５℃、特に好ましくは２４５〜２５５℃の温度で熟成する（工程ｃ）。これにより、Ｐｔ原子とＦｅ原子とが相互拡散して合金化され、ＰｔとＦｅとの合金であるＦｅＰｔナノ粒子が生成する。この熟成時間は、短すぎると十分な拡散がなされないおそれがあり、また、長すぎるとＦｅＰｔナノ粒子の凝集を引き起こすおそれがあるため、３０〜３００分間、特に１１０〜１３０分間とすることが好ましい。 Next, nanoparticles containing Fe and Pt produced by precipitation of metallic Fe are aged in the reaction solution at a temperature of 185 to 320 ° C, preferably 225 to 275 ° C, particularly preferably 245 to 255 ° C ( Step c). Thereby, Pt atoms and Fe atoms are interdiffused to form an alloy, and FePt nanoparticles that are an alloy of Pt and Fe are generated. If this aging time is too short, sufficient diffusion may not be achieved, and if it is too long, it may cause aggregation of FePt nanoparticles. Therefore, it is preferably 30 to 300 minutes, particularly 110 to 130 minutes. .
特に、２２５〜２７５℃の温度で熟成したものは、後述するアニール処理において、ＦｅＰｔナノ粒子の表面部にＦｅ酸化物層が生成する傾向にあり、この鉄酸化物層の生成により、アニール処理において、面心立方（ｆｃｃ）構造から面心直方（ｆｃｔ）構造への相転移がし易くなる傾向にあることから好適である。なお、このＦｅ酸化物層の厚さは１ｎｍ以下であることが好ましい。 In particular, those aged at a temperature of 225 to 275 ° C. tend to generate a Fe oxide layer on the surface portion of the FePt nanoparticles in the annealing process described later. It is preferable because the phase transition from the face-centered cubic (fcc) structure to the face-centered rectangular (fct) structure tends to be facilitated. In addition, it is preferable that the thickness of this Fe oxide layer is 1 nm or less.
なお、上記工程ａ〜工程ｃは、いずれもアルゴン等の不活性ガス雰囲気又は窒素ガス雰囲気下で実施することが好ましい。 In addition, it is preferable to implement all the said process a-process c in inert gas atmosphere, such as argon, or nitrogen gas atmosphere.
熟成後の反応液からは、ろ過等の常法に従い、生成したＦｅＰｔナノ粒子を分離することができる。また、溶媒を交換して液中で保存してもよい。特に、遠心分離によりＦｅＰｔナノ粒子を溶液から分離する際、例えば、溶媒の作用によるＦｅＰｔナノ粒子の凝集・再分散を利用して、微小な粒子を除去することが可能であり、これにより、粒子径分布がより揃ったＦｅＰｔナノ粒子とすることが可能である。 From the reaction solution after aging, the produced FePt nanoparticles can be separated according to a conventional method such as filtration. Further, the solvent may be exchanged and stored in the liquid. In particular, when separating FePt nanoparticles from a solution by centrifugation, for example, it is possible to remove fine particles by utilizing aggregation and redispersion of FePt nanoparticles by the action of a solvent. FePt nanoparticles having a more uniform diameter distribution can be obtained.
このようにして得られたＦｅＰｔナノ粒子が、面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子（なお、面心直方（ｆｃｔ）構造を含み、面心立方（ｆｃｃ）構造を含まないものであっても、面心立方（ｆｃｃ）構造及び面心直方（ｆｃｔ）構造の双方を含むものであってもよい。）である場合、磁気異方性を有する強い磁性を与える面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子は、そのままで（即ち、磁性を有する面心直方（ｆｃｔ）構造への相転移のためのアニール処理を施すことなく）磁性体材料として用いることが可能である。 The FePt nanoparticles obtained in this way are FePt magnetic nanoparticles containing a face-centered rectangular (fct) structure (note that they contain a face-centered rectangular (fct) structure and do not contain a face-centered cubic (fcc) structure). In the case of a face-centered cubic (fcc) structure and a face-centered rectangular (fct) structure), a face-centered rectangular (fct) that provides strong magnetism having magnetic anisotropy. ) FePt magnetic nanoparticles containing a structure can be used as a magnetic material as it is (that is, without being subjected to an annealing treatment for phase transition to a magnetic face-centered rectangular (fct) structure).
一方、ＦｅＰｔナノ粒子が面心立方（ｆｃｃ）構造を含むもの（なお、面心立方（ｆｃｃ）構造を含み、面心直方（ｆｃｔ）構造を含まないものであっても、面心立方（ｆｃｃ）構造及び面心直方（ｆｃｔ）構造の双方を含むものであってもよい。）である場合、合金化後のＦｅＰｔナノ粒子に、更に、４００℃以上、好ましくは５００℃以上、より好ましくは５５０℃、更に好ましくは６００℃以上でアニール処理を施すことにより、面心立方（ｆｃｃ）構造を面心直方（ｆｃｔ）構造に相転移させてＦｅＰｔ磁性ナノ粒子とすることが可能である。ＦｅＰｔナノ粒子が面心立方（ｆｃｃ）構造を含むものである場合、これを強い磁性を与える面心直方（ｆｃｔ）構造に相転移させることが可能であり、ＦｅＰｔナノ粒子にアニール処理を施すことにより、ＦｅＰｔナノ粒子をより強い磁性を有するＦｅＰｔ磁性ナノ粒子とすることが可能である。なお、アニール処理温度の上限は特に限定されないが、好ましくは７００℃以下、より好ましくは６５０℃以下である。また、アニール処理は、アルゴン等の不活性ガス雰囲気下、窒素ガス雰囲気下、又はアルゴン等の不活性ガス若しくは窒素ガス中に、水素ガスを１〜５容量％、特に２〜３容量％含む還元雰囲気下で処理することが好ましく、処理時間は０．５〜１０時間、特に２．５〜３．５時間とすることが好ましい。 On the other hand, even if the FePt nanoparticle includes a face-centered cubic (fcc) structure (note that it includes a face-centered cubic (fcc) structure and does not include a face-centered cubic (fct) structure) ) May include both a structure and a face-centered-rectangular (fct) structure.) In the case of FePt nanoparticles after alloying, 400 ° C or higher, preferably 500 ° C or higher, more preferably By performing an annealing treatment at 550 ° C., more preferably 600 ° C. or more, it is possible to transform the face-centered cubic (fcc) structure into a face-centered rectangular (fct) structure to form FePt magnetic nanoparticles. When the FePt nanoparticle includes a face-centered cubic (fcc) structure, it can be phase-shifted to a face-centered rectangular (fct) structure that gives strong magnetism, and by annealing the FePt nanoparticle, The FePt nanoparticles can be made into FePt magnetic nanoparticles having stronger magnetism. The upper limit of the annealing temperature is not particularly limited, but is preferably 700 ° C. or lower, more preferably 650 ° C. or lower. In addition, the annealing treatment is a reduction containing 1 to 5% by volume, particularly 2 to 3% by volume of hydrogen gas in an inert gas atmosphere such as argon, a nitrogen gas atmosphere, or an inert gas or nitrogen gas such as argon. The treatment is preferably performed under an atmosphere, and the treatment time is preferably 0.5 to 10 hours, particularly 2.5 to 3.5 hours.
本発明におけるＦｅＰｔナノ粒子及びＦｅＰｔ磁性ナノ粒子の平均粒子径は、いずれも３〜２０ｎｍ、特に４〜１０ｎｍ、とりわけ５〜７ｎｍである。なお、この平均粒子径は、透過型電子顕微鏡（ＴＥＭ）像から算出することができる。 The average particle diameter of the FePt nanoparticles and the FePt magnetic nanoparticles in the present invention is 3 to 20 nm, particularly 4 to 10 nm, particularly 5 to 7 nm. The average particle diameter can be calculated from a transmission electron microscope (TEM) image.
本発明によれば、四角柱形状乃至略四角柱形状（特に、立方体形状乃至略立方体形状）のＦｅＰｔナノ粒子を得ることができる。この四角柱形状乃至略四角柱形状は、面心立方（ｆｃｃ）構造又は面心直方（ｆｃｔ）構造の形状を反映した形状であり、このようなＦｅＰｔナノ粒子は、特に磁気異方性が高く、強い磁性を有するＦｅＰｔ磁気ナノ粒子を与えるものであることから好適である。 According to the present invention, FePt nanoparticles having a quadrangular prism shape or a substantially quadrangular prism shape (particularly, a cubic shape or a substantially cubic shape) can be obtained. This quadrangular prism shape or substantially quadrangular prism shape is a shape reflecting the shape of a face-centered cubic (fcc) structure or a face-centered rectangular (fct) structure, and such FePt nanoparticles have a particularly high magnetic anisotropy. It is preferable because it provides FePt magnetic nanoparticles having strong magnetism.
また、ＦｅＰｔナノ粒子中のＦｅとＰｔとの比率は、Ｆｅ：Ｐｔ＝５０：５０〜６０：４０（原子比）であることが好ましい。この比率は、図１に示される面心直方（ｆｃｔ）構造のＦｅとＰｔとの比率に近似するものであり、このようなＦｅＰｔナノ粒子が、特に磁気異方性が高く、強い磁性を有するＦｅＰｔ磁気ナノ粒子を与えるものであることから好適である。 Moreover, it is preferable that the ratio of Fe and Pt in FePt nanoparticle is Fe: Pt = 50: 50-60: 40 (atomic ratio). This ratio approximates the ratio of Fe and Pt in the face-centered rectangular (fct) structure shown in FIG. 1, and such FePt nanoparticles have particularly high magnetic anisotropy and strong magnetism. This is preferable because it provides FePt magnetic nanoparticles.
本発明においては、保磁力が３ｋＯｅ以上、特に５〜６ｋＯｅ、角型比が０．５以上、特に０．６〜０．９のＦｅＰｔ磁性ナノ粒子を得ることができる。なお、１Ｏｅは約７９Ａ／ｍである。 In the present invention, FePt magnetic nanoparticles having a coercive force of 3 kOe or more, particularly 5 to 6 kOe, and a squareness ratio of 0.5 or more, particularly 0.6 to 0.9 can be obtained. 1 Oe is about 79 A / m.
また、本発明においては、基板上に上記した方法で得たＦｅＰｔ磁性ナノ粒子が配列した配列体を製造すること、特に、基板上にＦｅＰｔ磁性ナノ粒子の配列体を有する磁気記録媒体を製造することができる。 In the present invention, an array in which FePt magnetic nanoparticles obtained by the above-described method are arranged on a substrate is manufactured, and in particular, a magnetic recording medium having an array of FePt magnetic nanoparticles on a substrate is manufactured. be able to.
まず、得られたＦｅＰｔナノ粒子が、面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子である場合、
［Ａ］ＦｅＰｔナノ粒子の表面に、分子鎖の一端側に上記ＦｅＰｔナノ粒子の表面と化学結合し得る第１の官能基、他端側に第２の官能基、好ましくは上記ＦｅＰｔナノ粒子の表面と化学結合しない第２の官能基を有する第１の有機コーティング剤を接触させ、上記第１の有機コーティング剤分子を上記第１の官能基を介して上記ＦｅＰｔナノ粒子の表面に化学結合させることにより、上記ＦｅＰｔナノ粒子の表面上に上記第１の有機コーティング剤分子の単分子膜を形成する工程、
［Ｂ］上記基板の表面に、分子鎖の一端側に上記基板の表面と化学結合し得る第３の官能基、他端側に、好ましくは上記基板の表面と化学結合せず、上記第２の官能基と反応して結合を形成し得る第４の官能基を有する第２の有機コーティング剤を接触させ、上記第２の有機コーティング剤分子を上記第３の官能基を介して上記基板の表面に化学結合させることにより、上記基板の表面上に上記第２の有機コーティング剤の単分子膜を形成する工程、
［Ｃ］上記第１の有機コーティング剤の単分子膜を備えるＦｅＰｔナノ粒子と、上記第２の有機コーティング剤の単分子膜を備える基板とを接触させ、上記第２の官能基と上記第４の官能基とを反応させて結合を形成させることにより、上記基板上に、上記第１及び第２の有機コーティング剤を介してＦｅＰｔナノ粒子が結合して配列したＦｅＰｔナノ粒子の配列体を形成する工程
により、基板上にＦｅＰｔ磁性ナノ粒子が配列したＦｅＰｔ磁性ナノ粒子配列体を製造することができる。
First, when the obtained FePt nanoparticles are FePt magnetic nanoparticles including a face-centered rectangular (fct) structure,
[A] On the surface of the FePt nanoparticle, a first functional group capable of chemically bonding to the surface of the FePt nanoparticle on one end side of the molecular chain and a second functional group on the other end side, preferably the FePt nanoparticle A first organic coating agent having a second functional group that is not chemically bonded to the surface is contacted, and the first organic coating agent molecule is chemically bonded to the surface of the FePt nanoparticle via the first functional group. Forming a monomolecular film of the first organic coating agent molecules on the surface of the FePt nanoparticles,
[B] A third functional group capable of chemically bonding to the surface of the substrate on one end side of the molecular chain on the surface of the substrate, and preferably not chemically bonding to the surface of the substrate on the other end side. A second organic coating agent having a fourth functional group capable of reacting with the functional group of the second functional group to form a bond, and contacting the second organic coating agent molecule via the third functional group with the substrate. Forming a monomolecular film of the second organic coating agent on the surface of the substrate by chemically bonding to the surface;
[C] The FePt nanoparticles provided with the monomolecular film of the first organic coating agent and a substrate provided with the monomolecular film of the second organic coating agent are brought into contact with each other, and the second functional group and the fourth By forming a bond by reacting with the functional group of FePt nanoparticles, an array of FePt nanoparticles is formed on the substrate by binding the FePt nanoparticles through the first and second organic coating agents. By performing the step, an FePt magnetic nanoparticle array in which FePt magnetic nanoparticles are arrayed on a substrate can be manufactured.
ここで、第１の官能基としては、チオール基、アミノ基、シアノ基など、第２の官能基としては、チオール基などを挙げることができ、第１の有機コーティング剤として具体的には１，６−ヘキサンジチオール、１，９−ノナンジチオール、１，１０−デカンジチオール等を挙げることができる。第１の官能基としては、ＦｅＰｔナノ粒子中のＦｅ原子又はＰｔ原子と結合を形成すること、特にＦｅ原子又はＰｔ原子と選択的に結合を形成することができるものであることが好ましい。一方、第２の官能基としては、後述する第２の有機コーティング剤の第４の官能基と反応して結合を形成し得るものであることが必要である。 Here, examples of the first functional group include a thiol group, an amino group, and a cyano group, and examples of the second functional group include a thiol group. Specifically, the first organic coating agent is 1 , 6-hexanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol and the like. The first functional group is preferably one capable of forming a bond with an Fe atom or Pt atom in the FePt nanoparticle, and particularly capable of selectively forming a bond with an Fe atom or Pt atom. On the other hand, the second functional group needs to be capable of forming a bond by reacting with a fourth functional group of a second organic coating agent described later.
この第１のコーティング剤をＦｅＰｔナノ粒子に接触させる方法としては、例えば、第１のコーティング剤をトルエン、ヘキサン等の溶媒に溶解させた溶液に、ＦｅＰｔナノ粒子を、例えば２０〜６０℃の温度で、１〜２０分間浸漬する方法が挙げられる。これにより、第１のコーティング剤分子が第１の官能基を介してＦｅＰｔナノ粒子の表面に化学結合して、ＦｅＰｔナノ粒子の表面上に第１の有機コーティング剤分子の単分子膜が形成される。 As a method for bringing the first coating agent into contact with the FePt nanoparticles, for example, the FePt nanoparticles are dissolved in a solution obtained by dissolving the first coating agent in a solvent such as toluene or hexane, and the temperature is, for example, 20 to 60 ° C. And the method of immersing for 1 to 20 minutes is mentioned. Thereby, the first coating agent molecule is chemically bonded to the surface of the FePt nanoparticle through the first functional group, and a monomolecular film of the first organic coating agent molecule is formed on the surface of the FePt nanoparticle. The
一方、第３の官能基としては、メトキシシラニル基、エトキシシラニル基等のアルコキシシラニル基、シラノール基、ヒドロキシル基など、第４の官能基としては、チオール基、アミノ基などを挙げることができ、第２の有機コーティング剤として具体的には３−メルカプトトリエトキシシラン等を挙げることができる。なお、第３の官能基は、基板と結合を形成し得るものであるが、この基板には、磁気記録媒体、特に垂直磁気記録媒体において、磁気記録層が積層される部分に軟磁性裏打ち層（ＳＵＬ）、酸化ケイ素（ＳｉＯ2）中間層等の下地層などを形成した基板が含まれ、この場合、第３の官能基はこの下地層などに結合するものとする。 On the other hand, examples of the third functional group include alkoxysilanyl groups such as a methoxysilanyl group and ethoxysilanyl group, silanol groups, and hydroxyl groups, and examples of the fourth functional group include thiol groups and amino groups. Specific examples of the second organic coating agent include 3-mercaptotriethoxysilane. The third functional group is capable of forming a bond with the substrate, and this substrate has a soft magnetic backing layer on the magnetic recording layer, particularly in a perpendicular magnetic recording medium, where the magnetic recording layer is laminated. (SUL), a substrate on which an underlayer such as a silicon oxide (SiO 2 ) intermediate layer is formed is included. In this case, the third functional group is bonded to the underlayer.
この第２のコーティング剤を基板に接触させる方法としては、例えば、第２のコーティング剤をトルエン等の溶媒に溶解させた溶液に、基板を、例えば５０〜７０℃の温度で、１〜２０分間浸漬する、又は上記溶液をスピンコート等により塗布して上記時間保持する方法が挙げられる。これにより、第２のコーティング剤分子が第３の官能基を介して基板（下地層）の表面に化学結合して、基板（下地層）の表面上に第２の有機コーティング剤分子の単分子膜が形成される。 As a method of bringing the second coating agent into contact with the substrate, for example, the substrate is placed in a solution obtained by dissolving the second coating agent in a solvent such as toluene at a temperature of, for example, 50 to 70 ° C. for 1 to 20 minutes. Examples of the method include dipping or applying the solution by spin coating or the like and holding the solution for the above time. As a result, the second coating agent molecule is chemically bonded to the surface of the substrate (underlayer) via the third functional group, and a single molecule of the second organic coating agent molecule is formed on the surface of the substrate (underlayer). A film is formed.
そして、第１の有機コーティング剤の単分子膜が形成されたＦｅＰｔナノ粒子を、例えば、トルエン、ヘキサン等の溶媒に分散させた分散液に、第２の有機コーティング剤の単分子膜が形成された基板を、例えば２０〜６０℃の温度で、１〜２０分間浸漬する、又は上記分散液をスピンコート等により塗布して上記時間保持することにより、第１の有機コーティング剤分子の第２の官能基と、第２の有機コーティング剤分子の第４の官能基とが結合して、例えば、図２（Ａ）に模式的に示されるような、基板（下地層）上に、第１及び第２の有機コーティング剤を介してＦｅＰｔナノ粒子が結合してＦｅＰｔナノ粒子が１層に配列したＦｅＰｔナノ粒子の配列体が形成される。なお、図２（Ａ）中、１はＦｅＰｔナノ粒子、２は第１の有機コーティング剤分子、３は第２の有機コーティング剤分子、４は基板である。 Then, a monomolecular film of the second organic coating agent is formed in a dispersion obtained by dispersing the FePt nanoparticles in which the monomolecular film of the first organic coating agent is formed in a solvent such as toluene or hexane. The substrate is dipped at, for example, a temperature of 20 to 60 ° C. for 1 to 20 minutes, or the dispersion is applied by spin coating or the like and held for the above time, whereby the second of the first organic coating agent molecules. The functional group and the fourth functional group of the second organic coating agent molecule are bonded to each other, for example, on the substrate (underlayer) as schematically shown in FIG. The FePt nanoparticles are bonded through the second organic coating agent to form an array of FePt nanoparticles in which the FePt nanoparticles are arranged in one layer. In FIG. 2A, 1 is an FePt nanoparticle, 2 is a first organic coating agent molecule, 3 is a second organic coating agent molecule, and 4 is a substrate.
なお、上述したＦｅＰｔナノ粒子の製造において用いた第１の粒子分散剤及び第２の粒子分散剤を第１の有機コーティング剤として利用することも可能である。その場合、上記［Ａ］工程の代わりに、ＦｅＰｔナノ粒子が生成した反応液からＦｅＰｔナノ粒子を分離する際に、例えば洗浄する溶媒を適宜選択して、ＦｅＰｔナノ粒子の表面に第１の粒子分散剤及び第２の粒子分散剤の一方又は双方、好ましくは一方の単分子膜を形成するようにすればよく、この場合、表面に第１の粒子分散剤及び／又は第２の粒子分散剤である第１の有機コーティング剤の単分子膜が形成されたＦｅＰｔナノ粒子を用い、更に、上記［Ｂ］及び［Ｃ］工程を実施することにより、基板上にＦｅＰｔ磁性ナノ粒子が配列したＦｅＰｔ磁性ナノ粒子配列体を製造することができる。 In addition, it is also possible to utilize the 1st particle dispersing agent and 2nd particle dispersing agent which were used in manufacture of the FePt nanoparticle mentioned above as a 1st organic coating agent. In that case, instead of the above step [A], when separating the FePt nanoparticles from the reaction solution in which the FePt nanoparticles are generated, for example, a solvent to be washed is appropriately selected, and the first particles are formed on the surface of the FePt nanoparticles. One or both of the dispersing agent and the second particle dispersing agent, preferably one monomolecular film may be formed. In this case, the first particle dispersing agent and / or the second particle dispersing agent is formed on the surface. FePt nanoparticles in which a monomolecular film of the first organic coating agent is formed, and further, the above [B] and [C] steps are performed, whereby FePt magnetic nanoparticles are arranged on the substrate. Magnetic nanoparticle arrays can be produced.
また、上記［Ｂ］工程における第２の有機コーティング剤の第４の官能基が、ＦｅＰｔナノ粒子中のＦｅ原子又はＰｔ原子と結合を形成するもの、特にＦｅ原子又はＰｔ原子と選択的に結合を形成することができるものである場合は、ＦｅＰｔナノ粒子を第４の官能基に直接結合させることもできる。その場合、上記［Ａ］工程を実施することなく上記［Ｂ］工程を実施し、更に、上記［Ｃ］工程の代わりに、
［Ｃ’］上記ＦｅＰｔナノ粒子と、上記第２の有機コーティング剤の単分子膜を備える基板とを接触させ、上記ＦｅＰｔナノ粒子と上記第４の官能基とを反応させて結合を形成させることにより、上記基板上に、上記第２の有機コーティング剤を介してＦｅＰｔナノ粒子が結合して配列したＦｅＰｔナノ粒子の配列体を形成する工程
を実施すればよい。
In addition, the fourth functional group of the second organic coating agent in the step [B] forms a bond with the Fe atom or Pt atom in the FePt nanoparticle, particularly selectively bonded with the Fe atom or Pt atom. Can form FePt nanoparticles directly to the fourth functional group. In that case, the step [B] is performed without performing the step [A], and instead of the step [C],
[C ′] contacting the FePt nanoparticles with a substrate having a monomolecular film of the second organic coating agent, and reacting the FePt nanoparticles with the fourth functional group to form a bond. Thus, a step of forming an array of FePt nanoparticles in which FePt nanoparticles are combined and arranged via the second organic coating agent may be performed on the substrate.
この場合、ＦｅＰｔナノ粒子を、例えば、トルエン、ヘキサン等の溶媒に分散させた分散液に、第２の有機コーティング剤の単分子膜が形成された基板を、例えば２０〜６０℃の温度で、１〜２０分間浸漬する、又は上記分散液をスピンコート等により塗布して上記時間保持することにより、ＦｅＰｔナノ粒子と、第２の有機コーティング剤分子の第４の官能基とが結合して、例えば、図２（Ｂ）に模式的に示されるような、基板（下地層）上に、第２の有機コーティング剤を介してＦｅＰｔナノ粒子が結合してＦｅＰｔナノ粒子が１層に配列したＦｅＰｔナノ粒子の配列体が形成される。なお、図２（Ｂ）中、１はＦｅＰｔナノ粒子、３は第２の有機コーティング剤分子、４は基板である。 In this case, a substrate in which a monomolecular film of the second organic coating agent is formed in a dispersion liquid in which FePt nanoparticles are dispersed in a solvent such as toluene or hexane, for example, at a temperature of 20 to 60 ° C., for example. By immersing for 1 to 20 minutes, or by applying the dispersion by spin coating or the like and holding for the above time, the FePt nanoparticles and the fourth functional group of the second organic coating agent molecule are bonded, For example, as schematically shown in FIG. 2B, FePt nanoparticles in which FePt nanoparticles are bonded to each other on a substrate (underlayer) via a second organic coating agent and FePt nanoparticles are arranged in one layer. An array of nanoparticles is formed. In FIG. 2B, 1 is an FePt nanoparticle, 3 is a second organic coating agent molecule, and 4 is a substrate.
このようにして形成したＦｅＰｔナノ粒子の配列体は、そのＦｅＰｔナノ粒子が、既に、強い磁性を与える面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子であることから、磁性を有する面心直方（ｆｃｔ）構造への相転移のためのアニール処理を施すことなく、配列体を磁気記録媒体の磁気記録層として適用することが可能である。 The array of FePt nanoparticles formed in this manner is an FePt magnetic nanoparticle that already contains a face-centered-rectangular (fct) structure that gives strong magnetism. The array can be applied as a magnetic recording layer of a magnetic recording medium without performing an annealing process for phase transition to the (fct) structure.
一方、得られたＦｅＰｔナノ粒子が、面心立方（ｆｃｃ）構造を含むＦｅＰｔ磁性ナノ粒子である場合、上記［Ａ］〜［Ｃ］の工程により、ＦｅＰｔナノ粒子を配列させた後、更に、
［Ｄ］上記配列したＦｅＰｔナノ粒子に４００℃以上でアニール処理を施すことにより、面心立方（ｆｃｃ）構造を面心直方（ｆｃｔ）構造に相転移させてＦｅＰｔ磁性ナノ粒子とする工程
を施すことにより、基板上にＦｅＰｔ磁性ナノ粒子が配列したＦｅＰｔ磁性ナノ粒子配列体を製造することができる。
On the other hand, the resulting FePt nanoparticles, if an FePt magnetic nanoparticles comprising a face-centered cubic (fc c) structure, the step of the [A] ~ [C], after arranging FePt nanoparticles, Furthermore,
[D] An annealing process is performed on the arranged FePt nanoparticles at 400 ° C. or more to perform a phase transition from a face-centered cubic (fcc) structure to a face-centered rectangular (fct) structure to form FePt magnetic nanoparticles. Thus, an FePt magnetic nanoparticle array in which FePt magnetic nanoparticles are arrayed on a substrate can be produced.
このアニール処理により、面心立方（ｆｃｃ）構造を、磁気異方性を有する強い磁性を与える面心直方（ｆｃｔ）構造に相転移させることが可能である。この場合のアニール処理の条件は、上述した合金化後のＦｅＰｔナノ粒子のアニール処理と同様の条件を適用することができる。 By this annealing treatment, the face-centered cubic (fcc) structure can be phase-shifted to a face-centered rectangular (fct) structure that gives strong magnetism having magnetic anisotropy. The annealing conditions in this case can be the same conditions as the annealing process for the FePt nanoparticles after alloying described above.
面心立方（ｆｃｃ）構造を含むＦｅＰｔナノ粒子（アニール処理をしていないＦｅＰｔナノ粒子）を基板上に配列させた後にアニール処理を施して、面心立方（ｆｃｃ）構造を面心直方（ｆｃｔ）構造に相転移させることにより、配列前に（即ち、多数のＦｅＰｔナノ粒子がランダムに集合した状態で）アニール処理する場合とは異なり、ＦｅＰｔナノ粒子の凝集などによる大粒径化を避けて、小粒径の均一な粒子が配列したＦｅＰｔ磁性ナノ粒子の配列体を得ることができる。 An FePt nanoparticle containing a face-centered cubic (fcc) structure (FePt nanoparticle that has not been annealed) is arranged on a substrate and then annealed to form a face-centered cubic (fcc) structure in a face-centered (fct) ) Unlike the case where annealing is performed before arrangement (that is, in a state in which a large number of FePt nanoparticles are randomly assembled) by phase transition to the structure, avoiding a large particle size due to aggregation of FePt nanoparticles, etc. An array of FePt magnetic nanoparticles in which uniform particles having a small particle diameter are arranged can be obtained.
なお、上記した第１の有機コーティング剤の単分子膜が形成されたＦｅＰｔナノ粒子の分散液にはシリカコート剤を添加することが可能である。シリカコート剤を用いることにより、ＦｅＰｔナノ粒子を配列させた配列体に対して施される熱処理やアニール処理におけるＦｅＰｔナノ粒子の凝集を更に抑制することができる。 In addition, it is possible to add a silica coating agent to the dispersion liquid of the FePt nanoparticles on which the monomolecular film of the first organic coating agent is formed. By using the silica coating agent, it is possible to further suppress aggregation of FePt nanoparticles in the heat treatment or annealing treatment applied to the array in which FePt nanoparticles are arranged.
なお、ＦｅＰｔナノ粒子を基板に配列させる場合、四角柱形状乃至略四角柱形状（特に、立方体形状乃至略立方体形状）のＦｅＰｔナノ粒子を用いることが好ましい。この四角柱形状乃至略四角柱形状は、面心立方（ｆｃｃ）構造又は面心直方（ｆｃｔ）構造の形状を反映した形状であり、特に、図１に示される面心直方（ｆｃｔ）構造を含むＦｅＰｔナノ粒子にあっては、第１の有機コーティング剤として、第１の官能基がＦｅとの結合を形成する（特にＦｅ原子と選択的に結合を形成する）ものを用いれば、四角柱形状の対向する３組の面のうち、５つのＦｅ原子で構成されている１組の端面側に集中して、上記第１の有機コーティング剤が結合することとなる。従って、第１の有機コーティング剤の単分子膜が形成されたＦｅＰｔナノ粒子は、この第１の有機コーティング剤が結合した両端面の一方の面を基板側として配列することになり、ＦｅＰｔナノ粒子、特に、ＦｅＰｔ磁性ナノ粒子をその磁化容易軸の向きを垂直に揃えて基板上に並べたＦｅＰｔ磁性ナノ粒子の配列体を形成することができる。 When arranging FePt nanoparticles on a substrate, it is preferable to use FePt nanoparticles having a quadrangular prism shape or a substantially quadrangular prism shape (particularly, a cubic shape or a substantially cubic shape). This quadrangular prism shape or substantially quadrangular prism shape is a shape reflecting the shape of a face-centered cubic (fcc) structure or a face-centered cuboid (fct) structure, and particularly the face-centered cuboid (fct) structure shown in FIG. In the FePt nanoparticles containing, if the first organic coating agent is one in which the first functional group forms a bond with Fe (especially forms a bond selectively with an Fe atom), a quadrangular prism is used. The first organic coating agent is bonded to one end face side composed of five Fe atoms among the three opposing faces in the shape. Therefore, the FePt nanoparticles on which the monolayer of the first organic coating agent is formed are arranged with one side of both end surfaces to which the first organic coating agent is bonded as the substrate side. In particular, it is possible to form an array of FePt magnetic nanoparticles in which FePt magnetic nanoparticles are aligned on a substrate with their easy magnetization axes aligned vertically.
本発明のＦｅＰｔ磁性ナノ粒子及びＦｅＰｔ磁性ナノ粒子配列体は、磁気記録媒体の磁気記録層として有効に機能するものであり、基板上にＦｅＰｔ磁性ナノ粒子の配列体を有する磁気記録媒体として、特に、次世代の超高密度磁気記録システムとして有望視されているディスクリートトラック型の磁気記録媒体の磁気記録層に適用すれば、例えば１Ｔｂｉｔ／ｉｎｃｈ2以上の記録密度を有する超高密度磁気記録媒体の提供も可能となる。 The FePt magnetic nanoparticles and the FePt magnetic nanoparticle array of the present invention effectively function as a magnetic recording layer of a magnetic recording medium, and particularly as a magnetic recording medium having an array of FePt magnetic nanoparticles on a substrate. When applied to a magnetic recording layer of a discrete track type magnetic recording medium that is regarded as a promising next-generation ultra-high-density magnetic recording system, for example, an ultra-high-density magnetic recording medium having a recording density of 1 Tbit / inch 2 or more Provision is also possible.
以下、実施例を示して本発明を具体的に説明するが、本発明は下記の実施例に制限されるものではない。 EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
［実施例１〜７］
Ｐｔ化合物としてＰｔアセチルアセトナート（Ｐｔ（ａｃａｃ）2）を０．５ｍｍｏｌ／ｄｍ3、還元剤として１−オクタデセンを１．５ｍｍｏｌ／ｄｍ3、第１の粒子分散剤としてオレイン酸を０．９４ｍｍｏｌ／ｄｍ3含む、ベンジルエーテルを溶媒とした溶液を調製した。この溶液を、フラスコ中、アルゴン雰囲気下で、１００℃まで加熱し、１００℃になったところで、Ｆｅ化合物として鉄カルボニル（Ｆｅ（ＣＯ）5）を０．９９ｍｍｏｌ／ｄｍ3添加し、更に温度を１２０℃まで昇温して５分間保持した後、鉄カルボニルが溶解したところで、第２の粒子分散剤としてオレイルアミンを１．４ｍｍｏｌ／ｄｍ3添加した。
[Examples 1-7]
P t compound as P t acetylacetonate (P t (acac) 2) a 0.5 mmol / dm 3, 1-octadecene 1.5 mmol / dm 3 as a reducing agent, oleic acid as a first particle dispersant 0 A solution containing .94 mmol / dm 3 and using benzyl ether as a solvent was prepared. This solution was heated to 100 ° C. in a flask under an argon atmosphere. When the temperature reached 100 ° C., 0.99 mmol / dm 3 of iron carbonyl (Fe (CO) 5 ) was added as an Fe compound, and the temperature was further increased. After raising the temperature to 120 ° C. and holding for 5 minutes, when the iron carbonyl was dissolved, 1.4 mmol / dm 3 of oleylamine was added as a second particle dispersant.
次に、各々、１９５℃（実施例１）、２１５℃（実施例２）、２２５℃（実施例３）、２４５℃（実施例４）、２５５℃（実施例５）、２６５℃（実施例６）、２７５℃（実施例７）まで昇温し、この温度で１２０分間熟成した後、室温まで冷却して、ＦｅＰｔナノ粒子を得た。 Next, 195 ° C. (Example 1), 215 ° C. (Example 2), 225 ° C. (Example 3), 245 ° C. (Example 4), 255 ° C. (Example 5), 265 ° C. (Example) 6) The temperature was raised to 275 ° C. (Example 7). After aging at this temperature for 120 minutes, the mixture was cooled to room temperature to obtain FePt nanoparticles.
〔ＦｅＰｔナノ粒子の配列、並びにＦｅＰｔナノ粒子の粒子径及び粒子形状〕
実施例４で製造したＦｅＰｔナノ粒子を用い、オレイン酸・オレイルアミン修飾されたＦｅＰｔナノ粒子がヘキサン中に分散した分散液を、カーボン膜塗布ＴＥＭ（透過型電子顕微鏡）用グリッド表面に滴下した後、自然乾燥して、ＦｅＰｔナノ粒子を配列させた。
[Arrangement of FePt nanoparticles, and particle diameter and shape of FePt nanoparticles]
After the FePt nanoparticles produced in Example 4 were used and the dispersion liquid in which oleic acid / oleylamine-modified FePt nanoparticles were dispersed in hexane was dropped onto the grid surface for carbon film-coated TEM (transmission electron microscope), Air dried to align FePt nanoparticles.
ＦｅＰｔナノ粒子を配列させたＴＥＭ用グリッド上のＦｅＰｔナノ粒子をＴＥＭにて観察したところ、図３（ａ）に示されるように、平均粒子径が６ｎｍのＦｅＰｔナノ粒子が規則的に配列していることが確認された。また、図３（ｂ）に示されるＦｅＰｔナノ粒子の制限視野電子線回折（ＳＡＥＤ）による回折線から、ｆｃｃ−ＦｅＰｔ（１１１）を示すリングより内側の４点のスポットから４回対称であることが確認された。これは、ＦｅＰｔナノ粒子が立方体乃至略立方体形状であることを意味する。 When the FePt nanoparticles on the TEM grid on which the FePt nanoparticles were arranged were observed with a TEM, FePt nanoparticles with an average particle diameter of 6 nm were regularly arranged as shown in FIG. It was confirmed that Moreover, from the diffraction line by the limited field electron diffraction (SAED) of the FePt nanoparticle shown in FIG. 3B, it is symmetrical four times from the four spots inside the ring showing fcc-FePt (111). Was confirmed. This means that the FePt nanoparticles have a cubic or substantially cubic shape.
〔ＦｅＰｔナノ粒子のアニール処理〕
実施例１，３及び４で得られたＦｅＰｔナノ粒子をＮ2雰囲気下、６００℃で３時間アニール処理し、Ｘ線回折（ＸＲＤ）により評価した。結果を図４（ｂ）に示す。また、アニール処理前の粒子のＸＲＤパターン、及びＪＣＰＤＳに記載されているｆｃｔ−ＦｅＰｔの標準ピーク位置及び強度を、各々、図４（ａ）及び（ｃ）に示す。
[Annealing of FePt nanoparticles]
The FePt nanoparticles obtained in Examples 1, 3 and 4 were annealed at 600 ° C. for 3 hours in an N 2 atmosphere and evaluated by X-ray diffraction (XRD). The results are shown in FIG. Moreover, the XRD pattern of the particle | grains before annealing processing, and the standard peak position and intensity | strength of fct-FePt described in JCPDS are shown to Fig.4 (a) and (c), respectively.
アニール処理前においては、熟成温度が高温側にシフトするにつれて、ｆｃｃ結晶性が向上すると共に３５°付近にＦｅ酸化物由来のピークが確認された。これからより高温側で熟成すると、粒子の表面部にＦｅ酸化物層が形成され易くなるものと考えられる。アニール処理後においては、ｆｃｔ相への相転移が進行していることが確認され、また、この場合も、熟成温度が高温側であったものでは３５°付近にＦｅ酸化物由来のピークが確認された。 Before the annealing treatment, the fcc crystallinity was improved as the aging temperature was shifted to the high temperature side, and a peak derived from Fe oxide was confirmed at around 35 °. From this, it is considered that when ripening at a higher temperature side, an Fe oxide layer is easily formed on the surface portion of the particle. After the annealing treatment, it was confirmed that the phase transition to the fct phase had progressed. In this case also, a peak derived from Fe oxide was confirmed at around 35 ° when the aging temperature was high. It was done.
また、実施例１〜７で得られたＦｅＰｔナノ粒子をＮ2雰囲気下、６００℃で３時間アニール処理して得たＦｅＰｔ磁性ナノ粒子の磁気特性（保磁力及び角型比）を超伝導量子干渉素子（ＳＱＵＩＤ）により測定した。結果を表１及び図５に示す。 In addition, the magnetic properties (coercivity and squareness ratio) of the FePt magnetic nanoparticles obtained by annealing the FePt nanoparticles obtained in Examples 1 to 7 at 600 ° C. for 3 hours in an N 2 atmosphere were determined as superconducting quantum. Measurement was performed with an interference element (SQUID). The results are shown in Table 1 and FIG.
熟成温度が高温側にシフトするにつれて、ＦｅＰｔ磁性ナノ粒子の磁気特性が向上することが確認された。また、比較的高い磁気特性を示すものは、ＸＲＤにおいて、Ｆｅ酸化物由来のピークが確認されることから、粒子の表面部にＦｅ酸化物層がある程度形成されている粒子のほうが、ｆｃｃ相からｆｃｔ相への相転移が進行し易いと考えられる。 It was confirmed that the magnetic properties of the FePt magnetic nanoparticles improved as the aging temperature shifted to the higher temperature side. In addition, since the peak derived from Fe oxide is confirmed in the XRD, the particles having a Fe oxide layer formed to some extent on the surface portion of the particles are more likely to show from the fcc phase. It is considered that the phase transition to the fct phase is likely to proceed.
１ ＦｅＰｔナノ粒子
２ 第１の有機コーティング剤分子
３ 第２の有機コーティング剤分子
４ 基板
DESCRIPTION OF SYMBOLS 1 FePt nanoparticle 2 1st organic coating agent molecule 3 2nd organic coating agent molecule 4 Substrate
Claims (12)
請求項１乃至１０のいずれか１項記載の方法により得られたＦｅＰｔナノ粒子であり、面心直方（ｆｃｔ）構造を含むＦｅＰｔ磁性ナノ粒子であるＦｅＰｔナノ粒子の表面に、分子鎖の一端側に上記ＦｅＰｔナノ粒子の表面と化学結合し得る第１の官能基、他端側に上記ＦｅＰｔナノ粒子の表面と化学結合しない第２の官能基を有する第１の有機コーティング剤を接触させ、上記第１の有機コーティング剤分子を上記第１の官能基を介して上記ＦｅＰｔナノ粒子の表面に化学結合させることにより、上記ＦｅＰｔナノ粒子の表面上に上記第１の有機コーティング剤分子の単分子膜を形成する工程、
上記基板の表面に、分子鎖の一端側に上記基板の表面と化学結合し得る第３の官能基、他端側に上記基板の表面と化学結合せず、上記第２の官能基と反応して結合を形成し得る第４の官能基を有する第２の有機コーティング剤を接触させ、上記第２の有機コーティング剤分子を上記第３の官能基を介して上記基板の表面に化学結合させることにより、上記基板の表面上に上記第２の有機コーティング剤の単分子膜を形成する工程、及び
上記第１の有機コーティング剤の単分子膜を備えるＦｅＰｔナノ粒子と、上記第２の有機コーティング剤の単分子膜を備える基板とを接触させ、上記第２の官能基と上記第４の官能基とを反応させて結合を形成させることにより、上記基板上に、上記第１及び第２の有機コーティング剤を介してＦｅＰｔナノ粒子が結合して配列したＦｅＰｔナノ粒子の配列体を形成する工程
を含むことを特徴とするＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体の製造方法。 A method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles on a substrate, comprising:
A FePt nanoparticle obtained by the method according to any one of claims 1 to 10, wherein the FePt nanoparticle is a FePt magnetic nanoparticle including a face-centered-rectangular (fct) structure. A first functional group capable of chemically bonding to the surface of the FePt nanoparticles, and a first organic coating agent having a second functional group not chemically bonded to the surface of the FePt nanoparticles on the other end, A monomolecular film of the first organic coating agent molecule on the surface of the FePt nanoparticle by chemically bonding the first organic coating agent molecule to the surface of the FePt nanoparticle through the first functional group. Forming a process,
A third functional group capable of chemically bonding to the surface of the substrate on one end side of the molecular chain on the surface of the substrate and reacting with the second functional group without chemically bonding to the surface of the substrate on the other end side. Contacting a second organic coating agent having a fourth functional group capable of forming a bond to chemically bond the second organic coating agent molecule to the surface of the substrate via the third functional group. Forming a monomolecular film of the second organic coating agent on the surface of the substrate, FePt nanoparticles comprising the monomolecular film of the first organic coating agent, and the second organic coating agent The first and second organic layers are formed on the substrate by contacting the second functional group and the fourth functional group to form a bond. FePt nano through coating agent Method of manufacturing a magnetic recording medium having a FePt magnetic nanoparticle array which comprises a step of forming an array of FePt nanoparticles child arranged bound to.
請求項１乃至１０のいずれか１項記載の方法により得られたＦｅＰｔナノ粒子であり、面心立方（ｆｃｃ）構造を含むＦｅＰｔナノ粒子の表面に、分子鎖の一端側に上記ＦｅＰｔナノ粒子の表面と化学結合し得る第１の官能基、他端側に上記ＦｅＰｔナノ粒子の表面と化学結合しない第２の官能基を有する第１の有機コーティング剤を接触させ、上記第１の有機コーティング剤分子を上記第１の官能基を介して上記ＦｅＰｔナノ粒子の表面に化学結合させることにより、上記ＦｅＰｔナノ粒子の表面上に上記第１の有機コーティング剤分子の単分子膜を形成する工程、
上記基板の表面に、分子鎖の一端側に上記基板の表面と化学結合し得る第３の官能基、他端側に上記基板の表面と化学結合せず、上記第２の官能基と反応して結合を形成し得る第４の官能基を有する第２の有機コーティング剤を接触させ、上記第２の有機コーティング剤分子を上記第３の官能基を介して上記基板の表面に化学結合させることにより、上記基板の表面上に上記第２の有機コーティング剤の単分子膜を形成する工程、
上記第１の有機コーティング剤の単分子膜を備えるＦｅＰｔナノ粒子と、上記第２の有機コーティング剤の単分子膜を備える基板とを接触させ、上記第２の官能基と上記第４の官能基とを反応させて結合を形成させることにより、上記基板上に、上記第１及び第２の有機コーティング剤を介してＦｅＰｔナノ粒子が結合して配列したＦｅＰｔナノ粒子の配列体を形成する工程、及び
上記配列したＦｅＰｔナノ粒子に４００℃以上でアニール処理を施すことにより、面心立方（ｆｃｃ）構造を面心直方（ｆｃｔ）構造に相転移させてＦｅＰｔ磁性ナノ粒子とする工程
を含むことを特徴とするＦｅＰｔ磁性ナノ粒子配列体を有する磁気記録媒体の製造方法。 A method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles on a substrate, comprising:
The FePt nanoparticle obtained by the method according to any one of claims 1 to 10, wherein the FePt nanoparticle includes a face-centered cubic (fcc) structure on the surface of the FePt nanoparticle on one end side of the molecular chain. A first organic coating agent having a first functional group that can be chemically bonded to the surface and a second functional group that is not chemically bonded to the surface of the FePt nanoparticle on the other end side is brought into contact with the first organic coating agent. Forming a monolayer of the first organic coating agent molecule on the surface of the FePt nanoparticle by chemically bonding a molecule to the surface of the FePt nanoparticle through the first functional group;
A third functional group capable of chemically bonding to the surface of the substrate on one end side of the molecular chain on the surface of the substrate and reacting with the second functional group without chemically bonding to the surface of the substrate on the other end side. Contacting a second organic coating agent having a fourth functional group capable of forming a bond to chemically bond the second organic coating agent molecule to the surface of the substrate via the third functional group. A step of forming a monomolecular film of the second organic coating agent on the surface of the substrate,
An FePt nanoparticle having a monomolecular film of the first organic coating agent and a substrate having a monomolecular film of the second organic coating agent are brought into contact with each other, and the second functional group and the fourth functional group are brought into contact with each other. Forming an array of FePt nanoparticles in which FePt nanoparticles are combined and arranged on the substrate via the first and second organic coating agents, And a step of subjecting the FePt nanoparticles arranged above to an annealing treatment at 400 ° C. or more to cause a face-centered cubic (fcc) structure to undergo phase transition to a face-centered rectangular (fct) structure to form FePt magnetic nanoparticles. A method of manufacturing a magnetic recording medium having a FePt magnetic nanoparticle array characterized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007200589A JP5136751B2 (en) | 2007-08-01 | 2007-08-01 | Method for producing FePt nanoparticles and method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007200589A JP5136751B2 (en) | 2007-08-01 | 2007-08-01 | Method for producing FePt nanoparticles and method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2009035769A JP2009035769A (en) | 2009-02-19 |
| JP5136751B2 true JP5136751B2 (en) | 2013-02-06 |
Family
ID=40437941
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007200589A Active JP5136751B2 (en) | 2007-08-01 | 2007-08-01 | Method for producing FePt nanoparticles and method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5136751B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016009926A1 (en) * | 2014-07-17 | 2016-01-21 | 国立大学法人東京大学 | Magnetic material loaded with magnetic alloy particles and method for producing said magnetic material |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101640730B1 (en) * | 2009-09-08 | 2016-07-19 | 제록스 코포레이션 | Ferromagnetic nanoparticles with high magnetocrystalline anisotropy for micr ink applications |
| CN101787522B (en) * | 2010-04-02 | 2011-11-09 | 南京大学 | Method for preparing ordered magnetic nanoparticle composite film with super-high density |
| JP5857448B2 (en) | 2011-05-24 | 2016-02-10 | 昭和電工株式会社 | Magnetic recording medium, method for manufacturing the same, and magnetic recording / reproducing apparatus |
| US10325705B2 (en) * | 2015-08-24 | 2019-06-18 | Nissan Motor Co., Ltd. | Magnet particles and magnet molding using same |
| CN106541147B (en) * | 2016-11-15 | 2018-03-27 | 哈尔滨工业大学 | A kind of method that hard magnetic nanometer Fe-Pt particle is prepared using inorganic salts as presoma |
| CN112909274B (en) * | 2021-03-26 | 2022-02-15 | 华中科技大学 | Platinum alloy nanocrystalline catalyst and preparation method and application thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10317022A (en) * | 1997-05-22 | 1998-12-02 | Daiken Kagaku Kogyo Kk | Production of metallic particulate powder |
| JP2002102679A (en) * | 2000-09-29 | 2002-04-09 | Toyota Motor Corp | Composite metal colloid and its production method |
| JP3597507B2 (en) * | 2001-01-24 | 2004-12-08 | 松下電器産業株式会社 | Fine particle array, method for producing the same, and device using the same |
| JP4078549B2 (en) * | 2003-07-31 | 2008-04-23 | 三菱化学株式会社 | Method for producing magnetic nanoparticles |
-
2007
- 2007-08-01 JP JP2007200589A patent/JP5136751B2/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016009926A1 (en) * | 2014-07-17 | 2016-01-21 | 国立大学法人東京大学 | Magnetic material loaded with magnetic alloy particles and method for producing said magnetic material |
| JPWO2016009926A1 (en) * | 2014-07-17 | 2017-05-25 | 国立大学法人 東京大学 | Magnetic material carrying magnetic alloy particles and method for producing the magnetic material |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2009035769A (en) | 2009-02-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5136751B2 (en) | Method for producing FePt nanoparticles and method for producing a magnetic recording medium having an array of FePt magnetic nanoparticles | |
| Kang et al. | Synthesis, self-assembly, and magnetic properties of [FEPT]/sub 1-x/au/sub x/nanoparticles | |
| JP5637362B2 (en) | Method for producing magnetic powder | |
| JP4213076B2 (en) | Method for manufacturing magnetic recording medium | |
| US20060153976A1 (en) | Magnetic recording medium and hard disk drive using the same, and manufacturing method thereof | |
| US7807217B2 (en) | Method of producing self-assembled cubic FePt nanoparticles and apparatus using same | |
| JP2006253325A (en) | Magnetic material, manufacturing method thereof, and high-density magnetic recording medium | |
| JP2008159177A (en) | Magnetic recording medium and method for manufacturing the same | |
| US20110195277A1 (en) | High density magnetic recording medium and manufacturing method thereof | |
| Takahashi et al. | Direct synthesis of Pt based L1 structured nanoparticles | |
| WO2006070572A1 (en) | Ordered alloy phase nanoparticle, process for producing the same, superdense magnetic recording medium and process for producing the same | |
| JP2016042399A (en) | Magnetic recording medium and manufacturing method thereof | |
| US20100323219A1 (en) | FeRh-FePt CORE SHELL NANOSTRUCTURE FOR ULTRA-HIGH DENSITY STORAGE MEDIA | |
| US9064520B2 (en) | Magnetic recording medium and method of manufacturing the same, and magnetic record/reproduction apparatus | |
| JP4221484B2 (en) | Metallic magnetic powder and method for producing the same | |
| JP3961887B2 (en) | Method for manufacturing perpendicular magnetic recording medium | |
| JP4642705B2 (en) | Method for manufacturing magnetic recording medium | |
| US20070218282A1 (en) | Hard-magnetic nanoparticles, manufacturing method therefor, magnetic fluid and magnetic recording medium | |
| Osaka et al. | A challenge of new materials for next generation's magnetic recording | |
| EP2343701A1 (en) | Discontinuous islanded ferromagnetic recording film with perpendicular magnetic anisotropy | |
| JP4051451B2 (en) | Magnetic materials for magnetic recording media | |
| JP2015153446A (en) | Method for manufacturing high density magnetic recording medium | |
| Zhang et al. | Ordering promotion and intergrain decoupling in FePt thin films by Ta and Ta/Bi buffer layers | |
| Sun et al. | Self-assembled magnetic nanoparticle arrays | |
| JP2008084384A (en) | Magnetic recording medium, its manufacturing method, and magnetic recording and reproducing device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20100721 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20120130 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20120229 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20120420 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20121017 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20121030 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 5136751 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20151122 Year of fee payment: 3 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313115 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |