铁基金属纳米颗粒/纳米线磁性载体的PECVD制备
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摘要
碳基壳层包裹铁基金属磁性纳米颗粒/纳米线材料以其优良的磁性性能、化学稳定性和生物相容性在纳米科学与技术研究领域日益受到广泛关注。化学气相沉积技术是合成磁性纳米胶囊的有效手段之一,纳米颗粒尺寸、形貌、包裹层厚度易于控制。但是磁性纳米颗粒往往成为碳纳米管生长的催化剂,因此优化生长参数对获得高纯度的纳米磁性载体至关重要。本论文采用多靶直流磁控溅射制备Fe4N催化剂薄膜,利用等离子体增强化学气相沉积技术,获得Fe_3C磁性纳米颗粒埋层非晶碳复合材料,样品中未发现碳纳米管;采用FeNi薄膜催化剂,分别制备了石墨碳包裹FeNi纳米颗粒和γ-Fe_2O_3纳米线填充碳氮纳米管。使用扫描电子显微镜、透射电子显微镜、X射线衍射仪、X射线光电子能谱仪、拉曼光谱仪和超导量子干涉仪分析样品的表面形貌、结构和磁性性能。
At the end of last century, the computer and semiconductor industry has been fueling an explosive growth in materials research to develop new magnetic nano-carriers. Recent years, iron-based magnetic nanoparticles have attracted extensive interests in field of biomedicine, such as hyperthermia of cancer, magnetic resonance imaging. Compared with traditional iron oxide nanoparticles, metal magnetic nanoparticles exhibit higher magnetic properties like saturation magnetization. However, the inner toxicity and poor oxidation resistance due to high surface activity and defect density of bare metal nanoparticles inhibit their further applications. Since the appearance of fullerence, carbon-based materials including graphite, amorphous carbon and carbon nanotube (CNT) encapsulate magnetic metals have aroused great research interests around the world. Carbon constitute the basic elements of life, and its biological toxicity is low, which can increase the biocompatible nature and chemical stability of magnetic nanoparticles. In addition, as a nonmagnetic materials, carbon shell can help to reduce the magnetic interaction between magnetic nanaoparticles that in turn increase coercivity of the system. Among the carbon-based materials, nitrogen-containing carbon is the most potential material showing higher properties than that of carbon. Nitrogen doping carbon nanotubes (CNNTs) also exhibit higher biocompatible and lower toxicity for decreasing van der Waals among tubes.
Preparation of carbon-based nanocapsules magnetic carriers in many different ways can be divided into liquid and gas phase reaction, including preparation of liquid-phase reaction method hydrothermal synthesis method, precipitation method, micro-emulsion method, spray pyrolysis vapor and suspended particles and other methods; Gas phase reaction of preparation methods are arc current, ion sputtering, laser evaporation, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD) methods. CVD is a favorable method for preparation magnetic nano-carriers for controllable size, morphology of magnetic nanoparticles and the thickness of shells. In this paper, we chose PECVD to prepare carbon nano-capsules magnetic carrier, a technique providing a low temperature synthesis propobility.
Ti/FeNi and Fe4N thin films have been deposited on SiO_2/Si substrate using magnetron sputtering. On Fe_4N film, magnetic nanoparticles Fe_3C embedded in amorphous carbon matrix have been obtained by PECVD. No CNT has been detected. Employing FeNi thin film as catalyst, graphite encapsulated FeNi nanoparticls andγ-Fe_2O_3 nanowires have been produced, respectively. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, superconducting quantum interference device investigate the surface morphology, microstructure and magnetic properties of the samples.
The detailed experimental contents are listed as follows:
一、Preparation and characterization of Fe_3C magnetic nanopartical carriers Fe_3C nanoparticles embedded in amorphous carbon matrix have been prepared by magnetron sputtering and PECVD technique. Fe_4N thin film, which could decompose into iron and nitrogen when heated up to 650℃was chosen as precursor in stead of iron film for avoiding formation of CNT. Annealing in the mixture of CH_4+H 2, iron will compound with carbon to form Fe_3C phase. In this work, we study the influence of CH_4 decomposition time on the structure, morphology and magnetic properties of amorphous carbon and Fe_3C nanoparticles.
二、Preparation and characterization of magnetic nano-carriers on FeNi catalyst
1.γ-Fe_2O_3 nanowires filled carbon nitride nanotubes
(1)Influence of catalyst thickness on the growth of CNNTs CNNTs were prepared in the atmosphere of CH_4+O_2+N_2. The thinner the catalyst film, the smaller the catalyst particles and the uniformed distribution of the catalyst, which in turn results in the higher density of CNTs. On film of Fe-Ni 2 nm, the CNNTs are open ended, with catalyst particles exposing or having been etched, few filling could be observed; On Fe-Ni 10 nm, By measuring the crystal plane spacing of filling materials could initially judge that carbon nanotubes can be filled with material for theγ-Fe_2O_3.
(2)Influence of hydrogen on the growth of CNNTs
Adding H_2 in the mixed gases of CH_4+Air, the synthesized CNNTs exhibit greater purity and density, smaller size of diameter, and higher amount of filling. Investigated by TEM and XPS,the filling nanowire was determined to be single crystalγ-Fe_2O_3;SQUID measurement suggests the magnetic nature of the filled CNNTs composite.
(3)Influence of deposition time on the growth of CNNTs
Deposition time of 5min, the growth of CNNTs exhibits a bamboo-shaped morphology, without obvious opened end. High degree fillings could be clearly observed in the CNNTs. In contrast, for CNNTs deposited for 8min, there is very obvious bamboo-like growth, with the top opening, and reduced filling degree of nanoparticles/nanowires.
2. Preparation and characterization of graphite encapsulated FeNi nanoparticles Graphite encapsulated FeNi nanoparticles have been synthesized at different
deposition temperatures by PECVD. The deposition gases were chosen as CH_4+Ar. With increasing deposition temperature from 600 to 800℃, the size of the particles increased. Selected area electron diffractions indicated the product of FeNi nanoparticles.
In summary, Fe_3C magnetic nanoparticles embedded amorphous carbon matrix could be prepared in the atmosphere of CH_4+H2 by PECVD. Increasing decomposition time of CH_4 could result in the increase of amorphous carbon matrix. On the Ti/FeNi catalyst film, graphite encapsulated FeNi nanoparticles have been synthesized in the mixture of CH_4+Ar. However, in the mixed gases of CH_4+H2+Air, single crystalγ-Fe_2O_3 nanowires are obtained that exhibit magnetic nature.
At the end of last century, the computer and semiconductor industry has been fueling an explosive growth in materials research to develop new magnetic nano-carriers. Recent years, iron-based magnetic nanoparticles have attracted extensive interests in field of biomedicine, such as hyperthermia of cancer, magnetic resonance imaging. Compared with traditional iron oxide nanoparticles, metal magnetic nanoparticles exhibit higher magnetic properties like saturation magnetization. However, the inner toxicity and poor oxidation resistance due to high surface activity and defect density of bare metal nanoparticles inhibit their further applications. Since the appearance of fullerence, carbon-based materials including graphite, amorphous carbon and carbon nanotube (CNT) encapsulate magnetic metals have aroused great research interests around the world. Carbon constitute the basic elements of life, and its biological toxicity is low, which can increase the biocompatible nature and chemical stability of magnetic nanoparticles. In addition, as a nonmagnetic materials, carbon shell can help to reduce the magnetic interaction between magnetic nanaoparticles that in turn increase coercivity of the system. Among the carbon-based materials, nitrogen-containing carbon is the most potential material showing higher properties than that of carbon. Nitrogen doping carbon nanotubes (CNNTs) also exhibit higher biocompatible and lower toxicity for decreasing van der Waals among tubes.
Preparation of carbon-based nanocapsules magnetic carriers in many different ways can be divided into liquid and gas phase reaction, including preparation of liquid-phase reaction method hydrothermal synthesis method, precipitation method, micro-emulsion method, spray pyrolysis vapor and suspended particles and other methods; Gas phase reaction of preparation methods are arc current, ion sputtering, laser evaporation, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD) methods. CVD is a favorable method for preparation magnetic nano-carriers for controllable size, morphology of magnetic nanoparticles and the thickness of shells. In this paper, we chose PECVD to prepare carbon nano-capsules magnetic carrier, a technique providing a low temperature synthesis propobility.
Ti/FeNi and Fe4N thin films have been deposited on SiO_2/Si substrate using magnetron sputtering. On Fe_4N film, magnetic nanoparticles Fe_3C embedded in amorphous carbon matrix have been obtained by PECVD. No CNT has been detected. Employing FeNi thin film as catalyst, graphite encapsulated FeNi nanoparticls andγ-Fe_2O_3 nanowires have been produced, respectively. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, superconducting quantum interference device investigate the surface morphology, microstructure and magnetic properties of the samples.
The detailed experimental contents are listed as follows:
一、Preparation and characterization of Fe_3C magnetic nanopartical carriers Fe_3C nanoparticles embedded in amorphous carbon matrix have been prepared by magnetron sputtering and PECVD technique. Fe_4N thin film, which could decompose into iron and nitrogen when heated up to 650℃was chosen as precursor in stead of iron film for avoiding formation of CNT. Annealing in the mixture of CH_4+H 2, iron will compound with carbon to form Fe_3C phase. In this work, we study the influence of CH_4 decomposition time on the structure, morphology and magnetic properties of amorphous carbon and Fe_3C nanoparticles.
二、Preparation and characterization of magnetic nano-carriers on FeNi catalyst
1.γ-Fe_2O_3 nanowires filled carbon nitride nanotubes
(1)Influence of catalyst thickness on the growth of CNNTs CNNTs were prepared in the atmosphere of CH_4+O_2+N_2. The thinner the catalyst film, the smaller the catalyst particles and the uniformed distribution of the catalyst, which in turn results in the higher density of CNTs. On film of Fe-Ni 2 nm, the CNNTs are open ended, with catalyst particles exposing or having been etched, few filling could be observed; On Fe-Ni 10 nm, By measuring the crystal plane spacing of filling materials could initially judge that carbon nanotubes can be filled with material for theγ-Fe_2O_3.
(2)Influence of hydrogen on the growth of CNNTs
Adding H_2 in the mixed gases of CH_4+Air, the synthesized CNNTs exhibit greater purity and density, smaller size of diameter, and higher amount of filling. Investigated by TEM and XPS,the filling nanowire was determined to be single crystalγ-Fe_2O_3;SQUID measurement suggests the magnetic nature of the filled CNNTs composite.
(3)Influence of deposition time on the growth of CNNTs
Deposition time of 5min, the growth of CNNTs exhibits a bamboo-shaped morphology, without obvious opened end. High degree fillings could be clearly observed in the CNNTs. In contrast, for CNNTs deposited for 8min, there is very obvious bamboo-like growth, with the top opening, and reduced filling degree of nanoparticles/nanowires.
2. Preparation and characterization of graphite encapsulated FeNi nanoparticles Graphite encapsulated FeNi nanoparticles have been synthesized at different
deposition temperatures by PECVD. The deposition gases were chosen as CH_4+Ar. With increasing deposition temperature from 600 to 800℃, the size of the particles increased. Selected area electron diffractions indicated the product of FeNi nanoparticles.
In summary, Fe_3C magnetic nanoparticles embedded amorphous carbon matrix could be prepared in the atmosphere of CH_4+H2 by PECVD. Increasing decomposition time of CH_4 could result in the increase of amorphous carbon matrix. On the Ti/FeNi catalyst film, graphite encapsulated FeNi nanoparticles have been synthesized in the mixture of CH_4+Ar. However, in the mixed gases of CH_4+H2+Air, single crystalγ-Fe_2O_3 nanowires are obtained that exhibit magnetic nature.
引文
[1] Chien C L., Granular magnetic solids (invited), J. Appl. Phys., 1991, 69, 5267.
[2] McHenry M E, Majetich S A, Artman J O, DeGraef M, and Staley S W., Superparamagnetiam in carbon-coated Co particles produced by the Kratschmer carbon arc process, Phys Rev B, 1994, 49, 11358.
[3] Liu Y, Tan C Y, Liu Z W, and Ong C K., FeCoSiN film with ordered FeCo nanoparticles imbedded in a Si-rich matrix, Appl. Phys. Lett., 2007, 90, 112506.
[4] Delaunay JJ, Hayashi T, Tomita M, Hirono S, and Umemura S., CoPtC nanogranular magnetic thin films, Appl Phys Lett., 1997, 71 (3), 427.
[5] Z.D. Zhang,“Magnetic nanocapsules”, J. Mater. Sci. Technol. 23 (2007) 1 (Review)
[6] W.S. Seo, J.H. Lee, et al.,“FeCo/graphitic-shell nanocrystals as advanced magnetic-resonance-imaging and near-infrared agents”, Nature Mater. 5 (2006) 971
[7] G. B. Sergeev, Usp. Khim. 2001, 70, 915–933.
[8] K. Klabunde in Nanoscale Materials in Chemistry (Ed.: K. Klabunde), Wiley-Interscience, New York, 2001, pp. 1–13.
[9] M.E. McHENRY, D.E. Laughlin,“Nano-scale materials development for future magnetic application”, Acta Mater. (2005) 48 223
[10] D.L. Huber,“Synthesis, properties, and applications of iron nanoparticles”, Small 1 (2005) 482
[11] Giri J, Ray A, Dasgupta S, Datta D and Bahadur D,Investigation of Tc tuned nanoparticles of magnetic oxidesfor hyperthermia applications,Biomed. Mater. Eng. (2003)13 387–99
[12] Jin H and Kang K A , Application of novel metal nanoparticles as optical/thermal agents in optical mammography and hyperthermic treatment for breast cancer,Adv. Exp. Med. Biol. (2007)599 45–52
[13] A.A. El-Gendy et al,The synthesis of carbon coated Fe, Co and Ni nanoparticles and an examination of their magnetic properties,CARBON 47 (2009) 2821– 2828
[14] Jordan A et al,Inductive heating of ferromagnetic particles and magnetic ?uids—physical evaluation of their potential for hyperthermia,Int. J. Hyperth(1993)9 51-68
[15] DeNardo S J et al ,Development of tumor targeting bioprobes (In-111-chimeric L6 monoclonal antibody nanoparticles) for alternating magnetic field cancer therapy Clin. Cancer Res. (2005)11 (Suppl. 19) 7087S–92S
[16] DeNardo S J et al,Thermal dosimetry predictive of efficacy of In-111-ChL6 nanoparticle AMF-induced thermoablative therapy for human breast cancer in mice J. Nucl. Med.(2007)48 437–44
[17] Dobson J,Magnetic micro- and nano-particle-based targeting for drug and gene delivery ,Nanomedicine (2007)1 31-7
[18] McBain S C, YiuHHPand Dobson J,Magnetic nanoparticles for gene and drug delivery Int. J. Nanomed.(2008)3 169–80
[19] Grief A D and Richardson G,Mathematical modeling of magnetically targeted drug delivery ,J. Magn. Magn.Mater.(2005)293 455-63
[20] Wilson M W et al,Hepatocellular carcinoma: regional therapy with a magnetic targeted carrier bound to doxorubicin in a dual MR imaging/conventional angiography suite—initial experience with four patients Radiology,(2004)230 287-93
[21] Iacob G et al ,Magnetizable needles and wires—modeling an efficient way to target magnetic microspheres in vivo Biorheology(2004)41 599–612
[22] E.P. Sajitha et al,Synthesis and characteristics of iron nanoparticles in a carbon matrix along with the catalytic graphitization of amorphous carbon, Carbon (2004) 42 2815–2820
[23] Junping Huo, Huaihe Song *, Xiaohong Chen, Wentao Lian, Formation and transformation of carbon-encapsulated iron carbide/iron nanorods, Carbon 44 (2006) 2849–2867
[24] N. Aguiló-Aguayo , J.L. Casta?o-Bernal, J. García-Céspedes, E. Bertran, Magnetic response of CVD and PECVD iron filled multi-walled carbon nanotubes, Diamond & Related Materials 18 (2009) 953–956
[25] J.L. Qi, X. Wang, H.W. Tian, C. Liu, Y.L. Lu, W.T. Zheng *, Synthesis of a composite consisting of carbon nanotubes and graphite shell-encapsulated cobalt nanoparticles using plasma-enhanced chemical vapor deposition, Applied Surface Science 256 (2009) 1486–1491
[26] A G Roca et al,Progress in the preparation of magnetic nanoparticles for applications in biomedicine,J. Phys. D: Appl. Phys. 42 (2009) 224002 (11pp)
[27] Molday R S and Mackenzie D,Immunospecific ferromagnetic iron-dextran reagents for the labeling and magnetic separation of cells,journal of ImmunoIogical Methods.(1982)52 353-367
[28] Wu J H, Ko S P, Liu H L, Kim S, Ju J S and Kim Y K,Sub 5 nm magnetite nanoparticles: Synthesis, microstructure, and magnetic properties, Material letters (2007)61 3124-3129
[29] Martinez-Mera I, Espinosa-Pesqueira M E, Perez-Hernandez R and Arenas-Alatorre J,Synthesis of magnetite (Fe3O4) nanoparticles without surfactants at room temperature,Mater. Lett. (2007)61 4447-4451
[30] Lu J, Yang S H, Ng K M, Su C H, Yeh C S, WuYNand Shieh D B,Solid-state synthesis of monocrystalline iron oxide nanoparticle based ferrofluid suitable for magnetic resonance imaging contrast application, Nanotechnology(.2006)17 5812
[31] MarquesRFC, Garcia C, Lecante P, RibeiroSJL,NoeL,SilvaNJO, Amaral V, Mill′an A and Verelst M,Electro-precipitation of Fe3O4 nanoparticles in ethanol,J. Magn. Magn. Mater. (2008) 320 2311
[32] Li Z, Chen H, Bao H and Gao M, One-Pot Reaction to Synthesize Water-Soluble Magnetite Nanocrystals ,Chem. Mater. (2004) 16 1391
[33] Park J, An K, Hwang Y, ParkJEG,NohHJ,KimJY,Park J H, Hwang N M and Hyeon T, Ultra-large-scale syntheses of monodisperse nanocrystals , Nature Mater. (2004) 3 891
[34] Wang Zhiyu ,Zhao Zongbin ,Qiu Jieshan. Development of Filling Carbon Nanotubes. PROGRESS IN CHEMISTRY,(2006) 18 5
[35] Czerw et al. Identification of Electron Donor States in N-Doped CarbonNanotubes,(2001) 1 457
[36] Choi et al,Experimental and theoretical studies on the structure of N-doped carbon nanotubes: Possibility of intercalated molecular N2, APL,2004,85, 5743
[37] Cao et al,Catalytic synthesis of nitrogen-doped multi-walled carbon nanotubes using layered double hydroxides as catalyst precursors,J. Chem. Sco.,2009,121, 225
[38] Jeong Young Lee , Byung Soo Lee,Nitrogen induced structure control of vertically aligned carbon nanotubes synthesized by microwave plasma enhanced chemical vapor deposition,Thin Solid Films 418 (2002) 85–88
[39] Yu H L and Taichun H., Effects of annealing on magnetic properties of Fe3C nanograins embedded in amorphous carbon films, J. J. Appl. Phys.,2004, 43, 7477.
[40] Guskos N, Anagnostakis E A, Likodimos V, Bodziony T, Typek J, Maryniak M, Narkiewicz U, Kucharewicz I, and Waplak S., Ferromagnetic resonance and ac conductivity of a polymer composite of Fe3O4 and Fe3C nanoparticles dispersed in a graphite matrix, J. Appl. Phys., 2005, 97, 024304.
[41] Seung H H and Atsushi N., Laser synthesis and magnetism of amorphous iron and cobalt carbide nanoparticles with carbon onion, J. Appl. Phys., 2006, 99, 064302.
[42] Ivanova N A, Onischuk A A, Vosel S V, Purtov P A, Vasenin N T, Anufrienko V F, and Ikorski V N., Reversible modification of magnetic properties of Fe3C nanoparticles by chemisorption of CO, Appl. Magn. Reson., 2008, 33, 285 (and the references therein).
[43] Talyzin A, Dzwilewski A, Dubrovinsky L, Setzer A, and Esquinazi P., Structural and magnetic properties of polymerized C60 with Fe, Eur. Phys. J. B, 2007, 55, 57.
[44] Rouquette J, Dolej? D, Kantor I Y, McCammon C A, Frost D J, Prakapenka V B, and Dubrovinsky L S., Iron-Carbon interactions at high temperatures and pressures, Appl. Phys. Lett., 2008, 92, 121912.
[45] Mi W B, Li Z Q, Wu P, Jiang E Y, Bai H L, Hou D L, and Li X L., Facing-target sputtered Fe–C granular films: Structural and magnetic properties, J. Appl. Phys., 2005, 97, 043903.
[46] Sajitha E P, Prasad V, Subramanyam S V, Eto S, Takai K, and Enoki T.,Synthesis and characteristics of iron nanoparticles in a carbon matrix along with the catalytic graphitization of amorphous carbon, Carbon , 2004, 42, 2815.
[47] Sajitha E.P., Prasad V., Subramanyam S.V., Mishra A.K., Sarkar S., Bansal C., Structural, magnetic and Mo¨ssbauer studies of iron inclusions in a carbon matrix, J. Magn. Magn. Mater.. 2007, 313, 329.
[48] Qiu J S, Li Q X, Wang Z Y, Sun Y F, and Zhang H Z., CVD synthesis of coal-gas-derived carbon nanotubes and nanocapsules containing magnetic iron carbide and oxide, Carbon, 2006, 44, 2565.
[49] Sajitha E P, Prasad V, Subramanyam S V, KumarMishra A, Sarkar S, and Bansal C., Size-dependent magnetic properties of iron carbide nanoparticles embedded in a carbon matrix, J. Phys.: Condens. Matter., 2007, 19, 046214.
[50] Melechko A V, Merkulov V I, McKnight T E, Guillorn M A, Klein K L, Lowndes D H, and Simpson M L., Vertically aligned carbon nanofibers and related structures: Controlled synthesis and directed assembly, J. Appl. Phys., 2005, 97, 041301.
[51] Wang Y, Wei W, Maspoch D, Wu J S, Dravid V P, MirkinCA , Superparamagnetic Sub-5 nm Fe@C Nanoparticles: Isolation, Structure, Magnetic Properties, and Directed Assembly,Nano Lett,2008,8 3761
[52] Leconte Y et al,Continuous production of water dispersible carbon–iron nanocomposites by laser pyrolysis: Application as MRI contrasts ,J. Colloid Interface Sci.2007,313 511
[53] E.P. Sajitha et al, Synthesis and characteristics of iron nanoparticles in a carbon matrix along with the catalytic graphitization of amorphous carbon, Carbon 42 (2004) 2815–2820
[54] Guangmin Yang, Xin Wang, Qiang Xu, Shumin Wang, Hongwei Tian, Weitao Zheng , Two types of carbon nanocomposites: Graphite encapsulated iron nanoparticles and thin carbon nanotubes supported on thick carbon nanotubes, synthesized using PECVD,Journal of Solid State Chemistry ,182 (2009) 966–972
[55] S.C. Tsang, M.L.H. Green et al, A simple chemical method of opening and filling carbon nanotubes, Nature, 372, 159, (1994)
[56] E. Palen et al., Iron filled single-wall carbon nanotubes– A novel ferromagnetic medium, CPL, 421, 129, (2006)
[57] C. Guerret Plecourt et al., Relation between metal electronic structure and morphology of metal compounds inside carbon nanotubes,Laboratoire des Solides Irradies, France,Nature, 372, 761, (1994)
[58] Mueller et al., Growth studies, TEM and XRD investigations of iron-filled carbon nanotubes, Phys. Stat. Sol., 203, 1064, (2006)
[59] Fujita et al., Encapsulation of segmented Pd–Co nanocomposites into vertically aligned carbon nanotubes by plasma-hydrogen-induced demixing, APL, 90, 133116, (2007)
[60] By Albrecht Leonhardt, Synthesis, Properties, and Applications of Ferromagnetic-Filled Carbon Nanotubes, Chem. Vap. Deposition , 2006, 12, 380–387
[61] Bui Thi Hang et al, Fe2O3-filled carbon nanotubes as a negative electrode for an Fe–air battery, Journal of Power Sources 178 (2008) 393–401
[62] Song Qu et al, Magnetic removal of dyes from aqueous solution using multi-walled carbon nanotubes filled with Fe2O3 particles, Journal of Hazardous Materials 160 (2008) 643–647
[63] Jae Won Jang and Cheol Eui Lee,Structural study of nitrogen-doping effects in bamboo-shaped multiwalled carbon nanotubes,APPLIED PHYSICS LETTERS (2004),84(15)
[64] Yuchen Ma, A. S. Foster, A. V. Krasheninnikov, and R. M. Nieminen,Nitrogen in graphite and carbon nanotubes: Magnetism and mobility,PHYSICAL REVIEW B 72, 205416, (2005)
[65] Jeong Young Lee,Byung Soo Lee,Nitrogen induced structure control of vertically aligned carbon nanotubes synthesized by microwave plasma enhanced chemical vapor deposition,Thin Solid Films 418 (2002) 85–88
[66] J.C. Carrero Sanchez, A.L. Elias, R. Mancilla et al,Biocompatiblity and toxicological studies of carbon nanotubes doped with nitrogen,NANO LETTERS ,(2006)6, 1609
[67] W. Xu, Y. Zhang, W.T. Zheng, X. Wang,“Synthesis and characteristics of Fe3C nanoparticles embedded in amorphous carbon matrix”, Chem. J. Chinese Uni. Accepted
[68] J.L. Qi, X. Wang, W.T. Zheng,“Ar plasma treatment on few layer graphene sheets for enhancing their field emission properties”, J. Phys. D In press
[69] Mchenry M E and Laughlin D E., Nano-scale materials development for future magnetic applications, Acta Mater., (2000), 48, 223.
[70] Sjostrom H, Stafstrom S, Boman M, Sundgren JE, Superhard and elastic carbon nitride thin films having fullerene like microstructure, Phys Rev Lett(1995);75(7):1336–9.
[71] V.Z. Mordkovich, E.A. Dolgova, A.R. Karaeva, et al.,“Synthesis of carbon nanotubes by catalytic conversion of methane: Competition between active components of catalyst”, Carbon 45 (2007) 62.
[2] McHenry M E, Majetich S A, Artman J O, DeGraef M, and Staley S W., Superparamagnetiam in carbon-coated Co particles produced by the Kratschmer carbon arc process, Phys Rev B, 1994, 49, 11358.
[3] Liu Y, Tan C Y, Liu Z W, and Ong C K., FeCoSiN film with ordered FeCo nanoparticles imbedded in a Si-rich matrix, Appl. Phys. Lett., 2007, 90, 112506.
[4] Delaunay JJ, Hayashi T, Tomita M, Hirono S, and Umemura S., CoPtC nanogranular magnetic thin films, Appl Phys Lett., 1997, 71 (3), 427.
[5] Z.D. Zhang,“Magnetic nanocapsules”, J. Mater. Sci. Technol. 23 (2007) 1 (Review)
[6] W.S. Seo, J.H. Lee, et al.,“FeCo/graphitic-shell nanocrystals as advanced magnetic-resonance-imaging and near-infrared agents”, Nature Mater. 5 (2006) 971
[7] G. B. Sergeev, Usp. Khim. 2001, 70, 915–933.
[8] K. Klabunde in Nanoscale Materials in Chemistry (Ed.: K. Klabunde), Wiley-Interscience, New York, 2001, pp. 1–13.
[9] M.E. McHENRY, D.E. Laughlin,“Nano-scale materials development for future magnetic application”, Acta Mater. (2005) 48 223
[10] D.L. Huber,“Synthesis, properties, and applications of iron nanoparticles”, Small 1 (2005) 482
[11] Giri J, Ray A, Dasgupta S, Datta D and Bahadur D,Investigation of Tc tuned nanoparticles of magnetic oxidesfor hyperthermia applications,Biomed. Mater. Eng. (2003)13 387–99
[12] Jin H and Kang K A , Application of novel metal nanoparticles as optical/thermal agents in optical mammography and hyperthermic treatment for breast cancer,Adv. Exp. Med. Biol. (2007)599 45–52
[13] A.A. El-Gendy et al,The synthesis of carbon coated Fe, Co and Ni nanoparticles and an examination of their magnetic properties,CARBON 47 (2009) 2821– 2828
[14] Jordan A et al,Inductive heating of ferromagnetic particles and magnetic ?uids—physical evaluation of their potential for hyperthermia,Int. J. Hyperth(1993)9 51-68
[15] DeNardo S J et al ,Development of tumor targeting bioprobes (In-111-chimeric L6 monoclonal antibody nanoparticles) for alternating magnetic field cancer therapy Clin. Cancer Res. (2005)11 (Suppl. 19) 7087S–92S
[16] DeNardo S J et al,Thermal dosimetry predictive of efficacy of In-111-ChL6 nanoparticle AMF-induced thermoablative therapy for human breast cancer in mice J. Nucl. Med.(2007)48 437–44
[17] Dobson J,Magnetic micro- and nano-particle-based targeting for drug and gene delivery ,Nanomedicine (2007)1 31-7
[18] McBain S C, YiuHHPand Dobson J,Magnetic nanoparticles for gene and drug delivery Int. J. Nanomed.(2008)3 169–80
[19] Grief A D and Richardson G,Mathematical modeling of magnetically targeted drug delivery ,J. Magn. Magn.Mater.(2005)293 455-63
[20] Wilson M W et al,Hepatocellular carcinoma: regional therapy with a magnetic targeted carrier bound to doxorubicin in a dual MR imaging/conventional angiography suite—initial experience with four patients Radiology,(2004)230 287-93
[21] Iacob G et al ,Magnetizable needles and wires—modeling an efficient way to target magnetic microspheres in vivo Biorheology(2004)41 599–612
[22] E.P. Sajitha et al,Synthesis and characteristics of iron nanoparticles in a carbon matrix along with the catalytic graphitization of amorphous carbon, Carbon (2004) 42 2815–2820
[23] Junping Huo, Huaihe Song *, Xiaohong Chen, Wentao Lian, Formation and transformation of carbon-encapsulated iron carbide/iron nanorods, Carbon 44 (2006) 2849–2867
[24] N. Aguiló-Aguayo , J.L. Casta?o-Bernal, J. García-Céspedes, E. Bertran, Magnetic response of CVD and PECVD iron filled multi-walled carbon nanotubes, Diamond & Related Materials 18 (2009) 953–956
[25] J.L. Qi, X. Wang, H.W. Tian, C. Liu, Y.L. Lu, W.T. Zheng *, Synthesis of a composite consisting of carbon nanotubes and graphite shell-encapsulated cobalt nanoparticles using plasma-enhanced chemical vapor deposition, Applied Surface Science 256 (2009) 1486–1491
[26] A G Roca et al,Progress in the preparation of magnetic nanoparticles for applications in biomedicine,J. Phys. D: Appl. Phys. 42 (2009) 224002 (11pp)
[27] Molday R S and Mackenzie D,Immunospecific ferromagnetic iron-dextran reagents for the labeling and magnetic separation of cells,journal of ImmunoIogical Methods.(1982)52 353-367
[28] Wu J H, Ko S P, Liu H L, Kim S, Ju J S and Kim Y K,Sub 5 nm magnetite nanoparticles: Synthesis, microstructure, and magnetic properties, Material letters (2007)61 3124-3129
[29] Martinez-Mera I, Espinosa-Pesqueira M E, Perez-Hernandez R and Arenas-Alatorre J,Synthesis of magnetite (Fe3O4) nanoparticles without surfactants at room temperature,Mater. Lett. (2007)61 4447-4451
[30] Lu J, Yang S H, Ng K M, Su C H, Yeh C S, WuYNand Shieh D B,Solid-state synthesis of monocrystalline iron oxide nanoparticle based ferrofluid suitable for magnetic resonance imaging contrast application, Nanotechnology(.2006)17 5812
[31] MarquesRFC, Garcia C, Lecante P, RibeiroSJL,NoeL,SilvaNJO, Amaral V, Mill′an A and Verelst M,Electro-precipitation of Fe3O4 nanoparticles in ethanol,J. Magn. Magn. Mater. (2008) 320 2311
[32] Li Z, Chen H, Bao H and Gao M, One-Pot Reaction to Synthesize Water-Soluble Magnetite Nanocrystals ,Chem. Mater. (2004) 16 1391
[33] Park J, An K, Hwang Y, ParkJEG,NohHJ,KimJY,Park J H, Hwang N M and Hyeon T, Ultra-large-scale syntheses of monodisperse nanocrystals , Nature Mater. (2004) 3 891
[34] Wang Zhiyu ,Zhao Zongbin ,Qiu Jieshan. Development of Filling Carbon Nanotubes. PROGRESS IN CHEMISTRY,(2006) 18 5
[35] Czerw et al. Identification of Electron Donor States in N-Doped CarbonNanotubes,(2001) 1 457
[36] Choi et al,Experimental and theoretical studies on the structure of N-doped carbon nanotubes: Possibility of intercalated molecular N2, APL,2004,85, 5743
[37] Cao et al,Catalytic synthesis of nitrogen-doped multi-walled carbon nanotubes using layered double hydroxides as catalyst precursors,J. Chem. Sco.,2009,121, 225
[38] Jeong Young Lee , Byung Soo Lee,Nitrogen induced structure control of vertically aligned carbon nanotubes synthesized by microwave plasma enhanced chemical vapor deposition,Thin Solid Films 418 (2002) 85–88
[39] Yu H L and Taichun H., Effects of annealing on magnetic properties of Fe3C nanograins embedded in amorphous carbon films, J. J. Appl. Phys.,2004, 43, 7477.
[40] Guskos N, Anagnostakis E A, Likodimos V, Bodziony T, Typek J, Maryniak M, Narkiewicz U, Kucharewicz I, and Waplak S., Ferromagnetic resonance and ac conductivity of a polymer composite of Fe3O4 and Fe3C nanoparticles dispersed in a graphite matrix, J. Appl. Phys., 2005, 97, 024304.
[41] Seung H H and Atsushi N., Laser synthesis and magnetism of amorphous iron and cobalt carbide nanoparticles with carbon onion, J. Appl. Phys., 2006, 99, 064302.
[42] Ivanova N A, Onischuk A A, Vosel S V, Purtov P A, Vasenin N T, Anufrienko V F, and Ikorski V N., Reversible modification of magnetic properties of Fe3C nanoparticles by chemisorption of CO, Appl. Magn. Reson., 2008, 33, 285 (and the references therein).
[43] Talyzin A, Dzwilewski A, Dubrovinsky L, Setzer A, and Esquinazi P., Structural and magnetic properties of polymerized C60 with Fe, Eur. Phys. J. B, 2007, 55, 57.
[44] Rouquette J, Dolej? D, Kantor I Y, McCammon C A, Frost D J, Prakapenka V B, and Dubrovinsky L S., Iron-Carbon interactions at high temperatures and pressures, Appl. Phys. Lett., 2008, 92, 121912.
[45] Mi W B, Li Z Q, Wu P, Jiang E Y, Bai H L, Hou D L, and Li X L., Facing-target sputtered Fe–C granular films: Structural and magnetic properties, J. Appl. Phys., 2005, 97, 043903.
[46] Sajitha E P, Prasad V, Subramanyam S V, Eto S, Takai K, and Enoki T.,Synthesis and characteristics of iron nanoparticles in a carbon matrix along with the catalytic graphitization of amorphous carbon, Carbon , 2004, 42, 2815.
[47] Sajitha E.P., Prasad V., Subramanyam S.V., Mishra A.K., Sarkar S., Bansal C., Structural, magnetic and Mo¨ssbauer studies of iron inclusions in a carbon matrix, J. Magn. Magn. Mater.. 2007, 313, 329.
[48] Qiu J S, Li Q X, Wang Z Y, Sun Y F, and Zhang H Z., CVD synthesis of coal-gas-derived carbon nanotubes and nanocapsules containing magnetic iron carbide and oxide, Carbon, 2006, 44, 2565.
[49] Sajitha E P, Prasad V, Subramanyam S V, KumarMishra A, Sarkar S, and Bansal C., Size-dependent magnetic properties of iron carbide nanoparticles embedded in a carbon matrix, J. Phys.: Condens. Matter., 2007, 19, 046214.
[50] Melechko A V, Merkulov V I, McKnight T E, Guillorn M A, Klein K L, Lowndes D H, and Simpson M L., Vertically aligned carbon nanofibers and related structures: Controlled synthesis and directed assembly, J. Appl. Phys., 2005, 97, 041301.
[51] Wang Y, Wei W, Maspoch D, Wu J S, Dravid V P, MirkinCA , Superparamagnetic Sub-5 nm Fe@C Nanoparticles: Isolation, Structure, Magnetic Properties, and Directed Assembly,Nano Lett,2008,8 3761
[52] Leconte Y et al,Continuous production of water dispersible carbon–iron nanocomposites by laser pyrolysis: Application as MRI contrasts ,J. Colloid Interface Sci.2007,313 511
[53] E.P. Sajitha et al, Synthesis and characteristics of iron nanoparticles in a carbon matrix along with the catalytic graphitization of amorphous carbon, Carbon 42 (2004) 2815–2820
[54] Guangmin Yang, Xin Wang, Qiang Xu, Shumin Wang, Hongwei Tian, Weitao Zheng , Two types of carbon nanocomposites: Graphite encapsulated iron nanoparticles and thin carbon nanotubes supported on thick carbon nanotubes, synthesized using PECVD,Journal of Solid State Chemistry ,182 (2009) 966–972
[55] S.C. Tsang, M.L.H. Green et al, A simple chemical method of opening and filling carbon nanotubes, Nature, 372, 159, (1994)
[56] E. Palen et al., Iron filled single-wall carbon nanotubes– A novel ferromagnetic medium, CPL, 421, 129, (2006)
[57] C. Guerret Plecourt et al., Relation between metal electronic structure and morphology of metal compounds inside carbon nanotubes,Laboratoire des Solides Irradies, France,Nature, 372, 761, (1994)
[58] Mueller et al., Growth studies, TEM and XRD investigations of iron-filled carbon nanotubes, Phys. Stat. Sol., 203, 1064, (2006)
[59] Fujita et al., Encapsulation of segmented Pd–Co nanocomposites into vertically aligned carbon nanotubes by plasma-hydrogen-induced demixing, APL, 90, 133116, (2007)
[60] By Albrecht Leonhardt, Synthesis, Properties, and Applications of Ferromagnetic-Filled Carbon Nanotubes, Chem. Vap. Deposition , 2006, 12, 380–387
[61] Bui Thi Hang et al, Fe2O3-filled carbon nanotubes as a negative electrode for an Fe–air battery, Journal of Power Sources 178 (2008) 393–401
[62] Song Qu et al, Magnetic removal of dyes from aqueous solution using multi-walled carbon nanotubes filled with Fe2O3 particles, Journal of Hazardous Materials 160 (2008) 643–647
[63] Jae Won Jang and Cheol Eui Lee,Structural study of nitrogen-doping effects in bamboo-shaped multiwalled carbon nanotubes,APPLIED PHYSICS LETTERS (2004),84(15)
[64] Yuchen Ma, A. S. Foster, A. V. Krasheninnikov, and R. M. Nieminen,Nitrogen in graphite and carbon nanotubes: Magnetism and mobility,PHYSICAL REVIEW B 72, 205416, (2005)
[65] Jeong Young Lee,Byung Soo Lee,Nitrogen induced structure control of vertically aligned carbon nanotubes synthesized by microwave plasma enhanced chemical vapor deposition,Thin Solid Films 418 (2002) 85–88
[66] J.C. Carrero Sanchez, A.L. Elias, R. Mancilla et al,Biocompatiblity and toxicological studies of carbon nanotubes doped with nitrogen,NANO LETTERS ,(2006)6, 1609
[67] W. Xu, Y. Zhang, W.T. Zheng, X. Wang,“Synthesis and characteristics of Fe3C nanoparticles embedded in amorphous carbon matrix”, Chem. J. Chinese Uni. Accepted
[68] J.L. Qi, X. Wang, W.T. Zheng,“Ar plasma treatment on few layer graphene sheets for enhancing their field emission properties”, J. Phys. D In press
[69] Mchenry M E and Laughlin D E., Nano-scale materials development for future magnetic applications, Acta Mater., (2000), 48, 223.
[70] Sjostrom H, Stafstrom S, Boman M, Sundgren JE, Superhard and elastic carbon nitride thin films having fullerene like microstructure, Phys Rev Lett(1995);75(7):1336–9.
[71] V.Z. Mordkovich, E.A. Dolgova, A.R. Karaeva, et al.,“Synthesis of carbon nanotubes by catalytic conversion of methane: Competition between active components of catalyst”, Carbon 45 (2007) 62.