Synthesis of Ultrasmall Ferromagnetic Face-Centered Tetragonal FePt-Graphite Core-Shell Nanocrystals

被引：28

作者：

Seo, Won Seok ^{[1
,2
,3
]}

Kim, Se Mi ^{[2
,3
]}

Kim, Young-Min ^{[4
]}

Sun, Xiaoming ^{[1
]}

Dai, Hongjie ^{[1
]}

机构：

[1] Stanford Univ, Dept Chem, Stanford, CA 94305 USA

[2] Sogang Univ, Dept Chem, Seoul 121742, South Korea

[3] Sogang Univ, Inorgan & Biomat Ctr BK21, Seoul 121742, South Korea

[4] Korea Basic Sci Inst, Div Elect Microscop Res, Taejon 305333, South Korea

来源：

SMALL | 2008年 / 4卷 / 11期

关键词：

carbon; FePt; ferromagnetism; nanocrystals; nanotechnology;

D O I：

10.1002/smll.200800257

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

A simple one-step chemical-vapor-deposition (CVD) method was used to synthesize ultrasmall ferromagnetic face-centered tetragonal (fct) FePt-graphite core-shell nanocrystals. The methane-loaded silica was dried and heated to 800°C under H2 and then subjected to methane CVD for carbon deposition on the FePt nanoalloy formed on silica. Energy-dispersive X-ray (EDX) analysis show Fe/Pt ratios of 40:60 for the 2.8-nm nanocrystals and 25:75 for the 1.9-nm nanocrystals, suggesting Pt richness in the particles. The FePt nanocrystals with partially broken carbon shells turned the color of the solution in HCl to yellow after the addition owing to the Fe etching. Magnetic hysterisis loops recorded for FePt nanocrystal samples at 5 and 300K show relatively high coercivities for small particle sizes, suggesting a high portion of fct-oredres nanocrystals.

引用

页码：1968 / 1971

页数：4

共 20 条

[11] FeCo/graphitic-shell nanocrystals as advanced magnetic-resonance-imaging and near-infrared agents [J].

Seo, Won Seok ;

Lee, Jin Hyung ;

Sun, Xiaoming ;

Suzuki, Yoriyasu ;

Mann, David ;

Liu, Zhuang ;

Terashima, Masahiro ;

Yang, Philip C. ;

McConnell, Michael V. ;

Nishimura, Dwight G. ;

Dai, Hongjie .

NATURE MATERIALS, 2006, 5 (12) :971-976

[12] Growth of FePt nanocrystals by a single bimetallic precursor [(CO)3Fe(μ-dppm)(μ-CO)PtCl2] [J].

Song, HM ;

Hong, JH ;

Lee, YB ;

Kim, WS ;

Kim, Y ;

Kim, SJ ;

Hur, NH .

CHEMICAL COMMUNICATIONS, 2006, (12) :1292-1294

[13] Recent advances in chemical synthesis, self-assembly, and applications of FePt nanoparticles [J].

Sun, SH .

ADVANCED MATERIALS, 2006, 18 (04) :393-403

[14] Compositionally controlled FePt nanoparticle materials [J].

Sun, SH ;

Fullerton, EE ;

Weller, D ;

Murray, CB .

IEEE TRANSACTIONS ON MAGNETICS, 2001, 37 (04) :1239-1243

[15] Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices [J].

Sun, SH ;

Murray, CB ;

Weller, D ;

Folks, L ;

Moser, A .

SCIENCE, 2000, 287 (5460) :1989-1992

[16] Optical properties of ultrashort semiconducting single-walled carbon nanotube capsules down to sub-10 nm [J].

Sun, Xiaoming ;

Zaric, Sasa ;

Daranciang, Dan ;

Welsher, Kevin ;

Lu, Yuerui ;

Li, Xiaolin ;

Dai, Hongjie .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2008, 130 (20) :6551-6555

[17] Well-ordered L10-FePt nanoparticles synthesized by improved SiO2-nanoreactor method [J].

Tamada, Yoshinori ;

Yamamoto, Shinpei ;

Takano, Mikio ;

Nasu, Saburou ;

Ono, Teruo .

APPLIED PHYSICS LETTERS, 2007, 90 (16)

[18] Thermal effect limits in ultrahigh-density magnetic recording [J].

Weller, D ;

Moser, A .

IEEE TRANSACTIONS ON MAGNETICS, 1999, 35 (06) :4423-4439

[19] Direct synthesis and size selection of ferromagnetic FePt nanoparticles [J].

Wellons, Matthew S. ;

Morris, William H., III ;

Gai, Zheng ;

Shen, Jian ;

Bentley, James ;

Wittig, James E. ;

Lukehart, Charles M. .

CHEMISTRY OF MATERIALS, 2007, 19 (10) :2483-2488

[20] Exchange-coupled nanocomposite magnets by nanoparticle self-assembly [J].

Zeng, H ;

Li, J ;

Liu, JP ;

Wang, ZL ;

Sun, SH .

NATURE, 2002, 420 (6914) :395-398

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