Synthesis, characterization, and magnetic properties of carbon- and boron-oxide-encapsulated iron nanocapsules.
Carbon- and boron-oxide-encapsulated iron nanocapsules have been synthesized by arc discharge in methane (CH4) and diborane (B2H6) atmospheres respectively. The characterization and magnetic properties of carbon- and boron-oxide-encapsulated iron nanocapsules [abbreviated as Fe(C) and Fe(B) respectively] were investigated and compared. The structure of the Fe(B) nanocapsules is different from that of the Fe(C) nanocapsules. The Fe(C) nanocapsules consist of a crystalline graphite shell and a core of alpha-Fe and/or Fe3C. The Fe(B) nanocapsules consist of an amorphous boron-oxide layer and a core of Fe(B) solid solution, alpha-Fe, gamma-Fe, FeB, and/or Fe3B phases. The saturation magnetizations of both the Fe(C) and the Fe(B) nanocapsules below 300 K decrease monotonically with increasing temperature. The coercivities of the Fe(C) and Fe(B) nanocapsules are almost 2 orders of magnitude higher than that of bulk Fe. The temperature dependence of magnetization at high temperatures indicates the existence of some phase transformations.
Zhang
Z D
ZD
International Centre for Materials Physics, Institute of Metal Research, Academia Sinica, Shenyang 110016, Peoples' Republic of China.
Zheng
J G
JG
Skorvanek
I
I
Kovac
J
J
Yu
J L
JL
Dong
X L
XL
Li
Z J
ZJ
Jin
S R
SR
Zhao
X G
XG
Liu
W
W
D001894:Borohydrides / Q000737:chemistry; D001896:Boron Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D002244:Carbon / Q000737:chemistry* / Q000302:isolation & purification; D004339:Drug Compounding / Q000379:methods*; D007501:Iron / Q000737:chemistry* / Q000302:isolation & purification; D046911:Macromolecular Substances; D008280:Magnetics; D008697:Methane / Q000737:chemistry; D008854:Microscopy, Electron; D008863:Microspheres; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013696:Temperature; D014961:X-Ray Diffraction
D001894:Borohydrides; D001896:Boron Compounds; D046911:Macromolecular Substances; C042168:boron oxide; D002244:Carbon; C024731:diborane; D007501:Iron; D008697:Methane