TY - JOUR
T1 - Large enhancements of magnetic anisotropy in oxide-free iron nanoparticles
AU - Monson, Todd C.
AU - Venturini, Eugene L.
AU - Petkov, Valeri
AU - Ren, Yang
AU - Lavin, Judith M.
AU - Huber, Dale L.
N1 - Funding Information:
The authors are grateful to P. Provencio for her assistance with electron microscopy and J. Hatch along with B. Frankamp for their assistance in sample preparation. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. This work was supported by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, United States Department of Energy. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract no. DE-AC02-06CH11357 .
PY - 2013/4
Y1 - 2013/4
N2 - Magnetic characterization of spherical, oxide-free, bcc iron nanoparticles synthesized with β-diketone surfactants has been performed. The results of this characterization, which included particles with diameters ranging between 2 and 5 nm show that the nanoparticles have an average anisotropy of 1.9×106±0.3×106 J/m3, which is more than an order of magnitude greater than the magnetocrystalline anisotropy of bulk iron. Despite their unusually large anisotropy, these particles can have saturation magnetizations of up to 210 A m2/kg (slightly lower than bulk iron). High-energy X-ray diffraction data indicates that the Fe particles have a distorted bcc lattice, which could, at least in part, explain the magnetic behavior of these nanoparticles. Dipolar coupling between particles, while present, is weak and cannot account for the high anisotropy of these nanoparticles.
AB - Magnetic characterization of spherical, oxide-free, bcc iron nanoparticles synthesized with β-diketone surfactants has been performed. The results of this characterization, which included particles with diameters ranging between 2 and 5 nm show that the nanoparticles have an average anisotropy of 1.9×106±0.3×106 J/m3, which is more than an order of magnitude greater than the magnetocrystalline anisotropy of bulk iron. Despite their unusually large anisotropy, these particles can have saturation magnetizations of up to 210 A m2/kg (slightly lower than bulk iron). High-energy X-ray diffraction data indicates that the Fe particles have a distorted bcc lattice, which could, at least in part, explain the magnetic behavior of these nanoparticles. Dipolar coupling between particles, while present, is weak and cannot account for the high anisotropy of these nanoparticles.
KW - Anisotropy
KW - Iron
KW - Nanoparticle
KW - Pair distribution function
KW - Superparamagnetism
UR - http://www.scopus.com/inward/record.url?scp=84872729006&partnerID=8YFLogxK
U2 - 10.1016/j.jmmm.2012.11.026
DO - 10.1016/j.jmmm.2012.11.026
M3 - Article
AN - SCOPUS:84872729006
SN - 0304-8853
VL - 331
SP - 156
EP - 161
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
ER -