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Title: Sintering Behavior of Spin-coated FePt and FePtAu Nanoparticles

Abstract

FePt and [FePt]{sub 95}Au{sub 5} nanoparticles with an average size of about 4 nm were chemically synthesized and spin coated onto silicon substrates. Samples were subsequently thermally annealed at temperatures ranging from 250 to 500 C for 30 min. Three-dimensional structural characterization was carried out with small-angle neutron scattering (SANS) and small-angle x-ray diffraction (SAXRD) measurements. For both FePt and [FePt]{sub 95}Au{sub 5} particles before annealing, SANS measurements gave an in-plane coherence length parameter a = 7.3 nm, while SAXRD measurements gave a perpendicular coherence length parameter c = 12.0 nm. The ratio of c/a is about 1.64, indicating the as-made particle array has a hexagonal close-packed superstructure. For both FePt and FePtAu nanoparticles, the diffraction peaks shifted to higher angles and broadened with increasing annealing temperature. This effect corresponds to a shrinking of the nanoparticle array, followed by agglomeration and sintering of the nanoparticles, resulting in the eventual loss of positional order with increasing annealing temperature. The effect is more pronounced for FePtAu than for FePt. Dynamic coercivity measurements show that the FePtAu nanoparticles have both higher intrinsic coercivity and higher switching volume at the same annealing temperature. These results are consistent with previous studies that show that additivemore » Au both lowers the chemical ordering temperature and promotes sintering.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [2];  [3]
  1. University of Alabama, Tuscaloosa
  2. ORNL
  3. National Institute of Standards and Technology (NIST)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Flux Isotope Reactor
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1003412
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 99; Journal Issue: 8
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ADDITIVES; AGGLOMERATION; ANNEALING; COHERENCE LENGTH; NEUTRON DIFFRACTION; SMALL ANGLE SCATTERING; SILICON; SINTERING; SPIN; SUBSTRATES; X-RAY DIFFRACTION

Citation Formats

Kang, Shishou, Jia, Zhiyong, Zoto, Ilir, Reed, R. C., Nikles, David E., Harrell, J. W., Vemuru, Krishnamurthy V, and Porcar, L. Sintering Behavior of Spin-coated FePt and FePtAu Nanoparticles. United States: N. p., 2006. Web. doi:10.1063/1.2165789.
Kang, Shishou, Jia, Zhiyong, Zoto, Ilir, Reed, R. C., Nikles, David E., Harrell, J. W., Vemuru, Krishnamurthy V, & Porcar, L. Sintering Behavior of Spin-coated FePt and FePtAu Nanoparticles. United States. doi:10.1063/1.2165789.
Kang, Shishou, Jia, Zhiyong, Zoto, Ilir, Reed, R. C., Nikles, David E., Harrell, J. W., Vemuru, Krishnamurthy V, and Porcar, L. Sun . "Sintering Behavior of Spin-coated FePt and FePtAu Nanoparticles". United States. doi:10.1063/1.2165789.
@article{osti_1003412,
title = {Sintering Behavior of Spin-coated FePt and FePtAu Nanoparticles},
author = {Kang, Shishou and Jia, Zhiyong and Zoto, Ilir and Reed, R. C. and Nikles, David E. and Harrell, J. W. and Vemuru, Krishnamurthy V and Porcar, L.},
abstractNote = {FePt and [FePt]{sub 95}Au{sub 5} nanoparticles with an average size of about 4 nm were chemically synthesized and spin coated onto silicon substrates. Samples were subsequently thermally annealed at temperatures ranging from 250 to 500 C for 30 min. Three-dimensional structural characterization was carried out with small-angle neutron scattering (SANS) and small-angle x-ray diffraction (SAXRD) measurements. For both FePt and [FePt]{sub 95}Au{sub 5} particles before annealing, SANS measurements gave an in-plane coherence length parameter a = 7.3 nm, while SAXRD measurements gave a perpendicular coherence length parameter c = 12.0 nm. The ratio of c/a is about 1.64, indicating the as-made particle array has a hexagonal close-packed superstructure. For both FePt and FePtAu nanoparticles, the diffraction peaks shifted to higher angles and broadened with increasing annealing temperature. This effect corresponds to a shrinking of the nanoparticle array, followed by agglomeration and sintering of the nanoparticles, resulting in the eventual loss of positional order with increasing annealing temperature. The effect is more pronounced for FePtAu than for FePt. Dynamic coercivity measurements show that the FePtAu nanoparticles have both higher intrinsic coercivity and higher switching volume at the same annealing temperature. These results are consistent with previous studies that show that additive Au both lowers the chemical ordering temperature and promotes sintering.},
doi = {10.1063/1.2165789},
journal = {Journal of Applied Physics},
number = 8,
volume = 99,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}