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Title: Stabilizing Fe Nanoparticles in the SmCo 5 Matrix

Abstract

In this paper, we report a new strategy for stabilizing Fe nanoparticles (NPs) in the preparation of SmCo 5–Fe nanocomposites. We coat the presynthesized Fe NPs with SiO 2 and assemble the Fe/SiO 2 NPs with Sm–Co–OH to form a mixture. After reductive annealing at 850 °C in the presence of Ca, we obtain SmCo 5–Fe/SiO 2 composites. Following aqueous NaOH washing and compaction, we produced exchange-coupled SmCo 5–Fe nanocomposites with Fe NPs controlled at 12 nm. In conclusion, our work demonstrates a successful strategy of stabilizing high moment magnetic NPs in a hard magnetic matrix to produce a nanocomposite with tunable magnetic properties.

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2];  [2]; ORCiD logo [1];  [1]; ORCiD logo [1]
  1. Brown Univ., Providence, RI (United States). Department of Chemistry
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Materials Science Division
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1409987
Report Number(s):
LLNL-JRNL-737360
Journal ID: ISSN 1530-6984
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 17; Journal Issue: 9; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; compaction; Magnetic material; nanocomposite; nanoparticle stability; rare-earth hard magnet

Citation Formats

Shen, Bo, Mendoza-Garcia, Adriana, Baker, Sarah E., McCall, Scott K., Yu, Chao, Wu, Liheng, and Sun, Shouheng. Stabilizing Fe Nanoparticles in the SmCo5 Matrix. United States: N. p., 2017. Web. doi:10.1021/acs.nanolett.7b02593.
Shen, Bo, Mendoza-Garcia, Adriana, Baker, Sarah E., McCall, Scott K., Yu, Chao, Wu, Liheng, & Sun, Shouheng. Stabilizing Fe Nanoparticles in the SmCo5 Matrix. United States. doi:10.1021/acs.nanolett.7b02593.
Shen, Bo, Mendoza-Garcia, Adriana, Baker, Sarah E., McCall, Scott K., Yu, Chao, Wu, Liheng, and Sun, Shouheng. Thu . "Stabilizing Fe Nanoparticles in the SmCo5 Matrix". United States. doi:10.1021/acs.nanolett.7b02593.
@article{osti_1409987,
title = {Stabilizing Fe Nanoparticles in the SmCo5 Matrix},
author = {Shen, Bo and Mendoza-Garcia, Adriana and Baker, Sarah E. and McCall, Scott K. and Yu, Chao and Wu, Liheng and Sun, Shouheng},
abstractNote = {In this paper, we report a new strategy for stabilizing Fe nanoparticles (NPs) in the preparation of SmCo5–Fe nanocomposites. We coat the presynthesized Fe NPs with SiO2 and assemble the Fe/SiO2 NPs with Sm–Co–OH to form a mixture. After reductive annealing at 850 °C in the presence of Ca, we obtain SmCo5–Fe/SiO2 composites. Following aqueous NaOH washing and compaction, we produced exchange-coupled SmCo5–Fe nanocomposites with Fe NPs controlled at 12 nm. In conclusion, our work demonstrates a successful strategy of stabilizing high moment magnetic NPs in a hard magnetic matrix to produce a nanocomposite with tunable magnetic properties.},
doi = {10.1021/acs.nanolett.7b02593},
journal = {Nano Letters},
number = 9,
volume = 17,
place = {United States},
year = {Thu Aug 03 00:00:00 EDT 2017},
month = {Thu Aug 03 00:00:00 EDT 2017}
}

Journal Article:
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  • The magnetic properties of SmCo{sub 5}, Sm(Co{sub bal-}Fe{sub 0.21}Cu{sub 0.06}Zr{sub 0.03}){sub 7.6}, Sm(Co{sub bal}Fe{sub 0.25}Cu{sub 0.06}Zr{sub 0.03}){sub .6}, Sm (Co{sub bal}Fe{sub 0.28}Cu{sub 0.06}Zr{sub 0.02}){sub 7.6}, sintered magnets have been measured up to 350, 400 and 450 C. For a fixed temperature range, the irreversible loss of Sm(Co, Fe, Cu, Zr){sub z} magnets has been found to increase with increasing Fe content. Despite the high B{sub r} obtained at 25 C, a magnet must have a low irreversible loss of induction to retain a high magnetization after thermal cycling. Compromising the B{sub r} of 11.3 kG obtained at 25 C andmore » the irreversible loss of 1.9% after thermal cycling to 450 C, a magnet with the composition of the Sm(Co{sub bal-}Fe{sub 0.21}Cu{sub 0.06}Zr{sub 0.03}){sub 7.6} was found to exhibit the highest retained magnetization among the magnets studied. This magnet also exhibited the highest H{sub cl} (2.8 kOe) and BH{sub max} (6.7 MGOe) at 450 C among all magnets studied. The reversible temperature coefficients of induction of Sm(Co, Fe, Cu, Zr){sub z} sintered magnets were found to be about{minus}0.03 to {minus}0.04%/C, while those of SmCo{sub 5} magnet were about {minus}0.05%/C.« less
  • Ferromagnetic SmCo{sub 5} nanoparticles with large size have been directly synthesized by a magnetron-sputtering-based gas-phase condensation method. Based on this method, we studied the effect of thermodynamic environment for the growth of SmCo{sub 5} nanoparticles. It was found that the well-crystallized SmCo{sub 5} nanoparticle tends to form a hexagonal disk shape with its easy axis perpendicular to the disk plane. More importantly, under the condition of high sputtering current, well-crystallized nanoparticles were found to be formed through a three-stage growth process: aggregation, coalescence, and second crystallization.
  • The authors have investigated the mechanism and determined the enthalpy of crystallization of x-ray amorphous iron garnets of rare-earth elements and their solid solutions. The authors have established a relation between the mechanism of the solid-phase reaction of formation of the iron garnets and the decrease in the ionic radius of the rare-earth element in the dodecahedral positions. A rise in the temperature during crystallization of amorphous phases facilitates a rapid completion of the reaction in which double oxides with a complex three-sublattice structure are released.
  • Magnetization curves and hysteresis loops for field-oriented powders of Sm{sub {ital n}+1}Co{sub 3{ital n}+5}B{sub 2{ital n}} ({ital n}=0, 1, and 3) and PrCo{sub 5} were measured at {ital T}=4.2 K and partly at 77 K, under a strong pulsed field up to 36 T. Magnetic measurements for Sm{sub {ital n}+1}Co{sub 3{ital n}+1}B{sub 2{ital n}} ({ital n}=1, 2, and 3) compounds were also performed. Huge anisotropy fields of 120 T for SmCo{sub 4}B and of 130 T for Sm{sub 2}Co{sub 7}B{sub 3} were obtained. The Sm sublattice anisotropy of SmCo{sub 4}B was found to be larger than that of SmCo{sub 5}.more » To explain this, the Sm {ital f}-electron state for {ital n}{ge} ({ital R}18)2 of Sm{sub {ital n}+1}Co{sub 3{ital n}+5}B{sub 2{ital n}} has been expected to change from that for {ital n}{le}1. Huge coercivities of 8 T and 27.5 T were observed at {ital T}=4.2 K for SmCo{sub 4}B and for Sm{sub 2}Co{sub 7}B{sub 3} respectively. Magnetization processes for field-oriented PrCo{sub 5} at {ital T}=4.2 K were found to be similar to those of Nd{sub 2}Fe{sub 14}B at {ital T}=4.2 K.« less
  • To find alternative high temperature magnets containing no heavy rare earths for power applications, SmCo{sub 5}/Fe bulk nanocomposite magnets with enhanced energy density and high thermal stability have been produced by using a ball-milling plus warm-compaction route. Up to 30% of the Fe soft magnetic phase has been added to the composites with grain size <20 nm distributed homogenously in the matrix of the SmCo{sub 5} hard magnetic phase. It was observed that the microstructure does not change with temperature up to 500 Degree-Sign C. It is also observed that the thermal stability of bulk nanocomposite samples is closely relatedmore » to bulk density. Energy products above 11 MGOe have been obtained at 300 Degree-Sign C in fully dense bulk SmCo{sub 5}/Fe nanocomposite magnets, which is 65% higher than that of a single-phase counterpart at the same temperature.« less