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Article

Magnetic [email protected]x, [email protected] and α-Fe2O3 Single-Crystal Nanoblends Synthesized by Femtosecond Laser Ablation of Fe in Acetone

1
RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
2
Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-Ro, Yuseong-Gu, Daejeon 34113, Korea
3
Department of Nano-Manufacturing Technology, Korea Institute of Machinery and Material (KIMM), 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 34103, Korea
4
Condensed Molecular Materials Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
5
Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
6
Department of Laser & Electron Beam Application, Korea Institute of Machinery and Material (KIMM), 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 34103, Korea
7
Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
8
Department of Applied Chemistry, National Chiao Tung University, Science Building 2, 1001 Ta Hsueh Road, Hsinchu 300, Taiwan
9
Nano Medical Engineering Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0193, Japan
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Nanomaterials 2018, 8(8), 631; https://doi.org/10.3390/nano8080631
Received: 24 July 2018 / Revised: 17 August 2018 / Accepted: 18 August 2018 / Published: 20 August 2018
(This article belongs to the Special Issue Laser-Based Nano Fabrication and Nano Lithography)
There are few reports on zero-field-cooled (ZFC) magnetization measurements for [email protected]x or FeOx particles synthesized by laser ablation in liquids (LAL) of Fe, and the minimum blocking temperature (TB) of 120 K reported so far is still much higher than those of their counterparts synthesized by chemical methods. In this work, the minimum blocking temperature was lowered to 52 K for 4–5 nm α-Fe2O3 particles synthesized by femtosecond laser ablation of Fe in acetone. The effective magnetic anisotropy energy density (Keff) is calculated to be 2.7–5.4 × 105 J/m3, further extending the Keff values for smaller hematite particles synthesized by different methods. Large [email protected]α-Fe2O3 and [email protected] particles of 10–100 nm in diameter display a soft magnetic behavior with saturation magnetization (Ms) and coercivities (Hc) values of 72.5 emu/g and 160 Oe at 5 K and 61.9 emu/g and 70 Oe at 300 K, respectively, which mainly stem from the magnetism of amorphous Fe cores. Generally, the nanoparticles obtained by LAL are either amorphous or polycrystalline, seldom in a single-crystalline state. This work also demonstrates the possibility of synthesizing single-crystalline α-Fe2O3 hematite crystals of several nanometers with (104), (113), (116) or (214) crystallographic orientations, which were produced simultaneously with other products including carbon encapsulated amorphous Fe ([email protected]) and [email protected]x core-shell particles by LAL in one step. Finally, the formation mechanisms for these nanomaterials are proposed and the key factors in series events of LAL are discussed. View Full-Text
Keywords: hematite α-Fe2O3; core-shell; blocking temperature; superparamagnetism; laser ablation in liquids; femtosecond laser; single-crystalline hematite α-Fe2O3; core-shell; blocking temperature; superparamagnetism; laser ablation in liquids; femtosecond laser; single-crystalline
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MDPI and ACS Style

Zhang, D.; Choi, W.; Oshima, Y.; Wiedwald, U.; Cho, S.-H.; Lin, H.-P.; Li, Y.K.; Ito, Y.; Sugioka, K. Magnetic [email protected]x, [email protected] and α-Fe2O3 Single-Crystal Nanoblends Synthesized by Femtosecond Laser Ablation of Fe in Acetone. Nanomaterials 2018, 8, 631. https://doi.org/10.3390/nano8080631

AMA Style

Zhang D, Choi W, Oshima Y, Wiedwald U, Cho S-H, Lin H-P, Li YK, Ito Y, Sugioka K. Magnetic [email protected]Ox, [email protected] and α-Fe2O3 Single-Crystal Nanoblends Synthesized by Femtosecond Laser Ablation of Fe in Acetone. Nanomaterials. 2018; 8(8):631. https://doi.org/10.3390/nano8080631

Chicago/Turabian Style

Zhang, Dongshi, Wonsuk Choi, Yugo Oshima, Ulf Wiedwald, Sung-Hak Cho, Hsiu-Pen Lin, Yaw K. Li, Yoshihiro Ito, and Koji Sugioka. 2018. "Magnetic [email protected]x, [email protected] and α-Fe2O3 Single-Crystal Nanoblends Synthesized by Femtosecond Laser Ablation of Fe in Acetone" Nanomaterials 8, no. 8: 631. https://doi.org/10.3390/nano8080631

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