Abstract
Polycrystalline magnetite hollow spheres with diameter of about 200 nm and shell thickness of 30–60 nm were prepared via a
facile solution route. For the reaction, ethylene glycol (EG) served as the reducing agent and soldium acetate played the
role of precipitator. In addition, polyvinylpyrrolidone (PVP) served as a surface stabilizer. The morphologies and structures
were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The intermediate
products at different stages were also studied to shed light on the evolution of phase formation. It revealed that the hollow
structure formed via self-assembly of nanocrystallites (about 15 nm) using sodium acetate as mild precipitator. Evidences
further pointed out that the Ostwald ripening process well explained the growth mechanism of the hollow structure. Magnetization
measurements showed that the coercivity of magnetite hollow spheres at low temperature is about 200 Oe and the saturation
magnetization is about 83 emu g−1, roughly 85% that of the bulk phase, close to the value of its solid counterpart. In addition, a freezing transition was
observed at 25 K.
facile solution route. For the reaction, ethylene glycol (EG) served as the reducing agent and soldium acetate played the
role of precipitator. In addition, polyvinylpyrrolidone (PVP) served as a surface stabilizer. The morphologies and structures
were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The intermediate
products at different stages were also studied to shed light on the evolution of phase formation. It revealed that the hollow
structure formed via self-assembly of nanocrystallites (about 15 nm) using sodium acetate as mild precipitator. Evidences
further pointed out that the Ostwald ripening process well explained the growth mechanism of the hollow structure. Magnetization
measurements showed that the coercivity of magnetite hollow spheres at low temperature is about 200 Oe and the saturation
magnetization is about 83 emu g−1, roughly 85% that of the bulk phase, close to the value of its solid counterpart. In addition, a freezing transition was
observed at 25 K.
- Content Type Journal Article
- Category Research Paper
- DOI 10.1007/s11051-010-0020-5
- Authors
- Qian Sun, Beijing University of Aeronautics and Astronautics Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), Department of Physics Beijing 100191 People’s Republic of China
- Zheng Ren, Beijing University of Aeronautics and Astronautics Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), Department of Physics Beijing 100191 People’s Republic of China
- Rongming Wang, Beijing University of Aeronautics and Astronautics Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), Department of Physics Beijing 100191 People’s Republic of China
- Weimeng Chen, Peking University Department of Physics Beijing 100871 People’s Republic of China
- Chinping Chen, Peking University Department of Physics Beijing 100871 People’s Republic of China
- Journal Journal of Nanoparticle Research
- Online ISSN 1572-896X
- Print ISSN 1388-0764
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