Functionalization of carbon nanotubes with magnetic nanoparticles: general nonaqueous synthesis and magnetic properties
Zhang, Hui; Du, Ning; Wu, Ping; Chen, Bingdi; Yang, Deren; Yang, Deren;; Zhang, Hui; State Key Lab of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People’s Republic of China; Du, Ning; State Key Lab of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People’s Republic of China; Wu, Ping; State Key Lab of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People’s Republic of China; Chen, Bingdi; State Key Lab of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People’s Republic of China
Журнал:
Nanotechnology
Дата:
2008-08-06
Аннотация:
A novel approach has been developed to synthesize magnetic nanoparticle and carbon nanotube (CNT) core–shell nanostructures, such as CoO/CNTs and Mn<sub>3</sub>O<sub>4</sub>/CNTs, by the nonaqueous solvothermal treatment of metal carbonyl on CNT templates using hexane as the solvent. The morphological and structural characterizations indicate that numerous cubic CoO or tetragonal Mn<sub>3</sub>O<sub>4</sub> nanoparticles are deposited on the surfaces of the CNTs to form CNT-based core–shell nanostructures. It is revealed that the hydrophobic interaction between nanoparticles and CNTs in hexane plays the critical role for the formation of CNT-based core–shell nanostructures. A physical property measurement system (PPMS-9, Quantum Design) analysis indicates that the CoO/CNT core–shell nanostructures show weak ferromagnetic performance at 300 K due to the ferromagnetic Co clusters and the uncompensated surface spin states, while the Mn<sub>3</sub>O<sub>4</sub>/CNT core–shell nanostructures display ferromagnetic behavior at low temperature (34.5 K), which transforms into paramagnetic behavior with increasing temperature.
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