Investigations on magnetic properties and structure for carbon encapsulated nanoparticles of Fe, Co, Ni
- 17 May 2000
- journal article
- Published by Elsevier BV in Materials Science and Engineering: A
- Vol. 286 (1), 157-160
- https://doi.org/10.1016/s0921-5093(00)00628-6
Abstract
In the present work, experiments aim at the encapsulation of foreign materials within hollow graphitic cage have been carried out for iron group metals (Fe, Co, Ni) using a modified arc-discharge (carbon arc) reactor. HRTEM (high resolution transmission electron miscroscope), and XRD (X-ray diffractometer) studies, for three carbon encapsulated materials, showing nanoparticles of both a metallic phase (α-Fe, γ-Fe; hcp-Co, fcc-Co; fcc-Ni) and also a carbide phase (M3C, M=Fe, Co, Ni) are encapsulated in graphitic carbon. The magnetic measurement for the three as-made nanoparticles, indicating that the values of saturation magnetic moment of three nanoparticle are 37.6, 55.5 and 15.7% of the bulk ferromagnetic elements counterparts, respectively. The different comparison values (Mr/Ms) of remanent magnetization (Mr) and saturation magnetization (Ms) suggest, the encapsulated Fe and Co nanoparticles are shown to be ferromagnetic with a ratio of remnant to saturation magnetization Mr/Ms∼0.3; whereas, the encapsulated Ni nanoparticles exhibits superparamagnetic behavior at room temperature.Keywords
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