Structure and magnetic properties of multi-walled carbon nanotubes modified with cobalt

✍ Scribed by U. Ritter; P. Scharff; G.E. Grechnev; V.A. Desnenko; A.V. Fedorchenko; A.S. Panfilov; Yu.I. Prylutskyy; Yu.A. Kolesnichenko

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 559 KB
• Volume: 49
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/j.carbon.2011.06.039

✦ Synopsis

The magnetic properties of multi-walled carbon nanotubes (MWCNTs) modified with cobalt nanoparticles were studied in the temperatures and magnetic field range of (4.2-290) K and (0.03-5) T, respectively. Nanoparticles of cobalt encapsulated inside MWCNTs were obtained by using the chemical vapor deposition technique. The low temperature SQUID magnetization measurements were supplemented with structural investigations by means of high-resolution transmission electron microscopy, scanning electron microscopy as well as thermogravimetric and X-ray diffraction analysis. X-ray diffraction revealed the presence of MWCNTs, f.c.c. Co and h.c.p. Co phases. The magnetic characterization provided the remanent magnetization value (M R ) of about 0.07 emu/g ($40% of the saturation moment), while the coercive field (H C ) value amounts to 600 Oe. Both parameters M R and H C slightly decrease with the rise of temperature. The substantial magnetization increase observed at low temperatures suggests the existence of nano Co clusters (in the atomic scale size).