COBALT-DOPED CARBON NANOTUBES - PREPARATION, TEXTURE, AND MAGNETIC-PROPERTIES

The nested carbon nanotubes discovered by Ijima and co-workers as a by -product of fullerene production extended the dimension and geometries of fullerenes into the domain of nanoparticles. These nanotubes are f iberlike structures consisting of concentric graphite sheets nested al ong the axis extending as long as several micrometers, and diameters o f these nanotubes are limited to less than 100 nm. In this paper we re port preparation, structural and magnetic properties of cobalt-doped c arbon nanotubes. We observed a tubular structure made of coaxial graph ite sheets. The inside, of these carbon nanotubes, was filled with cob alt particles. The magnetic properties of the Go-doped nanotubes were measured using a SQUID magnetometer. The undoped (pure) carbon nanotub es exhibit diamagnetic behavior The Co-doped nanotubes exhibit superpa ramagnetic behavior with saturation of magnetization at about 0.5 T an d coercive field of 750 G. (C) 1996 American Institute of Physics.