(FexCo1−x)-alloy filled vertically aligned carbon nanotubes grown by thermal chemical vapor deposition

Aligned Fe-Co alloy-filled multi-walled carbon nanotubes (MWNTs) were synthesized on silicon substrates via the pyrolysis of a ferrocene/cobaltocene mixture. The nanotubes are aligned normal to the substrate surface. The encapsulated metal nanowires have diameters of 10-20 nm and a length of up to a few micrometers. They consist of single crystals with BCC structure. Alternating gradient magnetometry investigations show that the magnetic wires exhibit a clear ferromagnetic behavior at room temperature. An enhanced coercivity of about 126 mT and uniaxial magnetic anisotropy with the easy axis of magnetization along the wire axis were observed.