  In this work we present a complete characterization and magnetic study of
vanadium oxide/hexadecylamine nanotubes (VOx/Hexa NT's) doped with Co2+ and
Ni2+ ions. The morphology of the NT's has been characterized by Transmission
Electron Microscopy (TEM) while the metallic elements have been quantified by
Instrumental Neutron Activation Analysis (INAA) technique. The static and
dynamic magnetic properties were studied collecting data of magnetization as a
function of magnetic field and temperature and by Electron Paramagnetic
Resonance (EPR). We observed that the incorporation of metallic ions (Co2+,
S=3/2 and Ni2+, S=1) decrease notably the amount of V4+ ions in the system,
from 14-16% (non-doped case) to 2-4%, with respect to the total vanadium atoms
into the tubular nanostructure, improving considerably their potential
technological applications as Li-ion batteries cathodes.
