L10 FePt-filled carbon nanotubes by wet chemical synthesis

This paper reports on the synthesis of iron-platinum (FePt) alloy clusters within Multi Wall Carbon Nanotubes using a novel wet chemical method that allows the filling of the nanotube cavity keeping clear their external wall. In the present case, the procedure permits the filling of the nanotubes with precursor salts of Pt and Fe and, by direct heating at 700°C of the Fe and Pt mixed salts, magnetic hard, face-centred-tetragonal (fct) crystallographic (L10) phase FePt alloy nanoparticles are obtained without the need to pass through the formation of the magnetic soft, face-centred-cubic (fcc) FePt alloy phase. By a suitable choice of the concentration of the starting material solution, we obtained particles of two different sizes into the nanotubes with magnetic blocked and super-paramagnetic states at room temperature. Morphological, structural and magnetic properties of the filled nanotubes have been performed by magnetic measurements, X-ray diffraction and transmission electron microscopy in normal and high resolution mode