The integration of inductors raises the need for highly magnetic monodomain and insulating materials. With this aim in mind, we investigate the synthesis of FeCo nanoparticles using an organometallic approach. The role of the nature of the ligands, of the organometallic precursors and of the experimental conditions are addressed, leading to the formation of nanoparticles displaying different compositions and structural and magnetic properties. After optimization of the reaction conditions, 20 nm monodisperse nanoparticles, self-organized into millimetre long super-crystals, are obtained. They display a structural atomic disorder, due to the kinetics of decomposition of the precursors leading to a loss in their magnetic properties. Organized arrays of these nanoparticles could also be generated onto silicon wafers with thicknesses from 100 nm to several microns. Such densely packed layers are suitable for inductor nanotechnology