Synthesis of superparamagnetic nanoparticles dispersed in spherically shaped carbon nanoballs

In this work, carbon nanoballs in spherical shape with diameter 70 ± 2 nm containing well-dispersed superparamagnetic magnetite/maghemite Fe₃O₄/γ-Fe₂O₃ nanoparticles of 5–10 nm in size were synthesised by a facile route using the radio frequency (rf) plasma in order to assist the pyrolysis of ferrocene. Ferrocene was placed in an inductively coupled rf plasma field without additional thermal heating to activate simultaneous sublimation and pre-pyrolysis processes. During this plasma activation, the resultant derivatives were carried by an argon gas stream into the hot zone of a resistance furnace (600 °C) for complete thermal decomposition. The deposition of the nanoballs could be observed in the hot zone of the furnace at a temperature of 600 °C. The synthesised nanoballs are highly dispersible in solvents that make them particularly suitable for different applications. Their morphology, composition and structure were characterized by high-resolution scanning and transmission electron microscopy, including selected area electron diffraction, electron energy loss spectroscopy and X-ray diffraction. Magnetic measurements demonstrated that the nanoballs possess superparamagnetic characteristics.