Easy single-step route to manganese oxide nanoparticles embedded in carbon and their magnetic properties

We present a facile and simple solid-state thermolysis approach for the formation of manganese oxide nanoparticles embedded in an amorphous carbon. This was accomplished through a single-step direct thermolysis of cetyltrimethylammonium permanganate. The as-synhtesized products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman microscope, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The product consists mainly of Mn3O4 and of MnOOH coated with carbon. The carbon coating was observed when reaction was carried out at 400 degrees C and the average particle size is 9 nm. The shape of the products can be controlled by varying parameters such as reaction temperature. As the temperature increases from 500 to 700 degrees C, laraer spherical particles were observed without any carbon coating. The magnetic properties of as-synthesized products were evaluated using superconducting quantum interference devices (SQUID). The field-dependent magnetic measurements showed that nanoparticles embedded in carbon exhibited a high coercivity value of 10.5 kOe at 2 K. The saturation magnetization values at 2 K are 42 and 46 emu/g for the reaction temperatures of 500 and 600 degrees C, respectively.