Synthesis and Characterization of Nanosized Cobalt Manganese Alloys

Abstract

Co–Mn alloy nanoparticles are synthesized by chemical route by the decomposition of metal chlorides by sodium borohydride using oleic acid as the capping agent. SEM, TEM and XRD are used to determine structural and morphological properties of the samples. From XRD spectra analysis, it is confirmed that the sample contains cobalt–manganese alloy. Transmission Electron Microscopy (HR-TEM) is used to estimate the particle size of the Co–Mn sample where a bimodal particle size distribution with one maximum at (3.5 ± 1.8) nm and another maximum at (7.6 ± 2.5) nm is observed. Magnetic investigation employed by Vibrating Sample Magnetometry (VSM) shows that the samples are magnetic with saturation magnetization of 0.018 emu/g for the prepared sample and 0.457 emu/g for the annealed sample. The nature of chemical conjugation of Co–Mn nanoparticles and oleic acid is analyzed by Fourier transform infrared spectroscopy. Thermogravimetric measurements of Co–Mn indicate exothermic peaks at 545 K and 723 K revealing the structural transition from amorphous phase to crystallined form. The chemical composition of the sample is verified using EDX spectra.