Cr2O3 Nanoparticles: Synthesis, Characterization, and Magnetic Properties

In this paper, semi-solid precursor of chromium was prepared from the reaction of Cr(NO3)3 and oxalic acid at the presence of NaOH. Then Cr2O3 nanoparticles were prepared by solid-state thermal decomposition of this precursor at 500 and 600 ºC, at standard atmospheric pressure for 3 h. The as-prepared Cr2O3 nanoparticles were characterized by Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis) spectroscopy, X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The sharp vibration bands in FT-IR spectra and high intensity peaks in XRD patterns confirmed the preparation of pure, single rhombohedral phase and crystalline Eskolaite structure of Cr2O3 nanoparticles. A broad absorption peak appeared at UV-Vis spectra indicates the d3 electronic transition of Cr3+. The TEM images show that the particles are similar and a little agglomerated with the average crystal size of 100 nm. The VSM results predict that the as-prepared Cr2O3 nanoparticles are weak ferromagnetic and paramagnetic.