Structural, Optical and Magnetic Studies of Cr2O3 Nanoparticles Prepared by Microwave-Assisted Synthesis

In this paper, quasi-rectangular Cr2O3 nanoparticles were prepared by microwave-assisted solution synthesis using Cr(NO3)2.6H2O and salicylic acid at the presence of NaOH in optimum conditions for the power of 360 W, the temperature of 50 ºC, and the time duration of 30 min. The asprepared chromium precursor was annealed in an air atmosphere at two different temperatures, 500 and 600 ºC, for 3 h. Quasi-rectangular Cr2O3 nanoparticles were prepared and characterized by Fourier transform infrared (FT-IR), ultraviolet–visible (UV-Vis) spectroscopy, X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The sharp peaks in FT-IR spectra and high intensity peaks in XRD patterns confirm the existence of a single and pure phase of the Cr2O3 nanoparticles with an average nanoparticle size of 25 nm. The calculated optical band gap (Eg) values of the as-prepared Cr2O3 nanoparticles were in the range of 1.6 and 1.8 eV. The TEM images revealed a highly homogeneous quasi-rectangular morphology without any agglomeration. The magnetic properties of the Cr2O3 nanoparticles showed weak ferromagnetic behavior.