Dielectric and optical band gap studies of Cobalt-Manganese oxide nanoparticles at different temperatures

Nanoparticles of Cobalt-Manganese oxides were prepared by chemical co-precipitation method. The samples were heated at 400, 600 and 800
^o
C. The average particle size was determined from the X-ray line broadening. The diffractogram was compared with JCPDS data to identify the crystallographic phase and cubic structure of the particles. The FTIR studies have been used to confirm the metal oxide formation. The surface morphology and chemical compositions of the sample was verified using SEM and EDAX respectively. From the analysis of the absorption spectra, the direct band gap of the material was calculated. It has been found that with increasing frequency, the dielectric constant decreases. The high value of dielectric constant at low frequencies may mainly be due to the space charge polarization and rotational polarization.