Oxide Nanostructures: Characterizations and Optical Bandgap Evaluations of Cobalt-Manganese and Nickel-Manganese at Different Temperatures

Author(s) C.R. Indulal1, G.S. Kumar1, A.V. Vaidyan2, R. Raveendran1

1 Department of Physics, S N College, Kollam, India

2 Department of Chemistry, St Stephens College, Pathanapuram, India

Е-mail cr_indulal@yahoo.com
Issue Volume 3, Year 2011, Number 1, Part 1
Dates Received 04 February 2011, in final form 18 March 2011, published online 23 March 2011
Citation C.R. Indulal, G.S. Kumar, A.V. Vaidyan, R. Raveendran, J. Nano- Electron. Phys. 3 No1, 170 (2011)
PACS Number(s) 61.46.Hk, 81.07.Bc
Key words Nanoparticles (61) , Arrested precipitation, SEM (86) , EDX, Optical band gap (7) .
Cobalt-Manganese and Nickel-Manganese oxide (CoMnO and NiMnO) nanoparticles were prepared by chemical co-precipitation method by decomposition of their respective metal sulfides and sodium carbonate using ethylene diamene tetra acetic acid as the capping agent. The samples were heated at 400, 600 and 800 °C. The average particle sizes were determined from the X-ray line broadening. The diffractograms were compared with JCPDS data to identify the crystallographic phase and cubic structure of the particles. The samples were characterized by XRD, FTIR and UV analyses. The internal elastic micro strains were calculated and it was seen that as the particle size increases strain decreases. The FTIR studies have been used to confirm the metal oxide formation. The chemical compositions of the samples were verified using EDX spectra. The surface morphologies of the samples were studied from the SEM images. The absorption spectra of the materials in the UV-Vis-NIR range were recorded. From the analysis of the absorption spectra, the direct band gaps of the materials were calculated.