Structure and Optical Properties of Nickel-cobalt Ferrite Obtained by the Sol-gel Methodwith Participation of Auto-combustion

Authors V.S. Bushkova
Affiliations

Vasyl Stefanyk Pre-Carpathian National University, 57, Shevchenko Str., 76025 Ivano-Frankivsk, Ukraine

Е-mail [email protected]
Issue Volume 7, Year 2015, Number 3
Dates Received 25 June 2015; published online 20 October 2015
Citation V.S. Bushkova, J. Nano- Electron. Phys. 7 No 3, 03021 (2015)
DOI
PACS Number(s) 75.50.Tt, 81.07.Wx, 61.05.cp, 78.67.Bf
Keywords Sol-gel technology, Nickel-cobalt ferrite, Lattice parameter, Cationic distribution (2) , Absorption coefficient, Optical band gap (7) .
Annotation In this work ferrite nickel-cobalt powders were synthesised using sol-gel technology with participation of auto-combustion. After completing the auto-combustion process, only one phase which corresponds to the cubic structure of spinel space group Fd3m was obtained. It was found that the average size of coherent scattering regions does not exceed 62 nm. The dependences of the lattice parameter, X-ray density and specific surface area of the ferrite powders on the nickel content were found. It was shown that at substitution of cobalt cations by nickel cations, the latter occupy only B positions, thus displacing a part of Fe3 + into A positions. The optical properties of the powders depending on the degree of substitution of cobalt cations by nickel cations are studied. As a result of analysis of the absorption spectra it is revealed that the allowed direct transition of electrons from the valence band to the conduction band is inherent for all investigated powders. It was shown that the optical band gap increases with increasing concentration of nickel cations in the composition of ferrites.

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