Effect of Ce4+substitution on the structural, electrical and dielectric properties of NiAl2O4spinel

✍ Scribed by Augustin, C. O. ;Hema, K. ;Berchmans, L. John ;Kalai Selvan, R. ;Saraswathi, R.

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 208 KB
• Volume: 202
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200420027

✦ Synopsis

Abstract

The structural, electrical and dielectric properties of a series of Ni~1–x~Ce__~x~__Al~2~O~4~ (x = 0.0, 0.2, 0.4, 0.6, 0.8) compositions have been studied. The samples were prepared by a novel glycine–nitrate combustion synthesis route. The substitution of Ce^4+^ for Ni^2+^ results in an increase in the lattice constant owing to the larger size of the substituent. The X‐ray density increases with increasing Ce^4+^ content. The IR spectra show two fundamental absorption bands, which are shifted gradually towards higher energy with the addition of Ce^4+^. The UV–visible spectra confirm the preference of Ni^2+^ for the octahedral site. The dc electrical conductivity increases with increasing temperature due to the mobility of thermally activated charge carriers. Due to the electrostatic screening effect of B‐site cations, the conductivity decreases with increasing Ce^4+^ content. The dielectric constant and loss tangent of the synthesized compounds show the normal behavior of spinel compounds. The ac electrical conductivity increases with increasing applied frequency and decreases with increasing Ce^4+^ substitution. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)