Structural and optical properties of Ni substituted CaCu3Ti4 − xNixO12

Ni2+ doped CaCu3Ti4 − xNixO12 (x = 0.0, 0.08, 0.12, and 0.20) [CCTO] ceramics were synthesized by solid-state reaction route method and their structural properties were investigated. X-ray diffraction along with the Rietveld refinement showed no change in crystal structure from cubic (Im-3) to any other with enhanced divalent Ni2+ ion concentration. It has been observed that the lattice parameter increases with increasing Ni concentration and is attributed to the difference in ionic radius of Ni2+ (0.69 Å) is larger than the ionic radii of Ti4+ (0.60 Å). Furthermore, there is a good agreement between observed and calculated interplanar spacing (d-values) of hkl planes. From FT-IR spectroscopy, it have been notice that the CCTO phase present resonance absorptions at 560, 522 and 446 cm−1 which are associated to TiO and TiOTi.