Influence of defect on the electrical and optical properties of A-site non-stoichiometry Ca(0.67)La(0.22)□(0.11)Ti((1−x))Cr(x)O(3−δ) perovskite

An investigation of the dielectric dispersion, electrical properties, scaling behavior and optical defects of Ca(0.67)La(0.22)□(0.11)Ti((1−x))Cr(x)O(3−δ) (CLT((1−x))Cr(x)) with x = 0 and x = 0.1 compositions is presented. The square in the formula is attributed to a vacancy in A-site. Relaxation phenomena were studied with dielectric and modulus formalism, while, the conductivity mechanism was investigated using electrical conductivity. A high permittivity of around 10(4), low dielectric loss and low electrical conductivity of around 10(−3) S cm(−1) for Ca(0.67)La(0.22)TiO(3) (CLT) was observed. These values make this composition interesting for microelectric applications. A comparison between the Z′′ and M′′ indicated that the short-range carrier motion dominates at low temperature and becomes less localized at high temperature. The optical defects of CLT and Ca(0.67)La(0.22)Ti(0.9)Cr(0.1)O(3) (CLT(0.9)Cr(0.1)) were studied by electron paramagnetic resonance (EPR) spectroscopy. The results suggest the formation of a [TiO(6)](9−) center, a (Ti(3+)–V(O)) center, and [Image: see text] dipole defect for CLT compound and Cr(3+)–V(O) center defect for CLT(0.9)Cr(0.1) compound. These defects are the source of the in-gap electron traps, which improve the optical properties of CLT((1−x))Cr(x) and hence make it an interesting optical material for different applications.