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 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.