Abstract
New relaxor ferroelectric ceramic perovskites Ca0.67La0.22Ti(1−x)CrxO3 (x = 0.15 and x = 0.2) (CLT(1−x)Crx) were prepared by solid state reaction route. X-Ray diffraction study suggested that these compounds crystallize with orthorhombic symmetry with Pnma space group. The microstructure study of sintered pellets revealed that the grains size decrease with the increase in doping concentration. The dielectric study showed two temperature anomalies that induced an improvement in piezoelectric applications. This study exhibits a relaxor behavior for all compositions with excellent properties. A high permittivity was around 25000 and ΔTrelax = 79 K for x = 0.15. The best way to characterize the degree of the dielectric relaxation for relaxor ferroelectrics was established using the Lorentz fit model. Dielectric modulus measurement showed three thermally-activated dielectric relaxations. The low-temperature relaxations R1 are related to the polaron relaxations which are due to the hopping holes. The high-temperature relaxations R2 and R3 are associated with the conductivity originating from the hopping motions of double ionized oxygen vacancies.
•All samples crystallize in the orthorhombic structure with Pnma space group.•All compounds show three thermal-dielectric relaxations.•Low-temperature relaxation is a polaron relaxation related to hopping holes.•High-temperature relaxations caused by doubly ionized oxygen vacancies.