Enhanced electrical behavior in Ca 1-x Sr x Cu 3 Ti 4 O 12 ceramics

Polycrystalline Ca 1-x Sr x Cu 3 Ti 4 O 12 ceramics were studied as a function of the strontium content in order to understand its effects on the structure, microstructure and electrical characteristics of these compounds. Our results showed that the Sr 2+ cationic substitution into the A sites of the initial CaCu 3 Ti 4 O 12 (CCTO) phase leads to crystalline phases with specific stoichiometry. Although the same space group is observed, the cationic substitution induces larger lattice parameter, phase density, and chemical bonding length when compared to the initial CCTO phase. Microstructure results indicated that the strontium content has a significant influence on sample sinterability leading to changes in grain growth and densification process. The non-ohmic characterization showed that the Ca 0.5 Sr 0.5 Cu 3 Ti 4 O 12 phase exhibits improved breakdown electric field (32 kV/cm), non-linear coefficient (269) and lower leakage current (26 μA), while the SrCu 3 Ti 4 O 12 phase presents permittivity of about 5000 at 1 kHz.