Dielectric and non-Ohmic properties of CaCu3Ti4O12 ceramics modified with NiO, SnO2, SiO2, and Al2O3 additives

In order to conciliate dielectric and non-Ohmic properties of CaCu 3 Ti 4 O 12 (CCTO) ceramics, NiO, SnO 2 , SiO 2 , and Al 2 O 3 were added as sintering aids to promote the grain growth of CCTO ceramics. Microstructure, dielectric properties, and non-Ohmic behavior of the CCTO ceramics were investigated. Among them, NiO-modified CCTO exhibits good dielectric and non-Ohmic properties ( ε = 69833, tan δ = 0.073, α = 3.66 and E B = 296.7 V/cm), due to NiO is also one of giant dielectric materials. Therefore, it is suitable for applying semiconductor circuits. The relationship between electrical current density ( J ) and electrical field ( E ) demonstrated that Schottky barrier should exist at grain boundaries. Non-linear coefficient α was directly proportional to the height of barrier. Depressing barrier width would improve significantly dielectric permittivity but decrease breakdown voltage.