Improved Dielectric and Nonlinear Electrical Properties of Fine‐Grained CaCu 3 Ti 4 O 12 Ceramics Prepared by a Glycine‐Nitrate Process

Pure CaCu 3 Ti 4 O 12 was successfully prepared by a glycine‐nitrate process using a relatively low calcination temperature and short reaction time of 760°C for 4 h. Fine‐grained CaCu 3 Ti 4 O 12 ceramics with dense microstructure and small grain size were obtained after sintering for 1 h. The nonlinear coefficient of a fine‐grained CaCu 3 Ti 4 O 12 ceramic calculated in the range 1–10 mA/cm 2 was found to be very high of ~16.39 with high breakdown electric field strength of 1.46 × 10 4  V/cm. This fine‐grained CaCu 3 Ti 4 O 12 ceramic also exhibited a very low loss tangent of 0.017 at 20°C with temperature stability over the range −55°C to 85°C. The grain growth rate of the CaCu 3 Ti 4 O 12 ceramics was found to be very fast after increasing the sintering time from 1.5 to 3 h, leading to formation of a coarse‐grained CaCu 3 Ti 4 O 12 ceramic with grain size of about 100–200 μm. The dielectric permittivity of this coarse‐grained ceramic was found to be as high as 1.03 × 10 5 with a low loss tangent of 0.054.