An effective way to tune the microstructure and dielectric properties of CaCu3Ti4O12 ceramics

CaCu3Ti4−xMnxO12 (x ≤ 0.1) ceramics has been prepared via the conventional solid-state method. The Mn substitution has strong effects on the microstructures and dielectric properties of CaCu3Ti4O12 ceramics. The grain becomes obviously uniform and fine after a very small amount of Mn substitution for Ti. The intergranular phase gradually disappeares. The bulk resistivity increases from 107 to 109 Ω cm. Dielectric permittivity is abruptly suppressed to 102, and dielectric loss is significantly reduced to 10−3 for x = 0.004–0.04. The better microwave dielectric properties are also achieved for CaCu3Ti4−xMnxO12 (x = 0.004) ceramics as follows: ɛr = 68.1, Q × f = 4030 GHz, τf = 220 ppm/K. These results suggest that a small amount of Mn substitutions for Ti is an effective way to tune the microstructure and dielectric properties of CaCu3Ti4O12 ceramics.