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

CaCu(3)Ti(4-x)MnxO(12)(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 10(7) to 10(9) Omega cm. Dielectric permittivity is abruptly suppressed to 10(2), 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: epsilon(r) =68.1, Q x f= 4030 GHz, tau(f) =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. (C) 2010 Elsevier B.V. All rights reserved.