Ca Cu 3 Ti 4 O 12 ∕ Ca Ti O 3 composite dielectrics: Ba∕Pb-free dielectric ceramics with high dielectric constants

We have measured dielectric properties of Ca1+xCu3−xTi4O12 (x=0, 0.1, 0.5, 1, 1.5, 2, 2.9 and 3), and have found that Ca2Cu2Ti4O12 (a composite of CaCu3Ti4O12 and CaTiO3) exhibits a high dielectric constant of 1800 with a low dissipation factor of 0.02 below 100kHz from 220to300K. These are comparable to (or even better than) those of the Pb∕Ba-based ceramics, which could be attributed to a barrier layer of CaTiO3 on the surface of the CaCu3Ti4O12 grains. The composite dielectric ceramics reported here are environmentally benign as they do not contain Ba∕Pb.