CaCu_3Ti_4O_(12)/CaTiO_3 composite dielectrics: Ba/Pb-free dielectric ceramics with high dielectric constants

摘要

We have measured dielectric properties of Ca_(1+x)Cu_(3-x)Ti_4O_(12) (x = 0,0.1,0.5,1,1.5, 2, 2.9 and 3), and have found that Ca_2Cu_2Ti_4O_(12) (a composite of CaCu_3Ti_4O_(12) and CaTiO_3) exhibits a high dielectric , constant of 1800 with a low dissipation factor of 0.02 below 100 kHz from 220 to 300 K. These are comparable to (or even better than) those of the Pb/Ba-based ceramics, which could be attributed to a barrier layer of CaTiO_3 on the surface of the CaCu_3Ti_4O_(12) grains. The composite dielectric ceramics reported here are environmentally benign as they do not contain Ba/Pb.