Synthesis And Dielectric Properties Of Rare Earth Doped Calaium Copper Titanate

Recently, CaCu₃Ti₄O₁₂ ceramic has generated much interest because of its extraordinarily high dielectric constant s about 10⁵. The research works focuses on CaCu₃Ti₄O₁₂ are the origin of dielectric relaxation and how to lower the dielectric loss. In present work, CaCu₃Ti₄O₁₂ ceramics were synthesized with doping rare earth elements, and the dielectric property and its origin were discussed.A_xCa_1-xCu₃Ti₄O₁₂ (A= Sm, Nd, x=0.0%, 0.1%, 0.5%, 1.0%) ceramics were fabricated by conventional ceramic solid-state-reaction processing techniques. We investigated the phase composition by XRD. The results indicated that the doped CaCu₃Ti₄O₁₂ ceramics were all single phase and no obvious peaks of secondary phase were observed.For Nd_xCa_1-xCu₃Ti₄O₁₂ ceramics, the optimal sintering temperature is 1075℃, and there are two dielectric relaxations in all of the ceramics. One of the relaxation was caused by electrons that was hopping between Ti⁴⁺/Ti³⁺and Cu²⁺/Cu⁺ at the low temperature range; and the other relaxation was resulted in V_o⁺ at middle temperature range.The optimal sintering temperature of Sm_xCa_1-xCu₃Ti₄O₁₂ ceramics was 1050℃, and there were two dielectric relaxation in Sm doped-ceramics, too. The low temperature relaxation type was similar with the Nd doped samples. However, in the middle temperature range, the mechanism for 0.1% and 0.5%Sm was because of V_o⁺, but for 1.0%Sm it was because of V_o⁺⁺.