The effect of different dopant site (Cu and Ca) by magnesium on CaCu₃Ti₄O₁₂ dielectric properties

Abstract

CaCu₃Ti₄O₁₂ (CCTO) is known as a material that possesses high dielectric constant (ε_r ~ 10⁴) and can be the best candidate to be used in electronic components that can be operated at low and high frequency. Unfortunately, high dielectric loss of CCTO can be the main obstacle for this material to be commercialized. In this paper, Mg was used as dopant into CCTO ceramics in order to reduce dielectric loss of CCTO and the dielectric properties of CCTO samples were characterized at high frequency (1 MHz–1 GHz). The samples were prepared via solid state method. Mg was used as dopant at different site of CCTO (Cu and Ca sites). All mixed powders were calcined at 900 °C for 12 h and subsequently sintered at 1030 °C for 10 h. X-ray diffractometer analysis proved the formation of complete single phase CCTO for all sintered samples. Scanning electron microscopy analysis showed the grain size became larger with the addition of dopant concentration. Enhanced dielectric constant was observed for most of the doped samples with most of the CaCu_3−xMg_xTi₄O₁₂ (Mg doped at Cu site) samples had higher dielectric constant and lower dielectric loss at frequency 1 MHz whereas the Ca_1−xMg_xCu₃Ti₄O₁₂ (Mg doped at Ca site) samples exhibited higher dielectric constant and lower dielectric loss compared to the CaCu_3−xMg_xTi₄O₁₂ samples at 1 GHz. Thus, Mg replacement on Cu and Ca sites in CCTO gave a great influence on dielectric properties.