Very high-performance dielectric properties of Ca1−3x/2YbxCu3Ti4O12 ceramics

• High ε′ = 1.6 × 104 and very low tan δ = 0.015 were obtained in Ca0.925Yb0.05Cu3Ti4O12.
• Good temperature stability with Δε′ < ±15% ranging from −70 to 130 °C was achieved.
• ε′ was nearly independent of frequency (102–106 Hz) and dc voltage (0–40 V).
• Rgb of Ca1−3x/2YbxCu3Ti4O12 ceramics was estimated to be ∼0.7–12.5 G Ω cm at RT.

Dielectric properties of Ca1−3x/2YbxCu3Ti4O12 ceramics were investigated. Grain growth of CaCu3Ti4O12 ceramics was strongly inhibited by Yb3+ doping ions, which can be ascribed to the effect of solute drag of an aliovalent Yb3+ dopant. High dielectric permittivity (ε′ = 1.6 × 104) and very low loss tangent (tan δ = 0.015) at 1 kHz with good temperature stability of ε′ ranging from −70 to 130 °C (Δε′ < ±15%) were achieved in a Ca0.925Yb0.05Cu3Ti4O12 ceramic prepared by a modified sol–gel method. ε′ was found to be nearly independent of frequency (102–106 Hz) and dc voltage (0–40 V). Notably, the grain boundary resistances of Ca1−3x/2YbxCu3Ti4O12 ceramics at room temperature were estimated to be ∼0.7–12.5 G Ω cm. Very high-performance dielectric properties of Ca1−3x/2YbxCu3Ti4O12 ceramics were primary attributed to their improved electrical response at grain boundaries.