Dielectric properties and electrical response of grain boundary of Na1/2La1/2Cu3Ti4O12 ceramics

The dielectric properties and electrical response of grain boundaries of Na1/2La1/2Cu3Ti4O12 ceramics were investigated as a function of temperature. High dielectric permittivity (6.1–8.7 × 103) and low loss tangent (0.032–0.038 at 10 kHz) were observed in Na1/2La1/2Cu3Ti4O12 ceramics. Through analyses using complex impedance and electric modulus, it was found that the dielectric properties of Na1/2La1/2Cu3Ti4O12 ceramics are closely related to the electrical response of grain boundaries. The investigation of non-Ohmic characteristics at various temperatures suggests that the potential barrier at the grain boundaries of Na1/2La1/2Cu3Ti4O12 ceramics is due to the Schottky effect. The giant low frequency dielectric response in Na1/2La1/2Cu3Ti4O12 ceramics is attributed to Maxwell–Wagner polarization at the grain boundaries.