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

Abstract The dielectric properties and electrical response of grain boundaries of Na 1/2 La 1/2 Cu 3 Ti 4 O 12 ceramics were investigated as a function of temperature. High dielectric permittivity (6.1–8.7 × 10 3 ) and low loss tangent (0.032–0.038 at 10 kHz) were observed in Na 1/2 La 1/2 Cu 3 Ti 4 O 12 ceramics. Through analyses using complex impedance and electric modulus, it was found that the dielectric properties of Na 1/2 La 1/2 Cu 3 Ti 4 O 12 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 Na 1/2 La 1/2 Cu 3 Ti 4 O 12 ceramics is due to the Schottky effect. The giant low frequency dielectric response in Na 1/2 La 1/2 Cu 3 Ti 4 O 12 ceramics is attributed to Maxwell–Wagner polarization at the grain boundaries.