Relaxor behavior of (Sr,Ba,Bi)TiO 3 ferroelectric ceramic

Abstract

The dielectric behavior of (Sr 0.4Ba 0.6) 0.925Bi 0.05TiO 3 (SBBT) ceramic was investigated in the temperature range from 100 K to 450 K. Broad dielectric maxima, which shift to higher temperature with increasing frequency, and the value of the relaxation parameter γ = 1.6 –2 estimated from the linear fit of the modified Curie–Weiss law, indicated the relaxor nature of the SBBT ceramic. The dielectric relaxation which follows the Vogel–Fulcher relationship with T VF = 188 K, E a = 0.0392 eV, and ν o = 2.98 × 10 11 Hz, further supports such a relaxor nature. The P – E hysteresis loop at different temperatures and ‘butterfly’ shape dc bias field dependence of permittivity at T > T m (the temperature of permittivity maximum) signifies the occurrence of nanopolar clusters, which is the typical characteristic of relaxor ferroelectrics. At 300 K and 10 kHz, the dielectric constant and loss t g δ are ∼ 2210 and 0.00118, respectively. The tunability (28%) and figure of merit (237) at room temperature show that the SBBT ceramic could be a promising candidate for tunable capacitor applications.