Dielectric, ferroelectric, piezoelectric properties, and conduction behavior of (Bi0.5Na0.5)0.94+xBa0.06TiO3 ceramics

The electrical properties and conduction behavior of (Bi0.5Na0.5)(0.94+x)Ba0.06TiO3 (x = 0, 0.01; denoted as BNBT, BNBT + 0.01BN) ceramics were studied. Both samples demonstrated a single-phase perovskite structure. Compared to the BNBT sample, the BNBT + 0.01BN sample showed a reduction in grain size and decreased values for Curie temperature (T-m) and depolarization temperature (T-d). Normalized spectroscopic plots of M"/M"(max) and Z"/Z"(max) revealed a single relaxation peak. The complex impedance plots were modeled using an equivalent circuit, and the grain resistance (R-g) decreases with increasing temperature. At 500 degrees C, the R-g values for BNBT and BNBT + 0.01BN samples were 339.97 and 886.98 k Omega x cm, respectively. Jonscher's law was applied to fit the AC conductivity, and the obtained n values indicated different conduction mechanisms for the two samples. Additionally, the conduction activation energy (E-con) for DC conductivity followed the Arrhenius relation. Introducing a small (Bi,Na) excess suppresses oxygen and cation vacancies, significantly increasing resistivity. Consequently, the BNBT + 0.01BN sample exhibited excellent remanent polarization (P-r) of 34.2 mu C/cm(2) and piezoelectric constant (d(33)) of 135 pC/N.