Ferroelectric Properties and Electric Field Dependent Polarization in 0.86BaTiO3-0.14(Bi3/4Na1/4)(Mg1/4Ti3/4)O3 Ceramics

Ceramics of composition 0.86BaTiO3-0.14(Bi3/4Na1/4)(Mg1/4Ti3/4)O3 (0.86BT-0.14BNMT) are synthesized and verified to be of perovskite tetragonal symmetry. The ceramics also exhibit saddle-back shaped dielectric anomalies as a function of temperature. The high temperature anomaly at Tm (393 K) is essentially frequency independent; the low temperature anomaly at T1 (301 K at 1 kHz) however is strongly dispersive with frequency. The temperature dependence of the relaxation time, (T), can be fitted well with a Vogel-Fulcher type relation. The P-E relation below 228 K is of characteristic hysteresis type of a normal ferroelectric. As the temperature approaches to 333 K, the P-E loops became slim resembling relaxor characteristics. Three pyroelectric peaks were found that correspond to respective phase transitions of BaTiO3, which indicates the dominance of ferroelectric BT clusters in the solid solution compositions.