Sodium bismuth titanate (Na0.5Bi0.5)TiO3 (NBT) of perovskite structure is among the best known lead-free piezoelectric∕ferroelectric that promises a number of applications in sensors and actuators. However, NBT in thin film form has not been properly investigated, although NBT in bulk ceramic form has been widely studied. In this letter, we report the growth of polycrystalline NBT thin films by radio-frequency magnetron sputtering and their ferroelectric behavior. The NBT thin films exhibit a well-defined hysteresis loop, with a remanent polarization of 11.9μC∕cm2 and coercive field of 37.9kV∕cm when measured at room temperature. There is a steady decrease of dielectric constant in the range of 650–470 over the frequency range of 10–105Hz. A change in the controlling mechanism of electrical behavior from the grain interior to the grain boundary is observed for the NBT thin film with increasing temperature. Hopping of oxygen vacancies trapped at the grain boundaries is responsible for the high dielectric loss at low frequencies and high dc conductivity observed.

B-site complex ions (Li 1/4 Nb 3/4 ) 4z modification (Bi 1/2 Na 1/2 ) 0?94 Ba 0?06 TiO 3 ceramics with compositions of (Bi 1/2 Na 1/2 ) 0?94 Ba 0?06 Ti 12x (Li 1/4 Nb 3/4 ) x O 3 (x50, 0?01, 0?03 and 0?06) have been synthesised via the conventional solid state reaction. The effect of (Li 1/4 Nb 3/4 ) 4z content and sintering temperature on structures and electrical properties were investigated. It was found that both compositions and sintering temperatures have no significant effect on the crystal structure, and trace (Li 1/4 Nb 3/4 ) 4z addition and sintering temperatures have a great influence on the microstructure. Two obvious dielectric anomaly peaks (T d and T m ) were observed and dielectric constant for all poled specimens displayed significant frequency dispersion at T d and diffusion phase transition at T m . The piezoelectric properties of the ceramics are insensitive to the sintering temperatures, and the composition with x50?03 sintering at 1150uC exhibits favourable piezoelectric properties of d 33 5155 pC N 21 and k p 50?312.