Structural and dielectric studies of the Na0.5Bi0.5TiO3–BiFeO3 system

Solid solutions (1 − x)NBT–xBF, between rhombohedral compounds Na0.5Bi0.5TiO3 (NBT) and BiFeO3 (BF) were studied and a continuous R3c solid solution was evidenced. Lattice parameters and rhombohedral distortion evolution with BF content were studied. The “a” pseudo-cubic parameter (ap) increases linearly with BF rate, as the “α” pseudo-cubic one (αp) presents a more complex behaviour. The study of the dielectric properties evidenced two different ranges, with a limit composition around 50% of BF. TEM studies of the reciprocal space showed that the relaxor behaviour of NBT-rich samples is correlated both with superstructure spots and diffusion rows along some particular directions.