Properties of the solid solution (1-x)Na0.5 Bi0.5 TiO3 – (x)BiFeO3

A previous study has shown that Na0.5Bi0.5TiO3 (NBT) and BiFeO3 (BF) form a continuous R3c solid solution at the ambient temperature. In this solid solution an evolution of the properties is expected. Indeed, on one hand NBT exhibits a relaxor behavior while BF does not and on the other hand, NBT is solely ferroelectric while BF is also antiferromagnetic. In this contribution, both electrical and magnetic properties are reported. 1)In a large range of the solid solution (x≤0.7) the dielectric constant maximum corresponding to the Curie point (Tm) is shifted through high temperatures, as the BF content increases. This evolution is due to the strong displacement of the bismuth in the cuboctahedral site which enhances the polar character and consequently the ferroelectric behavior. At high temperature, a tremendous increase of the permittivity is observed which is attributed to a conductivity phenomenon. This conductivity is here relevant to an oxygen vacancies jumps mechanism. 2)The main point of the topic is that two distinct domains are evidenced in the solid solution. 3)Finally, it is shown that starting from BF, the substitution of iron by titanium gives rise to a ferro or ferrimagnetic behavior of the compounds