Structure and phase transition of the (1−x)PbTiO3–(x)BiAlO3 system

The system (1−x)PbTiO3−(x)BiAlO3 has been studied with regard to its structure and phase transition behaviour using x-ray, neutron and dielectric measurements. The structure is tetragonal within the solid solubility limit (x<0.25)(x<0.25). Interatomic distance analysis revealed that the Pb–O bond lengths remain unaffected and the only the Ti–O lengths are altered by BiAlO3 substitution. The results are suggestive of a crossover from and A-site & B site driven ferroelectric system for x=0x=0 to a dominant A-site driven ferroelectric system for higher xx. This cross-over is brought about by (i) a reduction in the contribution to the ferroelectric stability from B-site cations due to dilution of the Ti-sublattice by Al and (ii) a reinforcement to the stability of the ferroelectric state by the A-site cations by the Bi+3 cations.