Chemical strain effects arising from the large size mismatch between the two A-site cations results in a lowering of the symmetry from polar R3c to a polar Cc in Bi0.95Dy0.05FeO3.

Despite the high prominence of the perovskites BiFeO(3) and KNbO(3) the solid solution between the two has received little attention. We report a detailed neutron and synchrotron X-ray powder diffraction, and Raman spectroscopy study which demonstrates an R3c→P4mm→Amm2 series of structural phase transitions similar to that exhibited by the PbZrO(3)-PbTiO(3) solid solution.