Multiferroic properties of BiFeO3-(K0.5Bi0.5)TiO3 ceramics

Ceramics of xBiFeO3-(1−x)(K0.5Bi0.5)TiO3 (where x=0.6, 0.7 and 0.8) have been produced, and characterized using neutron diffraction, revealing a G-type antiferromagnetic structure. The ferroelectric Curie temperature was >430 °C, and the Néel temperature was in the range 228–254 °C, increasing with x. Ferroelectricity was confirmed using strain and polarization-field measurements, for the composition x=0.6, with a Ps=26 μC/cm2 and a coercive field=3.85 kV/mm. Piezoelectricity was observed for this material with a low-field d33 of 37 pm/V, and a high-field d33⁎ of 80 pm/V where x=0.6. The reduction in coercive field in this system is shown to correlate with the oxygen octahedral tilt angle. The solid solution xBiFeO3-(1−x)(K0.5Bi0.5)TiO3 has potential as a high temperature, piezoelectric, multiferroic system.

► Fabricated the xBiFeO3-(1−x)(K0.5Bi0.5)TiO3 system where x=0.6, 0.7 and 0.8.
► A perovskite with a G-type antiferromagnetic structure was observed.
► The oxygen octahedral tilt angle, coercive field, TC and TN all reduce with x.
► PUND measurements for x=0.6 suggests that there is significant remanence.