Dielectric properties and related ferroelectric domain configurations in multiferroic BiFeO3–BaTiO3 solid solutions

Dielectric properties and ferroelectric domain configurations of multiferroic xBaTiO3–(1−x)BiFeO3 (x=0.10–0.33) solid solutions synthesized by conventional solid-state reaction, were reported. A structural transition from rhombohedral to pseudo-cubic structures appeared around x=0.33, and the formation of impurity phase of Bi2Fe4O9 was effectively depressed by doping BaTiO3. Dielectric constants of xBaTiO3–(1−x)BiFeO3 solid solutions decreased with increasing the frequency, and the degree of decrease was related to the doping content of BaTiO3. Transmission electron microscopy images revealed that the ferroelectric domain configurations in the multiferroic BiFeO3–BaTiO3 solid solutions with rhombohedral symmetry, exhibited a wavy character whereas a predominant intricate domain structure with fluctuating mottled contrast was observed in the multiferroic BiFeO3–BaTiO3 solid solution with pseudo-cubic phase structure. The presence of 1/2{111} superlattice spots in the selected area electron diffraction patterns taken from the multiferroic BiFeO3–BaTiO3 solid solutions with rhombohedral symmetry indicated that the ordered regions have a doubled perovskite unit cell.