Crystal structure and multiferroic properties of Gd-substituted BiFeO3

Room-temperature crystal structure, local ferroelectric, and magnetic properties of the Bi1-xGdxFeO3 (x=0.1,0.2,0.3) polycrystalline samples have been investigated by x-ray diffraction, piezoresponse force microscopy, and magnetometry techniques. Performed measurements have revealed a sequence of the composition-driven structural phase transitions R3c -> Pn2(1)a (occurs at x similar to 0.1) and Pn2(1)a -> Pnma (takes place within the concentrational range of 0.2 < x < 0.3). The latter structural transformation is attributed to the substitution-induced suppression of the polar displacements. Gd substitution has been shown to effectively induce the appearance of the spontaneous magnetization, thus indicating a promising way for improving multiferroic properties of antiferromagnetic BiFeO3.