Improved multiferroic properties in (1−x)BiFeO3-xBaTi0.95(Yb0.5Nb0.5)0.05O3 system (0≤x≤0.3)

Polycrystalline samples of (1−x)BiFeO3-xBaTi0.95(Yb0.5Nb0.5)0.05O3 (x=0, 0.1, 0.2 and 0.3) were prepared by the conventional solid state reaction method. The phase purity and composition were cheeked using powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The grain size and morphology of the ceramics were confirmed by scanning electron microscopy (SEM). X-ray diffraction showed that these compounds crystallized, at room temperature, in the Rhomboedral R3c for x=0 and in tetragonal P4mm for compositions 0.1≤x≤0.3 distorted perovskite structures. The BaTi0.95(Yb0.5Nb0.5)0.05O3 substitution led to an improvement of magnetic and ferroelectric properties at room temperature. The highest magnetization was reported for composition x=0.2 which was due to the enhancement of canting angles and the suppression of cycloid spin structure, as confirmed by 57Fe Mössbauer spectroscopy and the presence of Fe2+, as detected by XPS. The electric polarization increased significantly for doped samples, which proves the enhancement of the ferroelectric behavior and resistivity of our ceramics. Large electric field induced strains were observed for 0.7BiFeO3-0.3BaTi0.95(Yb0.5Nb0.5)0.05O3, as an evidence of piezoelectric behavior. These results show that BaTi0.95(Yb0.5Nb0.5)0.05O3 doped BiFeO3 is a promising multiferroic material.