Effect of La and Ni substitution on structure, dielectric and ferroelectric properties of BiFeO 3 ceramics

Abstract In this communication, we present the results on Bi 1− x La x Fe 1− y Ni y O 3 (x=0.0, 0.1; y=0.0, 0.05) samples processed by solid-state reaction route in order to study crystalline and electronic structure, dielectric and ferroelectric properties. The best refinement was achieved by choosing rhombohedral structure ( R 3 c ) for BiFeO 3 and Bi 0.9 La 0.1 FeO 3 samples. Whereas, the XRD pattern of BiFe 0.95 Ni 0.05 O 3 and Bi 0.9 La 0.1 Fe 0.95 Ni 0.05 O 3 samples were refined by choosing rhombohedral ( R 3 c ) and cubic ( I 23) structure. Raman scattering measurement infers nine Raman active phonon modes for all the as prepared samples. The substitution of Ni ion at Fe-site in BiFeO 3 essentially changes the modes position i.e . all the modes are observed to shift to lower wave number. Dielectric constant (e′) and dielectric loss (tan δ) as a function of frequency have been investigated and they decreases with increasing frequency of the applied alternating field and become constant at high frequencies. This feature is a characteristic of Maxwell Wagner type of interfacial polarization. The remnant polarization ( P r ) for Bi 0.9 La 0.1 FeO 3, BiFe 0.95 Ni 0.05 O 3 , and Bi 0.9 La 0.1 Fe 0.95 Ni 0.05 O 3 are 0.08, 0.11, 0.69 μC/cm 2 , respectively and the value of coercive field for Bi 0.9 La 0.1 FeO 3, BiFe 0.95 Ni 0.05 O 3 , and Bi 0.9 La 0.1 Fe 0.95 Ni 0.05 O 3 are 0.53, 0.67, 0.68 kV/cm, respectively. X-ray absorption spectroscopy (XAS) experiments at Fe L 2 , 3 and O K -edges are performed to investigate the electronic structure of well-characterized Bi 1− x La x Fe 1− y Ni y O 3 (x=0.0, 0.1; y=0.0, 0.05) samples. The presence of reasonable ferroelectric polarization at room temperature in Bi 0.9 La 0.1 Fe 0.95 Ni 0.05 O 3 ceramics makes it suitable for technological applications.