Influence of Mn-doping on di-/piezo-/ferro-electric properties of 0.49BiFeO₃-0.20Pb(Mg_1/3Nb_2/3)O_{3-0.31PbTiO3 ceramic at morphotropic phase boundary}

Pure and Mn-doped 0.49BiFeO(3)-0.20Pb(Mg1/3Nb2/3)O-3-0.31PbTiO(3) (BF-PMN-PT) ceramics at morphotropic phase boundary (MPB) have been prepared by solid state reaction method. A systematic investigation of its microstructure and electrical properties was conducted. Powder X-ray diffraction (XRD) and Field emission scanning electron microscope (FESEM) showed the formation of pure perovskite phase with homogeneous microstructure having average grain size of 2.48 mu m at optimum temperature 920 degrees C. As compared to the pure BF-PMN-PT ceramic, enhanced dielectric constant value (similar to 800) was observed for Mn-doped sample at room temperature. Polarization vs. electric field (P-E) hysteresis curves exhibits improved ferroelectric properties (P-r = 97.65 C/cm(2) at coercive field E-c = - 17.08 kV/cm) after doping and showed a fatigue free nature over 10(4) switching cycles. The displacement voltage (D-V) curve showed a high value of the piezoelectric coefficient d(33)* = 786 pm/V after Mn doping. The magnetic hysteresis loop (M-H) curve showed a weak ferromagnetic nature with coercive field (H-c = 54.19 Oe) and remanent magnetization (M-r = 0.0087 emu/g) of the sample. Therefore, Mn-doped BF-PMN-PT ceramic can be a promising candidate for applications in the electronic ceramic industries.