Effect of Cu2+ substitution on the relaxor behavior of BaBi2Nb2O9 ferroelectric nanoceramics prepared by chemical route

Abstract

Ba0.5Cu0.5Bi2Nb2O9 (BCuBN) crystalline nano ceramics were prepared by chemical precursor solution decomposition method. A structure property correlation of BCuBN done through dielectric impedance, density of states, hopping mechanism and discharge polarization study after the incorporation of Jahn-Teller active Cu2+ (d9, s = ½) ions. X-ray diffraction study, scanning electron microscopy demonstrated the orthorhombic structure with A21am space group of BCuBN. Ferroelectric to paraelectric phase transition temperature (Tc) obtained in the temperature range from 515 °C to 545 °C at different frequency range. The activation energy of relaxation behaviour in complex imaginary impedance plot with frequency is 0.80 eV closer to dc conductivity (0.73 eV). The frequency dependent ac conductivity becomes much higher at higher frequency. The density of states and hopping mechanism were successfully explained here. The field induced polarization hysteresis loops demonstrated the pseudo static saturation of polarization. Maximum discharge energy density was 1.12 J cm−3 at 10 kV cm−1 electric field.