Raman scattering, structural, electrical studies and conduction mechanism of Ba0.9Ca0.1Ti0.95Zr0.05O3 ceramic

Ba0.9Ca0.1Ti0.95Zr0.05O3 BCZT (10%, 5%) ceramic was prepared via solid state route. BCZT (10%, 5%) presents a coexistence of orthorhombic and tetragonal structures. By Raman spectroscopy the ferroelectric-paraelectric phase transition (TC) is detected. So as to investigate the electrical transport, a complex impedance spectroscopy is highlighted. With the Debye theory-based analysis and a series of Arrhenius relations, the Nyquist diagrams (Z″ versus Z′) are well suitable to an equivalent circuit model. The relaxation was argued to be related with the hopping motions of charge carriers between Ca2+ and Zr4+ ions. At various temperatures, the dielectric datum was analyzed using complex electrical modulus M*. The plot of modulus versus frequency presents a peak of relaxation. Using the universal Jonscher's power law, the AC conductivity for grain contribution is interpreted. Activation energies, determined from conductivity (Ea = 1.23eV) and complex modulus (Ea = 1.06 eV) are different, which confirms that the transport is ensured by an ion hopping mechanism. However, a dispersion of the conductivity was observed at medium frequencies and was explained using the correlated barrier hopping (CBH) model.