Impedance and modulus studies of Na0.9Ba0.1Nb0.9(Sn0.5Ti0.5)0.1O3 ceramic

Polycrystalline Na[Formula: see text]Ba[Formula: see text]Nb[Formula: see text](Sn[Formula: see text]Ti[Formula: see text]O3is prepared by the solid-state reaction technique. The formation of single-phase material was confirmed by an X-ray diffraction study and it was found to be a tetragonal phase at room temperature. Nyquist plots ([Formula: see text]ˆ2 versus [Formula: see text] show that the conductivity behavior is accurately represented by an equivalent circuit model which consists of a parallel combination of bulk resistance and constant phase elements (CPE). The frequency dependence of the conductivity is interpreted in terms of Jonscher’s law. The conductivity [Formula: see text] follows the Arrhenius relation. The modulus plots can be characterized by the empirical Kohlrausch–Williams–Watts (KWW), [Formula: see text] = exp([Formula: see text]/[Formula: see text] function and the value of the stretched exponent ([Formula: see text] is found to be almost independent of temperature. The near value of activation energies obtained from the analyses of modulus and conductivity data confirms that the transport is through an ion hopping mechanism dominated by the motion of the (O[Formula: see text] ions in the structure of the investigated material.

Investigation of Microstructure and Dielectric Behavior of Bi2/3Cu3-xMgxTi4O12(x=0, 0.05, 0.1 and 0.2) Ceramics Synthesized by Semi-Wet Route

In this manuscript, We have reported the synthesis and characterization of Mg-doped and undoped BCTO ceramic (Bi2/3Cu3-xMgxTi4O12, x=0,0.05,0.1,0.2) sintered at 1173 K for 8 h, which have been prepared by the semi-wet path. Single-phase formation of ceramic was approved by the XRD pattern. The Microstructural properties were studied by TEM and AFM. The samples were characterized by dielectric and impedance spectroscopic properties. The dielectric constant (εr) was calculated to be 3024 for BCTO ceramics at 423 K and 100 Hz. The tangent loss (tan δ) value was calculated to be 0.45 for BCTO ceramic at 423 K and 10 kHz. The internal Barrier Layer Capacitance (IBLC) mechanism was responsible for the high value of dielectric constant. XPS spectroscopy confirmed the oxidation state of the ceramic. It was observed from Impedance and modulus studies that there was the existence of the Maxwell-Wagner form of relaxation in the ceramics.