Electrical and dielectric properties for bulk ethylcarbazole-terphenyl (PEcbz-Ter) have been studied over frequency range 1 kHz–2 MHz and temperature range (R.T –120°C). The copolymer PEcbz-Ter was characterised by using X-ray diffraction. The frequency dependence of the dielectric constant (εr′) and dielectric loss (εr″) has been investigated using the complex permittivity. εr′ of the copolymer decreases with increasing frequency and increases with temperature. AC conductivity (σac) data were analysed by the universal power law. The behaviour of σac increases with increasing temperature and frequency. The change of the frequency exponent (s) with temperature was analysed in terms of different conduction mechanisms, and it was found that the correlated barrier-hopping model is the predominant conduction mechanism. The electric modulus was used to analyze the relaxation phenomenon in the material.

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In this work, the effect of BaTiO3 (BT) addition on structural, dielectric and electrical properties of CaCu3Ti4O12 (CCTO) ceramic was investigated. Ceramic samples with the chemical formula (1-x)CaCu3Ti4O12 -xBaTiO3, (1-x)CCTO-xBT, (x = 0.00, 0.10, 0.20, 0.30, 0.50 and 1.00) were synthesized by solid state route. The structural studies carried out by X-ray diffraction technique and showed that the perovskite structure cubic and tetragonal phases were formed without any other impurity phases. The addition of BaTiO3 into CCTO system lowered the last crystallite size to about 52 nm and increased the dielectric constant by four orders compared to pure CCTO. Moreover, the results of the complex impedance analyses of (1-x)CCTO-xBT ceramics samples confirmed the presence of non-Debye type of relaxation phenomenon and exhibited a negative temperature coefficient of resistance behaviour.Keywords: Ceramics, Barium titanate, Raman spectroscopy. Chemistry; Vol. 29, No. 8 (2017), 1811-1816 a mixture CCTO and BaTiO3 characteristics. In the present work we are reporting the synthesis of (1-x)CCTO-xBT by solid state reaction route. The structural, dielectric and electrical properties of (1-x)CaCu3Ti4O12-xBaTiO3 ceramics (where x = 0.00-1.00) were investigated. Asian Journal of EXPERIMENTALThe (1-x)CCTO-(x)BT samples were synthesized by means of a conventional mixed oxide route. High-purity oxides and carbonates; CaCO 3 (99.8 %) CuO (purity, 99 %), TiO 2 (purity, 99.95 %) and BaCO 3 (purity 99.5 %) (All Sigma Aldrich chemicals, USA) were used as starting materials.Synthesis of (1-x)CaCu 3 Ti 4 O 12− − − − −xBaTiO 3 : The powders were weighed in stoichiometric proportion and milled for 1 h. Then the slurry was dried in an oven at 80 °C. The calcinations processes of CCTO and BaTiO 3 powders were carried at 1050°Cand 1100 °C for 4 h, respectively. The synthesized powders were mixed in acetone according to the formula (1-x)CCTO-(x)BT for 2 h and dried at 400 °C for 1 h, after that the powders were crushed in agate mortar and pressed into pellets of about 12 mm diameter and 1.5 mm thickness. Then, the pellets sintered at 1050°C for 8 h and left at room temperature. The samples surfaces were coated by silver paste to serve as poles for the electrical measurements uses. Characterization of (1-x)CaCu3Ti4O12− − − − −xBaTiO3XRD analysis: The crystal structure of (1-x)CCTO-xBT was determined by using an X-ray diffractometer with a scanning rate of 0.02°/min for 2θ range 20°-80° by employing CuKα radiation wavelength λ = 1.5406 Å (diffractometer system = XPERT-PRO) under the conditions of 40 KV and 30 mA.Raman spectroscopy analysis: A micro Raman spectrometer, equipped with an excitation source of monochromatic with wavelength of 410 nm, was used to study the relationship between Raman lines and different types of atomic motions of CCTO and BaTiO3 in the (1-x)CCTO-xBT ceramics. After the sample processing, Raman spectra was collected at room temperature.Dielectric measurements analysis: The electrical properties of the ceramics were measu...

In this paper, composite ceramics (1-x)CaCu 3 Ti 4 O 12 -(x)PbZr 0.48 Ti 0.52 O 3 (with x =0.00, 0.50 and 1.00), denoted CCTO-PZT, were prepared by a three-stages modified method, in order to achieve high dielectric constant and low loss. Structural investigations carried out by X-ray diffraction (XRD), and FT-IR spectroscopy showed the formation of pure cubic and tetragonal phases for x = 0.00 and x=1.00 compositions, respectively. XRD showed the coexistence of both phases in the CCTO-PZT composite. The morphology of the ceramics was examined by scanning electron micrograph (SEM), results reveal a homogeneous microstructure with two types of grains corresponding to PZT (smaller grains) and CCTO (large grains). Dielectric measurements carried out by an impedance analyzer; show that the dielectric constant of the CCTO-PZT composite is higher than the pure samples (CCTO and PZT) one. The temperature dependence of the ac conductivity indicated that the conduction follows the Arrhenius law and the conduction process is due to the single and the doubly ionized. The optical band gap of the PZT is 2.25 eV, and the band gap decreased in the CCTO/PZT composite.