The Bechgaard salts (TMTSF)2X (with X a small centro-or non-centrosymmetric anion) show several kinds of ground states, in particular a superconducting one at low temperatures (T

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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The influences of calcination temperature and doping with cobalt in A–site on structural and dielectric properties of CaCu3-xCoxTi4O12 (CCCxTO, x = 0.00, 0.02 and 0.10) ceramics sintered at 1050 0C for 8h were investigated. The ceramic samples are prepared by the conventional solid-state method using high purity oxide powders, and they are calcined at 850 °C, 950 °C and 1050 0C for 4h. The X-ray diffraction (XRD) analysis of pure and doped CCTO samples calcined at 950 °C and 1050 0C showed no traces of any other secondary phases, while impurity phases alongside CCTO phase in the x=0.00 sample calcined at 850 0C was observed. Scanning electron microscopy (SEM) investigation showed an increase in grain size with increasing of Co content and calcining temperature. Dielectric measurements indicated that the dielectric constant of the pure CCTO calcined at 1050 0C/4h has a low value in the frequency range of 1kHz up to 1MHz, whereas the substitution of Co up to x = 0.10 into CCTO caused a huge increase in the dielectric constant value of the calcined samples which is equal to 153419 and 18957 at 950 °C and 1050 0C respectively. The complex impedance analysis of all samples shows a decrease in resistance with an increasing temperature, which suggests a semiconductor nature of the samples

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