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In this study, ZnTe thin films were prepared using the R-F sputtering technique. X-ray diffractogramme indicates that our samples are crystallized in a cubic phase with a F-43 m space group. The UV visible spectrophotometer confirms the surface homogeneity of the deposited films and also the similitude of the value of the optical band gap energy with those reported in the literature. Electrical impedance spectroscopy data were analyzed to estimate the activation and relaxation energies. The AC electrical conductivity data are discussed in the light of existing theoretical models. • ZnTe thin film were prepared by RF- sputtering on glass substrates. • The film was characterized by UV–Visible spectrophotometer, and X-Ray diffraction for the optical and structural properties. • The electrical properties were investigated by impedance spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract Strontium (Sr) doped Calcium Copper Titanate Ca 1−x Sr x Cu 3 Ti 4 O 12 with two values x = 0 and x = 0.05 commonly known as CSCTO ceramics have been obtained by using the semi wet route synthesis method. Rietveld refinement shows that the powders crystallize in the cubic perovskite related structure with Im3 space group. Scanning Electron Micrograph (SEM) analysis shows that the average grain size of ceramics becomes larger when Sr doping is considered. Both DC and AC electrical conductivity are investigated throughly in the temperature and frequency ranges between [373–653 K] and [20 Hz–1MHz], respectively. The values of the average activation energies for CSCTO-0 (x = 0) and CSCTO-5 (x = 0.05) were found to be 612 meV and 576 meV, respectively. In Fact, Sr doping has an effect on the broadening of the impurity band that can lead to a dramatic decrease in the activation conduction energy of CSCTO ceramics. A systematic study of AC electrical conductivity reveals that the predominant conduction mechanism existing in these ceramics is generated by large polaron hopping process. This mechanism has also been identified by the modulus analysis and confirmed by comparing the hopping polaron size with the lattice parameter. Highlights • Strontium (Sr) doped CCTO was synthesized with a chemical semi wet route. • Electrical properties have been investigated in the temperature range [373–673 K] and frequency range [20 Hz–1 MHz]. • OLPT mechanism have been attributed as the most suitable model for CSCTO system. • The OLPT was identified by modulus analysis and structural data. [ABSTRACT FROM AUTHOR]

By using the semi-wet synthesis method, lead-free ferroelectric materials Ba 0.9 Sr 0.1 Ti 1-x Sn x O 3 with x = 0, 0.02, 0.05, and 0.10 (abbreviated as BSTS) were prepared and their structural, electric and electrocaloric properties were investigated. The X-ray diffraction (XRD) patterns show that the samples calcined at 950 °C have well crystallized into perovskite structure suggesting the substitution of Ti4+ by Sn4+ in BST lattice. With increasing content of Sn, the enhancement of the dielectric permittivity was observed for (0 ≤ x ≤ 0.05) and the ferroelectric transition temperature (T C) was found to shift towards the room temperature (T C = 20 °C for x = 0.10). Direct measurements of the electrocaloric effect (ECE) were performed on all samples by using the high-resolution calorimeter. It is found that Ba 0.9 Sr 0.1 Ti 0.95 Sn 0.05 O 3 exhibits a high ECE temperature change of ΔT EC = 0.188 K at an applied electric field of only 7 kV/cm. Impedance spectrum analysis of all the samples performed in the temperature range of 300–360 °C reveals the existence of two relaxation contributions related to the grain and grain boundaries that are well separated in frequency. Activation energies of conduction and relaxation processes were deduced for both contributions in order to determine the conduction mechanism of the studied compositions. • Semi-wet synthesis method is used to prepare the ferroelectric Ba 0.9 Sr 0.1 Ti 1-x Sn x O 3 (BSTS) with x = 0, 0.02, 0.05, and 0.10. • This work shows the effect of Sn on electrocaloric, structural, dielectric and electric of BSTS. • Direct electrocaloric measurements show that BSTS (x = 0.05) exhibits the highest value of EC responsivity (ξ = 0.027 K cm/kV). • Enhancement of dielectric permittivity is observed for (0 ≤ x ≤ 0.05). • Impedance spectroscopy shows that the conduction and relaxation processes can be described by the same activated mechanism. [ABSTRACT FROM AUTHOR]