Dielectric, AC Conductivity, and DC Conductivity Behaviours of Sr2CaTeO6 Double Perovskite

Abstract

Relatively new double perovskite material, Sr2CaTeO6, has been prepared through conventional solid-state procedures. Structural, dielectric, and optical characteristics of this exquisite solid-state material were analysed in this study. The single-phase monoclinic P21/n structure of this prepared compound was well correlated with the literature review. Good distribution of grain sizes and shapes was observed in the morphological study of this compound. The discussions on its optical and dielectric properties are included in this manuscript. High dielectric real permittivity, low dielectric loss, and good capacitance over a range of temperatures possessed by this compound, as shown in dielectric and electrical modulus studies, indicated good potential values for capacitor applications. The Ro(RgQg)(RgbQgb) circuit fitted well with the impedance and electrical modulus plot of the compound. Its relatively high electrical DC conductivity in grain at high frequencies and its increasing value with the temperature are typical of a semiconductor behaviour. This behaviour might be attributed to the presence of minor oxygen vacancies within its lattice structure and provides a long-range conduction mechanism. A small difference between activation energy and Ea of DC conductivity indicates that the same charge carriers were involved in both grains and the grain boundaries’ long-range conduction. The electrical AC conductivity of this compound was found to contribute to the dielectric loss in grain structure and can be related to Jonscher’s power law. The presence of polarons in this compound was exhibited by non-overlapping small polaron tunnelling (NSPT) and overlapping large polaron tunnelling (OLPT) conduction mechanisms over a range of temperatures. Wide optical band gap and Eopt in the range of 2.6 eV to 3.6 eV were determined by using an indirect and direct allowed mechanism of electrons transitions. These values supported the efficient semiconducting behaviour of the grain in this material and are suitable for applications in the semiconductor industry.

Role of Ca2+ doping on the enhancement of dielectric properties of Sr2–xCaxNiWO6 for energy storage device application

“…Using LEO model 982 Gemini equipment, a scanning electron microscope (SEM) with energy dispersive X-ray (EDX) spectroscopy was used to examine the surface morphology and the composition of the raw materials. Using the UV–Vis spectrophotometer Lambda 750, Perkin Elmer, Waltham, USA equipment with a wavelength range of 200 nm to 800 nm, the UV–Vis diffuse reflectance spectra were observed at room temperature 18 . The Kubelka–Munk and the Tauc plot were used to convert the spectra to absorbance in order to calculate the compounds’ energy band gap.…”

The Structural and Magnetic Transition Behaviour Analysis of La0.7Pb0.3MnO3 Perovskite-Type Manganites

“…The agglomeration of grains was conducted in the samples due to the grain quick rate of nucleation as the samples undergo calcination and the sintering process at a relatively high temperature. The accumulation of grains happened because of the limited duration of proper grain dispersal from each other [12,13]. The average grain size obtained from the morphology was 2.13 μm.…”

Investigation of the structural, dielectric, magnetic properties and NTC-thermistor response of CaBiFeMnO6 double perovskites

“…Higher frequency mediated electrons exhibit a hopping process that results in this pattern, which is characterised by dispersion and saturation. [62][63][64] Since localized charge carriers participate in this conduction process, polaron entities arise at places close by. [64][65][66] The AC conductivity versus frequency plot shows a plateau and a dispersion.…”