Investigation of frequency dependent dielectric properties of La-doped BaSnO3-ZnSnO3 solid-solutions

Relaxation processes and conduction mechanism in bismuth ferrite lead titanate composites

In this work we synthesized the multifunctional (La0.8Ca0.2)0.4Bi0.6FeO3 material using a sol–gel process. Structural and morphologic investigations reveal a Pnma perovskite structure at room temperature with spherical and polygonal nanoparticles. A detailed study of the temperature dependence of the dielectric and electrical properties of the studied material proves a typical FE–PE transition with a colossal value of real permittivity at 350 K that allows the use of this material in energy storage devices. Thus, the investigation of the frequency dependence of the ac conductivity proves a correlated barrier hopping (CBH) conduction mechanism to be dominant in the temperature ranges of 150–170 K; the two observed Jonscher's power law exponents, s1 and s2 between 180 K and 270 K correspond to the observed dispersions in the ac conductivity spectra in this temperature region, unlike in the temperature range of 250–320 K, the small polaron tunnel (NSPT) was considered the appropriate conduction model.

Dy3+ and Sm3+ ratio variation effects on electrical properties of lithium fluoride bismuth borate glass system

Lithium diphosphates, and particularly Li2CoP2O7, have garnered increasing attention due to their promising properties for applications in energy storage and electronic devices. In the present study, Li2CoP2O7 was successfully synthesized using a conventional solid-state reaction route. X-ray powder diffraction (XRD) analysis confirmed the formation of a pure monoclinic phase with C2/c space group symmetry and an average grain size of approximately 2.66 μm. Infrared (IR) spectroscopy revealed distinct vibrational modes characteristic of P2O7 4- groups, in line with the expected structural framework. Optical absorption measurements indicated that the material exhibits semiconducting behavior, with an estimated indirect band gap of approximately 3.78 eV. Dielectric studies demonstrated that Li2CoP2O7 possesses excellent dielectric performance, including a remarkably high dielectric constant (∼2 × 108), suggesting its suitability for low-frequency energy storage applications. Impedance spectroscopy measurements revealed a non-Debye relaxation mechanism, with temperature-dependent relaxation dynamics analyzed using the Arrhenius model. Furthermore, the frequency-dependent ac conductivity followed Jonscher's universal power law, and the behavior of the frequency exponent s was consistent with the correlated barrier hopping (CBH) conduction model. Overall, these findings offer valuable insights into the dielectric relaxation processes and charge transport mechanisms in Li2CoP2O7, underscoring its potential for high-performance applications in advanced electronic systems and energy storage technologies.

Enhancement of optical, dielectric and transport properties of (Sm, V) co-doped ZnO system and structure-property correlations

Modification and development in the microstructure of PVA/CMC-GO/Fe3O4 nanocomposites films as an application in energy storage devices and magnetic electronics industry

The polycrystalline sample of (Bi0.5Li0.5)(Fe0.5Nb0.5)O3 was prepared by a solid-state reaction method. Preliminary X-ray structural analysis of the sample suggests the formation of a tetragonal phase with a new unit cell configuration. Dielectric, electrical, impedance and modulus properties of the material were investigated in a wide range of temperature (25–500 °C) and frequency (1 kHz–1 MHz). Two dielectric anomalies observed at 295 °C and 400 °C clearly suggest the existence of magnetic phase transition and two relaxation processes in the system. Dielectric properties have greatly been improved on addition of LiNbO3 to BiFeO3. The appearance of a hysteresis loop at room temperature confirms the ferroelectric properties of the material. The nature of the Nyquist plot confirms the presence of both bulk and grain boundary effects in the material. The ac conductivity was found to obey Jonscher's power law. The dc conductivity variation with temperature follows the Arrhenius equation. The induced voltage changes with the applied magnetic field, showing that the sample is multiferroic.

Enhancement of structural, magnetic, dielectric, and transport properties of Nb substituted 0.7BiFeO3-0.3BaTiO3 solid solution

The effects of Na+ substitution by Y3+ on the structural, microstructural, dielectric and electrical properties of Ba2Na(1-3x)YxNb5O15 compositions with (x = 0, 0.02 and 0.04) have been studied in detail. The solid solutions of different compositions were prepared by the solid state reaction route method and characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Complex Impedance Spectroscopy (CIS) techniques. The XRD study confirmed that all prepared compositions have a single-phase orthorhombic tungsten bronze structure with space group Cmm2 at room temperature. The microstructural studies revealed a grain shape and size change in response to increasing Y3+ concentration. The dielectric properties of the obtained compositions are evaluated over a temperature range of 40–600 °C. The dielectric properties were improved for the Y2O3-substituted Ba2NaNb5O15 compound compared to the undoped Ba2NaNb5O15 compound. The non-Debye type relaxation mechanism is confirmed by the -Z″ versus Z′ traces. The grain contribution was studied using an equivalent electrical circuit with a Resistor R, a Capacitor C, and a Constant-Phase Element CPE in parallel, in the absence of the grain boundary response and the electrode effect in the frequency range 10 Hz-1MHz. The experimental AC conductivity data were evaluated by using Jonscher's power law. The activation energies obtained from the relaxation and conduction processes, present two different regions as a function of temperature related to the two electrical processes for the prepared ceramics.

NiFe2O4 nano-hollow spheres with improved magnetic and dielectric properties

Structural and conduction behaviour of (BaSr)0.5TiO3 modified in BFO perovskite

Improved dielectric performance of polyvinylidene fluoride (PVDF) - Carbon dots composites

Structural, dielectric and transport properties of samarium-doped cobaltites

Dielectric characteristics and thermal behaviour of terbium fumarate heptahydrate crystals

This study aims to investigate the electric, dielectric poperies, and the charge transport mechanism in Polyaniline/Tin disulfide (PANI/SnS2) nanocomposites. SnS2 nanoflowers were synthesized using the hydrothermal method and were utilized to synthesize PANI/SnS2 nanocomposites by in‐situ polymerization of the aniline. PANI/SnS2 nanocomposites were composed of hexagonal nanoflowers and amorphous PANI. The charge transport mechanism was investigated by using DC and AC conductivities. DC conductivity increased and reached a maximum value at 5 wt. % sample and then it decreased indicating the percolation effect. To understand the charge transfer mechanism in the PANI/SnS2 composites, AC conductivity, dielectric properties, and impedance characteristics were investigated in the frequency range of 20 Hz to 2 MHz. PANI/SnS2 nanocomposites follow Jonscher's Power Law of disordered materials with an exponent value ranging from 0.8 to 0.9. The Havriliak – Negami model confirmed that the samples display a non‐Debye relaxation mechanism. The dielectric constant value increases with an increase in the SnS2 content. These enhanced properties of PANI/SnS2 nanocomposites suggest that the proposed PANI/SnS2 nanocomposites are the potential materials for multifunctional applications, especially in nano‐electronic devices.Highlights Hydrothermal synthesis of SnS2 Nano flowers. SnS2/PANI composites were synthesized by the in situ polymerization method. The DC conductivity of 5 wt. % sample shows Percolation threshold. Jonscher's & Havriliak–Negami fittings suggest non‐Debye dielectric relaxation. Charge transfer mechanisms in the composites were studied using Nyquist plots.