Small Polaron Tunneling Research Articles

Characterization of Cs2AgInCl6: Bridging Optical and Electrical Properties for Advanced Optoelectronic Applications

ABSTRACTLead‐free double perovskites, such as Cs2AgInCl6, represent a promising class of materials for optoelectronic applications due to their favorable properties and environmental sustainability. This work focuses on the synthesis and comprehensive characterization of Cs2AgInCl6, employing a range of techniques including X‐ray diffraction (XRD) for structural verification, thermogravimetric analysis (TGA) to assess thermal stability, and UV–visible absorption measurements to determine the optical bandgap energy of 3.32 eV. Additionally, we explore photoluminescence (PL) and decay measurements to elucidate the luminescent properties of the compound. Complex impedance measurements are performed under both blue and red light to investigate the electrical behavior, revealing two distinct conduction mechanisms: the overlapping large–polaron tunneling (OLPT) and nonoverlapping small–polaron tunneling (NSPT). We analyze the implications of our findings on the current–voltage (I–V) behavior and trap density, further supported by Raman spectroscopy under both illumination conditions. The combined insights from optical and electrical characterizations highlight the potential of Cs2AgInCl6 in optical applications, paving the way for its use in advanced optoelectronic devices.

Exploring giant dielectric constant in Dy2CoMnO6: evidence of non-overlapping small polaron hopping

Abstract Perovskites, both natural and synthetic, form a large class of materials are a vast class of materials with significant technological relevance due to their remarkable physical properties, such as superconductivity, magnetoresistance, ionic conductivity, and diverse dielectric behaviors. In this study, the dielectric relaxation and transport properties of the double perovskite Dy2CoMnO6(DCMO) synthesized via high-energy ball milling are investigated. DCMO exhibits a notably large dielectric constant, attributed to a combination of intrinsic and extrinsic mechanisms. Frequency-dependent dielectric studies reveal non-Debye-like behavior, validated by augmented Havriliak-Negami function fitting. Impedance spectroscopy confirms the semiconducting nature of DCMO, showing a negative temperature coefficient of resistance, and identifies two distinct relaxation processes corresponding to grain boundaries and grain interiors thereby highlighting the impact of microstructure and defects. The Cole-Cole plot further supports the non-Debye behavior, while thermally activated relaxation suggests damped charge carrier dynamics at grain boundaries. Conduction analysis using augmented Jonscher's power law reveals non-overlapping small polaron tunneling as the dominant mechanism driving both the dielectric response and transport properties, with DC conductivity suggesting a three-dimensional variable range hopping model. These results provide significant insights into the dielectric and transport properties of DCMO, highlighting its promising potential for advanced electronic applications.

Study of electric transport and impedance analysis in copper chloride modified bismuth boro-tellurite glasses

CuCl2 substituted bismuth borate tellurite glasses were examined for electrical conductivity at frequencies between 10−1 Hz and 106 Hz and temperatures between 463 K and 563K. The Almond West law used for fitting experimental data of ac conductivity, and determining cross-over frequency (ωH), frequency exponent (s), and dc conductivity (σdc). Depending on the glass composition, ac conduction process was modeled using correlated barrier hopping and non-overlapping small polaron tunneling. The imaginary component of the electric modulus included in the experimental data fitted by non-exponential Kohlrausch-Williams-Watts. Impedance examination reveals minimization of mixed former effect on electric charge transport at low frequencies in studies glasses. For x = 20, conduction occurs due to charge carriers (Cu2+ ions/polarons). An excellent match is found between the Nyquist plots and equivalent circuit models. There is good agreement between the estimated activation energy from conductivity EC (0.82–1.13 eV), electric modulus ER (0.81–1.12 eV), and impedance EZ (0.82–1.15 eV) analyses.

Conduction mechanisms and dielectric relaxations in ternary ZnO/Zn2SiO4/SiO2 composites for energy storage systems

In this paper, ZnO-based composite (ZnO/Zn2SiO4/SiO2) powders were prepared and investigated as a function of SiO2 added amount. Indeed, the X-ray diffraction patterns (XRD) confirm the formation of ternary ZnO/Zn2SiO4/SiO2 composites. The structural defects are shown to increase with the SiO2 amount. In addition, the SEM observations reveal agglomerated and heterogenic grain shape distribution. Furthermore, dielectric properties were investigated as a function of SiO2 added amount. The Nyquist plots are simulated by an electric circuit formed by a parallel distribution of resistance (R), capacitance (C), and a constant phase element (CPE), in all composites. Moreover, using the Jonscher's law, we demonstrate a change in conduction mechanism as a function of SiO2 content. Indeed, for the 10 % SiO2 doping, the conduction process is ensured by defects such as Zn interstitial and the oxygen vacancies, consistent with the Correlated Barrier Hopping (CBH) model. Whereas, for the 20 % SiO2 doping, the conduction is dominated by grain boundaries contribution, according to the Non-Overlapping Small Polaron Tunneling (NSPT) model. Besides, the 10 % SiO2-doped composite exhibits localized relaxation process, while the 20 % SiO2-doped sample reveals simultaneously long-range and localized relaxations. These variations, caused by the increase of SiO2 percent, can be explained by the influence of the growth of Zn2SiO4 phase, and subsequently the development of further interfacial defects. Accordingly, the composites display capacitive behavior, high permittivity, and low dielectric losses, which make them good candidates for energy storage systems.

Broadband Dielectric Spectroscopy: Unraveling Na+diffusion and mixed conduction in Na₂O-modified zinc phosphate glasses for electrode material applications

The fundamental understanding of electric charge (ion + polarons/electrons) transport and relaxation mechanism is essential for applications in solid state ionics. In present work, to study Na+ transport, the electrical conductivity of zinc phosphate glasses modified with Na2O has been investigated in temperature range 313K and 473K and frequency range of 100 mHz to 1 MHz. The experimental data of Nyquist plots is fitted with appropriate equivalent circuits at different temperatures which reveals presence of mixed conduction (polaronic + ionic) and Na+ diffusion (at 50 mol% Na2O) in studied glass samples. The values of frequency exponent (s) obtained from the fitting of experimental data of the real part of electrical conductivity with Almond–West equation (WAE) have been used to determine the conduction mechanism. The electric transport in studied glasses occurred via correlated barrier hopping and non-overlapping small polaron tunnelling conduction models depending on the glass composition and temperature range of investigation. Electric Modulus studies further supports the assertion of composition and temperature dependent conduction mechanisms. The activation energies determined from conductivity, electric modulus, and impedance measurements are found to be consistent, indicating a good correlation in the study.

Electrical properties and evaluation of band tail states in Mg doped p-type multilayer hBN

A series of Mg doped p-type multi-layered hBN films were prepared by atmospheric pressure chemical vapor deposition. Temperature dependent conductivity measurements were performed from 0.1 Hz to 10 MHz to analyze the characteristics of tail states close to the valence band edge. Jonscher's power law (Aωs) is successfully applied to understand charge carrier transport through these states. In this work, exponent S increases from 0.6 → 0.8, 0.8 → 0.995, and 1.4 → 1.6 for samples B (precursor temperature, 750 °C), D (850 °C), and E (900 °C), indicating that non-overlapping small polaron tunneling dominates to 548 K. Polaron binding energies of 0.2–0.40 eV and tunneling distances <4.9 Å are calculated, confirming transport through localized states. The density of states near the Fermi level N(EF) was extracted from a fit to the AC conductivity data, yielding values of 1015 and 1017eV−1cm−3 as the precursor temperature increases. Singular Mg acceptor levels of 74, 30, and 17 meV are identified for each sample. A hole concentration from 6.5 × 1017 to 1 × 1018 cm−3 and carrier mobility from 18 to 25 cm2/V s is measured at 300 K. From RC fitting, carrier recombination lifetimes of 1.2, 0.4, and 0.35 μs are determined. Fermi's golden rule is used to determine an optical joint density of states of 1.1 × 1021 eV−1 cm−3 at a band edge. Overall, we show that AC conductivity is an effective method to evaluate midgap states in 2D (two-dimensional) materials at EF and p-type hBN possesses sufficient electrical properties to be integrated into a wide range of semiconductor applications.

Unraveling the properties of [TPA]2Cu2Br6: A holistic investigation into structure, optics, magnetism and dielectric characteristics

The recent technological advances require an aligned innovation in the materials used for the construction of electronic devices. Hybrid materials play a important role in the optoelectronic applications because they combine both the organic and inorganic components To this end, the [TPA]2Cu2Br6 compound was successfully synthesized using the slow evaporation solution growth approach at room temperature. The [TPA]2Cu2Br6 compound crystallizes in the triclinic system with P1‾space group. The atomic arrangement can be described by an alternation of organic and inorganic layers stacked along the c direction and made up of [N(C3H7)4]+ and [CuBr3]− groups, respectively. The examination of SEM analysis allows us to raise the morphology and the good quality of the crystals. The EDX analysis was performed to ensure that all chemical elements were discovered and located in the relevant locations.For the compound under study, the UV–visible spectroscopy spectrum shows the direct band-gap value of ∼3.52 eV, indicating that it is a semiconductor material. Magnetic measurements revealed the superparamagnetic behavior. Studies of the dielectric constant permittivity ε*(ω) confirmed that the relaxation process was thermally activated. The dominant transport mechanism is the s the non-overlapping small polaron tunneling (NSPT) model.

Upheaval of Negative Dielectric Permittivity and Semiconductor to Metallic Transition in a Thermally Induced Sn-Doped β-Ga2O3 (-201) Single Crystal.

Thermally induced dielectric and conductivity properties of an Sn-doped β-Ga2O3 (-201) single crystal were investigated by frequency-domain impedance spectroscopy in the frequency window from 100 Hz to 1 MHz with temperatures between 293 and 873 K. The (-201) plane-orientated single crystalline nature and the presence of an Sn dopant in β-Ga2O3 were confirmed by X-ray diffraction (XRD) and X-ray photoelectron (XPS) spectroscopy. Two different trends of impedance spectra have been discussed by the modulation of relaxation times and semiconductor to metallic transition after ∼723 K due to activation of a significant number of Sn dopants and their movements with temperature. The negative impedance values were encountered in the Nyquist plots (Z' vs Z″) after 573 K and constitute a reverse movement after 723 K with temperature. The average normalized change (ΔZ'/Δf)/Z0 of impedance exhibits a broad downward relaxation plateau near 723 K, indicating a weak electrical transition. The increases in the positive value of the dielectric constant (εr') below a percolating threshold temperature 573 K is attributed to the interfacial and dipolar polarizations, and the plasma oscillation of delocalized electrons governed by the Drude theory is responsible for the negative dielectric constant above 573 K. The 3D projections of the real dielectric constant create a sharp downward sinkhole near 723 K, indicating the existence of negative dielectric permittivity. The electrical conductivity dramatically changes its trends after 523 K and confirms a transition from hopping conduction (dielectric or semiconductor) following Jonscher's power law to metallic conduction by Drude theory. Below the percolating threshold temperature, a nonoverlapping small polaron tunneling conduction mechanism was unveiled with defect-induced activation energy of 0.21 eV. The Sn-doped β-Ga2O3 exhibits unique and tailored electromagnetic responses with temperatures that can be associated with a variety of applications in electromagnetic wave manipulations, cloaking devices, antennas, sensors, medical imaging, seismic wave propagation, etc.

Synthesis and study of structural, electric, and dielectric behavior of La0.5Sm0.2Sr0.3Mn1-xFexO3 perovskite

In this study, the synthesized samples La0.5Sm0.2Sr0.3Mn1-xFexO3 (x = 0.05, 0.15 and 0.20) were thoroughly investigated for their crystalline structure, electrical conductivity, and dielectric properties, the samples were prepared using autocombustion method. According to the X-ray diffraction study, the samples crystallized in an orthorhombic symmetry with the Pnma space group. To measure the dielectric characteristics, impedance spectroscopy was conducted over the temperature range of 100–260 K and a frequency range of 100 Hz to 1 MHz. Measurements of AC conductivity are indeed utilized to investigate the transport properties of materials being studied. The results indicated that both temperature and frequency significantly influence the conduction process. Three theoretical hypotheses were proposed to explain the hopping conduction: overlapping large polaron tunneling (OLPT), the non-overlapping small polaron tunneling (NSPT) mechanism, and correlated barrier hopping (CBH). It is also shown that the conductivity diminishes with an increase in Fe content. La0.5Sm0.2Sr0.3Mn1-xFexO3 (x = 0.05, 0.15 and 0.20) can be used in electronic applications because of the high permittivity values confirmed by the dielectric measurements. With the aim of evaluating the distinct impacts of electrodes, grain boundaries, and grains on the complex impedance results, an appropriate alternative electrical circuit was utilized. Analysis of the sample's modulus indicated non-Debye characteristics and electrical relaxation phenomena. The materials exhibit good electrical properties, as well as strong chemical and thermal stability.

Oxygen vacancy modulated optical and dielectric properties of photoactive γ-Fe2WO6

Ferrite compounds have gained scientific attention for their multifunctional attributes. This investigation explores the structural, optical, dielectric and conductivity properties of polycrystalline γ-Fe2WO6 synthesized by the solid state route. The X-ray diffraction confirmed the orthorhombic structure and single-phase formation, while the electron microscopy showed uniform distribution of dense micrometer-sized grains in γ-Fe2WO6. The FTIR spectroscopy analysis validated the presence of active stretching and bending modes, signifying oxygen anion vibration at both Fe and W sites. The simultaneous presence of Fe2+ and Fe3+ ions in the matrix, as confirmed by X-ray photoelectron spectroscopy (XPS), results in an augmented optical energy band gap and contributes to dielectric permittivity due to the charge carrier hopping mechanism between the trap sites. The compound manifests semiconductor attributes, evident in its indirect optical band gap measuring 1.7 eV. It is observed that the compound has effectively degraded the Methylene Blue (MB) under the visible light within 40 min with a degradation efficiency up to 63 %. The material's electrical conductivity, follows the Jonscher's power law, signifies its semiconductor nature and adheres to the Small Polaron tunneling model for charge conduction between neighboring sites. The impedance (Z′) curves exhibit dielectric relaxation (≤ 10 kHz) with a similar activation energy to the dc conductivity study. The activation energy, determined from both the impedance and conductivity analyses, indicates a connection with the migration of oxygen vacancies within the material. Our observation reveals the presence of oxygen vacancies, which possibly act as in-gap electron traps, enhancing the correlated optical and ac conductivity properties, making it an appealing material for diverse multifunctional applications.

Evaluating the significance of rare earth and iron doping on structure-property of lead titanate

The samples (Pb0.8Ln0.2 Fe0.2 Ti0.8O3, (Ln= La, Nd, Sm, Gd)) were synthesized successfully by mixed oxide method. A significant reduction in tetragonality is observed with the modification of structure. The grain size from FESEM study was observed to be decreasing with increase in ionic radii of rare earth ions. Specifically, the dielectric constant is found to be maximum for the Sm-doped sample. Conductivity studies at varying temperature and frequencies reveal the NTCR behaviour of these samples. In Sm, Nd and Gd doped samples, tunnelling of small polarons is responsible for conduction process whereas for La doped sample, the conduction process is mediated through the combined effect of small polaron tunnelling and bipolaron hopping. The Sm-doped sample exhibits highest remanent polarization. All the results of this comprehensive study provide valuable insights into the effect of dopant ions on various properties of the studied materials, paving the way for device applications.

Small polaron hopping and tunneling mechanisms in Ba0.9La0.1Fe12O19 hexaferrite ceramic at low temperatures

The correlation between dielectric relaxation and conduction mechanisms in the Ba0.9La0.1Fe12O19 ceramic hexaferrite, at temperatures below 100 K was investigated. The sample was prepared using the conventional solid-state reaction method. X-ray diffraction analysis indicated that the sample is composed of a hexagonal BaFe12O19 phase (lattice parameters a = 5.8778(6) Å and c = 23.170(3) Å) and a small proportion of hematite (α-Fe2O3). The average grain size is 1.48 ± 0.4 μm, with irregular hexagonal and agglomerated grains. The magnetic hysteresis curve shows characteristics typical of ferro and ferrimagnetic materials, with an effective magnetic anisotropy coefficient of 0.960×106 emu/cm3 and an anisotropy field of 1.587×104 Oe. A dielectric relaxation process is observed between 50 and 100 K, with an activation energy of 60.4 ± 0.4 meV and a characteristic relaxation time of 2.09 ×10−10 s, mainly attributed to the electrical behavior of the grains. Two conduction mechanisms were identified: small polaron tunneling (high temperatures and low frequencies) and correlated barrier hopping of electrons (low temperatures and high frequencies). The activation energy for free polaron formation, according to the Komine-Iguchi hopping polarization model, was 7.12 ± 0.02 meV. In the dielectric modulus relaxation process between 30 and 54 K, the activation energy was 40.8 ± 0.9 meV, with a characteristic relaxation time of 2.41×10−10 s. The small polaron conductivity in the grain region was 67.52 meV and 54.0 meV in the grain boundary region. The results highlight that the polarization and conduction mechanisms in this ceramic at low temperatures are dominated by small polaron hopping and tunneling, and emphasize the influence of La3+ doping on the structural, magnetic, and electrical properties of barium hexaferrite.

Structural, Thermal, Optical, Electrical, and Dielectric Properties of Complex Lead-Free Compound: [Bi1∕2Na1∕2][Fe1∕2W1∕2]O3

Some physical properties (structural, dielectric and optical) of a complex lead-free ceramic [[Formula: see text][Formula: see text]][[Formula: see text][Formula: see text]]O3 have been thoroughly examined in different experimental conditions in this study. It was fabricated via a solid-state reaction method. The crystal structure is monoclinic, according to the detailed analysis of the X-ray diffraction pattern. Also, the functional vibrational bands can be observed in the FT-IR and Raman spectra, which support the creation of the molecular structure. Scanning electron microscope (SEM) images of the sample clearly show the effects of [Formula: see text] and [Formula: see text] incorporation in morphology, and energy dispersive X-ray spectroscopy (EDX) indicates the existence of all constituents. The non-overlapping small polaron tunneling (NSPT) and correlated barrier hopping (CBH) model conduction mechanisms are examined through Jonscher’s power law. The contribution of the grain and grain boundary to the capacitive behavior is shown by Nyquist plots. According to a leakage current analysis, the compound exhibits Ohmic and space charge limited conduction (SCLC) conduction mechanisms. Electric field polarization was used to study the ferroelectric nature. The findings of this study show that the inclusion of [Formula: see text] and [Formula: see text] is an efficient technique to improve its dielectric and optical characteristics.

Electrical conductivity and relaxation mechanisms of nanocrystalline Ba0.75Ca0.2Cs0.05TiO3

Ca and Cs doped barium titanate lead-free ceramic with the formula Ba0.75Ca0.2Cs0.05TiO3 has been prepared by the solid-state reaction method. X-ray diffraction (XRD) confirms the crystallization of the sample in a tetragonal structure with a P4mm space group. The phase purity and grain morphology were evaluated using X-ray diffraction and scanning electron microscopy (SEM). The material exhibits a primary phase of Ba0.75Ca0.2Cs0.05TiO3 with a minor secondary phase of BaO2, and the average grain size is determined to be 1.66 μm. Using non-destructive complex impedance spectroscopy (CIS), we extensively studied the electrical behavior, including complex impedance (Z*), complex modulus (M*), electrical conductivity, and relaxation mechanisms, of Ba0.75Ca0.2Cs0.05TiO3 over a wide temperature (85 K–290 K) and frequency range. The ac conductivity analysis reveals that the dominant conduction mechanism is the non-overlapping small polaron tunneling (NSPT) model. The impedance analysis indicates a single semi-circle in the real and imaginary parts, suggesting a single relaxation mechanism. Additionally, the activation energy was calculated to be approximately 0.0489 eV. These findings contribute to the understanding of the structural and electrical properties of Ba0.75Ca0.2Cs0.05TiO3, highlighting its potential applications in electronic devices such as capacitors, thermistors, and ferroelectric random access memories (FRAMs).

Exploring the structural, magnetic, and dielectric properties of Fe and Y substituted NiCr2O4

This paper presents the successful single phase synthesis of NiCr2O4 and NiFe0.50Cr1.50-xYxO4 (x = 0 – 0.08) compounds followed by an investigation into their structural, magnetic and dielectric properties. The structural analysis confirms tetragonal structure for NiCr2O4 while a partially inverse cubic spinel structure for Fe and Y substituted samples (x = 0 – 0.08). Fe substitution (x = 0) induces a shift in room temperature hysteresis loop behaviour from paramagnetic to ferrimagnetic, suggesting enhanced superexchange interactions and a significant rise in magnetic transition temperature beyond room temperature. However, it is found that further inclusion of Y (x = 0.04 – 0.08) leads to a slight weakening of superexchange interactions. The saturation magnetization increases with Y substitution, while coercivity and magnetocrystalline anisotropy follows a decreasing trend. The complex impedance studies unveil a relaxation phenomenon and the dielectric constant is found to increase with the substitution of Fe and Y. Analysis of temperature dependent ac conductivity data and the frequency exponent profile suggests small polaron hopping as the predominant transport mechanism up to 380 K in NiCr2O4 and x = 0 samples, shifting to large polaron hopping beyond this temperature. In samples with x =0.04 and 0.06 the transport mechanism is found to follow the small polaron tunneling model. However, in the x = 0.08 sample, large polaron tunneling becomes predominant beyond 365 K.

Development of Lead‐Free Defect Brownmillerite Perovskite Ceramic LiBiFeMnO5 Solid Solution for Electronic Devices

This article reports the fabrication (synthesis) and characterizations (structural, microstructural topographic surface, dielectric, transport, impedance, current–voltage, and resistive properties) of a complex lead‐free defect perovskite material of composition LiBiFeMnO5. A preliminary structural investigation of the X‐ray diffraction pattern using N‐TREOR09 methods shows monoclinic symmetry. The scanning electron microscopic spectrum examines the sample's microstructural topographic surface, fractal study, and roughness (using the standard ISO25178). The analysis of Maxwell–Wagner dielectric dispersion, relaxation, and transport mechanisms is investigated utilizing dielectric, impedance, and conductivity spectrum accumulated within the experimental frequency of (1 kHz–1 MHz) at different temperatures (30–500 °C). A nonoverlapping small polaron tunneling conduction mechanism and correlated barrier hopping mechanism in the material have helped to understand its conduction phenomena. The Ohmic and space–charge limited conduction mechanisms are investigated by the slope of the logarithmic electric field (E) and current density (J). The thermistor constant (β) is determined to be 1982.87. The temperature coefficient of resistance is found to be −0.00419, which may be suitable for negative temperature coefficient thermistors, sensors, and other related devices.

Enriched electron donor sites and non-overlapping small polaron tunneling electrical conduction in oxygen-deficient β-Ga2O3 thin film on p-Si (100)

Enriched electron donor sites and non-overlapping small polaron tunneling electrical conduction in oxygen-deficient β-Ga2O3 thin film on p-Si (100)

Unveiling the role of ZrO2 doping in Sr2SmTi2Nb3O15 ceramics: From structural study to dielectric enhancement

Solid-state processing was used to synthesize tungsten bronze type (TTB) solid solutions, specifically Sr2Sm(Ti1-xZrx)2Nb3O15 with x values of 0, 0.2, 0.3, and 0.4. The study examined the crystalline structure, optical properties, morphology, and electrical and dielectric characteristics of these compounds. X-ray diffraction revealed a tetragonal structure (space group P4bm). Scanning electron microscopy showed significant sample densification with grain sizes decreasing from 6.19 μm to 2.78 μm. Dielectric measurements indicated that the dielectric constant varied from 150 for x = 0 to 567.24 for x = 0.2, then decreased to 380.88 for x = 0.4, with the x = 0.3 compound having the lowest dielectric loss. The Curie temperature (Tc) decreased from 332 °C to 248.5 °C with increasing Zr content, corresponding with a reduction in grain size. The energy gap (Eg) narrowed from 2.914 eV to 2.714 eV as Zr content increased. AC conductivity increased with temperature and frequency. Electrical conductivity followed Jonscher's power law, with activation energies decreasing from 1.54 eV to 0.87 eV, explained by the small polaron tunneling (NSPT) model.

Strong magnetoelectric coupling in novel Na0.5Bi0.5TiO3–BaFe12-2xCoxTixO19 multiferroic composite

Multiferroic composites of sol-gel synthesized Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) and Co–Ti substituted Barium Hexaferrite (BaFe12-2xCoxTixO19; x = 0.0, 0.5, 1.0, 1.5 and 2.0) in the ratio 3:1 was synthesized through ceramic route. Successful formation of R3c rhombohedral and P63/mmc hexagonal phases corresponding to Na0.5Bi0.5TiO3 and BaFe12-2xCoxTixO19 respectively was confirmed from the XRD and Rietveld refinement pattern. The frequency and temperature dependence of dielectric constant and loss of the composite systems exhibited typical dispersion behaviour which could be understood using the Maxwell-Wagner model. Substituted samples showed enhanced dielectric behaviour where dielectric constant was observed to increase while loss tangent decreased. Using the Universal Jonscher's Power law (JPL), conductivition mechanisms of the composite systems were studied from the ac conductivity behaviour which revealed that the x = 0.0 sample followed Non-overlapping Small Polaron Tunnelling (NSPT) model while the remaining samples followed the Correlated Barrier Hopping (CBH) model. The complex impedance and Nyquist plot analysis showed the enhancement of resistive property in the x≠0 systems. Magnetic hysteresis loop measurements were conducted, and the associated parameters were determined with the assistance of the Law of Approach to Saturation (LAS). Favourable reduction in the magnetic anisotropy was observed indicating the disturbance of magnetic spin structure in the hexaferrite phase. The P-E loops established the novel room temperature multiferroic nature of the composite systems. Significant magnetoelectric coupling was detected at room temperature in all samples, with the x = 0.5 sample exhibiting the highest value of approximately 59.81 mV/cmOe. These desirable properties suggest that the composites may find future device applications as in magnetically tunable energy harvesting devices and self-powered magnetoelectric sensors in the future.

Synthesis, Structural characterization and complex impedance analysis of a novel organic-inorganic hybrid compound based on Mercury (II) chloride

The organic-inorganic hybrid compounds are promising materials due to their electro-optical and semiconducting properties. In this study, a single crystal of (C6H16N)2[HgCl4] has been synthesized and characterized using single-crystal X-ray diffraction at room temperature, SEM/EDS and complex impedance spectroscopy. The crystal structure is centrosymmetric with the monoclinic system (P21/c space group). It consists of isolated tetrahedral anions [HgCl4]2− and protonated amines (C6H16N) +. SEM/EDS analyses proved the composition of the title compound. The frequency-dependent electrical and dielectric properties were analyses using complex impedance spectroscopy in the frequency range of 10−1 Hz – 1 MHz. The Nyquist plots (-Z’’ vs Z’) was characterized by the appearance of a single semicircle arc, indicating a non-Debye type relaxation process in the (C6H16N)2[HgCl4] material. The AC conductivity followed Jonscher law, and the variation of frequency exponent s with temperature suggested that non-overlapping small polaron tunneling (NSPT) is the dominant electrical transport mechanism. So, this work will be very beneficial to the further development of the (C6H16N)2[HgCl4] compound and its potential electrical applications.