Complex Impedance Spectra Research Articles

Investigation of structural, dielectric, impedance, and conductivity properties of layered perovskite type compound; NaYSnO4

In this paper, the structural study of NaYSnO4 (NYSO), a layered perovskite ceramic oxide, was done using an X-ray diffractometer (XRD) to identify the phase and determine the composition of NYSO. The microscopic structure of the sample seen by Scanning Electron Microscopy (SEM) was found to be polycrystalline and a mixture of large and small grains, which indicate the anisotropic nature of the sample. A FTIR spectroscopic behaviour of the material was used to identify the formation of different bonds in the material, and the XPS study gives an idea of the binding energy of each element in NYSO. A thorough analysis of the impedance, dielectric constant, dielectric loss, modulus and AC conductivity properties concerning temperature and frequency displays the electronic device characteristics. The complex impedance spectra were studied at temperatures range between 25 and 500˚C and frequency of 100 Hz to 1 MHz range. Nyquist plots reveal the charge conduction mechanism of the grain and well-defined grain boundaries that correspond to the resistive and capacitive phenomena of the material. Furthermore, the activation energy has been estimated to investigate the charge transportation mechanism. This article concludes by discussing future possibilities and scientific challenges in NTCR thermistors using NYSO.

Fabrication of a novel sensor based on ionic porous polymer microspheres for humidity monitoring

A novel humidity sensor based on ionic porous polymer (IPP) microspheres was prepared in this work. The chemical structure and morphology of IPP microspheres were carefully characterized. The intrinsic hydrophilic ionic units of IPP, –N+R– and Br–, could enhance the adsorption of water molecules and ionic conductivity. The aromatic groups in IPP can adjust its hydrophobicity and ensure stability. Meanwhile, the structure of microspheres provides a favorable space of channels for water molecules transport, which improves the response speed of sensing film further. The impedance of the sensor based on IPP microspheres changed more than three orders of magnitude in the relative humidity (RH) range of 11–95 % RH with a good linearity (R2=0.996) and a fast response speed (6 s/ 27 s). Finally, the mechanism was systematically studied by complex impedance spectrum and theoretical calculation. This study shows a new type of sensor based on ionic porous polymer microspheres, which will pave the way for IPP applications in humidity sensing.

RADIATION-STIMULATED CONVERSION TO SUPERIONIC STATE OF TlSe AND TlS CRYSTALS

The electrical properties of TlSe and TlS compounds were studied in a constant and alternating measuring field when exposed to various doses of gamma radiation in the temperature range of 300…400 K. In a constant electric field, a decrease in electrical conductivity with time was detected. Complex impedance spectra were measured in the frequency range 20…106 Hz. It is shown that in the studied range of temperatures, frequencies and doses of γ-radiation, conductivity is ionic in nature. The electrical properties of TlSe and TlS crystals are determined by the conductivity of Tl+1 ions and the accumulation of charge carriers near the blocking silver electrodes.

Impact of Nickel doping on microstructure and impedance spectroscopy of multiferroic YCrO3

In this work, we study the effect of Ni-doping on the structural and impedance spectroscopy properties of the polycrystalline YCrO3 ceramic sample. The structural analysis shows all the samples crystallize in an orthorhombic structure with the Pnma space group. The depressed and asymmetric semicircle of complex impedance spectra indicates that the relaxation of charge carriers is of non-Debye type, where the thermally activated charge carriers control it. The temperature dependence of relaxation time and electrical conductivity exhibit an anomaly in the vicinity of diffuse-like relaxor transition temperature (TC ∼ 460 K). The analysis of conductivity data shows hopping-type charge conduction. The analysis further indicates that while the dc conductivity increases continuously, the activation energy shows a non-monotonous variation with Ni concentration.

Investigation of the role of sintering temperature on microstructure, ac conductivity, and dielectric constant of single phase NiSnO3 nanopowder

This study investigates the effect of sintering temperature on the structural and electrical properties of co-precipitated nickel stannate (NiSnO3) nanopowder. Sintering temperatures, determined using Thermo Gravimetric Analysis (TGA), reveal a pure hexagonal perovskite structure through X-ray diffraction (XRD) analysis. Crystallite size increased from 10.56 nm to 26.04 nm and lattice strain decreased from 23.05×10−3 to 2.35×10−3 with higher sintering temperatures, analyzed via the Scherrer formula. d-spacing values from SAED patterns align with XRD results, and TEM analysis shows particle size growth from ∼11.43 nm to ∼28.16 nm as sintering temperature rises from 600°C to 900°C. Elemental composition has been confirmed through EDX, and elemental mapping analysis. Impedance spectroscopy via Cole-Cole plots indicated non-Debye-type or multiple relaxations with depressed semicircles due to grain and grain boundary effects. The sample sintered at 900°C exhibits the highest conductivity (8.35×10−5 Ω−1cm−1) with lowest activation energy of 0.31 eV and maximum dielectric constant values, with a minimum relaxation time of 0.00029 sec. Also the frequency variation of Z′′ and M′′ confirm the presence of non-Debye type relaxation. Scaling behavior of the imaginary part of complex impedance and conductivity spectra confirms temperature-independent conduction and relaxation mechanisms. These materials are used in energy storage applications.

Meshed, Flexible, and Self-Supported Humidity Sensors by Direct-Writing with Multifunctional Applications.

Flexibility endows humidity sensors with new applications in human health monitoring except for traditionally known environmental humidity detection in recent years. In this study, a flexible, mesh-structured, and self-supported humidity sensor was designed and manufactured by direct writing in a homemade two-dimensional stepping numerical control workstation. Bacterial cellulose with humidity sensitivity and good film-forming properties was applied as the self-supporting substrate, in which conductive activated carbon and water-absorptive magnesium chloride (MgCl2) were incorporated. The humidity sensing performance of the printed sensor was measured and optimized. Besides, the fundamental insight into the sensing mechanism of the printed humidity sensor was analyzed by a complex impedance spectrum. The multifunctional applications of the self-supported humidity sensor were demonstrated by human breathing detection, noncontact distance sensing, and speaking recognition. The simple self-supported structure combined with the meshed attribute of the flexible sensor showed large use potential in real-time monitoring of human respiration, voice detection, environmental humidity monitoring, and noncontact switches.

Exploring the AC conductivity and dielectric properties of PVA films doped with Erythrosin B

Erythrosin B (EB) doped in PVA film was processed utilizing the casting procedure, and the structure was investigated via the Fourier Transformation infrared technique (FTIR). FTIR analysis presented a strong formation of intermolecular hydrogen bonds among PVA and EB hydroxyl groups (OH). Characteristic temperature and frequency variation of dielectric behavior and AC electrical conductivity for films of PVA doped with Erythrosin B were analyzed at (293–383 K) temperature and (102–106 Hz) frequency. The AC conductivity dependency indicates that the predominant conduction mechanism in PVA doped with Erythrosin B films follows the correlated barrier hopping (CBH) model. The charge carriers’ hopping involving localized states causes a relaxation process. Estimates were made for the AC conductivity activation energy and the conductivity relaxation energy. Frequency and temperature affect the dielectric constant (ε′) and the dielectric loss (ε″). The complex impedance spectrum (Z′ versus Z″) showed single semicircular arcs with a decreased radius with increasing temperature. The relaxation peaks in the electric modulus representation are clearly defined, and the relaxation period has been calculated.

Electrical analysis and molecular dynamics of anion in ferroelastic [(CH3)4P]2CoBr4 crystal near high-temperature phase transitions

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 [(CH3)4P]2CoBr4 compound was successfully synthesized using the slow evaporation solution growth approach at room temperature. In-depth research has been conducted on the structural, morphological, vibrationnal and electrical characteristics. The [(CH3)4P]2CoBr4 compound crystallises in the monclinic system with P121/C1 space group. The examination of SEM images reveals that the majority of grains have an average size of around 4 μm with irregularly shaped and non-spherical particles. The measured Raman spectra demonstrate the coexistence of two transition phases located at 373 K and 428 K. In fact, these observations suggest that the anionic components play a significant role in influencing the phase transitions mechanism. Analysis of the complex impedance spectra reveals that the electrical characteristics of the material is strongly dependent on both frequency and temperature. That indicates the existence of a relaxation phenomenon and of a semiconductor-type behavior. One single semicircle is detectable in the Nyquist plots of the complex impedance spectra, which can be satisfactorily fitted with a combination of R//C//CPE elements assigned to the bulk response. Therefore, we can conclude from this behavior that the sample is electrically homogeneous. The dependency of s(T) on temperature also shows that the correlated barrier hopping and the non-overlapping small polar on tunneling model are the responsible mechanisms for the AC conduction in [(CH3)4P]2CoBr4.

Magnetic exchange interactions and non-Debye relaxation in spin-3/2 frustrated Kagomé magnet Co3V2O8

We report the experimental determination of the magnetic exchange parameter ( J/kB = 2.88 ± 0.02 K) for the Spin-3/2 ferromagnetic (FM) Kagomé lattice system: Co3V2O8 using the temperature dependence of dc-magnetic susceptibility χ(T) data by employing the fundamental Heisenberg linear chain model. Our results are quite consistent with the theoretically reported nearest neighbor dominant FM exchange coupling strength Jex−NN∼ 2.45 K. Five different magnetic phase transitions (6.2–11.2 K) and spin-flip transitions (9.6–7.7 kOe) have been probed using the ∂ ( χT )/ ∂T vs. T, heat capacity (CP -T) and differential isothermal magnetization curves. Among such sequence of transitions, the prominent ones being incommensurate antiferromagnetic (AFM) state at 11.2 K, commensurate AFM state at 8.8 K, and commensurate FM state across 6.2 K. All the successive magnetic phase transitions have been mapped onto a single H-T plane through which one can easily distinguish the above-mentioned different phases. The magnetic contribution of the CP -T near TN (11.2 K) has been analyzed using the power-law expression CM = A|T — TN|−α resulting in the critical exponent α = 0.18 ± 0.01 (0.15 ± 0.003) for T < TN (T > TN ), respectively for the Co3V2O8. It is interesting to note that non-Debye type dipole relaxation is quite prominent in Co3V2O8 and was evident from the Kohlrausch–Williams–Watts analysis of complex modulus and impedance spectra (0 ⩽β⩽ 1). Mott’s variable-range hopping of charge carriers process is evident through the resistivity analysis ( ρac -T −1/4 ) in the temperature range 275 ∘C–350 ∘C. Moreover, the frequency-dependent analysis of σac (ω) follows Jonscher’s power law yielding two distinct activation energies ( Ea∼ 0.37 and 2.29 eV) between the temperature range 39 ∘C–99 ∘C and 240 ∘C–321 ∘C.

Colossal permittivity with ultra-wide temperature stability in Bi + Ca co-doped BaTiO3

The poor temperature stability of the BaTiO3 ceramic has always been the main problem limiting their application. This situation has been improved but sacrifices the intrinsic polarization, which significantly reduces the dielectric constant. In this work, the mechanism of multiple polarization was creatively introduced, and the temperature stability and dielectric properties of BaTiO3-based ceramics are simultaneously enhanced. In particular, the Ba0.9925Bi0.005Ti0.995Ca0.005O2.995 (BBTC0.5) ceramic sample achieved excellent temperature stability (−14.8% to 8.85%) over an ultra-wide temperature range (−47 to 400 °C) and exhibited colossal permittivity (27,125, 25 °C, 1 kHz) and low dielectric loss (0.07, 25 °C, 1 kHz). The dielectric properties, complex impedance spectra combined with XPS results indicate that the defective dipole clusters (Ti3+-VO..-Ti3+, BiBa. and CaTi″-VO..) along with surface effects lead to colossal permittivity effect. More importantly, SEM images show the presence of the second phase at grain boundaries, which prevent the carriers within the grains from accumulating at the grain boundaries. As a result, the dielectric loss was reduced and the temperature stability was further extended. This strategy breaks the traditional limitation of single/noncomprehensive enhancement by single-polarization mechanism, and is of great theoretical and practical significance to promote the research and application of high-performance BaTiO3-based ceramic materials.

Carbon nanotubes for optimizing response stability and speed of acrylate hybrid copolymers humidity sensor

AbstractCarbon nanotubes (CNTs) are one‐dimensional nanomaterials with a hollow structure, high specific surface area and excellent chemical conductivity, which show great potential for application in the field of humidity‐sensitive responsive materials and humidity sensors. In this paper, CNTs were composited with a hybrid copolymer (HAC) of octavinyl POSS/acrylate to prepare the hybrid copolymer composites HAC/CNTs and their humidity sensors, which demonstrated exceptional thermal stability and fast response speed. Among them, acrylic resin serves as a humidity‐sensitive material; POSS introduce a stable three‐dimensional cage skeleton structure to the material; and CNTs are used as conductive fillers, which further enhance the stability of the material, as well as improve the sensitivity and humidity‐sensitive response speed of the material. The experimental findings indicate that the HAC/8.0% CNTs composite material exhibits a remarkable sensitivity of 119.94 KΩ/%RH within the humidity range of 11%–95%RH. Compared with HAC, HAC/8.0% CNTs demonstrate a significant reduction in response/recovery time from 16.0 s/70.0 s to 0.8 s/80.0 s, representing a considerable improvement in response speed; the wet hysteresis is reduced from 0.88 %RH to 0.77 %RH; and the temperature change coefficient is reduced from 0.035 %RH/°C to 0.008 %RH/°C over the temperature range of 20–60°C, indicating superior stability against temperature variation. Meanwhile, the humidity response mechanism of HAC/CNTs was discussed by using complex impedance spectrum. The hybrid copolymer composites, HAC/CNTs, that were prepared in this study have tremendous potential in the development of advanced, high‐performance, and miniaturizable humidity sensing technologies.Highlights A hybrid copolymer composite humidity‐sensitive material HAC/CNTs is prepared. HAC/CNTs are compounds consisting of CNTs and POSS/acrylate hybrid copolymer. POSS improve the skeleton structural stability of acrylic resins. CNTs enhance the sensitivity and response speed of humidity sensor. The HAC/8.0% CNTs have higher response stability and faster response speed.

Disk flower-like structure of PANI Modulated electronic transport dynamics of Sr[formula omitted] ferrite

This study conducted a comprehensive analysis of the low frequency-based electrical characteristics of ferrite composites, exploring the influence of morphology on tunning and optimizing dielectric and conductivity relaxation. Specifically, composites of PANI: Sr CoxZnxFe12−2xO19 in 1:4 ratio by weight, with varying levels of substitution x = 0.0, 0.4, 0.8, 1.2, 1.6, and 2.0 were synthesized using the physical blending method. X-ray diffraction analysis of composites shows the existence of M-type hexagonal and PANI particles, along with some secondary phases in all synthesized samples. The morphology of composites revealed disk flower-like and hexagonal platelet-type structures of PANI and hexagonal ferrite, respectively. Substituting Co–Zn ions induced a non-linear increase in grain size from 0.781 to 1.566 μm, calculated using ImageJ software. The dielectric and electrical properties of composites were examined over the frequency range of 20 Hz to 2 MHz. The replacement of Fe ions with Co–Zn ions resulted in a non-linear variation in conductivity and is maximum for FP3 (1.33 × 10−2 Ω−1m−1) at 2 MHz. The complex impedance spectra deviated from an ideal Debye type and were modeled using an equivalent circuit encompassing resistances of grain boundaries and grains, grain capacitance, and a constant phase element. Modulus and impedance spectra analysis illustrated the contribution of both grain and grain boundaries in their respective relaxations. The simulation of impedance parameters in EIS software elucidated a substantial value of Cg = 290 μF for FP1, which aligned with the large-sized grain observed in FESEM micrographs.

Magnetoelectric Properties of Aurivillius-Layered Perovskites

In the present work, we have synthesized rare-earth ion modified Bi4−xRExTi2Fe0.7Co0.3O12−δ (RE = Dy, Sm, La) multiferroic compounds by the conventional solid-state route. Analysis of X-ray diffraction by Rietveld refinement confirmed the formation of a polycrystalline orthorhombic phase. The morphological features revealed a non-uniform, randomly oriented, plate-like grain structure. The peaks evident in the Raman spectra closely corresponded to those of orthorhombic Aurivillius phases. Dielectric studies and impedance measurements were carried out. Asymmetric complex impedance spectra suggested the relaxation of charge carriers belonging to the non-Debye type and controlled by a thermally activated process. Temperature-dependent AC conductivity data showed a change of slope in the vicinity of the phase transition temperature of both magnetic and electrical coupling natures. Based on the universal law and its exponent nature, one can suppose that the conduction process is governed by a small polaron hopping mechanism but significant distortion of TiO6 octahedral. The doping of the A-sites with rare-earth element ions and changes in the concentrations of Fe and Co ions located on the B-sites manifested themselves in saturated magnetic hysteresis loops, indicating competitive interactions between ferroelectric and canted antiferromagnetic spins. The magnetic order in the samples is attributed to pair-wise interactions between adjacent Fe3+–O–Fe3+, Co2+/3+–O–Co3+/2+, and Co2+/3+–O–Fe3+ ions or Dzyaloshinskii–Moriya interactions among magnetic ions in the adjacent sub-lattices. As a result, enhanced magnetoelectric coefficients of 42.4 mV/cm-Oe, 30.3 mV/cm-Oe, and 21.6 mV/cm-Oe for Bi4−xDyxTi2Fe0.7Co0.3O12−δ (DBTFC), Bi4−xLaxTi2Fe0.7Co0.3O12−δ (LBTFC), and Bi4−xSmxTi2Fe0.7Co0.3O12−δ (SBTFC), respectively, have been obtained at lower magnetic fields (&lt;3 kOe). The strong coupling of the Aurivillius compounds observed in this study is beneficial to future multiferroic applications.

Structural characterization and dielectric behavior of substituted bismuth niobate Bi17Nb3-4xV2xP2xO33 with fluorite-like structure

Structural, morphological, and dielectric properties of substituted bismuth niobates Bi17Nb3-4xV2xP2xO33 with a fluorite-like structure have been reported. The study focuses on substituting Nb5+ with V5+ and P5+ cations in Bi17Nb3O33. The resulting ceramics were synthesized using the solid-state reaction technique, and their crystal structure was analyzed using X-ray diffraction. The analysis confirmed the stabilization of the compounds in a single phase of a cubic fluorite structure. Structural refinement analysis has been performed for the compound Bi17Nb2.4V0.3P0.3O33 to investigate the details of the crystalline structure which was found to be a cubic fluorite structure at room temperature (space group Fm3‾m). Scanning Electron Microscopy (SEM) was used to examine the surface morphology of the samples, which exhibited irregular shapes and heterogeneous size distribution. The dielectric properties of the ceramics were analyzed, and the dielectric permittivity (ε’) and loss factor (tan δ) were measured at different frequencies and temperatures. The results showed anomalies in each frequency-dependent curve, indicating a relaxation phenomenon. The electrical conductivity (σ) of the ceramics was studied, and it was found that the conductivity displayed a frequency-independent plateau at low frequencies, indicating a semiconductor behavior. The complex impedance spectra and electrical modulus analysis were also conducted to investigate the relaxation processes in the material.

The effect of Ti/Ba ratio on the microstructures and microwave dielectric properties of BaTi4O9–Ba2Ti9O20 composite ceramics

Considering the strengths and weaknesses of the two distinct physical phases of BaTi4O9 and Ba2Ti9O20, we opted to combine them in order to harness the synergistic effects of their properties. In contrast to conventional two-phase composites, we synthesized BaTi4O9–Ba2Ti9O20 microwave ceramics with varying Ti/Ba ratios utilizing the solid-state reaction method. The phase compositions, surface morphologies, microwave dielectric properties and impedance analyses of the composite ceramics with different Ti/Ba ratios were systematically investigated. The X-ray diffractograms showed that the content of BaTi4O9 decreases rapidly as the Ti/Ba ratio increases from 4.15 to 4.35 and Ba2Ti9O20 becomes the main phase when Ti/Ba = 4.25. From complex impedance spectra, it can be seen that the arc gradually compresses as the Ti/Ba ratio increases, representing a decrease in the resistance. The ceramic possessing a Ti/Ba ratio of 4.15 exhibited superior microwave dielectric properties, characterized by Q × f = 16,622 GHz, εr = 38.01, and τf = 10.37 ppm/°C. These results provide guidance for the future design of high-performance microwave ceramics with medium dielectric constant.

1D/2D Heterostructured WS2@PANI Composite for Highly Sensitive, Flexible, and Room Temperature Ammonia Gas Sensor.

Flexible and room-temperature (RT) ammonia gas sensors are needed for exhaled breath detection and recognition. Two-dimensional transition metal disulfides are potential materials for RT gas sensing because of their low band gap and a large number of edge-exposed sites that can provide strong binding to gas molecules. In this work, a 1D/2D heterostructured composite material of 2D tungsten disulfide (WS2) modified with 1D polyaniline (PANI) was proposed. The fibrous PANI adsorbed on the edges and inserted in the interlayers of the laminated WS2 provide more diffusion channels for the ammonia gas and act as sensing sites. The WS2@PANI-based sensor shows high selectivity for ammonia with satisfying reproducibility and long-term stability. A response of 216.3% and a short response/recovery time of 25 s/39 s were achieved for 100 ppm ammonia gas. The sensing mechanism was investigated in detail via complex impedance spectra and in situ FT-IR, which was attributed to the synergistic effect of WS2 and PANI. The excellent sensing performance coupled with its resistance to thermal and humidity interference endows the WS2@PANI-based sensor with potential for human exhaled detection and wearable electronics.

Magnetic and dielectric properties of Nd-Sn-Cu co-doped yttrium iron garnet ferrite

Ion doping to regulate the magnetic and dielectric properties of yttrium iron garnet ferrites is highly desirable for microwave devices. This study successfully fabricated Y3-xNdxFe4.8Cu0.1Sn0.1O12 (x = 0, 0.5, 1.0, 1.5) ceramics, controlling their magnetic and dielectric properties via Nd ion doping. The results indicate that the introduction of Nd ions into the YIG lattice, occupying dodecahedral sites and replacing Y3+ ions, leads to an increase in the lattice parameter. The hysteresis loops demonstrate that as the concentration of Nd ion doping increases, the saturation magnetization initially decreases and then increases. Additionally, the complex impedance and dielectric spectrum analysis reveal that the resistivity and dielectric constant of the material increase with the increasing concentration of Nd ion doping. The real part of the dielectric constant reaches its maximum value, 29.5@200 kHz, at x = 1.5. Consequently, Nd doping concentration effectively controls the crystal structure, microstructure, magnetic, and dielectric properties of garnet ferrite, enhancing its magnetic and dielectric properties and potential application in microwave devices.

Enhancing grain boundary contributions to improve the dielectric properties of (In0.5Nb0.5)0.05Ti0.95O2 ceramics by Bi aided sintering

The internal barrier layer capacitance effect substantially contributes to the colossal permittivity in In and Nb co-doped TiO2 (INTO) ceramics. Therefore, enhancing grain boundary density and ceramic compactness can efficaciously reduce their low-frequency dielectric loss. In this investigation, Bi2O3 addition was utilized to aid sintering and refine grains for INTO ceramics. The results reveal that Bi-doped INTO ceramics, in contrast to their undoped counterparts, exhibit a more refined and compact grain structure with a significant increase in the quantity of grain boundaries. Moreover, a noticeable reduction in low-frequency dielectric loss from above 0.1 to below 0.05 and enhanced frequency stability of permittivity from below 10 Hz to approximately 10 kHz were observed, along with a decrease in the sintering temperature to 1300 °C. In comparison to undoped INTO ceramics, Bi doping also enhances the withstand voltage capability by a factor of 1.5–4 for Bi-doped INTO ceramics. However, as the sintering temperature of Bi-doped INTO ceramics increases and the grain size enlarges, their breakdown voltage gradually decreases, but the non-linear coefficient of current-voltage characteristics progressively increases. Analysis of complex impedance spectra confirms that the increased grain boundary density and resistance in Bi-doped INTO ceramics is the primary factor for the enhanced dielectric properties and withstand voltage capability.

Exploration of the charge transport mechanism, complex impedance, dielectric/electric modulus and energy storage characteristics of the aloe vera (Aloe Barbadensis Miller) plant

Complex impedance spectra at room temperature in the frequency range of 8 Hz—5 MHz were measured on freshly cut leaf sections of the Aloe vera plant by AC impedance spectroscopy. They were analyzed using a classical ‘brickwork’ equivalent circuit composed of grain and grain boundary contributions commonly applied to solid-state materials. The obtained grain resistance/capacitance was 0.4 MΩ/72 pF and grain boundary resistance/ capacitance was 66.4 MΩ/50 nF. The determined conductivity changed according to the Jonscher power law with σ DC of 4.02 · 10–5 (Ωm)−1 and frequency constant of 0.92 characteristic for hopping as the conduction mechanism. Analysis of dielectric permittivity and electric modulus confirmed the non-Debye relaxation behavior. Nyquist plots for electric modulus revealed conductivity relaxation in the low frequency attributed to grain boundaries and impedance modulus displayed dielectric relaxation in the high frequency region associated with grains. A correlation has been established among the investigated parameters, morphology, and EIS-derived simulated parameters.

Crystal structure, Hirshfeld surface analysis, conduction mechanism and electrical modulus study of the new organic-inorganic compound [C8H10NO]2HgBr4.

There has been a lot of interest in the development of a novel hybrid material based on mercury that has fascinating structural properties. In this paper, single crystals of [C8H10NO]2HgBr4 was successfully synthesized by the slow evaporation method at room temperature. In fact, the latter crystallizes in the orthorhombic system (Cmca space group) with cell parameters a = 20.824(2) Å, b = 15.352(1) Å and c = 13.700(1) Å and Z = 8. Its structure is constituted by one [C8H10NO]+ cation and one type of isolated anion [HgBr4]2- tetrabromomercurate(ii). The atomic arrangement presents an alternation of organic and inorganic layers along the a-axis. To maintain the cohesiveness of the structure, these components are joined via π⋯π interactions and hydrogen bonds (N-H⋯Br and N-H⋯O). A general network of hydrogen bonds ensures the interconnection of several entities. Greater knowledge of these interactions has been obtained based on the Hirshfeld surface analysis and 2D fingerprint plots. The analysis of complex impedance spectra shows that the electrical properties of the material are heavily dependent on frequency and temperature. The obtained results were analyzed by fitting the experimental data to an equivalent circuit model. The temperature dependence of conductivity and the relaxation frequency ωmax fulfill the Arrhenius relation and activation energies are estimated. The material follows Jonscher's universal dynamic law or here there is a decrease in the exponent 's' as the temperature increases. This result indicates that the Correlated Barrier Hopping (CBH) model represents the conduction mechanism. Besides, the non-Debye type conductivity relaxation is revealed by the electrical modulus analysis.