Dielectric Parameters Research Articles

Solvatochromism, optical and electronic properties of thiosemicarbazone derivatives in solution phase

The electronic structure, solvatochromic and some optoelectronic properties of five different thiosemicarbazone (TSCs) derivatives with different substituents consisted from indole ring, benzyl ring and conjugated thiosemicarbazide have been investigated in detail. UV–vis. absorption spectra of TSC compounds have been analyzed in solvent media with different polarity. The spectral changes are observed to forming of solvent effects and substituents. Spectral behaviors and electronic transitions are interpreted based on the UV-Vis. spectra. Solvatochromic behaviors were defined by linear solvation energy relationships via multiple linear regression analysis by using Kamlet-Abboud-Taft and Catalán parameters. In addition, the correlations of electronic absorption transition energy with Marcus optical dielectric parameter and Reichardt-Dimroth parameter were also determined. Some optoelectronic parameters such as forbidden band gap energy and refractive index have been determined in different solvent medium. Thiosemicarbazone derivatives have a global electronic absorption transition energy of about 3.351 eV. According to LSER calculations, polarizability-induction of electronic transitions of the investigated molecules is effective. The (E)-4-(4-nitrobenzyl)-1-(2-oxo-2H-indol-3(3aH)-ylidene)thiosemicarbazide (TSC-B) compound that does not a methoxy group and contain nitro group substituent and has the highest forbidden energy range.

Gamma Ray-Induced Changes in Polyvinyl Alcohol/Carboxymethyl Cellulose/Cadmium Selenide Nanocomposite Films: Optical Analysis for Optoelectronic Devices

In order to create nanocomposite films (NC) of polyvinyl alcohol, carboxymethyl cellulose and cadmium selenide nanoparticles (PVA/CMC/CdSe), thermolysis and ex-situ casting techniques were used. The microstructure and shape of the CdSe nanoparticles (NP) were characterized with the Rietveld method and transmission electron microscopy (TEM). Rietveld refinement of the x-ray data showed that the prepared CdSe NP had the cubic zinc blend structure with a lattice parameter 6.057 Å. The TEM showed the formation of the dotted shape of CdSe with a particle size around 2 nm, confirming the quantum dot size of the mother phase CdSe. Samples from the prepared PVA/CMC/CdSe films were irradiated with γ radiation doses of 20−150 kGy. The resultant effects of the γ ray irradiation on the optical and color properties of the prepared films were investigated using UV–vis spectroscopy and the International Commission on Illumination (CIE) color difference technique. When the γ dose was increased to 150 kGy, the maximum dose used, the direct and indirect optical band gaps (Eg) decreased. We attribute this decrease to the domination of crosslinking that destroyed the ordered structure and thus increased the amorphous regions. In addition, we used the optical dielectric loss (ε”) to identify the type of microelectronic transition for the PVA/CMC/CdSe NC samples, which was found to be a direct allowed transition. The effect of γ ray irradiation on the absorbance, extinction coefficient, refractive index, dielectric parameters and optical conductivity of the NC samples were studied. The enhancement in the optical properties indicated that the γ radiation is a useful tool that allows the use of the resulting PVA/CMC/CdSe NC in optoelectronic devices. Finally, the color differences between the pristine and irradiated films were estimated. The irradiated PVA/CMC/CdSe NC film exhibited significant color differences relative to the pristine films.

Optical and Color Modification in Polycarbonate/Polybutylene Terephthalate/Zinc sulfide-Nickel Oxide Nanocomposite Films due to Gamma Irradiation

Nanocomposites (NC) of amorphous polycarbonate (PC), semicrystalline polybutylene terephthalate (PBT), zinc sulfide (ZnS) and nickel oxide (NiO) nanoparticles (NP) were synthesized. We believe that this study is novel in the area of the effect of γ radiation on such NC. Both the synthesized NiO and ZnS had a nanonature of average particle size 4 and 18 nm, respectively, as indicated from the Rietveld refinement of the XRD records. Samples of the PC-PBT/ZnS-NiO NC films were irradiated with several γ doses (10–140 J/cm2). The resultant outcome of the γ irradiation on the optical behavior of the NC films was studied applying ultraviolet spectroscopy (UVs). Upon raising the dose up to 140 kGy, the direct bandgap decreased from 4.11 to 3.6 eV. The Urbach energy showed an opposite tendency; it increased from 0.61 to 0.95 eV. We attribute this to the dominance of chain crosslinks. Also, the optical dielectric loss (ε″) aided in detecting the nature of the microelectronic transitions. It was found that the PC-PBT/ZnS-NiO NC films had direct allowed transitions. Additionally, the γ induced alterations in the dielectric parameters and optical conductivity were studied. Moreover, the optical color changes between the pristine and the irradiated films were assessed. The pristine NC film was uncolored. It showed significant color alterations when irradiated with γ radiation up to 140 kGy. The induced enhancements in the optical properties suggest that the γ radiation is an effective means that allows the use of PC-PBT/ZnS-NiO NC in optoelectronic devices.

Study of electrical and dielectric properties as an effect of nanoparticle concentration and UV irradiation of PVA-Ag nanocomposites

PVA incorporated with different concentrations of silver nanostructures were prepared using chemical reduction technique and these prepared nanocomposites were exposed to UV irradiation for 2, 3 and 4 h. Fundamental aim is to investigate tailoring of conductivity and dielectric parameters due to changes of concentration of nanoparticles and irradiation time. XRD was done to study structural characterization. FE-SEM and EDX were employed for structural and morphological analysis of nanocomposites. AC conductivity was observed to increase and values of dielectric constant were noticed to decrease whereas dielectric loss was observed to show increment with increasing concentration of nanostructures and UV exposure.

Properties of ferroelectric composites in the microwave range

Ferroelectric ceramics of barium titanate and its solid solutions have found wide applications in technology, while compositions of a binary system with strontium titanate are most in demand. Electrically controlled components based on the barium titanate – strontium titanate ferroelectric ceramics are widely used in accelerator technology and the use of these materials is relevant at the present time. In the microwave range, composites based on the solid solution system barium titanate – strontium titanate ВаxSr1–xTiO3 (BST). Ferroelectric samples based on ВаxSrx–1TiO3 compound, where x = 0; 0.1; 0.3; 0.5; 0.7 were obtained using a conventional ceramic technology. The temperature dependences of the electrical properties of bulk ceramic samples based on ferroelectric composites were received in the temperature range 100°C to 350°C at a frequency of 1 kHz. It has been established that dielectric parameters significantly depend on the BaTiO3 content in BST compositions. To carry out a research in the frequency range from 0.1 to 8.5 GHz, an experimental setup was manufactured for measuring the electrical properties of ferroelectric materials based on an Agilent E5071C vector analyzer and a microstrip line. To conduct temperature studies, a microstrip line with a controlled sample was placed in a heat, cold and moisture chamber of the Bench-Top SU-261 series, in which it has been heated up to 60°C. The amplitude-frequency characteristics of the transmission coefficient (S21) of samples when heated from 20 °C to 60°C with an interval of 10 degrees were studied. The resonant frequency and quality factor of the resonator have been determined from the amplitude-frequency characteristic. Based on the value of the resonant frequency and the geometric dimensions of the sample, the dielectric constant of the sample material was calculated. It has been shown that with increasing barium titanate content (x = 0.1–0.3), the dielectric constant of the samples under study increases, and the resonant frequency shifts to lower frequencies. For samples with a barium titanate content of 50% and higher (x≥0.5), there are no resonance dependences and strong absorption of electromagnetic waves is observed. It has been established that with increasing temperature, the resonant frequency of composite material samples shifts to higher frequencies. Frequency dispersion of the dielectric constant is observed, which indicates the relaxor properties of the ceramic samples under study. Experimental investigations were carried out using a microwave strip line, a coaxial measuring cell and a capacitive converter; this made it possible to measure the dielectric constant of materials with values of more than several hundred in the microwave range and significantly reduce the control time when conducting thermal studies. It was shown that with a change in temperature, the electrophysical properties of the samples change significantly, which can be used in various systems and devices to change the reflection coefficient and phase of the electromagnetic wave.

Engineering the optical, and dielectric properties of (PVA: PVP)/BaSnO3 polymer nanocomposites as promising films for optoelectronics and energy storage applications

AbstractThis work is devoted to optimizing the optical and dielectric parameters of polyvinyl alcohol (PVA): polyvinyl pyrrolidone (PVP) (1:1) polymer nanocomposites by controlling barium stannate contents (BaSnO3) aspiring to engage it into flexible optoelectronics and thermally stable capacitors. Herein, high purity BaSnO3 was synthesized by solid‐state route and loaded with different ratios (5–20 wt%) into PVA/PVP blend to form films by solution casting method. Further, the degree of crystallinity (Xc) was highly increased upon increasing the filler contents (BaSnO3), as confirmed by X‐ray diffractometer measurement. The surface morphology pictured by a field emission scanning electron microscope revealed the variation of the surface from smooth to rough surface upon insertion of BaSnO3. The thermodynamic parameters including enthalpy (ΔH), entropy (ΔS), and Gibb's free energy (ΔG) were extracted from TGA measurements and studied in detail. The optical characteristics of plain PVA/PVP and polymer nanocomposite films are explored by UV–Vis–NIR spectrophotometer. The presence of charge‐transfer complexes within the polymer nanocomposites was certified via shifting of band gap energy from 5.02 to 4.33 eV and variation of band tailing energy (Eu) from 0.22 to 0.44 eV. The real and imaginary part of optical conductivity (σp1, σp2) was confirmed to be enhanced with the insertion of BaSnO3. It is also found that the dielectric constant and DC current increased with the insertion of BaSnO3 content, while the dielectric loss decreases. The findings recommend these polymer nanocomposites as a good candidate for green energy applications and high‐performance capacitors.

Dielectric and FTIR Investigation of the Cholesteric Liquid Crystal with the Doping of the Polymer

AbstractThe present work investigates fluorescent polymer dispersion in the cholesteric liquid crystal (LC) as a function of temperature and concentration of polymer. The dielectric parameters of the cholesteric LC are determined by measuring capacitance and inductance with the function of the frequency and temperature. The material used for doping is a polymer‐poly[(4,4′‐hexafluoroisopropylidene) diphthalic anhydride‐alt‐3,6‐diaminoacridine hemisulfate] and it is one concentration doped in pure cholesteryl stearate. The temperature dependence of dielectric permittivity has been discussed for the pure and polymer‐doped system. In addition to this Fourier transform infra‐red (FTIR) spectroscopy has also been performed to understand the interaction between cholesteric LC and polymer molecules.

Structural, dielectric, and antimicrobial evaluation of PMMA/CeO2 for optoelectronic devices

In the current report, we have successfully synthesized nanocomposites of PMMA incorporating different doping of CeO2 through a chemical approach. XRD results reflects decent matching for CeO2 nanoparticles with 29 nm crystallite size. FTIR spectroscopy demonstrates the characteristic functional groups validating the successful formation of the composite. The optical study of PMMA and the nanocomposites has proven that the optical properties such as band gap, refractive index, optical permittivity, and loss tangent factor are affected by adding CeO2 to the PMMA matrix.The peak residing around 420 nm by UV measurements is allocated to occurring electrons photoexcitation from the valence to conduction band inherent in CeO2. The dielectric measurements were achieved using broadband dielectric spectroscopy upon a wide span of frequencies (10–1–107 Hz) and within temperatures from − 10 to 80 °C with a step of 10 °C. The permittivity decreases by adding CeO2 and the dielectric parameters are thermally enhanced, however, the temperature influence is based on CeO2 content, the higher the CeO2 amount, the higher the influence of temperature. The results of the nanocomposites revealed antibacterial activity counter to gram-positive bacteria strain (S. aureus, and B. subtilis), and gram-negative bacteria (E. coli, and K. pneumoniae), yeast (C. albicans, as well as fungi (A. niger). Inherently, the change in CeO2 concentration from 0.01 to 0.1 wt% delivers maximum influence against gram-negative bacteria. These PMMA CeO2-doped composites are beneficial for optoelectronic areas and devices.

Adjusting the Effects of Cr3+ Doping on Structural, Dielectric, Antimicrobial Properties of Delafossite SrCuO2 Nanoparticle

SrCu(1−x) Cr x O2 nanoparticles (x = 0.0, 0.6, 1.2, and 1.8) nanoparticles were synthesized using sol-gel processing and subjected to calcination at 650 °C. The investigation delved into the influence of varying chromium concentrations on the structural, FTIR, electrical, and antimicrobial characteristics. The microstructure of the SrCu(1−x)Cr x O2 nanoparticles (x = 0.0, 0.6, 1.2, and 1.8) nanoparticles were analyzed through X-ray diffraction and transmission electron microscopy. Additionally, changes in chemical bonds were observed as the Cr content increased. The dielectric parameters exhibit an increase with higher Cr ratios. Additionally, there is a decrease in these parameters as the frequency rises, which could be attributed to the mobility of charged particles within the SrCu(1−x)Cr x O2 nanostructure. Our investigation underscores the significant role of Cr incorporation in influencing both the dielectric properties and antimicrobial activity of Cr, emphasizing its relevance for diverse applications.

Impact of annealing temperature on optical, morphological, and surface characteristics of PC/PBT blend exposed to alpha particles

The induced modifications of the optical and surface characteristics in the annealed α-irradiated polycarbonate/polybutylene terephthalate (PC/PBT) blend have been studied in the temperature annealing range from 100 to 200 °C for 15 min. Several techniques have been used to study the changes in chemical composition, optical-electronic transitions, photoemission, contact angle, surface roughness, and hardness of annealed samples comparable to the pristine one. The FTIR spectra exhibit aggregate changes in the band intensities after annealing, indicating the scission and cross-linking of the polymer chains. The intensity of the peaks reduced with α-irradiation but began to increase with increasing annealing temperature. The trend of the function groups found in the annealed samples with the rise in annealing temperature supports the crosslinking mechanism. The UV/Vis spectra revealed that the absorption edges of annealed samples were shifted toward lower photon energy (red shift), reflecting the decrease of optical energy gap from 4 eV to 3.6 eV for direct transition and from 3.8 eV to 3.5 eV for indirect transition at the highest temperature. Further, the number of carbon atoms and the number of carbon clusters increases with the increase in the annealing temperature. The refractive index of the samples decreases from 1.5479 for the pristine sample to 1.4008 for the sample at the highest temperature. Moreover, the dielectric parameters and optical conductivity of the annealed samples were modified after thermal annealing. The PL emission yields are decreased with the increase in annealing temperatures that indicating an enhancement in the non-radiative recombination rate relative to the radiative recombination, which may be due to the increasing in the surface density states. The α-irradiated samples showed a notable increase in contact angle and a notable decrease in surface tension values with increasing the annealing temperatures. The side chain induction, which readily bundles and recombines the annealed parts by raising temperatures, also causes the surface roughness of annealed samples to decrease from 1.099 μm for the pristine sample to 0.696 μm for the annealed sample at the highest temperature. It is noteworthy that there is an increase in the hardness from 10.49 ΜPa for the pristine sample to 41.98 ΜPa for the annealed sample at the highest temperature. This is related to the results of changes in the polymer chains due to the active sites or branching points created by scission, which can lead to cross-linking.

Dielectric Depiction of 1-Butyl-3-methylimidazolium Tetrafluoroborate/1-Butyl-3-methylimidazolium 1,4-Bis(2-ethylhexyl) Sulfosuccinate/Benzene Microemulsions: Percolation, Interface Polarization, and Electrical Parameters.

Two dielectric relaxations located at approximately 10 and 300 MHz were analyzed in the microemulsion composed of the polar ionic liquid (PIL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), the surface-active ionic liquid (SAIL) 1-butyl-3-methylimidazolium 1,4-bis(2-ethylhexyl) sulfosuccinate ([bmim][AOT]), and benzene. The curve of the dc conductivity vs PIL weight fraction shows two inflection points, namely, 16.69 and 27.90 wt %, which are used to divide the PIL/O, bicontinuous (B.C.), and O/PIL subregions. The critical exponents of percolation u = 0.75, 0.79, and 0.80 are suggested from the scaling dependence of dc conductivity on the PIL weight fraction, together with frequency dependences of both permittivity and loss angle, which all infer that static percolation occurs in the microemulsion. Only one dielectric relaxation at high frequency was observed in the PIL/O subregion, when the concentration increased to the boundary between the PIL/O and B.C. subregions; the second dielectric relaxation appeared at low frequency. The high-frequency relaxation is caused by interfacial polarization. The low-frequency relaxation is attributed to the dipole-oriented polarization of AOT-. When the oil content of the system was reduced, the interface became softer to allow more AOT- to rotate, and the cation shifted from moving around its long axis to rotating along its short axis. The static dielectric constant of [bmim][AOT] was given. The dielectric constants and conductivity of the dispersed and continuous phases in the PIL/O and O/PIL subregions were calculated from the dielectric parameters of high-frequency relaxation.

Molecular interaction analysis and relaxation findings of amphiphilics in solution state

The interaction of stearic acid with non-polar benzene along polar co-solvent (amyl alcohol) is revealed in the present study. The dielectric nature of complex mixture examined in the frequency regime of 10 MHz to 30 GHz over a various temperature and concentration using time domain reflectometry(TDR). Dielectric parameters (static dielectric constant, dielectric loss, relaxation time, dielectric permittivity) were estimated from the obtained complex spectra. The excess dielectric values validate the molecular interaction between the solute and solvents. The obtained dielectric and relaxation parameter reveals the fluctuating electrostatic type interaction among the complex mixture. Thermal parameters are determined from the obtained relaxation time, in which the negative Gibb’s free energy indicates the formation of high ordered complex. The FT-IR spectrums and their assignments confirm the molecular interaction between the mixture.

Influence of anion variation on dielectric response of amide functionalized benzimidazolium dicationic ionic liquids

The present work centered attention on novel ionic liquid (IL) based on dicationic benzimidazolium ion containing amide group (DBimIL) synthesized using dialkylation of N-ethyl benzimidazole to followed with anion exchange reaction. To explore the potential application of ILs, there is a great need to grasp their structural and physical properties. We have developed three different set of DBimIL based ionic liquids with chloride, hexafluorophosphate and perchlorate anions in aqueous media, respectively. Their structural features were studied using 1H, 13C-NMR, FTIR, and HRMS spectroscopy, respectively. The temperature-dependent dielectric characteristics of ILs were closely examined angular frequency in the range of 0.6–125 rad/s from 30 to 150 °C. The relationship between the structural and dielectric properties of ILs established. The dielectric parameters like dielectric constant, dissipation factor and the real part of ac conductivity were found to be affected significantly with the tuning of anionic moieties of ionic liquids. The ability of materials to store a charge in electromagnetic field was measured. From dielectric and electrical studies, to bring to an end, especially in particular way that the present IL systems have an enormous potential for the designing of modern-day energy storage devices.

Studies on electromagnetic properties of lithium based ferrimagnetic spinel oxides prepared with different additives and microwave sintering

Soft ferrimagnetic spinel lithium based oxides were prepared with additives like V2O5 and Na2SiO3 and sintered with the efficient microwave sintering technique. Tetravalent metal ions substituents like Mn+4, Ti+4 were used to enhance the important properties like D. C. resistivity, saturation magnetization, permeability, hysteresis and dielectric behavior. The ferrites were sintered at different sintering temperatures viz., 900, 950 and 1000 °C for 10 min by microwave technique and by conventional technique at 1050 °C for 4h. X-ray diffraction (XRD) studied the structural behavior which confirmed the spinel characteristics, Scanning electron microscopy (SEM) and EDAX revealed the microstructural and elemental compositions respectively of the ferrites. The use of additives and the microwave sintering significantly influencing the microstructural behavior and subsequently on the electromagnetic properties could be observed. Studies of initial permeability and initial permeability loss found to remain nearly constant with change in frequency until at certain frequency they showed resonance behavior. The resonance frequency’s dependence on the microstructures of the ferrites could be observed. Temperature dependence behavior of the dielectric parameters and the B-H loop traced from torroidal samples of the ferrites were studied.

Surface induced effects on the dielectric and optical properties of polymer-stabilized cholesteric liquid crystal composites

Polymer-stabilized cholesteric liquid crystal is one of the most coveted systems in the ever-expanding field of liquid crystal due to its wider potential application in smart windows, optical shutters, tunable lenses, etc. The dispersion of polymer into liquid crystal by introducing a small amount of chiral dopant prepared polymer-stabilized cholesteric liquid crystal. In this work, two samples of polymer- cholesteric liquid crystal were prepared. Surface treatment is applied on one composite while another sample is prepared without any treatment on the indium tin-oxide coated glass substrates. Frequency and temperature-dependent dielectric parameters are observed for both samples. The dielectric studies revealed that after surface treatment, the permittivity of the sample significantly increased. AC conductivity of the sample also increased. The photoluminescence spectra also show improvement in the intensity with the surface-treated sample.

Dielectric relaxation studies of 1-nitropropane-dimethyl sulfoxide mixtures using a Time Domain Reflectometry

ABSTRACT Complex dielectric measurements were performed in 1-nitropropane (NTP) and DMSO mixtures at various concentrations in the frequency range of 10 MHz to 50 GHz using time domain reflectometry technique. The excess inverse relaxation time values were found to be negative, indicating that the dipoles rotated more slowly. Alenka Luzar’s hydrogen-bonded theory is used to calculate theoretical estimates of the static dielectric constant. The variations in dielectric parameters such as dielectric constant, relaxation time, Kirkwood correlation factor and excess properties observed in the study confirm the existence of intermolecular interactions within the NTP-DMSO mixtures.

Study the effect of nano NiCo2O4 doping on the optical and dielectric properties of PMMA/PEO/MWCNTs

In this study, NiCo2O4 nanoparticles were prepared using a hydrothermal process and examined by x-ray diffraction. After that, using the casting technique, blends of polymethyl methacrylate (PMMA)/poly(ethylene oxide) (PEO) were loaded with multi-walled carbon nanotubes (MWCNTs) and different amounts (x) of NiCo2O4 nanoparticles. The obtained blends were characterized using X-ray diffraction and scanning electron microscopy techniques. Utilizing diffuse reflectance measurements, various optical parameters, including energy gap, refractive index, extinction coefficient, optical dielectric constant, optical conductivity, and nonlinear optical parameters, were investigated. Following incorporation of MWCNTs/NiCo2O4 in the blend, the transmittance of the PMMA/PEO blend (90 %) displayed a drop reaching 21 %, the reflectivity and refractive index increased. The direct/indirect optical band gap values of PMMA/PEO (5.07/4.8 eV) decreased attaining 4.96/4.54 eV for the blend with 2.5 wt% NiCo2O4. The optical conductivity greatly enhanced, and the linear and nonlinear optical parameters increased as the amount of NiCo2O4 doping increased. The dispersion parameters for all blends were also calculated. Fluorescence spectra (FL) measurements revealed a reduction in the FL intensity with increasing the NiCo2O4 content (x). Through the dielectric measurements, the impact of increasing NiCo2O4 content on the ac conductivity, dielectric properties, energy density, and electric modulus was analyzed for all blends. Remarkably, a significant increase in AC conductivity was obtained upon loading with 1.5 wt% NiCo2O4. Overall, variation in the dielectric and optical features of the PMMA/PEO/MWCNTs/x wt.% NiCo2O4 blends makes them appropriate for optoelectronic and energy storage applications.

Thermodynamics Properties of Amino Acid with Water Mixture using Time Domain Reflectometry Technique

In this paper we have reported the thermodynamics properties of the amino acids (L-alanine) in water solution were carried out using time domain reflectometry at 250C to -50C in the frequency range between 10 MHz to 30 GHz. The dielectric parameters i.e. static dielectric constant and relaxation time, were obtained from the complex permittivity spectra using a nonlinear least square fit method. From the values of the relaxation time, the thermodynamic parameters are determined. The dielectric relaxation parameters increase with an increase in concentration (mM) of amino acid due to the structure of hydrogen bond groups by the amino acid molecules in the aqueous solution. The relaxation peak shifted to lower frequency with an increase in molar concentration of amino acid.

Quantum tunnelling in hafnia-based metal-insulator-metal diodes: atomistic-to-continuum modelling approach and experimental validation

In this work, we present a metal-insulator-metal (MIM) diode, based on quantum tunnelling phenomena. Its model is based on a multilevel modelling approach consisting of atomistic and continuum simulations, fully validated by extensive measurements. The MIM structure comprises a hafnium oxide (or hafnia, HfO2) dielectric layer, less than 4 nm thick and a square contact area of only 4 μm2, placed between two metallic electrodes, namely platinum as the source and titanium as the drain. The current–voltage (I–V) curve has been estimated by Density Functional Theory (DFT) calculations through an optimisation of the interfaces between metals and monoclinic HfO2. The dielectric parameters arising from ab initio computations have then been used as inputs for the successive circuit and electromagnetic simulations. Finally, the multilevel model has been validated with great accuracy, first measuring the I–V characteristics by applying a drain-source voltage between −1 V and +1 V, and then extracting the scattering parameters up to 40 GHz, thus demonstrating that DFT and circuit/electromagnetic simulations match almost perfectly the experimental ones. These outcomes represent the first study of such nanoscale devices investigated by means of a rigorous atomistic-to-continuum approach, providing invaluable information in order to improve fabrication and correctly assess the macroscale performance of nanoelectronics systems.

Structural, morphological, dielectric, and spectral properties of Sr-Mg-Ho X-type magnetic nano materials suitable for microwave absorption application

Holmium (Ho3+) substituted Sr2Mg2Fe28O46 X-type hexa-ferrites were synthesized using the sol-gel auto-combustion route. The single phase of Sr2Mg2Fe28-xHoxO46 where 0.00 ≤ x ≤ 0.20, Δx = 0.05, X-type hexa-ferrites was confirmed using XRD peaks. The crystalline size was studied from XRD data and found to be in the 11 nm–24 nm range. The micro strain increased with the substitution of Ho3+. FTIR exposed the specific stretching vibration and absorption peaks in the 400 cm−1 - 600 cm−1 range. The force constant (ko) decreased from 1.74 N/cm to 1.65 N/cm with the increasing concentration of Ho3+. The grain size range is 371–493 nm, measured by SEM analysis, and plate-like structure plays a crucial role in enhancing the permeability of magnetic material. Transmission electron microscopy (TEM) analysis showed the hexagonal structure of X-type ferrites (x = 0.20). The results of the X-ray photoelectron spectroscopy (XPS) experiment confirmed the presence of all metal ions in the given composition with their required valences. The dielectric constant, dielectric loss, and tangent loss are found to increase with the substitution of the Ho3+ ion. In addition, the higher values of dielectric parameters and dielectric loss suggest that the material may suitable for high-frequency applications and best for microwave absorbers. Our aim is to discuss the characteristics and applications of microwave absorption materials, understand their behavior, and contribute to the development of upcoming novel devices. The resonance peak's appearance shows that these materials are best for multilayer chip inductors and EMI attenuation.