In this study, we examine the negative electromagnetic properties and refractive index in yttrium iron garnet (YIG) -based nanocomposites, specifically Cu10%/YIG and nickel-doped Cu10%/YIG, synthesized via an in-situ method. Field Emission Scanning Electron Microscopy (FESEM) analysis confirmed the successful formation of the target nanostructures. Particle size distribution analysis indicated an approximately normal and uniform distribution across the YIG nanoparticles. UV spectroscopy verified that the electronic structure and optical properties of the samples matched predicted characteristics Measurements of dielectric permittivity and magnetic permeability were conducted at room temperature using scattering parameters from a Vector Network Analyzer (VNA) and processed through MATLAB software. The results showed simultaneous negativity in both ε and μ within certain frequency ranges, confirming the potential for a negative refractive index.This feature opens promising opportunities for advanced electromagnetic wave control, with implications for optical, communication, and electronic technologies.
In the present work, hexagonal MoS2/ZnO thin film was synthesized via pulsed laser deposition method. We studied the structural and optical properties of MoS2/ZnO thin film deposited on Si (100) substrate at room temperature using a Nd:YAG laser (248 nm, 10 ns pulse duration and 10 Hz repetition rate). FESEM images demonstrated a flower-like topography of MoS2/ZnO with the well-defined hexagonal microrods and flat top surface. The band gap was determined from the analysis of UV-Visible spectrum and found to be 2.90 eV for MoS2/ZnO microrods and 3.12 eV for pure ZnO. The hexagonal wurtzite crystal structure of MoS2/ZnO composite thin film was confirmed by XRD pattern. Raman spectrum of MoS2/ZnO microrods showed two characteristics peaks at 379 and 403 corresponding to and modes, respectively. Enhancement of the near-band-edge ultraviolet emission was achieved by deposition of MoS2 on the surface of ZnO microrods. The Ossila four-point probe device measured the DC electrical conductivity. The results indicate that MoS2/ZnO microrods are regarded as promising prospects for the future of optoelectronic applications.
Recently, the finite size effects, via superconducting nanograins, have attracted much attention from physicists. The effect of the small size can enter via the interaction matrix element and the spectral energy. We suppose that the mean level spacing near the Fermi energy is smaller than the bulk gap, allowing the BCS formalism to remain a valid approximation. For a nanograin, the gap function, in general, depends on the size of the system, and the Fermi energy. By entering the effect of the small size on the gap equation for a rectangular nanograin, specific heat in terms of temperature and length of a superconducting nanograin is obtained. Our results reveal that the spectral energy of the nanograin does not affect the change in the behavior of specific heat. However, the effect of the energy gap of nanograin strongly affects the behavior of specific heat. One of the interesting results is that at some fixed temperatures, the behaviour of specific heat shows a peak in a special length. Also, we compare specific heat in 2- and 3-dimensional cases.
The study explored the effects of aluminum doping on the optical and electrical properties of ZnO thin films, along with their gas sensing capabilities, specifically in response to blood serum. Thin films were prepared using a spin-coating method, followed by annealing at 500°C, with varying Al doping concentrations (0%, 0.5%, 1%, 1.5%, 2%, and 2.5%). The results showed that higher Al doping improved the transmittance, likely due to enhanced crystallinity and the Burstein-Moss effect, with 2.5% Al-doped ZnO exhibiting the highest transmittance of around 85%. The refractive index and extinction coefficient analyses indicated a decrease in light absorption and scattering at higher doping levels, reflecting improved film quality. The real and imaginary parts of the dielectric constant also varied with doping, with 0.5% Al-doped ZnO showing the highest real part, suggesting better dielectric properties. The optical band gap of Al-doped ZnO films decreased with increasing Al concentration, consistent with previous studies, indicating potential improvements in electrical conductivity. The electrical properties, particularly I-V characteristics, revealed that higher Al doping decreased conductivity, likely due to increased charge carrier scattering. Gas sensing experiments demonstrated that 2% Al-doped ZnO exhibited higher sensitivity to blood serum, while resistance varied with time and serum volume, highlighting the dynamic interaction between the ZnO films and their environment. The study's findings suggest that Al doping enhances the optical and sensing properties of ZnO thin films, with an optimal doping concentration around 2% for maximum sensitivity.
In this paper, a chitosan nitrogen-doped graphene (CNGO) electrode is synthesized by using carbon paper (CP). This electrode demonstrates enhanced electrochemical properties as a supercapacitor electrode compared to CP. The CNGO nanocomposite is synthesized using a hydrothermal method and is deposited on CP via dip coating method. To characterize the CNGO nanocomposite, X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy (EDS) mapping analyses are performed. The electrochemical properties of the electrodes are studied through cyclic voltammetry, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy. The specific capacitance is increased from for the CP to for the CNGO electrodes at a current density of . The reversibility ratio is calculated to be 0.89 and 0.94 for CP and CNGO electrodes, respectively. The proposed electrode demonstrates exceptional performance due to its outstanding stability and durability over extended cycling, as evidenced by its 100% capacitance retention after 1100 charge-discharge cycles. This remarkable retention highlights its ability to maintain consistent electrochemical properties under prolonged and repetitive operational conditions. The results indicate that the presence of CNGO nanocomposite on CP enhances the electrochemical properties of the electrode.
Metal oxide nanoparticles display significant roles in antimicrobial and anticancer activities. In the present study, Cu, and Fe-doped ZnO nanoparticles have been synthesized and investigated for their antioxidant, antibacterial, and anticancer properties. The above-mentioned nanoparticles have been synthesized by the low-cost and simple sol-gel method. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay was conducted to assess the antioxidant activity. The antibacterial activity of NPs was tested against E. coli and S. aureus bacteria according to the broth microdilution method in Mueller Hinton Broth. The anticancer potency on cancerous AsPC-1 cell lines was examined. The structural and morphology of samples confirm that all NPs formed with different crystallite sizes in the hexagonal wurtzite system. The DPPH assay showed the Zn1-XCuXO to have more antioxidant properties than other samples. We observed that the S. aureus bacterium is more sensitive to NPs than the E. coli bacterium. The strongest and weakest substances used for these bacteria are Zn1-XCuXO and Zn1-XFeXO NPs, respectively. Our anticancer results showed that the loaded drug on the NPs surfaces has more anticancer properties than pure drugs. ZnO and Zn1-XFeXO NPs possess similar anticancer properties approximately, while sunitinib@Zn1-XCuXO eliminates 92% of cancer cells at 200 μg/ml concentration. We observed that ZnO, Zn1-XFeXO, and Zn1-XCuXO NPs have antioxidant, antibacterial, and anticancer properties. Adding copper dopant to ZnO NP significantly increases its anticancer property.
In this paper, ZnFe2O4 nanoparticles were synthesized using the co-precipitation method, aiming to investigate the effect of pH on their structural and optical properties. The synthesis was carried out at various pH levels of 7, 9, and 11, to explore how acidic and basic conditions can influence the characteristics of these nanoparticles. Structural analysis was conducted using X-ray diffraction (XRD), which allowed for a comprehensive understanding of the phase composition and crystallinity of the nanoparticles. The XRD results revealed that as the pH increased from 7 to 11, the diffraction peaks became broader, indicating a reduction in crystalline size, which is a common phenomenon attributed to increased defects within the crystalline structure. This size reduction corresponds with an increase in dislocation density and strain within the samples, suggesting that higher pH environments lead to more significant structural alterations. Optical properties were investigated using a UV-Vis spectrometer. The optical analysis showed a noteworthy trend: as the pH increased from 7 to 11, the absorption capacity of the ZnFe2O4 nanoparticles decreased. This reduction in absorption may imply a modification in band gap energy, which is crucial for potential applications in photonic devices and sensors.
In this research, TiO2 nanostructures were prepared using the hydrothermal method. The aerosol was regenerated from the precursor solution droplets by entering the non-thermal plasma and TiO2 nanostructures were deposited on the surface of the substrate. XRD and SEM analyses have been used to investigate nanostructure morphology. Dye-sensitized solar cells were fabricated using TiO2 nanostructures as a photoanode. The results showed that the surface prepared with TiO2 nanostructures by the hydrothermal method has a higher specific surface area, more pigment absorption, and short circuit current density than the unmodified surface. In addition, the TiO2 photoanode-based pigment solar cell using the hydrothermal method showed a short circuit current density of 21.67 mA/cm2, an open-circuit voltage of 0.67 V, and a photon-to-electricity conversion efficiency of 5.62%, which is about 17% more than the yield obtained. This comes from a solar cell without plasma modification with an efficiency of 5.11%. The increase in efficiency can be attributed to the increase in electrical conductivity in the photoanode, the tight connection of the conductive surface of the anode with the pigment molecules, and the greater contact surface of the photoanode with the electrolyte.
In this work, the three-layer SnO2/Ag/SnO2 coating on the glass substrate was designed and the optimal thickness was calculated using Film Wizard software. Then the designed samples were fabricated using thermal evaporation technique. Analysis was conducted on optical, electrical, and thermal properties of the samples, including coefficient of merit, surface resistance, and optical transmittance and reflectance. The results showed that the three-layer structures, SnO2/Ag/SnO2, have the necessary and favorable conditions for use as heat insulating and energy saving coatings on glass windows. The optimal thickness was determined 20nm for silver and 70 nm for SnO2. The recorded optical transmission in the visible spectrum and the reflected light in the infrared spectrum are 79.66% and 88.66%, correspondingly. The surface electrical resistance of 11.69 Ω⁄sq has been obtained for the constructed system, which is a suitable value for this coating. The calculated optical values show that the heat transfer from sunlight is minimized through this coating and this coating can be used as a suitable energy storage.
In this study, we synthesized a series of La...Ca.Co0.5Mg0.5O. perovskites with varying Ca content (x = 0.00, 0.15, 0.45, 0.75) using the citrate method, aiming to explore the relationship between magnesium doping and the nonlinear optical (NLO) behavior of the materials. Structural and optical characterizations were carried out, with a focus on the impact of Mg substitution on the diffraction ring patterns observed during NLO measurements. Our results reveal that increasing Mg content leads to significant changes in the nonlinear optical response, with a notable enhancement in NLO properties as Mg concentration rises. This suggests that the modification of the perovskite structure through Mg doping plays a crucial role in tuning its optical properties. Convection and conduction flow are also discussed in this article. It is shown that the nanofluid becomes dominated by one flow over the other after some time. The findings demonstrate the potential of La...Ca.Co0.5Mg0.5O. perovskites as promising materials for applications in nonlinear optics and photonic devices, where compositional control can be used to optimize performance.
In this study, the propagation of electromagnetic (EM) waves and band gap structure in a one-dimensional ternary plasma photonic crystal (PPC) is investigated. The unit cell of the structure consists of dielectric I-plasma-dielectric II and an external constant magnetic field is applied perpendicular to the PPC boundary. In under study PPC, effects of thermal velocity of plasma electrons are taken into account as a dissipative factor. This structure irradiated by obliquely incident linear EM wave, but right-handed and left-handed waves are propagated with different velocities due to existence of DC magnetic field along the wave vector; and therefore, the well-known Faraday rotation effect occurs. The dispersion relation, band gap structure and absorption of the electromagnetic wave will be studied for right-handed waves. It will be shown by changing different parameters such as intensity of the external magnetic field, filling factor and the electron thermal velocity of the plasma layer and dielectric constant of the dielectric layer, the width, number and the location of band gaps can be adjusted.
In this paper, we conducted a numerical study to investigate the role of magnetic nanoparticles (MNPs) in the treatment of cancerous tissues in three dimensional. First, we considered the governing equations associated with this method. Next, we utilized the finite element method (FEM) and Comsol Multiphysics software package to calculate parameters such as temperature distribution, generated heat, and the fraction of damage in tumor and normal tissues over a 40-minute period. The applied frequencies and current in the coil were 150 and 300 kHz and 550 A, respectively. Our calculations revealed that the maximum temperatures of the tumor at frequencies of 150 and 300 kHz were 45.4 and 47 degrees, respectively. These temperatures are sufficient to destroy cancer cells. Furthermore, the comparison of results at 150 and 300 kHz frequencies demonstrated that parameters such as temperature, heat, and degradation rate increase with the increase of frequency. Additionally, we found that the tumor damage at the end of the process for frequencies of 150 and 300 kHz was 100% in the center of the tumor, but reduced to 63% and 75% at the border, respectively.
The development of efficient strategies for fabricating binder-free electrodes to electrochemical energy storage applications is of interest. Here, a novel approach of layer-by-layer chemical deposition was proposed for the preparation of binderless cobaltite (Co3O4) and nickel cobaltite (NiCo2O4) pseudocapacitive electrodes. The structure and morphology of the electrodes were obtained by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) examinations. The results demonstrated that the active materials were uniformly deposited on the surface of the nickel current collector. Also, a more porous structure was obtained in the case of nickel cobaltite electrode, which could improve the diffusion of ions to the active materials. Pseudocapacitive performance of the electrodes was obtained by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) measurements. The results demonstrated that the nickel cobaltite electrode exhibited superior charge storage performance including a high specific capacitance of 1251 F g-1 at 1 A g-1 and good rate capability (89.7% capacitance retention with a 10-fold increase in the current rate), which were higher than those for the cobaltite electrode.
This study presents a theoretical model to explain the bubble oscillation phenomenon that occurs after each flash in single-bubble sonoluminescence (SBSL). Our model reveals that these fluctuations are caused by the pressure effect of electrons produced during the flash, which interact with the surrounding fluid and cause bubble formation. The authors use the Monte Carlo method to calculate the number of released electrons and demonstrate that the amplitude and frequency of these oscillations can be reduced by manipulating the electron density and energy distribution. By controlling the released electrons, we show that it is possible to reduce the number of unwanted oscillations and increase the number of flashes that can be performed in a given time interval. The results provide new insights into the mechanism of SBSL and have implications for its application in various fields. Furthermore, our findings offer a method for reducing these oscillations, which limit the number of flashes that can be produced in a time interval, allowing for more efficient and reliable operation. The results from our theory are in good agreement with experimental results, validating our understanding of this phenomenon.
In this study, we investigated the surface morphology of Au coatings using atomic force microscopy (AFM). we aimed to understand the growth mechanisms and control the nano- and micro-structure of the films to achieve desired morphological properties. The study focused on films formed by the electrodeposition technique and examined the morphology evolution as a function of film thickness. To verify the crystalline structure of the films, X-ray diffraction (XRD) technique was employed. Statistical tests were conducted to confirm that the gold thin film surfaces under investigation exhibited multifractal properties. It is found that as the film thickness increased, the multifractality of the films became more pronounced, and the nonuniformity of the height probabilities also increased. Furthermore, it was observed that surfaces with greater roughness displayed larger nonlinearity and wider width of the multifractal spectrum. The results indicated that the multifractal spectrum had a right-hook shape, distinguishing between different film thicknesses even in small sizes of hundreds of nanometers. Overall, this study provides important insights into the surface morphology of Au coatings and highlights the significance of controlling growth mechanisms for fabricating flat Au films with desired morphological properties. These findings have implications for various applications in biological, electronic, and optical devices.
The research presented herein involves the synthesis of ZnO nanoparticles (NPs) via a simple thermal treatment approach, utilizing a solution comprising Polyvinylpyrrolidone (PVP) as capping reagent and Zn nitrate as the metal source. Subsequently, these ZnO NPs underwent a conversion process into a ZnO/RGO nanocomposite (NCs) through a simple process of polymerization. Various characterization techniques such as Fourier transform infrared spectroscopy, field emission scanning electron microscopy and X-ray diffraction, were employed to investigate the phase composition, microstructure form, and degree of crystallinity. At room temperature, Analysis using Energy dispersive X-ray analysis confirmed the presence of C, Zn, and O elements in the prepared nanocomposite composition. Surface area of the ZnO/RGO NCs was determined through the adsorption–desorption isotherms of N2 gas using Brunauer–Emmett–Teller analysis. The antibacterial and antifungal activities of graphene, ZnO, and ZnO/RGO NCs with results from the disc agar diffusion method indicating the absence of antibacterial activity in graphene and ZnO NPs, while the ZnO/RGO nanocomposites displayed notable antifungal activity. Moreover, graphene alone did not exhibit any noticeable antifungal properties.
Experimental observations show that the zero-field ground state of honeycomb-layered cobaltates is an incommensurate spiral order with an ordering wave vector along the line. However, in the presence of a magnetic field, the incommensurate magnetic phase becomes unstable and the quantum spin liquid phase becomes stable in this class of materials. Here, the central question we address is how to realize the incommensurate order theoretically. For this purpose, we are interested in studying the generalized Kitaev-Heisbenerg model and investigating the interplay effect between conventional Heisenberg and bond-dependent exchange interactions on the stability of the incommensurate spiral order. Our results show that the interplay between the second neighbor Heisenberg interaction and bond-dependent exchange interactions play a vital role in the stability of incommensurate phases. The competition between the second nearest nearest-neighbor interaction and the off-diagonal bond-directional exchange for may place this material in proximity to a quantum spin liquid phase. The quantum spin liquid can be accessible for in the presence of an external magnetic field.
This study examined the electronic, magnetic, and structural properties of Fe2TiP full-Heusler compound, using the pseudo-potential plane wave (PP-PW) formalism based on density functional theory (DFT). Energetically, the AlCu2Mn-type structure of Fe2TiP had greater stability in comparison with the CuHg2Ti-type structure and show the half-metallic (HF) ferrimagnetic behavior. Based on the results at the lattice constant of 5.65 Å, the total magnetic moment (Mtot) was 1 μB/unit cell; this finding is consistent with the Slater-Pauling (SP) rule. The minority spin band exhibited a semiconductor behavior (spin-flip gap of 0.21 eV; gap of 0.35 eV), whereas the majority spin band was metallic. The origin of half-metallicity and appearance of the minority band gap were discussed using the band structure calculations and density of states (DOS). In addition, dependence of magnetic properties on the lattice constant was evaluated. In the lattice constant range of 5.55-5.85 Å, the Fe2TiP compound can retain the half-metallicity. Therefore, the half-metallic feature was not influenced by the lattice distortion, and this material seems to have potential applications in future spintronics devices.
The distance between conduction and valence bands which is known as bandgap energy is an important factor for semiconductors and is different in various materials. The bandgap energy determines the electrical and optical properties of semiconductors and has a direct effect on the performance of diodes and transistors. In this article, the effect of bandgap energy of the channel region of a npn transistor has been investigated and its effects on capacitance and conductivity, threshold voltage, and the Ion-Ioff ratio were studied. An npn transistor is designed and then the bandgap energy is changed between 0.8 eV and 2.2 eV with a step of 0.2 eV, and subthreshold slope and other electrical quantities have been obtained numerically. By comparing the results, the best performance of the transistor can be obtained. This simulation was done with Silvaco Atlas software. This study can open new windows in design of transistor devices.
The manipulation of magnetic characteristics in 2D materials is essential for their utilization in spintronic and magnetic devices. this study was carried out to investigate the doping process involving a single Fe dopant and the co-doping of two Fe impurities at the Pt site within the Pt2Te4 monolayer. The examination revealed that the introduction of a single iron (Fe) atom and a pair of Fe atoms into the non-magnetic semiconductor monolayer of Pt2Te4 leads to magnetic moments measuring 2 µB and 4µB, respectively. The origin of magnetic moments is observed predominantly around Fe-3d orbitals. In the instances of co-doping involving Fe-Fe substitution, four distinct configurations were examined. One of the configurations, specifically FeFe (1), was identified as the most stable due to its minimal energy level. This configuration also demonstrates a ferromagnetic coupling mechanism between the two Fe substitutions, a phenomenon that can be justified by the significant magnetic moment of 4µB.
