Brazilian Journal of Physics最新文献

{"title":"Characteristic Study of Head-on Collision of Ion Acoustic Dissipative Solitons in a Ultracold Neutral Plasma Through the Both Sided Damped KdV-Burgers Equation","authors":"Jayshree Mondal,&nbsp;Santanu Raut,&nbsp;Prasanta Chatterjee,&nbsp;Laxmikanta Mandi","doi":"10.1007/s13538-025-01818-6","DOIUrl":"10.1007/s13538-025-01818-6","url":null,"abstract":"<div><p>This study examines the head-on collisions of solitons within an ultracold neutral plasma (UNPs), taking into account the effects of ion-neutral collisions and longitudinal viscosity. The ion-fluid equations are analyzed under consideration of a q-nonextensive electron distribution. By employing the extended Poincare-Lighthill-Kuo (ePLK) method, two Damped Korteweg-de Vries Burgers (dKdVB) equations are derived. Approximated analytical solutions for the damped KdV Burger equation are obtained, allowing for an investigation into how the ion-neutral collision frequency parameter <span>( nu _{in} )</span>, the longitudinal viscosity parameter <i>L</i>, the effective temperature ratio parameter <span>( sigma _* )</span>, and the nonextensive parameter <i>q</i> affect soliton propagation. The primary aim of this research is to explore the dissipation of soliton collisions in the context of damping.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural, Morphological, and Optical Properties of Chemically Deposited Cd1-xMnxS Thin Films at Varying Temperatures","authors":"Himanshu Sharma Pathok,&nbsp;Prasanta Kumar Saikia","doi":"10.1007/s13538-025-01821-x","DOIUrl":"10.1007/s13538-025-01821-x","url":null,"abstract":"<div><p>Chemically deposited Cd_1-xMn_xS thin films were synthesized by varying the deposition temperature using the cost-effective and scalable Chemical Bath Deposition (CBD) technique. This work addresses a gap in prior research by optimizing a relatively low-temperature deposition range (60–75 °C), which has been less explored for <span>(C{d}_{1-x}{Mn}_{x}S)</span> thin films. This study demonstrates that high-quality crystalline films can be achieved at lower temperatures, making the process more energy-efficient and suitable for large-area and flexible substrate applications. Various structural, optical, and electrical properties were investigated using advanced characterization techniques, including XRD, FESEM, TEM, and UV–Vis spectroscopy. XRD analysis revealed the cubic phase of the <span>(C{d}_{1-x}{Mn}_{x}S)</span> thin films, which was further confirmed by TEM analysis. The crystallinity of the film is highly influenced by the deposition temperature within the range of 60–75 °C, with 75 °C identified as the optimal temperature for achieving the best crystalline quality. The FESEM micrographs revealed that the grain size varied between 231 and 415 nm with changes in deposition temperature, exhibiting nanostructured, crack-free, and spherical grains. Additionally, a significant reduction in voids was observed with increasing deposition temperature, indicating improved film density and surface uniformity. The film thickness was determined through FESEM cross-sectional analysis. EDX analysis confirmed the presence of Cd, <span>(text{Mn})</span>, and <span>(text{S})</span> ions and revealed the variations in the atomic percentages of the metallic constituents with changing deposition temperatures. The optical transmittance of the sample was observed to be approximately 80%, indicating high transparency. Notably, the optical band gap of the deposited <span>(C{d}_{1-x}{Mn}_{x}S)</span> thin films gradually decrease from 2.80 eV to 2.75 eV as the deposition temperature increases from 60 °C to 75 °C. The broader band gap makes these films more suitable for UV–visible optoelectronic applications. Overall, the study introduces an improved deposition approach that yields better crystallinity and optical performance at lower thermal budgets, highlighting the material's potential for use in window layers of photovoltaic cells, anti-reflective coatings, and optical waveguides.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of Hydrogen Ion-Acoustic, Periodic, and Superperiodic Waves in Magnetized Cometary Plasma Comprising Oxygen Ions and Superthermal Electrons","authors":"A. Atteya,&nbsp;Reem Altuijri,&nbsp;Abdel-Haleem Abdel-Aty,&nbsp;Kottakkaran Sooppy Nisar,&nbsp;M. Abd-Elzaher,&nbsp;Pralay Kumar Karmakar,&nbsp;Eman Mohammed El-Bayoumi","doi":"10.1007/s13538-025-01802-0","DOIUrl":"10.1007/s13538-025-01802-0","url":null,"abstract":"<div><p>The modified Zakharov-Kuznetsov equation was developed using the reductive perturbation method for ion-acoustic waves in a magnetized cometary plasma. The system includes hydrogen fluid ions as well as positively and negatively charged oxygen ions, kappa-described hot sun electrons, and somewhat colder cometary electrons. Depending on the system’s properties, we investigated the bifurcation analysis. All possible phase images are presented, including periodic, homoclinic, and superperiodic trajectories. The presence of rarefactive and compressive solitary waves is shown. Furthermore, the plasma system under consideration may support both nonlinear and supernonlinear periodic waves. It has been revealed that the nonextensivity of ions significantly modifies the characteristics and influences wave bifurcation. The amplitudes of the solitary waves appear to be strongly related to the presence of water molecules in cometary plasma, and they are also accompanied by photoionization processes.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysing COVID-19 Outbreaks Through Deterministic and Stochastic Agent-Based Models with Public Perception","authors":"Fahad Awadh Al-Abri,&nbsp;Mohd Hafiz Mohd","doi":"10.1007/s13538-025-01819-5","DOIUrl":"10.1007/s13538-025-01819-5","url":null,"abstract":"<div><p>This study compares the newly developed stochastic agent-based model (ABM) and deterministic system within the context of COVID-19 transmission dynamics, using the Susceptible-Exposed-Infectious-Removed-Perception (SEIRP) compartments. The primary aim is to analyse the similarities and differences between these modelling approaches, providing insights into the emergent behaviours of the epidemiological systems. We also investigate how social phenomena like public perception affect the two epidemiological models’ outcomes, focusing on scenarios with varying awareness levels and proportions of severe cases. Our results show that while deterministic model outputs align well with the ABM for large populations, discrepancies emerge for small populations in the ABM due to the impacts of stochastic extinction and discreteness of individuals. In scenarios with high proportions of severe cases and for large population sizes, the deterministic model exhibits oscillatory behaviour. In this situation, the averaged ABM densities initially capture the fluctuation dynamics when a substantial number of realisations is used in simulation; however, this stochastic system exhibits diminishing fluctuations across different realisations, contributing to a consistent average akin to an endemic steady state over a longer period. Interestingly, as the number of realisations is reduced, the agreement between stochastic and deterministic systems in depicting recurrent outbreaks is evident (i.e., realisations-dependent dynamical behaviour). In the next case study, the joint effect of recovery, latency period, disease severity and public perception is explored, highlighting how different factors can combine to influence the systems’ outcomes. Notably, our case study finds that even when the deterministic model demonstrates the persistence of sustained oscillations, the ABM can depict an extinction state; this stochastic ABM observation is caused by the realisations in this epidemiological system fluctuating to a very low population density and being excluded over a long run. Overall, our findings suggest the importance of considering both deterministic and stochastic models in infectious disease modelling, highlighting the need for comprehensive analyses to guide evidence-based decision-making in public health and epidemiology.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-025-01819-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chiral Quasi-Bound State in the Continuum in Dielectric Metasurface for Third Harmonic Generation with Strong Circular Dichroism","authors":"Wudeng Wang,&nbsp;Yingjie Ju,&nbsp;Zhaojun Han,&nbsp;Jiaheng Liu,&nbsp;Yujie Zhang","doi":"10.1007/s13538-025-01804-y","DOIUrl":"10.1007/s13538-025-01804-y","url":null,"abstract":"<div><p>In this work, we design and numerically investigate a chiral metasurface based on two-layer distorted silicon resonators on the silicon dioxide substrate. This distorted metasurface can support a chiral quasi-bound state in the continuum (quasi-BIC) with an ultrahigh Q-factor (exceeding 10⁵) and strong circular dichroism (CD = 0.887) by breaking the in-plane inversion symmetry. The sharply chiral quasi-BIC realized in this metasurface can generate high local field enhancement and be used in strong CD nonlinear responses. Numerical results show that the third-harmonic generation (THG) efficiency of 9.24 × 10⁻⁵ for a peak amplitude of the pump of 1.55 × 10⁸ V/m can be achieved, and the THG-CD reaches up to 0.94. Meanwhile, we have theoretically demonstrated that this metasurface shows potential for applications in chiral sensing with high sensitivities.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural, Optical, and Dielectric Properties of Double Perovskite La2NiMnO6","authors":"Dhyani Parikh,&nbsp;Vedvyas Dwivedi,&nbsp;C. R. Vaja,&nbsp;Aditya Vora,&nbsp;Nisha Thankachen","doi":"10.1007/s13538-025-01812-y","DOIUrl":"10.1007/s13538-025-01812-y","url":null,"abstract":"<div><p>Double perovskite materials incorporating rare earth elements, such as La₂BB′O₆ (here B represents Ni and B′ denotes Mn), have been extensively investigated. In this study, La₂NiMnO₆ (LNMO) was synthesized by employing solid-state reaction approach. X-ray diffraction (XRD) analysis confirmed development of a monoclinic crystal structure with P2₁/n space group. Diffuse reflectance spectroscopy demonstrated strong reflectance and minimal absorbance in visible and near-infrared regions, indicating optical transparency. Direct optical band gap, estimated to be 2.96 eV using the Kubelka–Munk-transformed Tauc plot, highlights its potential for UV-filtering and optoelectronic applications. FTIR spectra exhibited pronounced antisymmetric stretching at ~ 556.78 cm⁻¹ and bending modes around 913.24 cm⁻¹, affirming the presence of Ni–O and Mn–O bonds within (Ni/Mn) O₆ octahedral network. Ferromagnetic transitions observed near 150 K and 280 K were attributed to B-site cation ordering. Dielectric studies over the 20 kHz–2 MHz range, modelled by the Maxwell–Wagner and Koops theories, revealed Debye relaxation behaviour and characteristic impedance trends.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Physicochemical Properties Exhibited by Thermotropic Liquid Crystalline Binary Mixtures","authors":"J. Vivekanandan,&nbsp;N. Pongali Sathya Prabu,&nbsp;Sang Yeol Lee","doi":"10.1007/s13538-025-01814-w","DOIUrl":"10.1007/s13538-025-01814-w","url":null,"abstract":"<div><p>Five binary mixtures are obtained as the resultant liquid crystalline complexes obtained from the liquid crystal precursors formed between α-Keto Glutaric acid (KGA) with hexyloxy benzoic acid (6BAO) and α-keto glutaric acid (KGA) with dodecyloxy benzoic acid (12BAO). Variation in the molar proportion of the precursors in a well-defined odd step leads to the formation of five liquid crystalline binary mixtures. Rich-phase polymorphism exhibited by the precursors has triggered this analysis which leads to a wide range of results obtained completely investigated by means of spectral, optical, and thermal characterization techniques. Surface morphology investigation confirms the uniformity in obtaining the binary mixture. KGA + 6BAO exhibit smectic C and smectic G mesophases whereas KGA + 12BAO exhibit nematic, smectic C, and smectic G mesophases. Chemical analysis confirming the intermolecular hydrogen bonding is carried through Fourier transform infrared spectroscopy analysis. Optical analysis corresponding to the mesophase variance of the binary mixtures is carried through polarizing optical microscope. Thermal analysis confirming the transition temperatures and enthalpy values is carried out by differential scanning calorimeter.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of the Tantawy Technique for Modeling Fractional Ion-Acoustic Waves in Electronegative Nonthermal Plasmas, Part (II): Fractional Modified KdV-Solitary Waves","authors":"Samir A. El-Tantawy,&nbsp;Weaam Alhejaili,&nbsp;Muhammad Khalid,&nbsp;Amnah S. Al-Johani","doi":"10.1007/s13538-025-01800-2","DOIUrl":"10.1007/s13538-025-01800-2","url":null,"abstract":"<div><p>Building on our previous analysis of the planar fractional Korteweg-de Vries (FKdV) solitary waves [Part (I)] (El-Tantawy et al., Braz. J. Phys. <b>55</b>, 123, 2025), this research tackles the more complex realm of fractional modified KdV (mKdV) wave propagation in non-Maxwellian unmagnetized electronegative plasmas (ENPs) composed of inertial positive and negative ions and Cairns-distributed inertialess electrons. Our study has two main objectives: The first one is to derive the cubic nonlinearity mKdV equation, which governs solitary wave (SW) propagation in this plasma model, using the reductive perturbation technique (RPT). The second objective, notable for its novelty and significance, entails utilizing the “Tantawy technique” to analyze the fractional planar mKdV (FmKdV) equation. Thus, highly accurate and stable approximations will be generated to clarify the properties of fractional mKdV solitary waves (SWs) and enable a deeper understanding of the dynamic behavior of these complex phenomena during propagation. Additionally, the Laplace transform iterative method (LTIM) is applied to examine and analyze the FmKdV equation and derive analytical approximations, facilitating a comparative analysis with the results of the Tantawy technique. To evaluate the accuracy of all generated approximations using the two proposed techniques, the absolute error of all generated approximations is estimated compared to the exact solution for the integer case. The influence of various plasma parameters on the characteristic behavior of the profile of the FmKdV-SWs is numerically investigated. This research offers valuable insights into laboratory, space, and astrophysical plasma systems.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the Vibrational, Optical, Impedance, Electrical, and Thermal Properties of l-Histidine Acetate Dihydrate Crystals","authors":"Helen Merina Albert,&nbsp;SK. Fakruddin Babavali,&nbsp;M. Kumara Dhas,&nbsp;D. Neelima Patnaik,&nbsp;K. Lakshmi Sarada,&nbsp;R. Priya,&nbsp;Nellore Manoj Kumar,&nbsp;C. Alosious Gonsago","doi":"10.1007/s13538-025-01807-9","DOIUrl":"10.1007/s13538-025-01807-9","url":null,"abstract":"<div><p>This investigation used the slow evaporation method to synthesize the amino acid derivative <span>l</span>-histidine acetate dihydrate (LHADH) from a water-based solution. The single-crystal X-ray diffraction (SCXRD) study revealed that the LHADH crystallized into the triclinic crystal form. FTIR and Raman spectral studies identified the vibrational modes and functional groups of the LHADH. UV–visible analysis was used to measure the optical absorption of the produced crystal. The optical attributes were assessed, including its bandgap, optical conductivity, refractive index, and extinction coefficient. The second harmonic generation ability of LHADH was evaluated to be 0.93 times that of KDP. The impedance and electric modulus features of the LHADH were ascertained between 100 Hz and 5 MHz region at varying temperatures. The electric modulus was used to study the relaxation process of the LHADH. The appearance of a semicircle arc in the complex modulus spectra at various fixed temperatures indicates the single-phase nature of the compound. Jonscher power was applied to describe the LHADH crystal’s electrical conductance process. Thermogravimetry and differential thermal analysis (TG–DTA) measurements were used to evaluate the thermal properties of LHADH. The LHADH crystals are suitable for optoelectronic uses because of their significant optical, SHG, electrical, thermal, and impedance parameters.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation-Based Optimization of Alkaline Earth Metal Sulfide Buffer Layers for High-Efficiency CdTe Solar Cells","authors":"Zalak S. Kachhia,&nbsp;Sunil H. Chaki,&nbsp;Bhoomi S. Shah,&nbsp;Sefali R. Patel,&nbsp;Jiten P. Tailor,&nbsp;Millind. P. Deshpande","doi":"10.1007/s13538-025-01810-0","DOIUrl":"10.1007/s13538-025-01810-0","url":null,"abstract":"<div><p>Cadmium telluride (CdTe) is one of the most recognized thin film solar cell materials. The present study explores and investigates the integrability of alkaline earth metal sulfides (AeMS) as potential buffer layer for CdTe solar cells. A theoretical simulation study is conducted through Solar cell Capacitance Simulator-1D (SCAPS-1D) software. The study focuses on the use of AeMS: CaS, MgS, SrS, and BaS as buffer layers in CdTe-based solar cells. The simulation approach is aimed to enhance PV parameters, developing the FTO/AZO/AeMS/CdTe/V₂O₅/Au heterojunction solar cell. The thickness and carrier density are tuned for each layer with all the buffer materials. The impact of the variation on the fundamental PV parameters is examined to optimize the cell. The temperature effect on the final cell is evaluated after optimization of each layer. The study indicates that the thickness and carrier density of the absorber layer have a huge impact on the cell parameters. The optimized parameters achieved are efficiency of 31.7%, 31.14%, 31.31%, and 31.73% for MgS, CaS, SrS, and BaS buffer layers at 303 K temperatures, respectively. The open circuit voltage ranges between 1.25 and 1.26 V for all buffer layers. Among all buffer layers, the MgS and BaS attain the highest short circuit current density of ~ 27.94 mA/cm². Each buffer layer configuration exhibits a fill factor that exceeds 89%. The findings underscore the utility of simulation-driven approaches in formulating experimental strategies for the development of AeMS-buffered CdTe solar cells with enhanced conversion efficiency.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}