Brazilian Journal of Physics最新文献

{"title":"The Dance of the Sheared Eigenfunctions","authors":"J. Oliveira-Cony,&nbsp;F. S. S. Rosa,&nbsp;C. Farina,&nbsp;Reinaldo de Melo e Souza","doi":"10.1007/s13538-026-02091-x","DOIUrl":"10.1007/s13538-026-02091-x","url":null,"abstract":"<div><p>In this work, we delve into the theory of sheared potentials in non-relativistic quantum mechanics. After defining what we mean by a family of sheared potentials, we consider these families in two particular but emblematic cases, the harmonic oscillator and the symmetric potential well proportional to |<i>x</i>|. In both cases, besides determining the spectra, we analyse the impact of the shearing process on the respective eigenfunctions. The latter analysis is typically left aside in the literature, but here we show that the sheared eigenfunctions yield insights that allow for a deeper understanding of the main features exhibited by the spectra. Finally, we make a few comments about the connection between the change in the spectra of a given sheared family and the necessary work that must be made by an external agent to implement such a change.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-026-02091-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148008581","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":"Optical and Electrical Properties of Gd3+ Ion-doped Lithium Aluminum Borate Glasses","authors":"J Nagaraju,&nbsp;B Eraiah","doi":"10.1007/s13538-026-02094-8","DOIUrl":"10.1007/s13538-026-02094-8","url":null,"abstract":"<div><p>Aluminum lithium borate mixing with Gd₂O₃ glasses was fabricated with the conventional melt quench method. Using the XRD technique, the produced material’s amorphous nature was examined. Conductivity study shows that the measured impedance value decreases from about 6 × 10⁸ Ω to 0.3 × 10⁸ Ω, whereas the dielectric constant rises from about 4 to 24, as the gadolinium content increases. It can be seen that Gd³⁺ ions increase the radii of semi-circular impedance graphs, indicating that bulk resistance decreases. As the quantity of gadolinium increases, an increasing trend in AC conductivity from about 10⁻⁹ to 10⁻⁵ S/m is also observed in the high-frequency region. The glass transition temperature (T_g) rises from 468 °C to 493 °C, displaying a variety of thermal patterns as the Gd³⁺ ion content increases, according to the results of differential scan calorimetry (DSC) and thermogravimetric analysis (TGA), which indicates that these materials are suitable for the fabrication of optical fibers and energy storage device applications.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148008908","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 Phase Variance Exhibited by Hydrogen Bond Liquid Crystals Formed Binary Mixtures","authors":"K. S. Usha,&nbsp;N. Pongali Sathya Prabu,&nbsp;Sang Yeol Lee","doi":"10.1007/s13538-026-02089-5","DOIUrl":"10.1007/s13538-026-02089-5","url":null,"abstract":"<div><p>Binary mixtures with an equimolar ratio are formed by the formation of hydrogen-bonded liquid crystalline complexes. The complexes are synthesized from precursors formed between α-Keto Glutaric acid (KGA) and hexyloxy benzoic acid (6BAO), as well as between α-Keto Glutaric acid (KGA) and dodecyloxy benzoic acid (12BAO). In order to make a comprehensive analysis of the mesomorphic properties that are presented, exhaustive studies are carried out employing optical, thermal, and spectral characterization techniques. The isolated binary mixes show three different types of mesophases: nematic, smectic C, and smectic G. Fourier Transform Infrared Spectroscopy (FT-IR) is used to validate the intermolecular hydrogen bonding by chemical analysis. Optical analysis is performed using a Polarizing Optical Microscope (POM) to confirm the mesophases and the phase variance exhibited. A Differential Scanning Calorimeter (DSC) is used in thermal analysis to ascertain enthalpy values, phase transition temperatures, and other thermal characteristics associated with the substance being investigated in the current research.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148008911","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":"Synthesis and Characterization of Polyvinyl Chloride/PbTe Polymer Nanocomposites for Optoelectronic Applications","authors":"W. S. Mohamed,&nbsp;N. M. A. Hadia,&nbsp;Taha Abdel Mohaymen Taha","doi":"10.1007/s13538-026-02096-6","DOIUrl":"10.1007/s13538-026-02096-6","url":null,"abstract":"<div><p>This study explores the development and characterization of novel polyvinyl chloride (PVC)/lead telluride (PbTe) nanocomposite films for advanced optoelectronic applications. PbTe nanopowder, synthesized via a hydrothermal method and exhibiting a cubic crystal structure with an average size of ~ 18 nm, were incorporated into a PVC matrix at concentrations of 0.1, 0.2, and 0.3 wt% using solution casting. TEM analysis revealed that the PbTe nanopowder consists of one-dimensional nanorods with lengths of 30–70 nm and diameters of 10–20 nm. Structural and morphological analyses confirmed the successful dispersion of PbTe without agglomeration. Optical characterization revealed that the direct band gap decreased from 5.75 eV (pure PVC) to 5.70–5.72 eV, while the indirect band gap showed a slight reduction from 5.52 eV to 5.48–5.50 eV. The static refractive index (n_o) increased substantially from 1.43 (pure PVC) to 1.82 (0.3 wt% PbTe), indicating enhanced polarizability. The nanocomposites also exhibited a rise in reflectance and a decline in transmittance due to PbTe-induced scattering and absorption. The Wemple-DiDomenico model quantified a dramatic increase in dispersion energy (E_d) and oscillator strength (f), leading to orders-of-magnitude enhancement in third-order nonlinear susceptibility (χ⁽³⁾) and nonlinear refractive index (n₂). These results underscore the efficacy of PbTe in tailoring PVC’s optical response, making these composites promising for nonlinear photonics, optical coatings, and IR technologies.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938576","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":"Phenomenological Mean–Field Theory of Antiferromagnetism and Metamagnetism for Heavy Fermion Compounds with Application to Antiferromagnetic Ce(Ru(_{1-x})Rh(_{x}))(_{2})Si(_{2})","authors":"Kazuyuki Matsumoto,&nbsp;Shigeyuki Murayama","doi":"10.1007/s13538-026-02095-7","DOIUrl":"10.1007/s13538-026-02095-7","url":null,"abstract":"<div><p>We explored the phenomenological mean-field theory of antiferromagnetic heavy fermion systems without considering a microscopic mechanism. Using the Bragg–Williams entropy, we describe an extension of the Landau-like free energy by the antiferromagnetic two-sublattice model. We obtained thermal equilibrium sublattice magnetizations by minimizing the free energy of these two-sublattice magnetizations as a function of temperature and the external magnetic field. As an example, we examine the antiferromagnetic heavy fermion compound Ce(Ru<span>(_{1-x})</span>Rh<span>(_{x})</span>)<span>(_{2})</span>Si<span>(_{2})</span> which exhibits metamagnetism-like behavior, and obtain magnetization curves and a magnetic phase diagram in agreement with experimental observations.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938256","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":"Breakup Dynamics of Proton- and Neutron-halo Nuclei on (^{28})Si, (^{120})Sn and (^{236})U Targets","authors":"Lucas Vusi Ndala,&nbsp;Mantile Leslie Lekala","doi":"10.1007/s13538-026-02093-9","DOIUrl":"10.1007/s13538-026-02093-9","url":null,"abstract":"<div><p>In this study, the Continuum Discretized Coupled Channels (CDCC) method is employed to investigate the breakup dynamics of neutron- and proton-halo nuclei in reactions involving <span>(^{8})</span>Be<span>(rightarrow ^{7})</span>Be+n and <span>(^{8})</span>B<span>(rightarrow ^{7})</span>Be+p on light (<span>(^{28})</span>Si) and heavy (<span>(^{120})</span>Sn and <span>(^{236})</span>U) targets. To ensure a consistent comparison, all systems are modeled with the same ground-state separation energy of <span>(S_{p,n})</span>=0.137 MeV. The total, nuclear, and Coulomb breakup cross sections are analyzed with the inclusion of continuum-continuum couplings (CCC). The results show that neutron-halo breakup cross sections, particularly the total and nuclear components, are generally larger than those of the proton-halo system, especially at forward angles. The inclusion of continuum-continuum couplings leads to a noticeable suppression of the total and nuclear breakup cross sections, most prominently in the proton-halo case, while the Coulomb breakup cross section remains relatively unaffected. In addition, differential elastic scattering cross sections are calculated and compared with available experimental data for the <span>(^{7})</span>Be+<span>(^{28})</span>Si and <span>(^{8})</span>B+<span>(^{120})</span>Sn systems, showing good agreement and confirming the reliability of the adopted model.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-026-02093-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147937825","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":"Characterization of SnO2 Thin Films deposited with SILAR: Effect of Annealing on Physical Properties","authors":"Tuba Çayır Taşdemirci","doi":"10.1007/s13538-026-02087-7","DOIUrl":"10.1007/s13538-026-02087-7","url":null,"abstract":"<div><p>SnO₂ thin films were deposited on glass substrates using the SILAR method at room temperature and subsequently annealed at 250 °C, 300 °C, and 350 °C for 30 min. The structural, morphological, and optical properties of the as-grown and annealed films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDAX), atomic force microscopy (AFM), and UV–Vis spectroscopy. XRD analysis revealed that increasing the annealing temperature improved crystallinity, enhanced peak intensities, and promoted the formation of the rutile SnO₂ phase. SEM and AFM analyses showed that annealing led to grain growth and smoother film surfaces. EDAX confirmed the presence of Sn and O elements, while the Si signal from the substrate decreased at higher annealing temperatures due to improved surface coverage. UV–Vis measurements indicated a reduction in optical band gap from 3.53 eV (as-grown) to 3.21 eV (350 °C), attributed to enhanced crystallinity and reduced structural defects. The results of this study demonstrate the strong influence of annealing temperature on the structural and optical performance of SILAR-grown SnO₂ thin films, which directly determines their suitability for optoelectronic devices. The enhanced crystallinity and increased crystallite size observed after annealing improve charge carrier mobility by reducing grain boundary scattering. This is particularly beneficial for applications such as transparent conducting electrodes, gas sensors, and thin-film transistors, where high electrical conductivity and structural order are essential.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147937785","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":"Zn²⁺ Induced Structural and Functional Modulations in CoFe₂O₄ Thin Films Synthesized by Spray Pyrolysis","authors":"Yuvraj R. Lingayat,&nbsp;Manjusha V. Gangurde,&nbsp;Ramesh T. Ubale,&nbsp;Suchita V. Deshmukh,&nbsp;Mahesh K. Babrekar,&nbsp;C. M. Kale","doi":"10.1007/s13538-026-02088-6","DOIUrl":"10.1007/s13538-026-02088-6","url":null,"abstract":"<div><p>Zn²⁺-substituted cobalt ferrite (Co₁₋ₓZnₓFe₂O₄, where 0.0 ≤ x ≤ 1.0) thin films were successfully fabricated using the spray pyrolysis technique. X-ray diffraction (XRD) analysis confirmed the formation of a single-phase cubic spinel structure, indicating successful ionic substitution. The lattice constant increased from 8.3443 to 8.4314 Å with increasing Zn²⁺ concentration. Field emission scanning electron microscopy (FE-SEM) revealed uniformly distributed, spherical, and agglomerated nanoparticles with grain sizes increasing from 41 nm to 78 nm. Atomic force microscopy (AFM) showed dense films with smooth surface morphology and enhanced crystallinity. Optical studies using UV–Visible spectroscopy indicated a direct allowed electronic transition, with the optical band gap narrowing from 2.75 eV to 2.41 eV due to lattice expansion and defect-induced localized states. DC resistivity measurements confirmed semiconducting behavior, showing a decrease in resistivity with increasing temperature. Magnetic characterization using vibrating sample magnetometry (VSM) revealed a gradual decrease in saturation magnetization, remanence, and coercivity with higher Zn²⁺ content. These results suggest that Zn²⁺ ions preferentially occupy the A-site, causing redistribution of Co²⁺ and Fe³⁺ ions between tetrahedral and octahedral sites, thereby modifying the magnetic exchange interactions. The optimized Co–Zn ferrite thin films exhibit potential for applications in magnetic sensors, memory devices, and optoelectronic systems.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938005","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":"A High-throughput Coaxial DBD Reactor for Water Purification through Synergistic Thin-film and Bubble-flow Dual-interface Design","authors":"Gabriel Silva Naime,&nbsp;Rodrigo Sávio Pessoa","doi":"10.1007/s13538-026-02092-w","DOIUrl":"10.1007/s13538-026-02092-w","url":null,"abstract":"<div><p>Non-thermal plasma (NTP) enables reagent-free in situ generation of reactive oxygen and nitrogen species (RONS) for water treatment, yet practical reactor designs face a persistent trade-off between stable discharge ignition and efficient gas–liquid mass transfer. This study presents a continuous-flow coaxial dielectric barrier discharge (DBD) reactor engineered with a dual-interface configuration that deliberately couples an annular thin liquid film with forced air bubbling to stabilize microdischarges and intensify plasma–liquid–gas interfacial transport. Two environmentally relevant water matrices—municipal utility backwash effluent and contaminated river water from Sorocaba, São Paulo (Brazil)—were treated at 120 L·h^− 1 with ambient air injection (~ 40 L·min^− 1) in a treatment train comprising pre-filtration, plasma contact, and a downstream mixed-media polishing filter. Performance was assessed using ISO/IEC 17,025-accredited analytical methods across five independent experimental runs. The integrated system achieved complete inactivation of total coliforms and <i>Escherichia coli</i> (non-detect in 5/5 replicates; Fisher’s exact test, <i>p</i> = 0.0079), reduced ammonia from 14.18 ± 0.28 mg·L^− 1 to below the limit of quantification (&lt; 0.01 mg·L^− 1; &gt;99.9%), and decreased dissolved aluminum and iron by ≥ 99%. The plasma-specific energy input was 2.4 kJ·L^− 1 (80 W discharge power determined by Lissajous analysis), corresponding to an ammonia removal efficiency of 21.3 g-NH₃·kWh^− 1 and an electrical energy per order (EE_O) of 0.37 kWh·m^− 3·order^− 1 (total system power basis). Microbiological indicators (total coliforms, <i>E. coli</i>, HPC) and dissolved metals (Al, Fe) were evaluated in the utility backwash matrix, while the remaining physicochemical endpoints were evaluated in river water; comparisons across analytes should therefore be interpreted with this matrix assignment in mind. The present results demonstrate the effectiveness of the integrated treatment train under the stated operating conditions and an electrical behavior consistent with stable filamentary microdischarge activity, but do not yet isolate the incremental contribution of the thin-film flow, the bubble injection, or their combination; the study is therefore positioned as a concept validation of the integrated dual-interface reactor rather than a component-by-component deconvolution.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-026-02092-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147937935","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":"Insights into the Deformation of Mask Openings Under Ion Tilting During Plasma Etching","authors":"Peng Zhang","doi":"10.1007/s13538-026-02090-y","DOIUrl":"10.1007/s13538-026-02090-y","url":null,"abstract":"<div><p>In this work, a simulation approach was employed to provide insights into the deformation of mask openings during plasma etching under ion tilting conditions. Simulations were performed focusing on an isolated round mask opening and two widely used patterned configurations: square and hexagonal patterns. Based on analyses of the surface electric field distribution and the evolution of the opening as a function of the ion tilting angle, it is found that ion tilting significantly alters the mask opening, with deformation highly dependent on the tilting angle. This study investigates the etching performance at the mask edge and fundamental deformation mechanisms of mask openings under ion tilting, which presents a key challenge for current and next-generation etching technologies.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829741","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}