物理最新文献

{"title":"The study of the effect of device downsizing on 1/f noise in deep submicron magnetic tunnel junctions","authors":"T. N. Anh Nguyen,&nbsp;Q. N. Pham,&nbsp;K. T. Do,&nbsp;H. K. Vu,&nbsp;H. N. Pham,&nbsp;D. T. Tran,&nbsp;H. M. Do","doi":"10.1007/s00339-025-08630-8","DOIUrl":"10.1007/s00339-025-08630-8","url":null,"abstract":"<div><p>In this study, nanoscale MgO magnetic tunnel junctions (MTJs) with an orthogonal magnetization structure between the free and pinned layers and various junction sizes were fabricated, and their tunnel magnetoresistance (TMR) ratio, resistance-area (RA) product, and low-frequency noise (LFN) behavior were experimentally investigated thoroughly. The circular MTJs with various diameters (80–400 nm) show high TMR ratios of greater than 100% at room temperature (RT) with relatively low RA in the range of 2.8–4.4 Ωµm². We found that the noise power spectral density (PSD) as a function of d.c. bias voltage (<i>V</i>_bias) and perpendicular d.c. bias magnetic field (<i>H</i>_DC) in all junction sizes exhibits 1/<i>f</i>-noise behavior within a wide investigated frequency range from 5 Hz up to 10 kHz. The bias voltage and magnetic field-dependent LFN indicated that the 1/<i>f</i> noise of the MTJs has both electric and magnetic origins. The results show that though the TMR ratio and RA product are size-independent, the Hooge parameter for the parallel (P) state (<i>α</i>_P) is strongly dependent on the MTJ size, and its values decrease with decreasing MTJ size, suggesting the reduction of electronic 1/<i>f</i> noise as the MTJ size shrinks. This is the first experimental report on the size dependency of electronic 1/<i>f</i> noise in nano-sized MTJs. The results may open a new approach for reducing not only magnetic but also electronic 1/<i>f</i> noises in MTJs by downscaling, thereby increasing the sensitivity of MTJ nanosensors.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of strong magnetic field, baryon chemical potential, and medium anisotropy on polarization and spin alignment of hadrons","authors":"Bhagyarathi Sahoo,&nbsp;Captain R. Singh,&nbsp;Raghunath Sahoo","doi":"10.1140/epjc/s10052-025-14260-4","DOIUrl":"10.1140/epjc/s10052-025-14260-4","url":null,"abstract":"<div><p>The recent observation of global spin polarization of <span>(Lambda )</span> (<span>(bar{Lambda })</span>) hyperons and the spin alignment of <span>(phi )</span> and <span>(K^{*0})</span> vector mesons create remarkable interest in investigating the particle polarization in the relativistic fluid produced in heavy-ion collisions at GeV/TeV energies. Among other sources of spin polarization phenomena, the Debye mass of a medium plays a crucial role in particle polarization. Any modification brought to the effective mass due to the temperature, strong magnetic field (<i>eB</i>), baryonic chemical potential (<span>(mu _{B})</span>), medium anisotropy (<span>(xi )</span>), and vorticity, etc., certainly affects the particle spin polarization. In this work, we explore the global hyperon spin polarization and the spin alignment of vector mesons corresponding to the strong magnetic field, baryonic chemical potential, and medium anisotropy. We find that the degree of spin polarization is flavor-dependent for hyperons. Meanwhile, vector meson spin alignment depends on the hadronization mechanisms of initially polarized quarks and anti-quarks. Medium anisotropy significantly changes the degree of spin polarization compared to the magnetic field and baryon chemical potential.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 5","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14260-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Friedmann–Lemaître universes and their metamorphoses","authors":"Spiros Cotsakis","doi":"10.1140/epjc/s10052-025-14312-9","DOIUrl":"10.1140/epjc/s10052-025-14312-9","url":null,"abstract":"<div><p>We analyze the dynamics of the Friedmann–Lemaître universes taking into account the different roles played by the fluid parameter and the cosmological constant, as well as the degenerate character of the equations. We find that the Friedmann–Lemaître system reduces to four qualitatively inequivalent normal forms and write down the sets of all stable perturbations that may result (the ‘versal unfoldings’). These sets are of small codimension up to three. We then describe all possible parameter-dependent solutions and their transfigurations to other forms during evolution through the bifurcation sets, these are also fully described. This analysis leads to a picture of cosmological evolution determined by new parameters related to codimension which are zero in standard cosmology. The emerging versal solutions are all free of singularities, while other properties of them are also discussed.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 5","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14312-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"A simulation study of electrical conductivity of porous rocks: effect of clay, porosity, temperature and Peclet number.","authors":"Supti Sadhukhan, Tapati Dutta","doi":"10.1140/epje/s10189-025-00494-3","DOIUrl":"10.1140/epje/s10189-025-00494-3","url":null,"abstract":"<p><p>This study investigates the impact of clay content and temperature variation on the electrical conductivity of three-dimensional fluid-filled porous rocks. The role of varying pore throat radii has been included in the course of clay fraction variation in the conducting channels of the rock samples. The research identifies a critical ratio of clay conductance to fluid conductance that dictates the regime of electrical conductance behaviour. A nonlinear increase in electrical conductance is observed when the clay-to-fluid conductance ratio exceeds the critical ratio, whereas a linear relationship is maintained below this critical ratio. A modified form of Archie's law relating effective conductivity and porosity has been proposed for the clay coated channels. The intricate relationship between Peclet number, pore throat size, and temperature on the electrical conductivity of fluid-filled straight channels in three dimensions has also been investigated. Results revealed a quadratic increase in conductance with porosity under steady-state conditions across all Peclet number ranges examined. While the conductivity remained constant with porosity for each Peclet number, the rate of increase in conductivity diminished with it. Nonlinear increase in conductivity was observed with temperature in the transient flow regime with a threshold temperature marking the onset of conductivity. Conductivity was augmented with increase in observation time in the transient state for the entire temperature range considered. Close to the attainment of saturation in electrical conductivity, the conductivity changed linearly with temperature until a steady value was reached.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 4-5","pages":"29"},"PeriodicalIF":1.8,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144155488","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":"Fine-tunings in nucleosynthesis and the emergence of life: status and perspectives","authors":"Ulf-G. Meißner,&nbsp;Bernard Ch. Metsch,&nbsp;Helen Meyer","doi":"10.1140/epja/s10050-025-01587-5","DOIUrl":"10.1140/epja/s10050-025-01587-5","url":null,"abstract":"<div><p>We discuss the fine-tunings of nuclear reactions in the Big Bang and in stars and draw some conclusions on the emergence of the light elements and the life-relevant elements carbon and oxygen. We also stress how to improve these calculations in the future. This requires a concerted effort of different communities, especially in nuclear reaction theory, lattice QCD for few-nucleon systems, stellar evolution calculations, particle physics and philosophy.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01587-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Dynamic analysis of Rayleigh waves in nonlocal porous orthotropic thermoelastic medium with diffusion","authors":"Abhishek Mallick,&nbsp;Siddhartha Biswas","doi":"10.1007/s00339-025-08607-7","DOIUrl":"10.1007/s00339-025-08607-7","url":null,"abstract":"<div><p>This research investigates the propagation of Rayleigh waves in an orthotropic medium containing voids, employing nonlocal elasticity and the three-phase lag (TPL) model. The presence of voids, nonlocal effects, and diffusion are critical factors that significantly influence the behavior of Rayleigh waves, which are crucial for various engineering applications and geophysical explorations. The orthotropic medium’s directional dependence on mechanical properties, combined with voids, adds complexity to the wave propagation dynamics. We utilize the TPL model to incorporate phase lags in heat conduction, mechanical deformation, and mass diffusion, providing a comprehensive framework for analyzing these interactions. Normal mode analysis is employed to derive the dispersion relations and study the effects of nonlocal elasticity on wave characteristics. The inclusion of nonlocal elasticity accounts for long-range interactions, enhancing the accuracy of the model in predicting wave behavior. Our findings reveal that the presence of voids, nonlocal elasticity, and diffusion significantly impact the propagation speed, attenuation coefficient, penetration depth, and specific loss of Rayleigh waves. The TPL model effectively captures the combined effects of these factors, showing that nonlocal elasticity introduces additional complexity and dispersion in wave propagation. Diffusion tends to smooth out the wave characteristics, while the presence of voids influences the propagation speed, attenuation coefficient, penetration depth, and specific loss. This study contributes to the development of more accurate predictive models for wave propagation in complex media, with implications for materials science, structural engineering, and geophysical exploration. The results highlight the necessity of considering voids, nonlocal elasticity, and diffusion when analyzing Rayleigh wave propagation in orthotropic media.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dopant-dependent spin–lattice coupling in La0.7Ca0.15Sr0.15MnO3: Fe/Co/Ni effects on magnetocaloric properties","authors":"Xiuxin Zheng,&nbsp;Lin Gong,&nbsp;Zhengguang Zou,&nbsp;Zhuojia Xie","doi":"10.1007/s00339-025-08622-8","DOIUrl":"10.1007/s00339-025-08622-8","url":null,"abstract":"<div><p>In this paper, La_0.7Sr_0.15Ca_0.15Mn_0.95A_0.05O₃ (A = Fe, Co and Ni) were fabricated via the sol–gel (S-G) approach. The samples are all rhombohedral structure shapes and belong to the trigonal space group R-3c, as shown by XRD. ZEISS Gemini SEM 300 scans showed irregular sub-micron particles with decreasing particle size for La_0.7Sr_0.15Ca_0.15Mn_0.95A_0.05O₃ (A = Fe, Co and Ni). The magnetic properties were characterized utilizing an MPMS, and the magnetocaloric effects (MCE) were further investigated. The investigations of La_0.7Sr_0.15Ca_0.15Mn_0.95A_0.05O₃ (A = Fe, Co and Ni) found that their Curie temperatures (Tc) were 289.5 K, 290.2 K, and 300 K, respectively. The maximum magnetic entropy change (<span>(-Delta {S}_{M}^{max})</span>) for La_0.7Sr_0.15Ca_0.15Mn_0.95A_0.05O₃ (A = Fe, Co and Ni) at 5 T is 5.107 J/(kg∙K), 4.177 J/(kg∙K) and 3.852 J/(kg∙K), and the relative cooling power (<i>RCP</i>) is 264.819 J/kg, 275.3409 J/kg and 288.7435 J/kg. The Arrott curve, normalization and Curie–Weiss law (CW) fit together to determine that the second-order ferromagnetic-to-paramagnetic (FM-to-PM) transition is observed in the three samples, along with a small magnetic hysteresis and thermal hysteresis, the super-exchange interactions (SE) and the double-exchange interactions (DE) competed with each other to increase half peak width and <i>RCP</i>, with La_0.7Sr_0.15Ca_0.15Mn_0.95A_0.05O₃ (A = Ni) having the largest <i>RCP</i>. While conventional low-temperature magnetic materials need to work in a liquid helium environment, room-temperature magnetic materials do not need to rely on extreme cooling conditions, which greatly reduces the cost of refrigeration equipment, and thus room-temperature magnetically cooled materials have a greater potential for research and development. In this paper, Ni is used as the doping element, and its <i>RCP</i> can reach 288.7435 J/kg, and its Tc is close to room temperature, so it is possible to be used as a room-temperature magnetic cooling material.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A theoretical framework for dynamic cell patterning and synchronization using optical tweezers","authors":"Xiao Yan,&nbsp;Xiao Fu,&nbsp;Yang Hong,&nbsp;Yiping Ruan","doi":"10.1140/epjp/s13360-025-06403-z","DOIUrl":"10.1140/epjp/s13360-025-06403-z","url":null,"abstract":"<div><p>Cell patterning is a pivotal technology in biomedical engineering, enabling precise spatial arrangement of cells and particles for applications such as tissue engineering, stem cell differentiation, and biosensors. While traditional methods like stencil-based patterning and microcontact printing lack dynamic control over cell positions, recent innovations such as dielectrophoresis (DEP), acoustic tweezers, magnetic manipulation, and optical tweezers offer enhanced precision. However, synchronizing cell group patterning remains a significant challenge. This study focuses on dynamic cell patterning using optical tweezers, with an emphasis on synchronizing cell positions within a group. We analyze the synchronization error—defined as the differential position error between two cells—and its impact on the overall cell group configuration. A novel feedback position controller is proposed, integrating both position and synchronization errors to ensure asymptotic convergence to zero. Simulation results indicate a significant improvement in precision, with the proposed method achieving a reduction in maximum synchronization error from 1.31 to 0.275 μm (79% decrease) and maximum position error from 2.12 to 1.43 μm (33% decrease) compared to conventional non-synchronized approaches. By enabling precise and scalable control over complex, reconfigurable cell arrangements, this work advances the field of cell patterning and opens new possibilities for applications in drug screening, disease modeling, and organoid development. </p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Analytical study of Love-type wave propagation in a composite structure of transversely isotropic poroelastic materials","authors":"Komal Gajroiya,&nbsp;Jitander Singh Sikka","doi":"10.1007/s12043-025-02921-8","DOIUrl":"10.1007/s12043-025-02921-8","url":null,"abstract":"<div><p>The primary aim of this paper is to undertake an analytical investigation of the dispersion and damping behaviours of Love-type waves propagation in a porous piezoelectric layer sandwiched between a dissipative transversely isotropic poroelastic layer of finite thickness and a homogeneous transversely isotropic poroviscoelastic half-space. The acquisition of a dispersion equation for the propagation of Love-type waves has been accomplished by employing appropriate boundary conditions. Calculations for specific cases have been conducted, demonstrating the transformation of dispersion equation into the conventional Love wave equation in those particular situations. This affirmation validates the current mathematical model. Numerical analyses were performed for the parameters involved and the results were depicted through graphical representations. The effects of viscoelastic parameter, porosity parameters, thickness ratio, dielectric and piezoelectric parameters in the dispersion curves are highlighted. The current investigation could prove valuable in applications related to geophysics, material science, oil and gas exploration and earthquake engineering, aiding in the comprehension of seismic wave propagation characteristics in complex layered structures.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135276","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":"Archaeometric philology for the study of deteriorated and overlapping layers of ink: the colour code of an early Qur’anic fragment","authors":"Giuseppe Marotta,&nbsp;Alba Fedeli,&nbsp;Sowmeya Sathiyamani,&nbsp;Claudia Colini","doi":"10.1140/epjp/s13360-025-06343-8","DOIUrl":"10.1140/epjp/s13360-025-06343-8","url":null,"abstract":"<div><p>A multidisciplinary approach involving archaeometry and philology can often be mutually beneficial in the field of manuscript studies. When forms of degradation occur, the manuscript page can in some cases be puzzling for philologists and palaeographers. On the other hand, the selection of the regions of interest to be subjected to material analyses and the choice of the analytical strategy to put in place need the support of the philological observations. Often the research questions cannot be fully addressed by either discipline independently, but only through their combination, the archaeometric philological approach. Among the various manuscript traditions in which the two disciplines can find a common ground of research, the field of early Qur’anic manuscripts represents a challenging area of investigation because of the use of a colour code in their writing system. This paper presents a successful application of a combined approach for the interpretation of a deteriorated and multi-layered Qur’anic codex. The non-invasive material analyses, in continuous dialogue with palaeographic and philological observations, allowed for a comprehensive assessment of the writing materials, identifying the nature of the deteriorated pigments and the rules of the adopted colour code.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06343-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}