Indian Journal of Physics最新文献

{"title":"Exchange interaction in metal oxides core-shell nanoparticles (hbox {Co}_3hbox {O}_4)–CoO","authors":"S. Goswami,&nbsp;S. Chakravarty,&nbsp;M. Chakraborty,&nbsp;D. De","doi":"10.1007/s12648-024-03351-9","DOIUrl":"10.1007/s12648-024-03351-9","url":null,"abstract":"<div><p>This article reports exchange bias (EB) effect in <span>(hbox {Co}_3hbox {O}_4)</span>–CoO nanoparticles despite having a ferromagnetic (FM) metal and antiferromagnetic (AFM) metal oxide interface. Pining mechanism in the overlapping domain of AFM spinel <span>(hbox {Co}_3hbox {O}_4)</span> and AFM CoO leads to a shift in magnetic hysteresis (<span>(M-H)</span>) loop towards the field axis followed by an increase in coercivity, when the system is cooled under static magnetic field − a typical signature of EB effect. Samples are prepared via sol–gel route followed by a controlled oxidation-reduction procedure; characterized via X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) analysis. Detailed studies of two samples of <span>(hbox {Co}_3hbox {O}_4)</span>–CoO show strong dependence of EB with a variation in crystallite size/phase fraction. Exchange interaction is maximum at lowest temperature and gradually vanishes above the AFM Néel temperature (<span>(T_N)</span>) of <span>(hbox {Co}_3hbox {O}_4)</span>. Another double interface ternary sample Co–<span>(hbox {Co}_3hbox {O}_4)</span>–CoO with FM Co at the center produces higher EB field than <span>(hbox {Co}_3hbox {O}_4)</span>–CoO nanostructures.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 3","pages":"1033 - 1040"},"PeriodicalIF":1.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776770","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":"Prediction of spectral characteristics of lithium-like ions by artificial neural network","authors":"Salman Raza,&nbsp;Ahmed Ali Rajput,&nbsp;Mustaqeem Zahid,&nbsp;Shafiq Ur Rehman,&nbsp;Arif Akhtar Azam,&nbsp;Zaheer Uddin","doi":"10.1007/s12648-024-03346-6","DOIUrl":"10.1007/s12648-024-03346-6","url":null,"abstract":"<div><p>An Artificial Neural Network has been employed to calculate spectral characteristics of lithium-like Beryllium (Be II), Boron (B III), Carbon (C 1V), and Nitrogen (N V) ions. The base data (input parameters) consisted of quantum defects and the inverse square of the principal quantum number of lithium atoms for calculating quantum defects and energies of lithium-like ions. The study has two parts; in the first part, the quantum defects of Lithium and lithium-like ions (Be II, B III, C 1V, and N V) were calculated using Quantum Defect Theory (QDT). In the second part, an Artificial Neural Network (ANN) with a single hidden layer and five neurons was utilized to predict lithium-like quantum defects. 70% of the data was used to train the network, and 15% was used for testing and validating the values of quantum defects up to n = 100 for each atom and ion. The extended Rydberg–Ritz formula was used to calculate the energies of the lithium-like elements.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1251 - 1259"},"PeriodicalIF":1.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776771","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":"Quantum flux effects on generalized Klein-Gordon oscillator field in a topologically charged Ellis-Bronnikov-type wormhole","authors":"Faizuddin Ahmed,&nbsp;Houcine Aounallah,&nbsp;Prabir Rudra","doi":"10.1007/s12648-024-03340-y","DOIUrl":"10.1007/s12648-024-03340-y","url":null,"abstract":"<div><p>The work primarily deals with the relativistic quantum dynamics of the oscillator field. It uses the generalized Klein-Gordon oscillator in an Ellis-Bronnikov-type wormhole space-time with a topological defect. The study involves deriving the radial wave equation and incorporating both Coulomb and Cornell-type potential functions. The analytical solution of the wave equation elucidates the influence of the topological defect of the geometry and the wormhole throat radius. The eigenvalue solution of the oscillator field highlights significant modifications to the results, underscoring the impact of the topological defect.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1225 - 1231"},"PeriodicalIF":1.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776768","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":"The effects of electric fields and biaxial strain on the structural, electrical, magnetical, and optical properties of bulk and monolayer AgN","authors":"Jabbar M. Khalaf Al-zyadi,&nbsp;Mustafa M. Jaafar","doi":"10.1007/s12648-024-03312-2","DOIUrl":"10.1007/s12648-024-03312-2","url":null,"abstract":"<div><p>By using the APW + lo approach within the context of density functional theory, the purpose of this research is to investigate the differences between the bulk and monolayer forms of AgN. An APW + lo approach, takes into account both electrons (core and valence) in a self-consistent manner throughout the process of full-potential treatment. A generalized gradient approximation and a structural model were used to conduct the analyses on the structural electronic, magnetic, and optical characteristics. Half-metallicity could be seen in the bulk form of the compound with an energy gap of 2.23 eV in the spin-up channel and an equilibrium lattice constant of 8.23 Å. In addition, the half-metallic behavior was maintained even after the crossover to the monolayer, which had an energy gap of 1.90 eV. In order to determine the band structures and the density of states that demonstrate the half-metallic character of the material, it is important to carry out an examination of the material's electronic properties. Rendering to the Slater-Pauling statute (Zt-4), the total magnetic moment equals 2 µ_B for each unit cell. The effect of the electric field and biaxial strain on a monolayer of AgN was also studied to calculate electronic, magnetic, and frequency-dependent optical properties such as, dielectric functions, reflectivity, absorption, optical conductivity, and energy loss. The findings highlighted that the AgN's monolayer is promise for spintronics applications.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 3","pages":"927 - 942"},"PeriodicalIF":1.6,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776775","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":"Geodesic deviation analysis of time conformal Schwarzschild like black hole","authors":"Muhammad Saad Ghafar,&nbsp;Farhad Ali,&nbsp;Zahir Shah,&nbsp;Shahid Iqbal,&nbsp;Mansoor H. Alshehri","doi":"10.1007/s12648-024-03341-x","DOIUrl":"10.1007/s12648-024-03341-x","url":null,"abstract":"<div><p>The astrophysical phenomena, for instance, the growth or decay of black holes (BHs), gravitational waves may continuously change the curvature of spacetimes. In addition, such phenomena also affect the thermodynamic structure of the sources over time. In this research, we examined the insertion of the time conformal factor <span>(e^{epsilon f(t)})</span> in the Renormalization Group Improved (RGI) Schwarzschild BH, without violating symmetry structure. We demonstrated that the curvature invariants, which are responsible for the spacetime structure around the time conformal Renormalization Group Improved Schwarzschild (TCRGIS) BH, depend explicitly on this time conformal factor. The parameter <span>(gamma)</span> that appeared in these invariants gives a complete radial profile of the square of the Ricci tensor, the Ricci scalar and the Kretschmann scalar. For positive values of <span>(gamma)</span> the behavior of the curvature of TCRGIS-BH is similar to both the RGI-BH and the Schwarzschild BH as it becomes infinite at center for <span>(gamma =0)</span>. Moreover, we have analyzed that the curvature invariants for TCRGIS BH decrease more rapidly as compared to both the RGI Schwarzschild BH and regular Schwarzschild BH, as a function of time.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 2","pages":"751 - 764"},"PeriodicalIF":1.6,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12648-024-03341-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776774","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":"Mean first-passage time for a stochastic tumor growth model with two different time delays","authors":"Qin Yu,&nbsp;Yong-Feng Guo,&nbsp;Hao-Yu Chen","doi":"10.1007/s12648-024-03356-4","DOIUrl":"10.1007/s12648-024-03356-4","url":null,"abstract":"<div><p>In this paper, the mean first-passage time (MFPT) of a stochastic tumor growth model driven by correlated white noises with two different time delays is investigated. The small time delay approximation is utilized to obtain the generalized potential function and the MFPT, and a detailed analysis is conducted on how time delays and noise parameters affect the generalized potential function and the MFPT, respectively. We further validate the effectiveness of the theoretical results using the fourth-order Runge–Kutta algorithm. The findings indicate that (1) when the intensity of multiplicative noise is higher and the intensity of additive noise is lower, there is a greater likelihood of tumor cells dying off, which promotes the healing of the system; (2) an increase in the correlation strength between multiplicative noise and additive noise promotes the carcinogenesis of tumor cells and accelerates the deterioration of the system; (3) increasing the time delay in the deterministic force and decreasing the time delay in the stochastic force lead to a higher likelihood of tumor cell extinction. Furthermore, the phenomenon of noise enhanced stability (NES) is found.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 3","pages":"893 - 905"},"PeriodicalIF":1.6,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776773","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":"Design and theoretical study of rectangular photonic crystal fiber based sensor for chemical sensing in terahertz regime","authors":"Deepak Garg,&nbsp;Jyotsna Singh,&nbsp;Ajeet Kumar","doi":"10.1007/s12648-024-03343-9","DOIUrl":"10.1007/s12648-024-03343-9","url":null,"abstract":"<div><p>This paper presents the design and theoretical analysis of a photonic crystal fiber (PCF) based chemical sensor model. To evaluate the efficiency of this model, various optical parameters are analysed using finite element method based COMSOL Multiphysics Software. Different analytes namely methanol (1.317), water (1.330), ethanol (1.354) and benzene (1.366) have been considered for the sensing purpose in this study. The core region is infiltrated with different analytes separately. The model is simulated in THz regime (0.5–1.5 THz) to evaluate optical properties. The proposed structure design exhibits a high relative sensitivity of 96.85%, 97.32%, 97.99% and 98.33% for methanol, water, ethanol, and benzene, respectively at an operating frequency of 1.3 THz. The proposed model demonstrates exceptionally low confinement loss values which are 2.22 × 10^–12 dB/m for methanol, 1.16 × 10^–11 dB/m for water, 1.34 × 10^–11 dB/m for ethanol and is 1.30 × 10^–12 dB/m for benzene. Additionally, the effective material loss for the designed PCF also comes out to be very low for all the analytes, 0.0044 cm⁻¹ for methanol, 0.0040 cm⁻¹ water, 0.0034 cm⁻¹ for ethanol and 0.0032 cm⁻¹, for benzene. Furthermore, the PCF shows large effective mode area and numerical aperture (NA) within the mentioned range, at 1.3 THz. The NA values obtained at 1.3 THz are 0.32 for methanol, 0.40 for water, 0.32 for ethanol, and 0.32 for benzene. The obtained Effective mode Area (EMA) values are 1.46 × 10⁵ μm² for methanol, 1.45 × 10⁵ μm² for water, 1.44 × 10⁵ μm² for ethanol and 1.43 × 10⁵ μm², for benzene. Subsequently, the optimal profile provides birefringence values of 0.0009 for methanol, 0.0010 for water, and 0.0011 for both ethanol and benzene. The practical implementation of the proposed PCF structure is possible using subsisting modern fabrication techniques. Consequently, the proposed PCF design should be helpful in industrial areas for chemical research, food and biomedical sensing.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 3","pages":"997 - 1005"},"PeriodicalIF":1.6,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776852","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":"Wettability measurements of agarose thin films patterned by 193 nm ArF excimer laser","authors":"Q. A. Al-Jarwany,&nbsp;Abdulsattar A. Aesa,&nbsp;A. F. Mohammed,&nbsp;C. D. Walton","doi":"10.1007/s12648-024-03345-7","DOIUrl":"10.1007/s12648-024-03345-7","url":null,"abstract":"<div><p>The control and knowledge over liquid–solid interactions is vital for the design optimization of materials, processes in a variety of uses. Thus, investigating wettability plays a great role in such interactions. In this paper, characterisation and the effect of 193 nm excimer laser patterning on the agarose thin films are studied. Different techniques; atomic force microscopy (AFM), scanning electron microscopy and white light interferometer are used to characterise the agarose thin films. UV–Vis spectrophotometer was used to measure the absorption and transmission of thin films. An absorption coefficient and grating period of 1.7 × 10³ cm⁻¹, and 11.5 μm respectively are reported. AFM measurements show the softness of non-irradiated thin films. The obtained results show that the agarose films' surface properties are considerably changed by the laser-induced structuring. Higher contact angles indicate an important reduction in wettability being a consequence of the laser grating's enhanced surface roughness. Measured contact angles and free surface energy of patterning thin film show alterations in surface wettability.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 3","pages":"1157 - 1163"},"PeriodicalIF":1.6,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776853","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":"Active polarization controlling in optical fiber links using optimization algorithms","authors":"Hamid Asgari,&nbsp;Majid Khodabandeh,&nbsp;Soheil Hajibaba,&nbsp;Amir Hosein Dadahkhani,&nbsp;Seyed Ahmad Madani","doi":"10.1007/s12648-024-03342-w","DOIUrl":"10.1007/s12648-024-03342-w","url":null,"abstract":"<div><p>Maintaining the state of polarization of a light beam in optical fiber links is a necessity for various applications. It is especially important for optical communication, polarization-based quantum key distribution, etc. There are several ways to compensate for polarization fluctuations, hence lowering the polarization drift error. In this paper, we have experimentally investigated the performance of two optimization algorithms for polarization compensation. We employed these algorithms to control an electrical polarization controller. Our results show that the particle swarm optimization and simulated annealing algorithms can efficiently compensate for polarization fluctuations and drifts. Thus, it is suitable for optical communication and quantum key distribution experiments.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 4","pages":"1471 - 1478"},"PeriodicalIF":1.6,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776855","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":"The control of the symmetry of quantum beam splitting in the hybrid nanosystem","authors":"Su-Ryon Ri,&nbsp;Myong-Chol Ko,&nbsp;Nam-Chol Kim,&nbsp;Ju-Song Ryom,&nbsp;Chol-Min Kim","doi":"10.1007/s12648-024-03319-9","DOIUrl":"10.1007/s12648-024-03319-9","url":null,"abstract":"<div><p>The quantum beam splitter plays the important role in the quantum information processing as the key element that control the quantum signals. We propose a theoretical model for the single photon quantum beam splitter that includes two plasmonic waveguides and 3 quantum dots (QDs). The waveguides are configured to form T-shape and the QDs are placed along the horizontal waveguide with separation. Here we considered the dipole–dipole interaction (DDI) between the adjacent QDs. We investigated the quantum beam splitting properties of this system using the real space approach. The result shows that with this system we can realize the symmetric or asymmetric beam splitting by adjusting the waveguide-QD coupling and the DDI strengths between the QDs. This system is a multi-channel quantum router, which can be used widely in the quantum networking.</p></div>","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":"99 3","pages":"1111 - 1117"},"PeriodicalIF":1.6,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776854","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}