Indian Journal of Physics最新文献

NZF ferrite thin films grown on Si (111) single crystal substrate were prepared using magnetron sputtering radio frequency at room temperature with a target of nominal composition Ni_0.5Zn_0.5Fe₂O₄. An examination of structural and Magnetic characteristics by annealing temperature was carried out through experiments at temperatures ranging from 700 to 900 °C on the deposited ferrite films. XRD as well as AFM and FE-SEM and VSM performed specific analyses to determine phase composition and surface topography along with the magnetic properties of NZF ferrite thin films. All synthesized Ni–Zn ferrite thin films established on Si substrates presented crystallite sizes within the range of 15–27 nm while maintaining a spinel structure. The films' crystallite size increased with elevated annealing temperature values. The atomic force microscopy assessment of annealed thin films occurred at a particular deposition height of 200 nm according to profilometry tests. Based on FE-SEM analysis the average grain sizes of NZF/Si nanoferrite thin films stood at 32.57 nm for 700 °C and were 35.92 nm at 800 °C and 40.46 nm at 900 °C. Room temperature magnetism evaluation of (NZF/Si) films indicated a positive correlation between the Ni–Zn film M_s values and grain dimensions. Annealed thin films with increasing grain sizes from 700 to 900 °C resulted in M_s values elevating from 42 to 58 and H_c values decreasing from 98 to 50 Oe. NZF-900 shows the best combination of high saturation ratio with narrow hysteresis loop, which confirms its superiority for high-frequency soft magnetic applications.

In this paper, we investigate the Grammian determinant solutions of a (2+1)-dimensional generalized nonlinear system in fluid mechanics. The solutions of this system are expressed in terms of Grammian determinants, with distinct classes of solutions obtained by selecting different functional forms for the determinant elements, including Airy functions, exponential functions, and semi-rational functions. Additionally, via modifying the Grammian determinant form and its elements using differential operators (P_{iota }) and (Q_{j}), a series of distinct solutions are obtained. The propagation and interaction dynamics of these nonlinear waves are analyzed. When the function m is represented by the Airy function, the distinct nonlinear wave propagation phenomena are observed. By utilizing the exponential functions, the lump chains and soliton-like waves are obtained. Moreover, asymptotic analysis of these solutions is performed, and the propagation velocities and periods of lump chains are explicitly calculated. The interaction dynamics between soliton-like waves and lump chains are systematically discussed. Employing semi-rational functions allows for a detailed investigation of the interaction between lump waves and soliton-like waves. Finally, increasingly complex lump wave patterns are demonstrated, with their interaction mechanisms are thoroughly analyzed. It is revealed by our findings that the properties of the solutions are fundamentally governed by both the determinant structure and the specific functional forms adopted for its elements.

In recent years, we have seen significant progress in the production of solar cells with high efficiency. One of the main solutions of this investigation is the performance of distinct cells under distinctive conditions with the help of simulations of their operation. This article describes the structure of multijunction solar cell consisting of Ge layers, InAlGaAs alloys and InAlGaP alloy for the first time. In order to attain optimal efficiency, the optical simulation of the bottom absorber layer of the Ge solar cell is conducted using Lumerical software. Subsequently, the electrical simulation is carried out using Silvaco software. Following the optimization of the Ge solar cell, the tunnel junctions, which are the middle layers between the cells, are then optimized. Finally, the topper absorber layers are optimized in a sequential manner. The purpose of optimizing the solar cell in each absorber layer is to achieve the highest efficiency depending on the thickness, impurity density and mole fraction of the layers. Based on the simulation results, the efficiency of more than 49% has been obtained for the mentioned five-junction solar cell.

6H-Silicon carbide (6H-SiC) is widely used in various fields, particularly power electronics, due to its high resistance to voltage and current under extreme environmental conditions. A Schottky diode with a silicon carbide base and an organic conductive poly(3-hexylthiophene) (P3HT) polymer interface, structured as Au/P3HT:n-6H-SiC/Au, was fabricated, and its electrical properties were characterized over a temperature range of 80–400 K. The ideality factor (n), barrier height (Φ_b), and saturation current (I_o) were calculated at each temperature using the temperature-dependent current–voltage (I–V) analysis. The series resistance (R_s) was determined using Cheung’s method, Norde’s method. Additionally, the mean barrier height (({overline{Phi } }_{bo})) standard deviation (σ₀), and voltage constants (ρ₂ and ρ₃) were extracted through Gaussian distribution analysis of the barrier. It was demonstrated that the barrier height at the interface exhibits an inhomogeneous nature rather than a uniform structure. The barrier was found to consist of two distinct regions, characterized by a double Gaussian distribution. Furthermore, the Richardson constant for the 6H-SiC semiconductor was calculated as 155.59 A cm⁻² K⁻², which was found to be in perfect agreement with the theoretically known value for 6H-SiC.

We study quantum tunneling in the presence of linear damping. To this end, a linearly damped free particle is canonically quantized to obtain its energy eigenvalues and energy eigenstates. To explore how dissipation influences quantum tunneling, we compute the transmission coefficient for a rectangular potential barrier. It is observed that dissipation helps suppress quantum tunneling.

This study utilizes mathematical modelling to offer computational insights into biological heat transfer within elastic skin tissues. This heat transfer is driven by a moving heat source that relies on various relaxation times. Time delay parameters were incorporated based on these relaxation times, highlighting the importance of understanding heat transfer mechanisms and thermo-mechanical interactions to ensure the effectiveness of thermal treatment procedures. Given the significant impact of different variables on thermal relaxation times, their effects were analyzed on the distributions of displacement, thermal stress, and temperature in living tissues. By applying advanced mathematical techniques such as Laplace transforms, precise evaluations of these distributions were achieved. The results are presented graphically, with a focus on enhancing treatment outcomes by deepening our understanding of the behaviour of living tissues in thermal environments.

This work examines the unstable nonlinear Schrödinger equation, which characterizes the temporal evolution of disturbances in marginally stable or unstable media. The ((frac{G'}{G},frac{1}{G}))-expansion method is employed to derive new exact soliton solutions, explicitly represented through exponential, trigonometric, and rational functions. These exact solutions are then compared with results obtained from the Levenberg–Marquardt artificial neural network and the split-step Fourier numerical method. Statistical analyses, presented through tables and graphs, show strong agreement between the exact solutions and those obtained using these methods. Furthermore, 2-D, contour, and 3-D plots are utilized to visually represent and validate the behavior of the solutions. The results demonstrate that the combination of the ((frac{G'}{G},frac{1}{G}))-expansion method, the Levenberg–Marquardt artificial neural network, and the split-step Fourier numerical method provides a robust and complementary framework for solving and analyzing the unstable nonlinear Schrödinger equation, offering reliable insights into its dynamic behavior.

In this paper, we investigate the evolution of dark energy parameters in the spatially homogeneous and isotropic Friedmann–Robertson–Walker model filled with barotropic fluid and dark energy in the framework of the scalar-tensor theory of gravitation formulated by Saez and Ballester (Phys Lett A 113:467, 1986). To obtain a determinate solution, we solve the field equations using the linearly varying deceleration parameter proposed by Akarsu and Dereli (Int J Theor Phys 51:612, 2012). We analyze two scenarios involving interacting and non-interacting fluids (barotropic and dark energy) and derive general results for each case. The physical implications of these findings are also discussed.

We investigate dust magnetosonic solitary waves (DMSWs) propagating in magnetized plasmas composed of hot electrons, warm light ions, and heavy ions within Earth’s magnetosphere. The dynamics of DMSWs in such multi-ion plasmas (MIP) are governed by a Korteweg–de Vries (KdV) equation. Using Hirota’s bilinear method, we study the overtaking collision between two DMSWs, and present the variations in amplitude, trajectory, and phase shift during the interaction. The results indicate that when two solitons merge into a new one, the amplitude initially decreases and then increases. Furthermore, we analyze how the phase shift is influenced by various physical parameters, including the density and temperature of light and heavy ions, the external magnetic field, as well as the density and charge number of dust grains. It is important to emphasize that the interaction between solitons in these plasmas can result in a redistribution of momentum and energy.

In this study, we calculate the scattering cross sections of two (Upsilon (1S)) mesons using a potential model combined with the Resonating Group Method (RGM), employing the adiabatic approximation to characterize meson interactions. We investigate two scenarios: one with a point-like form factor ((f=1)) and another with a Gaussian form factor, to explore how the internal structure of the meson affects the interaction. At a center-of-mass kinetic energy of 0.01 GeV, the maximum value of total spin-averaged cross section comes out to be 0.3 mb for the point-like form and 0.19 mb for the Gaussian form with quadratic potential. For the Cornell potential, the values are 0.18 and 0.11 mb, respectively, with the same center-of-mass kinetic energy. This shows a reduction in the cross section when the internal structure of the mesons is taken into account. The small variation between these values indicates that the form factor has a limited effect on (Upsilon (1S)) scattering, likely due to the larger mass of the mesons and smaller rms radii. In contrast, lighter mesons exhibit a more pronounced reduction in cross sections when the Gaussian form factor is applied, highlighting their greater sensitivity to the form factor’s detailed shape. This contrast opens up new avenues for future research and we discuss such possibilities at the end of the paper.