SPIN

The paper presents a synthesis (solid-state. reaction) and characterization of a lead-free double perovskite oxide Ba₂(FeMo)O₆ ceramic. The initial analysis using X-ray diffraction revealed that the material has a cubic crystal symmetry with a micro-lattice strain of 0.000824 and an average crystallite size of 62nm. The microstructural features and elemental composition of the prepared polycrystalline sample were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The SEM micrograph, EDX spectrum and elemental mapping show distinctly grown grains with well-defined grain boundaries, purity and distribution pattern of the grains, respectively. Raman scattering spectroscopy is a valuable tool for studying the vibrational modes to get information about structural and chemical properties of materials. The optical properties of the material were investigated using UV–Vis spectroscopy, which provides various parameters including energy bandgap for different technological applications. The electrical behavior of the synthesized double perovskite was examined through frequency- and temperature-dependent dielectric measurements as well as impedance spectroscopy. The electrical conduction in the material followed Jonscher’s power law and is supported by a thermally activated conduction mechanism. The analysis of electrical resistance versus temperature confirms negative temperature coefficient of resistance nature and can be used as NTC thermistors. The study of polarization-electric field loop opens up the possibility of the ferroelectric nature of the studied sample and also measures energy storage density, energy loss density and efficiency for searching different potential applications related to sensors. Overall, the results suggest its potential for various technological applications, such as in sensors and devices requiring specific electrical behavior or ferroelectric properties.

A ferrimagnetic hexagonal Ising nanotube with spin-1/2 core and spin-5/2 shell is investigated using the mean field approximation (MFA) and the Monte Carlo simulation (MCS). More exactly, we have examined the effects of the exchange interactions and crystal field on the magnetic properties of the system. Our phase diagrams show the appearance of critical and compensation behaviors, as well as first-order phase transitions terminating at isolated critical end-points in the ferrimagnetic phase region at low temperatures. Furthermore, we have made a comparison with other studies of similar nanosystems.

The growing utilization of neural networks has led to a heightened focus on the hardware implementation of such networks. Security concerns associated with these implementations pose a significant challenge in this regard. Among these problems, the vulnerability of these networks against side-channel attacks such as power attacks can be mentioned. This paper presents a technique to enhance the resilience of hardware implementations of neural networks, particularly Hopfield neural networks, to mitigate the risks posed by power attacks. In addition to the fact that the proposed method makes it impossible to attack the network, it also reduces the power consumption of the entire circuit by reducing the leakage currents. The simulation results demonstrate that the proposed approach also achieves about a 10% reduction in energy consumption while concurrently improving the accuracy of the implemented associative memory by 1.1%.

We show in this paper that the technologically relevant field-like spin–orbit torque (SOT) shows resilience against the geometrical effect of electron backscattering. As a device grows smaller in size, the effect of geometry on physical properties like spin torque, and hence switching current could place a physical limit on the continued shrinkage of such a device — a necessary trend of all memory devices (MRAM). The geometrical effect of curves has been shown to impact quantum transport and topological transition of Dirac and topological systems. In our work, we have ruled out the potential threat of line curves degrading the effectiveness of SOT switching. In other words, SOT switching will be resilient against the influence of curves that line the circumferences of defects in the events of electron backscattering, which commonly happens in the channel of modern electronic devices.

The Spin-Cherenkov effect (SCE) refers to the Cherenkov-type excitation of spin waves (SWs). The Dzyaloshinskii–Moriya interaction (DMI) can cause chiral-symmetry breaking of the magnetization dynamics in magnetic systems, resulting in asymmetric dispersion relations and relevant effects. Here, we report a correlated phenomenon for Cherenkov SW excitations in a transversely magnetized nanostrip. In the presence of DMI, when a moving source exceeds the propagation velocity of SWs, coherent SWs are excited with different velocities in opposite directions. The minimum phase velocity of SWs is significantly reduced in one direction and increased in another. It is shown that the Cherenkov emission of SWs exhibits directional dependence, manifesting nonreciprocity which is related to the values of DMI constant D. Micromagnetic simulations along with analytical calculations are presented.

The current-induced magnetization precession dynamics provoked by the spin transfer torque (STT) in a spin valve device i.e. tri-layer device (commonly spin torque nano oscillator (STNO)) is investigated numerically by solving the governing Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation. In this study, we have devised an STNO device made of EuO-based ferromagnetic alloy in free and fixed magnetic layers. The copper acts as a nonmagnetic spacer. Here, we have introduced the current induced Oesterd field (CIOF), which is generated when a spin-polarized current passes through the STNO device. In the device, we have tuned the free layer angle $\theta$ from $30^{\circ }$ to $90^{\circ }$ as an increment of $30^{\circ }$. For every individual $\theta$ ranging from $30^{\circ }$ to $90^{\circ }$, the generated Oersted field’s strength can be altered by increasing the STNO device’s diameter. Henceforth, it is apparent that the frequency tunability is achieved in the device for all the values of $\theta$. The frequency and power of the device depend entirely on the material’s saturation magnetization, which inherently reflects the current density and coherence of spin-polarized DC. From the results, it is apparent that for a particular $\theta$, the frequency keeps increasing with the eventual decrease in power when we increase the strength of the Oersted field from 10kA/m to 50kA/m. By doing so, the maximum frequency can be tuned up to 212GHz for $\theta =90^{\circ }$ with $H_{\mathrm{\text{oe}}}$ as 50kA/m. The high frequency emitted by the device acts as a linchpin ingredient, as well as a launch pad element in much of scientific and technological point of view. It paves way for a new route in the areas such as high capacity, high precision, high density as well as the sensing applications.

In this study, Monte Carlo investigation delves into the dielectric features of silicene–germanene nanosystem with junction connection. We emphasized the profound influence of physical parameters, coupling between Si–Si and Ge–Ge atoms and temperature, on these dielectric features. Our results highlight the pivotal role of the coupling parameter between Ge atoms in influencing blocking temperatures, underlining the significance of high values for spin and coupling parameters for achieving a high blocking temperature and delaying transitions. Furthermore, our analysis of electric hysteresis loops demonstrates their sensitivity to parameter variations, which can offer valuable insights for nanoelectronics and materials science applications.

In this research, we investigate the impact of strain on the optoelectronic and thermoelectric properties of the NaGeI₃ perovskite by employing a combination of density functional theory (DFT) and Boltzmann transport theory. Initially, we examine the NaGeI₃ material’s structural, electronic, and optical properties using the generalized gradient approximation (GGA). The results reveal that this material proves the behavior of a semiconductor with a p-type character and possesses interesting optical properties. Furthermore, we outline the thermoelectric properties of the material, including the Seebeck coefficient, the electrical and thermal conductivities, the figure of merit (ZT), and the power factor (PF). Our investigations indicate that the Seebeck coefficient exhibits positive and increasing values with the application of strain. This confirms the p-type semiconductor behavior observed in the studied material. Additionally, the NaGeI₃ compound demonstrates significantly high values of the ZT when compared with the existing thermoelectric materials, both at room and high-temperature values. This suggests that the NaGeI₃ compound stands as a promising potential candidate for optoelectronic and/or thermoelectric applications.

Quantum optics and photonic quantum-information technologies require emitters that have good stability and brightness, coupled with fabrication scalability and on-chip integrability. Most quantized emitters are presently based on 1D and 3D sources. Recently, monolayer transition metal dichalcogenides (TMDCs) hosting spatially localized excitons with narrow linewidths have garnered great interest. Advantages such as large binding energies and long room-temperature lifetimes of intralayer excitons suggest that TMDCs are promising candidates for use in optical devices. Here, we propose an emitter based on a 2D WSe₂ semiconductor monolayer integrated with a periodic 3D Si-based wrinkled pattern. Carriers confined within the wrinkled pattern can be electrically and optically pumped, and funneled, to boost emission from the 2D WSe₂ layer. This in turn acts as a monochromated quantum light source for the Si or any Si-based quantum optic and photonic information technologies. The brightness of the emission is enhanced by a factor greater than 40 compared with monolayer WSe₂ on conventional flat SiGe. Moreover, these monolayer 2D/3D semiconductor composite heterostructures are fully scalable and promisingly efficient chip-integrated emitters.

This paper presents a detailed synthesis method by solid-state reaction route and typical characterization (structural, microstructural, dielectric, impedance, modulus, and optical properties) of a double perovskite material Bi₂FeMn${}_{0.9}$Ce${}_{0.1}$O₆. An orthorhombic crystal structure having an average crystallite size of 32.2nm is suggested by X-ray diffraction data (XRD). Scanning electron microscope (SEM) micrograph detects the presence of cylindrical nanorod-shaped distinct grains and well-defined grain boundaries in this material and the average grain size is 5.82$\mu$m. Furthermore, the purity and the presence of all constituent elements in the material were confirmed from energy dispersive X-ray (EDX) analysis and color mapping. Dielectric, impedance, modulus, and AC conductivity properties are studied within the temperature range of 25–500^∘C and frequency range of 1kHz to 1MHz. The high dielectric constant at a low-frequency zone and low dielectric loss found in this material make it a promising candidate for better energy-storing devices. The negative temperature coefficient of resistance (NTCR) behavior is observed from the impedance study. The non-Debye relaxation is detected in the modulus study. The semiconducting nature of this material is verified by semicircular arcs observed in both Nyquist and Cole–Cole plots. The thermally activated conduction mechanism is confirmed by an AC conductivity study. The existence of Bi–O, Fe–O, Mn–O and Ce–O stretching vibrations are observed from the FTIR study and explain the presence of all constituent elements in the sample. The bandgap energy of 1.7eV is calculated from UV-DRS analysis and hence this material can be used for advanced optoelectronic and photovoltaic applications.

This paper presents the results of studies of the effects of magnetoresistance and magnetocapacitance in magnetic tunnel junctions ${\text{Tb}}_{22-\delta }$Co₅${\text{Fe}}_{73}$/Pr₆${\text{O}}_{11}$/${\text{Tb}}_{19-\delta }$Co₅${\text{Fe}}_{76}$ with perpendicular anisotropy of magnetic electrodes and a paramagnetic barrier layer. Experimentally measured values of tunnel magnetic resistance and tunnel magnetic capacitance in such contacts exceed 100% at room temperature. The paper analyzes the effect of magnetization reversal of one of the electrodes on the conductivity of magnetic tunnel junctions with electrodes that have perpendicular anisotropy. It is shown that significant changes in tunnel magnetic resistance and tunnel magnetic capacity in such contacts can be explained by the separation of electrons with major and minor spin polarization in the inverse nanolayer in the interface region. The separation of polarized electrons is caused by the magnetomotive force acting on the electron spin in a strongly gradient magnetic field. Such a magnetomotive force occurs with antiparallel magnetization of the magnetic electrodes and it has opposite directions for major and minor polarized electrons. As a result of the spatial separation of polarized electrons in the inversion layer, an inhomogeneous distribution of the electron density along the direction of magnetization of the magnetic contacts occurs. As a result, an additional Coulomb barrier between the magnetic electrodes and the dielectric nanolayer appears in the tunnel contacts and an additional spin capacitance appears.

The dielectric properties of a mixed Zethrene-inspired nanoscale system ($S_i^Z$-1, ${\sigma }_k^Z$-5/2) have been analyzed in detail using the Monte Carlo approach (MCa) in this study. First, the most stable configurations in different planes were investigated. Then, the influences of the physical factors, namely the coupling interaction factor, on the thermal behaviors of the polarization and the susceptibility of the studied nanostructure have been examined for nonzero temperatures and fixed external electric field values. It was found that the obtained transition temperature point relies weakly on the coupling interaction. Finally, the effects of the physical factors on the electric hysteresis cycles were discussed.