In this paper, structural, elastic, electronic and magnetic properties of half-Heusler XSrC (X=Li and Na) compounds have been investigated utilizing full potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). For exchange-correlation potentials, the generalized gradient approximation (GGA) has been used. The calculated cohesive and formation energy values showed that these compounds can be experimentally synthesized. The elastic properties were analyzed in detail and reveal that LiSrC and NaSrC compounds are mechanically stable. The spin-polarized band structure and density of states illustrate that LisrC and NaSrC alloys have a half metallic character. The total magnetic moment is 1μB per formula unit that confirms the half metallic behavior and follows the Slater-Pauling rule MT=(8−Ztot)μB. For half-Heusler XSrC (X=Li and Na) compounds, there are no available experimental or theoretical studies, our calculations are considered as first predictions.

In this paper, the synthesis and characterization (structural, dielectric, electrical and optical) of a double perovskite, BaSrZrMnO6 (BSZMO), by a conventional solid-state reaction route are reported. The sample has an orthorhombic crystal symmetry with an average crystallite size of 40.7nm and a micro-lattice strain of 0.226%. A microstructural and compositional analysis was presented by using a scanning electron microscope (SEM) and energy dispersive x-ray analysis (EDX), respectively. Grains are well-grown and distributed uniformly through well-defined grain boundaries on the sample surface to enhance physical properties. EDX analysis confirms the presence of all constituent elements and is well-supported by the Raman study. The analysis of the UV–Visible spectrum reveals an energy bandgap of 2.1eV, suitable for photovoltaic applications. The study of dielectric properties as a function of temperature and frequency reveals a Maxwell–Wagner type of dispersion and explores possible applications in energy storage devices. The discussion on the impedance spectroscopy supports the negative temperature coefficient of resistance (NTCR) character whereas the modulus study suggests a non-Debye type of relaxation in the sample. The study of AC conductivity confirms a thermally activated relaxation process. Both Nyquist and Cole–Cole plots support the semiconducting nature of the sample. The study of resistance versus temperature (R∼T) supports NTC thermistor character for temperature sensor applications. The analysis of the P-E loop reveals the possibility of the ferroelectrics’ character.

The exciting properties of multi-valued logic (MVL) in overcoming the limitations of binary systems have led to widespread research on this topic. Considering various types of MVL, quaternary logic is more compatible with the existing binary systems. This paper proposes a nonvolatile quaternary flip-flop (NQFF) based on the unique features of the carbon nanotube field-effect transistors (CNTFETs) and magnetic tunnel junctions (MTJs). The proposed NQFF utilizes Spin-Hall effect (SHE)-assisted spin-transfer torque (STT) MTJs to provide nonvolatility with lower write energy, and multi-Vt gate-all-around (GAA) CNTFETs offer higher performance. On the other side, due to the usage of a shadow latch and the design of the proposed circuit, the delay of MTJ switching does not affect the delay of the whole circuit. The simulation results show that the proposed NQFF offers 50% lower PDP when the system is idle for only 25% of its total operational time.

By the use of Monte Carlo simulation, we have investigated the phase diagrams and magnetic properties of a ferrimagnetic Ising multilayer system with mixed spins (1, 1∕2). The ground-state phase diagrams are first constructed for T=0K. To examine the influences of certain physical parameters of the system, namely the exchange interactions, the number of layers and the crystal field, we have studied the thermal behavior of the system magnetizations and the corresponding phase diagrams. The results obtained in this work show the existence of second- and first-order phase transitions and compensation temperatures. Moreover, we have investigated the hysteresis behavior, where the multi-loop phenomena are observed.

The magnetic tunnel junction is the heart of the STT-MRAM memory. The MTJ is a spintronic device, which is used to store and read the data. With the advancement, most of the work is done online and a useful device is needed in order to store the data. Hence, it is important to design a promising device to store the data for a long time without any damage or loss of information. In this paper, first, we use the MTJ LAB simulator to check the important parameters such as TMR, resistance, and STT components and check how these parameters change for different oxide thicknesses. After this, the device was hybrid with the CMOS for 1-bit STT-MRAM and the results were drawn. So, in this paper, the main focus is to select appropriate oxide thickness and tox=0.85nm is used to get better TMR ratio, resistance, and STT-components.

By using the density functional theory, we have studied the electronic structure and magnetism of the oxygen vacancy defect in GdCoO3 perovskite compound. We have carried out a magnetic stability calculation; between many possible magnetic configurations, the ferromagnetic ordering was predicted in both gadolinium and cobalt sublattices. We have demonstrated that the oxygen vacancy defect causes a ferromagnetic order via a mixture of octahedral HS Co3+, tetrahedral HS Co2+ and octahedral IS Co3+. From the spin magnetic moment and partial density of state investigation, we have predicted an induced long-range ferromagnetic ordering in nonstoichiometric GdCoO3−δ.

The magnetocaloric effect, electronic structure and magnetic properties of High Entropy Alloys AlCoxCr1−xFeNi (0≤x≤1) were calculated using the Monte Carlo simulation, the Korringa–Kohn–Rostoker method combined with the coherent potential approximation (KKR-CPA), method of linear augmented plane wave (FPLAPW) within generalized gradient approximation (GGA) and modified Becke–Johnson potential (TB-mBJ). Density of states of AlCoxCr1−xFeNi are studied and analyzed. The total magnetic moments of magnetic atoms were calculated and compared with theoretical and experimental results. On the other side, the magnetocaloric effect in AlCoxCr1−xFeNi was studied by first-principle calculations (FPCs) and Monte Carlo simulations. The magnetic phase transition temperature is estimated. The Curie temperature and exchange integrals were found to decrease with Co substitution. The magnetic entropy changes and relative cooling power are found.

Magnetic nanotubes are a new material platform to realize the spin-dependent Seebeck effect (SDSE) and thermal spin-filtering effect (TSFE) in spin caloritronics. Here, we designed several magnetic nanotubes using triangular graphene-flake-doped boron nitride nanotubes (GFBNNTs) and found that the band structure of these GFBNNTs can be effectively engineered by embedding graphene flakes (GFs) of different sizes. The magnetic boron nitride nanotubes (BNNTs) ((5, 5)-6N) generate a good SDSE with nearly symmetric spin-up and spin-down currents, while the magnetic BNNTs ((10, 0)-6N) generate a good TSFE. These theoretical results about the SDSE and TSFE in nanotubes enrich the spin caloritronics and suggest material candidates to realize the SDSE and other inspiring thermospin phenomena.

In this paper, we report the first theoretical results on the acoustic generation of spin accumulation in ferromagnet-semiconductor-ferromagnet trilayers. As a representative material system, we consider a Ni/GaAs/Ni trilayer coupled to a piezoelectric transducer, which injects a planar acoustic wave into the adjoining Ni film. By combining an analytical solution of the spin diffusion equation in the GaAs spacer with results of numerical simulations of the coupled elastic and magnetic dynamics in the Ni films, we quantify an oscillating inhomogeneous spin accumulation in GaAs. It is found that both dc and ac parts of the mean spin accumulation vary nonmonotonically with the spacer thickness tS, reaching maximal values at tS mostly close to 0.25 or 0.75 of the wavelength of the injected monochromatic acoustic wave. Remarkably, the transverse wave generates the spin accumulation much more efficiently than the longitudinal one. Our theoretical predictions provide guidelines for the development and optimization of energy-efficient acoustic spin injectors into semiconductors, which should have much lower power consumption than injectors driven by the microwave magnetic field.

We studied the dissipation effect induced by the internal relative motion between two nonlinear σ-models (NLSMs). The internal degrees of freedom (DOF) of the two NLSMs coupled to each other via an interface potential. We performed the path integral of the vacuum persistence amplitude (VPA) and got the quantum action. Then we introduced the relative motion via a boost transformation with velocity parameter v=|v|. Furthermore, we calculated the imaginary part of the boosted quantum action which was proportional to the vacuum decay probability. At last, we calculated the frictional force. The numerical results gave the velocity v dependency of the vacuum decay probability, and the velocity v dependency of the frictional force. There was a threshold of relative velocity v for the vacuum decay probability and the frictional force. We gave a classical argument of the existence of the threshold, and the argument matched the mathematical results.

In this paper, we study the thermal and dielectric properties of a carbon-like nanotube structure. The ferrielectric mixed spin (1,3/2) Blume–Capel Ising model has been investigated, using Monte Carlo simulations under the Metropolis algorithm. We illustrate the thermal and dielectric properties of different physical parameters. Besides, we examine the effects of the exchange coupling interactions, the external longitudinal electric and the crystal fields on the transition temperature. It is found that the polarization decreases toward a transition temperature and undergoing the paraelectric phase, faster for low values of the external longitudinal electric field and the exchange coupling interactions. Besides, the total polarization versus the crystal field undergoes two principal transitions and exhibits a first-order and a second-order transitions.

The electron tunneling in ZnO/ZnCdO semiconductor heterostructure is studied using the matrix method. The spin-polarization is examined due to Dresselhaus spin–orbit interaction and Rashba spin–orbit interaction. The total spin-polarization is mainly due to Dresselhaus spin–orbit interaction and the Rashba spin–orbit interaction is small. The high degree of spin polarization can be achieved at a high barrier width. With the increasing cadmium concentration in this heterostructure, the spin polarization efficiency is enhanced. The dwell time is reported and discussed.

As the popularity of mobile devices and services continues to increase, the demand for more efficient and effective algorithms to manage network utility is increased. Here, we aim to optimize Network Bandwidth Utilization (NBU) by managing user equipments (UEs) and base stations (BSs) association in 5G ORAN architecture. We consider the network total throughput as an objective function and try to find the suitable Cell Individual Offset (CIO) to trigger UE handover with the A3 event such that the network throughput is optimal. We formulate this problem into a Quadratic Unconstrained Binary Optimization (QUBO) problem such that we can explore the power of Quantum Annealing (QA), which is a promising approach to finding the optimal solution for the NP-Hard problem. We also analyze the penalty coefficients setting problem which impacts the outcome of QA significantly. We test our QUBO formulation on a dataset of 7 BSs and 150 UEs with Fujitsu’s third generation Digital Annealer (DA3). Using our QUBO formulation with DA3 solver with fine-tuning, we can improve the throughput with 60% hit rate on this dataset.

This paper presents the results of investigating the impact of temperature on the magnetic properties of Co/Gd/Co and Co/Cu/Co thin-film three-layer systems obtained via ion-plasma magnetron sputtering. The following features of the studied samples were found. In particular, when the temperature changes from 100 to 300K, the coercive force of studied systems decreases. The magnetic moment of Co/Cu/Co sample does not dependent on temperature. Strong influence of temperature on the magnetic properties of the studied samples is observed. In particular, a compensation point was found at temperature T=150K for a Co/Gd/Co sample with thickness of gadolinium of 9.0nm.

Ni nanoparticles layer of nominal thickness in the range of 5–40nm were deposited on polyvinyl alcohol (PVA) film by using the ion beam sputtering (IBS) technique. PVA films were made on a quartz substrate by the solution casting technique. Grazing incidence X-ray diffraction (GIXRD) results reveal Ni is present in a metallic form in the FCC phase. AFM shows that roughness increases with increase in thickness of Ni layer and corresponding MFM images of magnetic domains were recorded. Soft X-ray absorption spectroscopy (SXAS) studies on the PVA/Ni nanocomposites films were recorded using synchrotron radiation. This study is used to study the electronic structure of the as-prepared nanocomposite films and reveals that Ni nanoparticles are present in their metallic form. Magnetic properties were measured using the magneto-optical Kerr effect (MOKE) magnetometer and the films were found to be magnetically soft with higher value of coercivity at lower thickness of Ni nanoparticles layer. The results of magnetic studies are discussed in light of the microstructure and morphological features of PVA/Ni nanocomposite films. The PVA/Ni nanocomposites showed interesting anisotropic magnetic behavior; thus the investigative results may be useful for the development of futuristic flexible functional magnetic material system.

One avenue toward next-generation spintronic devices is to develop half-metallic ferromagnets with 100% spin polarization and Curie temperature above room temperature. Half-metallic ferromagnets have unique density of states, where the majority spins are metallic but the minority spins are semiconducting with the Fermi level lying within an energy gap. To date, the half-metallic bandgap has been predominantly estimated using Jullière’s formula in a magnetic tunnel junction or measured by the Andreev reflection at low temperature, both of which are very sensitive to the surface/interface spin polarization. Alternative optical methods such as photoemission have also been employed but with a complicated and expensive setup. In this study, we developed and optimized a new technique to directly measure the half-metallic bandgap by introducing circularly polarized infrared light to excite minority spins. The absorption of the light represents the bandgap under a magnetic field to saturate the magnetization of a sample. This technique can be used to provide simple evaluation of a half-metallic film.

In the present investigation, the synthesis of the strontium copper titanate (Sr3CuTi4O12,SCTO) ceramic by the cost-effective solid-state reaction was reported. The structural analysis suggests a single-phase tetragonal crystal symmetry with space group P4/mmm. The average crystallite size and mechanical compressive microlattice strain are found to be 65.8nm and 0.000594, respectively. The study of the field emission scanning electron microscope (FESEM) micrograph suggests that grains and grain boundaries are uniformly distributed on the sample surface with less porosity. The study of Raman lines suggests the presence of all constituent elements, which is well supported by EDAX analysis. The UV–Vis spectroscopy analysis shows that the bandgap of SCTO is about 3.2eV suitable for photovoltaic and other higher-temperature sensor applications. The decrease of dielectric constant with frequency supports the reduction of space charge polarization. The modulus analysis suggests that the immobile charge carriers at lower and defects and oxygen vacancies at higher temperatures are responsible for the thermally activated conduction process. The calculated activation energies are 4.54meV, 4.40meV, 3.39meV and 3.29meV at 1kHz, 10kHz, 100kHz and 1MHz; the decrease with the rise of the frequency confirms a thermally activated conduction process. Thermistor constant (β), sensitivity factor (α) and stability factor of the sample were calculated, which confirms the characteristics of the NTC thermistor. The Nyquist and Cole–Cole semicircular arcs confirm NTCR character and are found to be suitable applications for energy storage devices and thermistors.

In this work, we model the salient magnetic properties of the alloy lamellar ferrimagnetic nanostructures [Co1−cGdc]ℓ′[Co]ℓ[Co1−cGdc]ℓ′ between Co semiinfinite leads. We have employed the Ising spin effective field theory (EFT) to compute the reliable magnetic exchange constants for the pure cobalt JCo–Co and gadolinium JGd–Gd materials in complete agreement with their experimental data. The sublattice magnetizations of the Co and Gd sites on the individual hcp atomic (0001) planes of the Co–Gd layered nanostructures are computed for each plane and corresponding sites by using the combined EFT and mean field theory (MFT) spin methods. The sublattice magnetizations, effective site magnetic moments, and ferrimagnetic compensation characteristics for the individual hcp atomic planes of the embedded nanostructures, are computed as a function of temperature, and for various stable eutectic concentrations in the range c≤0.5. The theoretical results for the sublattice magnetizations and the local magnetic variables of these ultrathin ferrimagnetic lamellar nanostructured systems, between cobalt leads, are necessary for the study of their magnonic transport properties, and eventually their spintronic dynamic computations. The method developed in this work is general and can be applied to comparable magnetic systems nanostructured with other materials.

In this work, the Monte Carlo simulations have been performed to investigate the magnetic properties of the kesterite and the stannite nanostructures with mixed spins. The Blume–Capel model has been adopted to study the Cu2ZnSnSe4 nanostructures. Furthermore, we have examined different transitions as a function of the temperature, the crystal field, and the exchange coupling interactions. Also, the behavior of the magnetizations and magnetic susceptibilities are investigated as a function of the different physical parameters. A comparison of the magnetic properties of each nanostructure has been studied and discussed.

FeNi films were prepared by oblique deposition onto glass substrate using magnetron sputtering deposition technique. The deposition was carried out on a rotating or nonrotating substrate with or without a constant magnetic field applied parallel to the substrate plane. The magnetic properties of the samples were measured by a magneto-optical Kerr effect at room temperature. All films had in-plane uniaxial magnetic anisotropy. The presence of in-plane magnetic anisotropy was also confirmed by the features of the domain structure. The main factor determining the orientation of the induced anisotropy axis of films was the magnetic field applied during deposition.