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Current modulation and rectification is an important subject of electronics as well as spintronics. In this paper, an efficient rectifying mesoscopic device is introduced. The device is a two terminal device on the 2D plane of electron gas. The lateral contacts are half-metal ferromagnetic with antiparallel magnetizations and the central channel region is taken as ferromagnetic or normal in the presence of an applied magnetic field. The device functionality is based on the modification of spin-current by tuning the strength of the magnetic field or equivalently by the exchange coupling of the channel to the substrate. The result is that the (spin-) current depends on the polarity of the bias voltage. Converting an alternating bias voltage to direct current is the main achievement of this model device with an additional profit of rectified spin-current. We analyze the results in terms of the spin-dependent barrier in the channel. Detecting the strength of the magnetic field by spin polarization is also suggested.

The ab initio study of electronic, magnetic properties and Curie temperature of AlAs doped by single and double impurities is investigated using LDA–KKR–CPA method. It is shown that the Al substituted by V and/or Ti induces a half-metallic character and ferromagnetism in the system for different concentrations except co-doping by x=y=0.035. The stability of magnetism between the ferromagnetic and DLM states as well as the mechanism of exchange interaction are discussed. The density of states are plotted in the energy diagram for different concentrations of dopants. The co-doping with (V, Ti) increases Curie temperature in AlAs with respect to single substituant. The finding of this work confirms that the new compounds have a great potential for spintronic devices.

Spin-polarized electron transport through a zigzag zinc oxide nanoribbon (ZnONR) has been studied using first-principles transport simulations. Ribbons without edges passivated show 100% spin polarization at small bias voltage independently of width. The ribbons with edge zinc atoms passivated maintain absolute spin-filtering effect in much larger bias region. The results demonstrate that zigzag ZnONRs act as perfect spin-filters in the absence of magnetic electrodes and external fields.

First-principles calculations based on density functional theory (DFT) confirm the half-metallic ferromagnetism in both ${\mathrm{\text{Co}}}_2\mathrm{\text{TiSn}}$ and ${\mathrm{\text{Co}}}_2\mathrm{\text{VSn}}$, and the nearly half-metallic ferromagnetism in ${\mathrm{\text{Co}}}_2\mathrm{\text{CrSn}}$ Heusler alloys with the ${\mathrm{\text{AlCu}}}_2\mathrm{\text{Mn}}$-type structure $({\mathrm{\text{L2}}}_1)$. The electronic band structures and density of states (DOS) calculations of the ${\mathrm{\text{Co}}}_2\mathrm{\text{TiSn}}$ and ${\mathrm{\text{Co}}}_2\mathrm{\text{VSn}}$ compounds show that the spin-up electrons are metallic, whereas the spin-down bands are semiconducting with a gap of 0.47 eV and 0.53 eV, respectively, with 0.21 eV and 0.36 eV as a spin-flip gap, respectively. The ${\mathrm{\text{Co}}}_2\mathrm{\text{TiSn}}$ and ${\mathrm{\text{Co}}}_2\mathrm{\text{VSn}}$ Heusler were half-metal compounds with magnetic moment of $2{\mu }_{\mathrm{\text{B}}}$ and $3{\mu }_{\mathrm{\text{B}}}$ at the equilibrium lattice constants $a=6.097$ Å and $a=6.026$ Å, respectively, which agrees with the Slater–Pauling rule, and have 100% polarization for a wide range of lattice parameters. The ${\mathrm{\text{Co}}}_2\mathrm{\text{CrSn}}$ is a nearly half-metal (NHF) compound with magnetic moment of $4.01{\mu }_{\mathrm{\text{B}}}$ and 92.9% polarization at the equilibrium lattice constants $a=5.995$ Å and acquire half-metal behavior under the pressure 16.70 GPa.

In this study, the WIEN2k code, utilizing the full potential linearized augmented plane wave (FPLAPW) approach within the framework of density functional theory (DFT), explicitly employing the PBEsol approximation, is employed to investigate the fundamental properties of W-doped and (Mo, W) co-doped cubic CeO₂. Herein, lattice constants, bulk modulus and cell volumes were evaluated for structural properties. The total density of states (TDOS) for various doped and co-doped CeO₂ systems was used to explain the origin of magnetic behavior. The band structure (BS) calculations show that the doped and co-doped materials exhibit semiconductor behavior with a direct bandgap in both spin channels. The calculated total spin magnetic moments of W/CeO₂ and (Mo, W)/CeO₂ alloys are 2.002${\mu }_B$ and 4.007${\mu }_{B,}$ respectively.

Furthermore, the optical absorption shows absorption peaks in the visible range and a redshift. As a result, adding molybdenum and tungsten additives improves the electro-optical properties of previous materials.

The Bychkov–Rashba effect in metal–insulator–semiconductor (MIS) structures based on zero-gap HgCdTe with different doping level is investigated experimentally and theoretically. The relative difference between electron concentration in different spin-orbit split sub-subband increases with doping and reaches high values as Δn/n~0,5 at N_A-N_D~10¹⁸ cm^-3. Contrary to low-doped HgCdTe the splitting, in the samples investigated, exhibits strong concentration dependence in the wide concentration region.

The aim of this investigation is to study the ferromagnetism and magnetic properties of LiMgP HH with double impurities, namely $C$-2$p$ and (Fe and Ni)-3$p$, connected to LiMg${}_{0.95}$Fe${}_{0.05}$P${}_{0.95}$C${}_{0.05}$ and LiMg${}_{0.95}$Ni${}_{0.05}$P${}_{0.95}$C${}_{0.05,}$respectively. To achieve this, we perform KKR-CPA combined with GGA. The ferromagnetic stability of LiMg₀P${}_{0.95}$C${}_{0.05}$is observed, where C-2$p$ is set on the spin-down of $E$${}_F$ connected to the half metallicity. In the case of LiMg${}_{0.95}$Fe${}_{0.05}$P alloy, the Fe-3$d$ states show a variation in the exchange splitting ($t_2^{+}$,$t_2^{-}$) with respect to the spin-up ${}^{(\uparrow )}$ and spin-down ${}^{(\downarrow )}$. The Fe-3$d$ states are located around the $E$${}_F$ and exhibit half-metallic characteristic. Similarly, the LiMg${}_{0.95}$Ni${}_{0.05}$P alloy also exhibits half metallic characteristic. The co-doped LiMg${}_{0.95}$Fe${}_{0.05}$P${}_{0.05}$C${}_{0.05}$ and LiMg${}_{0.95}$Ni${}_{0.05}$P${}_{0.95}$C${}_{0.05}$ alloys predict an improvement in magnetic properties due to the presence of carbon, resulting in hybridization between C-2$p$ and Fe-3$d$ in the valence band (VB) maximum and conduction band (CB) minimum on the minority states. Similarly, in the case of LiMg${}_{0.95}$Ni${}_{0.05}$P${}_{0.95}$C${}_{0.05}$, hybridization occurs between C-2$p$ and Ni-3$d$ below $E$${}_F$ in the minority states, within the range of (−0.2 to 0 Ry) in the VB.

With the growing concerns of standby power in sub-100-nm CMOS technologies, alternative computing techniques and memory technologies are explored. Spin transfer torque magnetoresistive RAM (STT-MRAM) is one such nonvolatile memory relying on magnetic tunnel junctions (MTJs) to store information. It uses spin transfer torque to write information and magnetoresistance to read information. In 2012, Everspin Technologies, Inc. commercialized the first 64Mbit Spin Torque MRAM. On the computing end, nanomagnetic logic (NML) is a promising technique with zero leakage and high data retention. In 2000, Cowburn and Welland first demonstrated its potential in logic and information propagation through magnetostatic interaction in a chain of single domain circular nanomagnetic dots of Supermalloy (Ni₈₀Fe₁₄Mo₅X₁, X is other metals). In 2006, Imre et al. demonstrated wires and majority gates followed by coplanar cross wire systems demonstration in 2010 by Pulecio et al. Since 2004 researchers have also investigated the potential of MTJs in logic. More recently with dipolar coupling between MTJs demonstrated in 2012, logic-in-memory architecture with STT-MRAM have been investigated. The architecture borrows the computing concept from NML and read and write style from MRAM. The architecture can switch its operation between logic and memory modes with clock as classifier. Further through logic partitioning between MTJ and CMOS plane, a significant performance boost has been observed in basic computing blocks within the architecture. In this work, we have explored the developments in NML, in MTJs and more recent developments in hybrid MTJ/CMOS logic-in-memory architecture and its unique logic partitioning capability.

The paper presents the results of experimental studies of the physical mechanisms and dynamics of magnetization reversal of the films Al₂O₃/Tb₂₅Co₅Fe₇₀/Al₂O₃, Al₂O₃/Tb₂₂Co₅Fe₇₃/Al₂O₃, Al₂O₃/Tb₁₉Co₅Fe₇₆/Al₂O₃, Al₂O₃/Co₃₀Fe₇₀/Al₂O₃ with a single magnetic layer and the films Al₂O₃/Tb₂₂Co₅Fe₇₃/Pr₆O₁₁/Tb₁₉Co₅Fe₇₆/Al₂O₃, Al₂O₃/Co₈₀Fe₂₀/Pr₆O₁₁/Co₃₀Fe₇₀/Al₂O₃ with two magnetic layers radiated by picosecond (τ_i ≈ 80 ps) and femtosecond (τ_i ≈ 130 fs) laser pulses. The experimental samples of spin transistors and data recording devices on the spin storage medium are also described. The results of studies have shown that magnetic switching effects in the nanolayers under femtosecond laser pulses can be used for creation of systems of high-speed controlling of spin currents with the response time τ ≤ 10^-11s. Conclusions from the studies are the following: thermomagnetic switching under the influence of an external magnetic field or a demagnetization field, magnetic switching of antiferromagnetic films under the influence of an effective internal field of antiferromagnetic interaction between magnetic sublattices rare-earth and transitive metals, magnetic switching under the influence of a magnetic field of the inverse Faraday effect, or under the influence of a magnetic field of a spin current. The magnetic switching of magnetic layers under action of the magnetic field of a spin current is the most important for practical use in elements of spintronics. This mechanism of magnetic reversal takes place only in multilayer nanofilms and the heterogeneous multilayer magnetic nanofilms are the base material for creation of spintronic devices. The great advantage of the magnetization reversal of magnetic nanolayers of the spin current is that the mechanism of magnetization reversal is working in the films with perpendicular anisotropy and in the films with in-plane anisotropy. The injection of polarized electrons can also be realized using short electrical pulses. That is why the mechanism of magnetization reversal of the control electrodes spin current is the most appropriate for the management of high-spin current in the elements of spintronics. On the basis of this mechanism, we have realized the high-speed recording of information on the spin carrier and the experimental model memory with three magnetic nanolayers. The data recording in this memory cell is realized using an electric nanosecond pulse.

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 $t_{\mathrm{\text{ox}}}=0.85$nm is used to get better TMR ratio, resistance, and STT-components.

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.

Currently, static circuit power is becoming a major concern, dominating the total power consumption due to the scaling down of CMOS technology. The smaller sizes drastically affect the leakage current, which integrated circuit designers attempt to overcome this issue. Hence, several methods and technologies have been proposed to prevail this phenomenon. One of these methods is using memory structures in logic designs. A Hybrid MTJ/CMOS circuit is one of these promising techniques to design low-power nonvolatile circuits with power gating ability and low overhead for reconfigurable possibilities. In this paper, we have proposed a fully nonvolatile, low-power Full-Adder based on MTJs that uses the spin transfer torque method assisted by the spin hall effect. Simulation results of these designs by HSPICE show that they can work fast with low-power consumption compared to other state-of-the-art nonvolatile full-adders.

We present first-principles calculations of the structural, electronic and magnetic properties of Gd-doped ${\mathrm{\text{Al}}}_{0.25}{\mathrm{\text{Ga}}}_{0.75}\mathrm{\text{N}}$ based on the density functional theory within $\mathrm{\text{LSDA}}+U$ schemes. It is found that Gd atom favors substituting for Al site. Compared with undoped ${\mathrm{\text{Al}}}_{0.25}{\mathrm{\text{Ga}}}_{0.75}\mathrm{\text{N}}$, the Gd-doped ${\mathrm{\text{Al}}}_{0.25}{\mathrm{\text{Ga}}}_{0.75}\mathrm{\text{N}}$ has become an indirect band gap semiconductor of reduced band gap. The magnetic moment $7.15{\mu }_B$ per molecule mainly comes from Gd ion with little contribution from the Ga, Al and N atoms. It is confirmed that the ferromagnetic configuration is stable for ${\mathrm{\text{Al}}}_{0.1875}{\mathrm{\text{Gd}}}_{0.0625}{\mathrm{\text{Ga}}}_{0.75}\mathrm{\text{N}}$. It is found also that there is hybridization between the forbital of the Gd atom and the $p$ orbital of the N atom.