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Our current study employs the spin-polarized density functional theory (DFT) using the all-electron full potential linear augmented plane-wave method (FP-LAPW) to examine the structural, electronic, and magnetic properties of InSb doped with Tungsten (In WxSb with x = 0.125, 0.25) in the zinc blende crystal structure. We used, for the electronic exchange and correlation energy, the generalized gradient approximation (GGA) with the Wu-Cohen (WC) functional, improved with the Tran–Blaha modified Becke–Johnson (TB-mBJ) approach for the electronic properties. The obtained results show that this calculation method allows for reliable band gap values. The estimated structural properties match well with existing experimental results. The value of the total magnetic moment is around 3.00 µB for the investigated compounds, and because of their half-metallic ferromagnetic properties, they are regarded prospective candidates for spintronic applications. [ABSTRACT FROM AUTHOR]

In this article, we have conducted a comprehensive study on the structural, mechanical, electronic, magnetic and thermodynamic properties of the Heusler alloys FeZrTiZ ( Z = A l , G a , G e ). Our investigation utilize the GGA exchange correlational approximation functional. The results of our analysis indicate that among the Y1-, Y2- and Y3-type structures, the Y1-type structure exhibits stability and demonstrates ferromagnetic behavior. Furthermore, mechanical property analysis reveals that all alloys possess ductile characteristics. The analysis of the density of states of the Heusler alloys FeZrTiZ ( Z = A l , G a , G e ) demonstrates the presence of half-metallic nature in all of the alloys. Additionally, the investigated Heusler alloys exhibit integer spin magnetic moments. To study thermodynamic properties, we use quasi-harmonic approximation, which allows to analyze specific heat capacity, thermal expansion, Debye temperature, vibrational free energy, internal energy and entropy of the Heusler alloys FeZrTiZ ( Z = A l , G a , G e ). Overall, our findings provide a clear understanding of the structural, mechanical, electronic, magnetic and thermodynamic characteristics of Heusler alloys FeZrTiZ ( Z = A l , G a , G e ), shedding light on their potential applications in spintronics. [ABSTRACT FROM AUTHOR]

In this study, we employ first-principle calculations and the full-potential linearized augmented plane-wave (FLAPW) method to systematically investigate the impact of A-site doping on the properties of CoScO3. By creating nonstoichiometric perovskite compounds of Co1 − xNixScO3 with varying concentrations of Ni ions (x = 0, 0.25, 0.50, 0.75, and 1), we explore changes in the structural, electronic, magnetic, and optical characteristics. Our investigation reveals that all the compounds under consideration adopt a crystalline tetragonal structure. Intriguingly, as the concentration of Ni ions within the A-site increases, a reduction in the total magnetic moment is observed, suggesting a tunable magnetic behavior driven by the dopant ions. Importantly, our results demonstrate that all the doped compounds exhibit a remarkable half-metallic behavior, indicating the potential for efficient spin-dependent transport properties. Moreover, the optical properties of the doped compounds exhibit characteristics that render them suitable candidates for applications in spintronic and photovoltaics. These findings open up avenues for designing novel materials that bridge the gap between magnetic and electronic functionalities. [ABSTRACT FROM AUTHOR]

This research aims to employ a first-principles approach based on density functional theory (DFT) to predict the structural, electronic, and magnetic attributes of CdMX compounds, where M represents Ru , Rh , or Pd , and X represents either S or Se . We utilized the modified Beck-Johnson potential, combined with the generalized gradient approximation ( mBJGGA ), to scrutinize the electronic and magnetic features of these compounds. The results reveal robust magnetic ground states for M -doped CdX . The analysis of spin-polarized band structures and densities of states indicates that CdRuX and CdPdX compounds exhibit half-metallic ferromagnetism, characterized by complete spin polarization of 100% at the Fermi level. Conversely, CdRhX compounds exhibit the properties of ferromagnetic semiconductors. For Ru , Rh , and Pd -doped CdX , an integer-integrated total magnetic moment is observed, corresponding to 4, 3, and 2 μ B , respectively, with the primary contribution stemming from the doping atom and its four nearest neighboring X atoms. This ferromagnetic behavior is attributed to the strong p - d hybridization occurring between the states of the host X ions and the M impurity ion. Consequently, the outcomes of our study render these alloys as suitable materials for possible spintronic devices. [ABSTRACT FROM AUTHOR]

In this manuscript, structural, opto-electronic, and magnetic properties of pure LaN and binary compounds doped with third-order transition metal ions Mn, Fe, and Co have reported. Here, WIEN2k, spin-polarized plane-wave Density Functional Theory is incorporated into the Full Potential Linearized Augmented Plane Wave formalism. The band gap decrease was observed for every combination of dopants used turns LaN characteristics into a ferrimagnetic material. The magnetization in the transition metal-doped c-LaN compounds is caused by the p-d hybridization of the nitrogen and 3d transition metals. It has been found that Curie temperature Tc of more 747.24, 927.99 and 746.99 has been observed for La0.75Mn0.25N, La0.75Fe0.25N, and La0.75Co0.25N respectively. Mn/Fe/Co co-doped LaN performed best due to its enhanced absorption of visible-infrared and near ultraviolet photonic energies. As a result of the doping, both the dielectric constant and refractive index increased. LaN co-doped with Mn, Fe, and Co showed a static dielectric constant of 44.72 and a refractive index of 6.74. Hence the resulted values with high curie temperature specially for La0.75Fe0.25N suggests that TM doped LaN is a promising material for spintronic applications, especially as spin filter devices. [ABSTRACT FROM AUTHOR]

The magnetic characters of VPd2Br4 spinel were calculated using different spin orientations, and electronic properties were investigated using different potential approaches. The ferromagnetic (FM) phase was the most stable magnetic state according to magnetic orientation calculations. The lattice parameter of VPd2Br4 spinel in the FM phase was obtained as 11.17 Å. Elastic analyses showed that the FM phase was mechanically stable. Cauchy's pressure (C12–C44), B/G ratio, and Poisson's ratio (ν) values were obtained as 22.819 GPa, 5.89, and 0.419 at 0 GPa pressure, respectively. Therefore, VPd2Br4 spinel was ductile at 0 GPa pressure. As a result of elastic calculations, Debye temperature was obtained as 136 K. The total magnetic moment value of VPd2Br4 spinel in the FM phase was obtained as 2.00 µB/f.u. The V-atom with a magnetic moment value of 1.868 µB was the most partial contribution to the total magnetic moment. According to electronic properties, minority electron states of VPd2Br4 spinel had semiconductor character, while majority electron states showed metallic character. The band gaps in the minority electron states were calculated as 1.358 eV, 1.705 eV, 2.011 eV, and 2.253 eV according to the GGA, GGA + 1 eV, GGA + 2 eV, and GGA + 3 eV approaches, respectively. These band gaps in the minority electron states and the metallic characters in the majority electron states indicated that VPd2Br4 spinel had 100% spin polarization. Thus, using different approaches, VPd2Br4 spinel was obtained as a true half-metallic material in the FM phase. [ABSTRACT FROM AUTHOR]

High leakage power consumption has become one of the main concerns of data security protection with CMOS device scaling. Spintronic technology is one of the efficient solutions to control circuit leakage power consumption by benefiting from its non-volatility property. Spintronic devices such as magnetic tunnel junctions (MTJs) are also compatible with CMOS transistors and suitable for designing hybrid MTJ/CMOS circuits. Hybrid MTJ/CMOS circuits can be used in many applications, such as logic-in-memory (LiM) and high-security structures. These circuits demonstrate enhanced data security compared to CMOS-based circuits by leveraging their non-volatile feature, making information leakage and data access more challenging. However, these circuits are not completely immune to attacks, and information can be revealed by potent power analysis attacks such as differential power analysis (DPA) and correlation power analysis (CPA). This paper investigates the resistance to side-channel attacks, especially DPA and CPA, for the magnetoresistive RAM (MRAM) and hybrid MTJ/CMOS AND, OR, XOR gates, hybrid MTJ/CMOS full-adder, and multiplexer circuits. Comprehensive post-layout simulation results using 40 nm TSMC CMOS technology, Monte-Carlo results, and values of normalized energy deviation (NED), normalized standard deviation (NSD)), and normalized power deviation (NPD) of PCSA-based MRAM indicate that the power consumption pattern remains constant in circuits with symmetrical structures in the reading phase even in the presence of inevitable process variation, so these circuits are resilient to power attacks and are competent for use in high-security applications such as hardware implementation of encryption algorithms. [ABSTRACT FROM AUTHOR]

The electronic and magnetic features are investigated for doped diluted magnetic semiconductor, specifically magnesium selenide (MgSe). The semiconductor is doped with a single impurity of either zirconium (Zr) or niobium (Nb). To conduct this investigation, a combination of the Korringa-Kohn-Rostoker coherent potential approximation, generalized gradient approximation (GGA) first-principles calculation, and the parametrization method of Pedrew Burke and Ernzerhof (PBE) is used. Our results show that the incorporation of Zr and Nb into the host composite makes a significant contribution to the total magnetic moment of the doped system. The total magnetic moment for M g 1 - x D x S e (D= Nb,Zr) is - 0.58 μ B and - 0.38 μ B for Nb and Zr, respectively, induced by the polarization of the spin at Fermi level ( E F ). Moreover, the ferromagnetic state is stable due to the double exchange mechanism and exhibits a remarkable Curie temperature (Tc) with maximum values of 940 K and 619 K for 2% concentration of Nb and 20% of Zr, respectively. This result leads to interesting magnetic behavior. On the other hand, the double exchange, responsible for short-range interactions mediated by Selenium atoms, arises from the occurrence of p-d orbital hybridization. As a consequence, doping MgSe with Zr and Nb transition metals opens the door to explore and develop new devices in spintronic areas, under room temperature. [ABSTRACT FROM AUTHOR]

Co 2 FeSi Heusler alloys have attracted a lot of attention due to their interesting properties for various technological applications. In this study, we present the results of ab-initio calculations of the electronic, structural and magnetic properties using generalized gradient approximations (GGA and GGA + U). The energies obtained from GGA are used to calculate the magnetic coupling and establish an effective Hamiltonian. Additionally, we utilized mean-field theory and Monte Carlo simulation to evaluate physical properties such as magnetization, susceptibility and critical exponent of the material from the effective Hamiltonian. The results indicate that Co2FeSi, which exhibits a half-metallic behaviour, may be suitable for use in spintronic applications. [ABSTRACT FROM AUTHOR]

The purpose of this study is to conduct theoretical investigations on the electronic, structural and magnetic properties of lithium niobate (LiNbO3) doped with different concentrations of the transition metal chromium (Cr). All properties of LiNb1−xCrxO3 compounds (x = 0.25, 0.50 and 0.75) are achieved with spin-polarized density functional theory by the GGA-PBE and the TB-mBJ approximations. To ensure the stability of the LiNb1−xCrxO3 quaternary alloy in the ferromagnetic state, the total energy released from the optimized structure and the defect formation energy were calculated. The classical Heisenberg model estimated the Curie temperature of the compounds. The material studied exhibits a 100% spin-polarized semi-metallic ferromagnetism behaviour. In all compounds, the data of the magnetic moment demonstrated that the chromium impurity atom is the most important source by comparison with the Nb and Li, which have minor contributions. In addition, the magnetic moment of the Cr atoms decreases with doping; this comes from the p–d hybridization between the Cr-3d and O-2p states. The half-metal gap (GHM), the most important factor in spintronics applications, was also calculated. In addition, to assess the effects of the exchange separation process, the crystal field separation energy, the exchange separation parameters, and the exchange constants N0α, N0β, and ΔEC, ΔEV are predicted. [ABSTRACT FROM AUTHOR]

High-speed and low-power area-efficient memory solutions are in high demand in today's smart and internet environment. To program and store data and its associated information, it has grown as a fantastic concept to replace charge in semiconductor devices with electron spin. By further eliminating power dissipation, this leads to the development of "green electronics," a field of technology that is both energy and chip space efficient. A sort of spintronic device created for potential energy-efficient applications is the magnetic tunnel junction (MTJ) device controlled by spin orbit torques (SOTs). A three-terminal MTJ device with perpendicular to the plane magnetization may operate more quickly and efficiently thanks to the available spin orbit torques (PMTJ). The design of a novel modified non-volatile master slave flip flop (NVMSFF) for register memory array architectures is presented in this study. It is low-power, high-speed, and area-efficient. The NVMSFF design uses a hybrid approach that combines CMOS 45 nm technology with a Verilog-A Model-based SOT-PMTJ circuit that uses spintronics. Additionally, the planned NVMSFF and current NVSFF were used in the design of the 4 × 4 and 8 × 8 memory arrays. The suggested updated NVMSFF was shown to have a lower latency, use less space, and dissipate less power. Additionally, it was discovered that Designed Memory arrays were space and energy efficient. [ABSTRACT FROM AUTHOR]

We report here the structural, optical, photoluminescence (PL), and magnetic investigation of Zn1−x−yFexMyO nanoparticles. The lattice constants and crystallite size are decreased by Fe, followed by a further decrease up to (Fe + M) = 0.30. A compressive stress is approved and the size of particle is between 180 and 277 nm and follows the sample order of ZnO, (Fe + Cu), (Fe + Ni), and Fe. Although a single value of energy gap (Eg) is found for pure and Fe-doped ZnO, two values of Eg (Egh and Egl) are found for the co-doped samples. The Eg is generally increased by Fe, followed by a further increase for the Cu-series, whereas it is decreased for the Ni-series. The refractive indices nK and nT proposed by different methods are generally decreased by Fe, followed by a further decrease for both series. Although Fe doped ZnO depressed the density of carriers (N/m*), it increased again for the co-doped samples. The residual dielectric constant ϵL is decreased by Fe, followed by an increase for the Cu-series, but it is decreased for the Ni-series. The loss factor tan δ increases slightly with Fe, followed by an increase for the Ni-series, but it decreases in the Cu-series. A significant depression of optical conductivity σopt by Fe was obtained, followed by a further decrease which is higher for the Cu-series. The PL shows four visible emissions. Interestingly, an IR emission at about 825 nm is only obtained for the co-doped samples. Furthermore, the blue emission (Iblue) was higher than UV (IUV), [(Iblue/IUV) > 1], but it is greater for the Ni series than the Cu. Although ZnO exhibits diamagnetic behavior, the Fe and co-doped samples exhibit ferromagnetic with higher magnetization for the Ni-series than the Cu. The current results recommend the co-doped samples in nanoscale for some of advanced devices. [ABSTRACT FROM AUTHOR]

The structural, half-metallic, and elastic characteristics of XZrAs (X = Cr, Mn, and V) half-Heusler compounds were theoretically calculated using the WIEN2k code. For the term of the potential exchange and correlation (XC), we calculated structural, electronic, and magnetic properties using the generalized gradient approximation (GGA). The type 1 arrangement in ferromagnetic (FM) phases is more energetically stable than other type arrangements in all compounds. The spin-up electrons of both XZrAs (X = Cr, Mn) half-Heusler compounds in the type III structure are semiconducting with energy gaps, whereas the spin-dn electrons are metallic. Research has also been done on the VZrAs compound, which exhibits metallic characteristics in both type I and type III structures. XZrAs (X = Cr, Mn, and V) half-Heusler compounds are elastically stable and ductile, according to calculated Cij elastic constants. Finally, at equilibrium lattice constants a = 6.1196 A° for MnZrAs and 6.142 A° for CrZrAs, real half-metal ferromagnetic materials (HMF) were produced from XZrAs (X = Cr, Mn) half-Heusler compounds within 3 µB and 2µB, respectively. [ABSTRACT FROM AUTHOR]

Spintronic metal thin films excited by femtosecond laser pulses have recently emerged as excellent broadband sources of terahertz (THz) radiation. Unfortunately, these emitters transmit a significant proportion of the incident excitation laser, which causes two issues: first, the transmitted light can interfere with measurements and so must be attenuated; second, the transmitted light is effectively wasted as it does not drive further THz generation. Here, we address both issues with the inclusion of a high-reflectivity (HR) coating made from alternating layers of SiO2 and Ta2O5. Emitters with the HR coating transmit less than 0.1% of the incident excitation pulse. Additionally, we find that the HR coating increases the peak THz signal by roughly 35%, whereas alternative attenuating elements, such as cellulose nitrate films, reduce the THz signal. To further improve the emission, we study the inclusion of an anti-reflective coating to the HR-coated emitters and find the peak THz signal is enhanced by a further 4%. [ABSTRACT FROM AUTHOR]

Through first-principles investigation, two new Mn2-based full-Heusler alloys, Mn2HfSi and Mn2HfGe, have been studied using the full-potential linearized augmented plane wave (FP-LAPW) approach as implemented in the WIEN2k code. Our study focuses on these compound's stability (thermodynamic, dynamic, and mechanical), electronic, and magnetic properties. The L21 (Cu2MnAl-type) structure is shown to be more energetically favorable than the XA (Hg2CuTi-type) structure for both compounds, Mn2HfX (X = Si and Ge). We demonstrate that Mn2HfX (X = Si and Ge) are stable through the calculations of cohesive, formation energies, phonon dispersion curves, and the elastic constants, with the illustration of 3D and 2D bulk and Young's moduli. Using GGA and GGA-mBJ calculations show that Mn2HfX (X = Si and Ge) are half-metallic ferrimagnets (HMFs), with indirect band gap through the altered Becke-Johnson (mBJ), GGA approximation: 0.689 eV for Mn2HfSi and 0.520 eV for Mn2HfGe. Furthermore, the electrons at the Fermi level (EF) were fully spin-polarized. The total magnetic moment in these two compounds was found to have an integer value of 2 µB per formula, which complies with the Slater-Pauling rule Mtot = Ztot − 24. These compounds are favorable materials for spintronic applications. It was revealed that Mn2HfSi and Mn2HfGe maintained their half-metallicity for lattice constants in the range of 5.7–6.2 Å and 5.75–6.2 Å, respectively. [ABSTRACT FROM AUTHOR]

This paper reported on the theoretical investigations with first principle calculations on the electronic and band structure properties of Cr-doped GeO2 rutile. Firstly, it discussed the half-metallic characteristics of rutile GeO2 (r-GeO2) bulk crystal when this latter is doped with 3d-Cr transition metal. Secondly, and to understand the impact of doping Cr impurity, three amounts of Cr of 2, 6 and 10% were inserted in the r-GeO2 lattice which showed how doping can improve the magnetic properties of the obtained dilute magnetic semiconductor. The theoretical calculations were performed in the general framework of the density functional theory within the Korringa–Kohn–Rostoker approach combined with the coherent potential approximation. We adopted the local density approximation (LDA) as well as the self-interaction corrected LDA (LDA-SIC) to account for the exchange and correlation in the strong correlated electron systems. Based on calculations within LDA and LDA-SIC approximations, it was found that the compound behaves as half-metal material. Moreover, we have studied the interaction responsible of magnetism using both LDA and LDA-SIC approximations. In addition, we calculated the exchange coupling parameters of the classical Heisenberg model and studied the X-ray absorption spectrum at the K-edge of Ge1−xCrxO2. The obtained values of Curie temperature were found above the ambient value once doping concentration exceeds 6%. Hence, it can be inferred that Cr-doped r-GeO2 presents a good potential as a practical spintronic material when the doping concentration is greater than or equal to 6%. [ABSTRACT FROM AUTHOR]

The concept of using single molecules as functional building blocks in electronic circuitry represents the ultimate device miniaturization and has garnered tremendous attention from physics, chemistry, and engineering. Recent advances in single-molecule junction techniques have enabled direct investigation of charge transport in a quasi-one-dimensional conduction channel composed of an individual molecule. One of the main research focuses over the past decade has been to understand the conductance switching effect of single molecules as it is essential for developing molecular-scale optoelectronics, computing, and sensing applications. In this perspective, we highlight the established physical and chemical mechanisms for single-molecule conductance switching behavior and examine the associated stimuli in single-molecule junction systems. [ABSTRACT FROM AUTHOR]

Renewed interest in cryogenic transmission electron microscopy (cryo-TEM) for physical and materials science research has emerged in recent years after being awarded the Nobel Prize in 2017 for its success in structural biology. In this perspective, the recent advancement in cryo-TEM techniques and its applications in the research of emerging materials for quantum information sciences and clean energy technologies are summarized and discussed in relevant topical areas. Cryo-TEM for quantum materials is specifically focused on exotic electronic states in strongly correlated systems and novel topological spin textures in spintronic materials. For energy-related application, the focus is mainly towards the cryo-TEM characterization of electron radiation sensitive materials, including alkali metals and compounds in batteries, highly porous metal–organic frameworks, and hybrid halide perovskites in photovoltaic solar cells. The challenges and outlook on the future cryo-TEM developments are also provided. [ABSTRACT FROM AUTHOR]

This study uses the density functional theory method to accurately predict structural, electronic, magnetic, elastic, thermal and thermoelectric properties for two new half-Heusler RbCrSb and RbCrAs compounds. The exchange and correlation potential is treated by employing generalized gradient approximation of Perdew–Burke–Ernzerhof (GGA-PBE), Tran–Blaha-modified Becke–Johnson exchange potential (TB-mBJ) and PBE-GGA + U approaches, where U is the Hubbard on-site Coulomb interaction correction. Structural results reveal that RbCrSb and RbCrAs alloys are energetically stable in type 3 structure FM state. The negative formation and cohesive energies confirm the possibility of their experimental realization. Electronic and magnetic properties show that both compounds exhibit half-metallic character and integer magnetic moments of 4 μB following the Slater–Pauling rule. Elastic calculations unveil that both compounds fulfill the mechanical stability criteria and are anisotropic and ductile in nature. The thermodynamic properties show that the selected materials can be employed under high pressures and high temperatures. Thermoelectric results suggest that RbCrX (with X = Sb, As) exhibits high figure of merit (ZT) values close to the unity at room temperature. Consequently, our new half-Heusler compounds RbCrSb and RbCrAs will be beneficial for thermoelectricity as well as for spintronic device applications. [ABSTRACT FROM AUTHOR]

For the ultimate goal of adjusting the physical properties of the tin-carbide (SnC) semiconductor, a meticulous theoretical study based on density functional theory (DFT) and Korringa–Kohn–Rostoker (KKR) method combined with coherent potential approximation (CPA) on transition metals substitution is investigated. Iron (Fe) and chromium (Cr) ions have been chosen for their interesting magnetic properties (spin moment, Curie temperature). A value x corresponding to the substitution concentration is varied between 2% and 24% for both S n 1 - x C r x C and S n 1 - x F e x C compound types. All S n 1 - x F e x C compounds show a half-metallic ferromagnetic nature, while a similar behavior is also revealed for S n 1 - x C r x C compounds with x up to 12. Our self-consistent (SCF) spin-polarized calculations findings revealed that the main contributions to the net magnetization of our compound originate from Fe and Cr ions, with the partial spin moment of Fe is 3.68 μ B for 24 % and is around 2.4 μ B for Cr. The mean field approximation indicates that the Curie temperature reaches its highest value of 502.86K for Fe at the x-value of 12% , whereas with Cr substitution, the greatest value of 712K is found at x=24%. These findings show that S n 1 - x C r x C and S n 1 - x F e x C compounds are promising for spintronics applications. [ABSTRACT FROM AUTHOR]

Quaternary Heusler materials featuring intrinsic half-metallicity (HM) and high critical temperature Tc emerge as promising candidates for spintronic devices. The advanced density functional theory is used to examine the complicated interaction of the structural, electronic structure, and thermoelectric properties of novel NdCoMnZ (Z = Al, In), PrCoMnZ (Z = Ga, In), and PrCoCrZ (Z = Al, Ga) Quaternary Heusler compounds (QHAs). The total energies vs volume of the six materials were computed to formulate ground state characteristics. We have utilized TB-mBJ to estimate the band structure and density of states. The results show that the alloys are half metallic with considerable half-metallic gaps of 0.480 eV, 0.484 eV, 0.564 eV, 0.516 eV, 0.615 eV, and 0.580 eV for NdCoMnAl, NdCoMnIn, PrCoMnGa, PrCoMnIn, PrCoCrAl, and PrCoCrGa, respectively. All alloys have magnetic moments that are integers (5, 6, and 7 µB) and that satisfy the Pauli rule Mtot = (Ztot-18). Our calculation of the Curie’s temperature TC showed that the values range from 928 to 1290 K. The magnetic moments as a function of the lattice constant were also calculated for all materials. The thermoelectric properties of all materials are obtained using the BoltzTraB code based on Boltzmann transport theory. The Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor, and figure of merit were calculated. The investigation of thermoelectric characteristics showed that both alloys display higher electrical conductivities and lower thermal conductivities. [ABSTRACT FROM AUTHOR]

We investigated the structural, magneto-electronic, and thermoelectric properties of V2CoZ (Z = Ga, and Ge) Heusler alloys using the ab-initio method. The XA-type structure within the ferrimagnetic phase is more energetically stable than other phases through the chemical stability so the negative value of energy formation that both compounds are favorable and synthesizable experimentally. Both compounds' mechanical properties show anisotropic ductile materials. In addition to their half-metallic ferrimagnetic behavior with an integer total magnetic moment, according to magneto-electronic calculations. Boltzmann's transport theory was also used to investigate the thermoelectric response. Our findings show that these Heusler alloys have a lot of potential for thermo-spintronic devices. [ABSTRACT FROM AUTHOR]

Magnetite (Fe3O4) nanoparticles (NPs) and SiO2-coated Fe3O4 nanoparticles have successfully been synthesized using co-precipitation and modified Stöber methods, respectively. The samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), vibrating sample magnetometer (VSM) techniques, X-ray absorption spectroscopy (XAS), and X-ray magnetic circular dichroism (XMCD). XRD and FTIR data confirmed the structural configuration of a single-phase Fe3O4 and the successful formation of SiO2-coated Fe3O4 NPs. XRD also confirmed that we have succeeded to synthesize nano-meter size of Fe3O4 NPs. HRTEM images showed the increasing thickness of SiO2-coated Fe3O4 with the addition of the Tetraethyl Orthosilicate (TEOS). Room temperature VSM analysis showed the magnetic behaviour of Fe3O4 and its variations that occurred after SiO2 coating. The magnetic behaviour is further authenticated by XAS spectra analysis which cleared about the existence of SiO2 shells that have transformed the crystal as well as the local structures of the magnetite NPs. We have performed XMCD measurements, which is a powerful element-specific technique to find out the origin of magnetization in SiO2-coated Fe3O4 NPs, that verified a decrease in magnetization with increasing thickness of the SiO2 coating. Magnetite (Fe3O4) nanoparticles (NPs) and SiO2-coated Fe3O4 nanoparticles have successfully been synthesized using co-precipitation and modified Stöber methods, respectively. The samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), vibrating sample magnetometer (VSM) techniques, X-ray absorption spectroscopy (XAS), and X-ray magnetic circular dichroism (XMCD). XRD and FTIR data confirmed the structural configuration of a single-phase Fe3O4 and the successful formation of SiO2-coated Fe3O4 NPs. XRD also confirmed that we have succeeded to synthesize nano-meter size of Fe3O4 NPs. HRTEM images showed the increasing thickness of SiO2-coated Fe3O4 with the addition of the Tetraethyl Orthosilicate (TEOS). Room temperature VSM analysis showed the magnetic behaviour of Fe3O4 and its variations that occurred after SiO2 coating. The magnetic behaviour is further authenticated by XAS spectra analysis which cleared about the existence of SiO2 shells that have transformed the crystal as well as the local structures of the magnetite NPs. We have performed XMCD measurements, which is a powerful element-specific technique to find out the origin of magnetization in SiO2-coated Fe3O4 NPs, that verified a decrease in magnetization with increasing thickness of the SiO2 coating. [ABSTRACT FROM AUTHOR]

A theoretical investigation of the structural, electronic, magnetic, and magneto-elastic properties is provided for the non-perovskite HoMnO3 in low symmetry. This study has been carried out using density functional theory (DFT + U) with the inclusion of the polarized spin and spin–orbit coupling for both ferromagnetic and antiferromagnetic configurations. The generalized gradient approximation (GGA), the GGA + U, and modified Becke–Johnson (mBJ) approach have been used. The stability of the ground state of this compound in ferromagnetic (FM) and antiferromagnetic (AFM) configurations has been highlighted, confirming the magnetic behavior of HoMnO3. A good agreement has been observed between the internal atomic relaxation calculations and the experimental data. The calculated total magnetic moment of HoMnO3, localized on Ho atom is about ~ 9.6 µB for the ferromagnetic configuration, in good agreement with the available experimental data. On other hand, the GGA and GGA + U (where U ~ 7 eV) approximations have predicted a metallic behavior behavior for the h-HoMnO3, whereas, the implementation of mBJ approach has highlighted a semiconductor feature of the HoMnO3 with spin-polarized band gap about 0.5 eV (FM) and 0.6 eV (AFM). The calculated Bulk modulus has been found to be about 162.23 GPa (FM), and 169.34 GPa (AFM). [ABSTRACT FROM AUTHOR]

Based on the findings of skyrmion nature of stripes and the metastability of a state of an arbitrary number of skyrmions, precisely controlled manipulation of stripes of skyrmion number 1 in pre-designed structures and mutual transformation between helical states and skyrmion crystals (SkXs) are demonstrated in chiral magnetic films. As a proof of the concept, we show how to use patterned magnetic fields and spin-transfer torques (STTs) to generate nematic and smectic stripe phases, as well as "UST" mosaic from three curved stripes. Cutting one stripe into many pieces and coalescing several skyrmions into one by various external fields are good ways to transform helical states and SkXs from each other. [ABSTRACT FROM AUTHOR]

Electronic and magnetic properties of CdS-based, doped by various transition metal elements (Ti, V, Cr, Mn, Fe, Co or Ni), dilute magnetic semiconductors (DMS) have been examined using first-principle calculations. In order to determine the transition metals that gives most stable alloy, we have investigated and plotted the total and partial densities of states (DOS) by adopting the Korringa–Kohn–Rostoker method combined with the coherent potential approximation (KKR-CPA), first within the generalized gradient approximation (GGA), and then within the self-interaction-corrected generalized gradient approximation (GGA-SIC). We have also plotted the band structures of CdS, and the variation of the Curie temperature as a function of the concentration of the impurity for the transition metals which are likely to be used in spintronic. Our results show that when using the GGA-SIC, that leads to more accurate results by taking into account the self-interaction corrections, the ferromagnetic state is found stable for CdS doped with titanium (Ti) and vanadium (V), which makes these alloys suitable for spintronic applications, especially since their Curie temperatures are around room temperature. [ABSTRACT FROM AUTHOR]

Double perovskite oxides have attracted much attention in material science and spintronic applications due to their exceptional physical properties. In this paper, the transition-metal double perovskite oxides Sr2MNbO6(M = V, Cr) are studied to investigate the effect of the magnetic cation M, using the full-potential linearized augmented plane wave method (FP-LAPW) within a generalized gradient approximation (GGA), Hubbard correction (GGA + U), and exact exchange for correlated electrons (EECE) in the framework of the density functional theory (DFT). The cubic phase is the most stable polymorph in the ambient condition for both double perovskites. The lattice parameters, interne coordinates, are in agreement with previous measurements and theoretical calculations. Furthermore, both of the examined materials are brittle in nature and have an elastically anisotropic character. More importantly, for Sr2VNbO6, a half-metallic ferromagnetism is predicted with a narrow band gap in the minority spin, whereas Sr2CrNbO6 shows a ferromagnetic insulator nature, and the estimated Curie temperatures are higher than the room temperature. We deduce that the M3+ (3dn- t 2 g n ; S = n 2 ) ions (n = 2or 3) have a significant effect on the magnetic moment and the electronic conducting, on the contrary to the nonmagnetic Nb5+ (4 d0- t 2 g 0 ) ions. The thermodynamic properties are predicted in the temperature range from 0.0 to 1000 K where the quasi-harmonic model remains fully valid. These results indicate that Sr2MNbO6 might have an important potential application in spintronic devices. [ABSTRACT FROM AUTHOR]

In this paper, the LiMg0.95TM0.05N alloy (TM=Ti, V, and Cr) undergo the Korringa-Kohn-Rostoker framework and "coherent potential approximation" to examine the magnetic and electronic behaviors, based on the MACHIKANEYAMA2002v09 program. In LiMg0.95TM0.05N alloy, the N ions around TM ions form a zinc-blende structure crystal field, which causes the Ti[d], V[d], and Cr[d] orbitals to split into the lower doubly degenerate eg(dx2-y2,dz2) and higher triply degenerate t2g(dxy,dyz,dxz) states. The "electron spin polarization (P)" of TM[d] is around the Fermi energy (Ef) and exhibits the half metallic characteristic, and the ferromagnetic stability is depicted in LiMg0.95TM0.05N. Also, the computed magnetic and the Curie temperature are valuable at room temperature as promised ferromagnetic material. The obtained values are 541.05 and 453.23 K connected to LiMg0.95V0.05N and LiMg0.95Cr0.05N, respectively. For the LiMg0.95TM0.05N alloy, the exchange splitting ∆ Ex TM is larger than the crystal field splitting ∆ CR TM , where ∆ Ex Cr > ∆ Ex V > ∆ Ex Ti and ∆ CR Cr > ∆ CR V > ∆ CR Ti . Also, total spin moment is arranged as follows: M LiMg 0.95 Cr 0.05 N Total > M LiMg 0.95 V 0.05 N Total > M LiMg 0.95 Ti 0.05 N Total. [ABSTRACT FROM AUTHOR]

In this paper, an ab initio study of the electronic and magnetic properties of CdS doped by the transition metal elements has been investigated. Based on the KKR-CPA method within the Generalized Gradient Approximation (GGA), we have calculated the total energy to determine the most stable state in the system and found it to be the ferromagnetic state for Ti, V and Cr-doped CdS, while it is the stabilization in spin glass states for Mn and Co cases. On the other hand, we have investigated and plotted the density of states (DOSs) which reveals that the doped compounds exhibit a half-metallic character. The spin polarization at Fermi level is estimated and found to be around 100%. Furthermore, we have identified the type of mechanism of exchange interactions being double exchange for all components except Mn case where we find that the responsible mechanism is the p-d exchange. The evaluation of the Curie temperature variation TC for the three components stable in the ferromagnetic phase revealed values greater than 300 K for most cases. The effect of the crystal field and the exchange splitting as a function of the concentrations values has been also investigated. Half-metallic substances are very interesting for spin-dependent electronics devices as they boost their magnetoresistance capacity. [ABSTRACT FROM AUTHOR]

Citrate sol–gel method has been employed for synthesis of Zn1˗x˗yMnxCryO nanomaterials. Binary Zn0.9Mn0.1O and Zn0.9Cr0.1O nanomaterials were prepared and their optical and magnetic properties were investigated as reference compositions for the individual behavior of both of Mn- and Cr doping, respectively. The synthesized nanoparticles were analyzed using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), ultraviolet–visible (UV–Vis) spectroscopy and vibrating sample magnetometer. For low Mn–Cr-codoping contents, i.e., 2 and 4%, XRD revealed formation of single-phase ZnO nanoparticles in the wurtzite type hexagonal lattice, whereas 10% doping concentration, either Mn- or Cr-single doping or codoping, resulted in formation of wurtzite ZnO as a major phase with ZnMnO3 or/and ZnCr2O4 secondary phases. From XRD and HRTEM, the produced nanomaterials have average crystallite sizes ranged from 15 to 35 nm. Applying Kubelka–Munk function, optical band gap energy (Eopt) was determined. Eopt of single Mn- and Cr-doped ZnO increased than that of bulk ZnO mainly due to Burstein–Moss effect, whereas it decreased in the codoped Zn1−x−yMnxCryO because of the negative and positive corrections in the conduction and valence band, respectively, brought about by alteration of the sp–d exchange interactions between the band electrons and the localized d-electrons of the Mn2+ and Cr3+ ions. Magnetization measurements indicated that Cr induced the paramagnetism, while Mn induced the RT ferromagnetism in the synthesized Zn1−x−yMnxCryO nanoparticles. The ferromagnetic Zn1−x−yMnxCryO compositions could be potential candidates for Mn–Cr-codoped ZnO-based DMS nanoparticles. [ABSTRACT FROM AUTHOR]

Mechanical, electronic, and thermoelectric properties of the RhTiZ (Z = As, Sb) compounds and their [111] thin films have been calculated based on the DFT framework. The RhTiZ (Z = As, Sb) bulk structures have stability in the mechanical and thermodynamic viewpoints, with 1.1 eV and 0.98 eV energy gaps, respectively. Their thermoelectric behaviors referred to the proper ZT and power factor at high temperatures suitable for power generators. Most of the RhTiZ (Z = As, Sb) [111] films have a half-metallic nature, while the γ-phase cases have magnetic moments than others. The γ-phase RhTiSb has a suitable figure of merit and power factor for cooling applications. [ABSTRACT FROM AUTHOR]

In this study, theoretical investigation on structural, electronic and magnetic properties of the cubic perovskite oxide NdCrO3 has been performed within density functional theory. The exchange and correlation potential is treated by three approximations: generalized gradient approach of Perdew, Burke and Ernzerhof (GGA–PBE), GGA plus band correlated Hubbard parameter (GGA + U) scheme and GGA plus Tran–Blaha-modified Becke–Johnson (TB-mBJ–GGA) approximation which has been used to describe the energy band gap more accurately. Structural results found in the course of this study are in perfect agreement with experimental measurements and show that the ground state of the studied compound is ferromagnetic. The electronic band structures and density of states display a half-metallic behavior of the cubic perovskite NdCrO3 with an indirect band gap in minority spin. The magnetic study shows that the total magnetic moment of 6 μB mainly originates from the both atoms Nd and Cr. The integer value confirms a half-metallic nature of the studied material. Consequently, the NdCrO3 is a promising candidate for the useful spintronic applications. [ABSTRACT FROM AUTHOR]

First-principles calculations, based on the density functional theory (DFT), have been used to predict the structural, elastic, electronic and magnetic properties of XMg3O4 (X = Li, Na, K and Rb) compounds. They have been performed by employing the full-potential linearized augmented plane wave method (FP-LAPW), as implemented in Wien2k code. It was found that all compounds were ferromagnetic by energy minimization procedure. The computations of elastic constants show that our compounds are mechanically stable. The electronic properties, through the density of states and band structures, indicate that these compounds exhibit half-metallic nature, and the spin up band gaps (HMgaps) were found to be5.32 (0.18) eV, 4.49 (0.28) eV, 3.01 (0.38) eV and 1.53 (0.17) eV for LiMg3O4, NaMg3O4, KMg3O4 and RbMg3O4, respectively. In addition, for all compounds, the calculated integer magnetic moment value of 1.0 µB fulfills the necessary condition of the half-metallicity. The calculated Curie temperatures T c are 537, 365, 260 and 113 K for LiMg3O4, NaMg3O4, KMg3O4 and RbMg3O4, respectively. [ABSTRACT FROM AUTHOR]

The first-principle calculations were performed in the framework of the density functional theory (DFT) using FP-LAPW method as implemented in Wien2k code to determine the structural stability, electronic, and magnetic properties of quaternary Heusler alloys Cr2TaGe1-xSnx (x = 0, 0.25, 0.50, 0.75, 1.00), The results showed that for the compounds, the AlCu2Mnl-type structure is energetically more stable than CuHg2Ti-type structure at the equilibrium volume. The calculated lattice constants for Cr2TaGe and Cr2TaSn are 6.081 Å and 6.311 Å, respectively. For mechanical properties, shear modulus, Young's modulus, elastic constants, Poisson's ratio and shear anisotropy factor have studied. Their obtained values reveal that these compounds are mechanically stable. The electronic band structures and density of states of our compounds show a half metallic character with total magnetic moments, − 3.00 μB per formula unit with indirect band gap, 0.569 eV and 0.482 eV for Cr2TaGe and Cr2TaSn respectively. Regarding thermal properties such as the thermal expansion coefficient, heat capacity, and Debye temperature, we have applied a very suitable model for studying thermodynamics quantities called the quasi-harmonic Debye model. On the basis of these results, these alloys are predicted to be good candidates for future spintronic applications. [ABSTRACT FROM AUTHOR]

In this paper, we used the ab-initio calculations, based on the Korringa-Kohn-Rostoker (KKR) method combined with the coherent potential approximation (CPA), to simulate the magnetic properties of ZnO, doped and co-doped with manganese and carbon, respectively. For this purpose, we have used two different approximations: the Local Density Approximation (LDA) and the Local Density Approximation-Self-Interaction Correction (LDA-SIC). Numerical results are presented for the compound Zn1 − 0.06Mn0.06O1−xCx when doping and co-doping is performed with Mn and C as doping elements. Total and partial DOSs are given for different concentrations using the two approximations, LDA and LDA-SIC. It is found that for 6% with doping by Mn the system becomes magnetic. The co-doping with carbon changes the behavior of the system : it becomes also magnetic for 4, 6 and 10% concentrations within both, LDA and LDA-SIC approximations. Furthermore, we have discussed the type of mechanism of exchange interaction and found that the double exchange is responsible for the appearing magnetism in the system, within the LDA and p-d interaction for LDA-SIC approximation. For 10% of carbon, we have found that the critical temperature approaches 280 K in the LDA approximation solely; and is about 305 K in the LDA-SIC approximation. [ABSTRACT FROM AUTHOR]

The structural, electronic, and magnetic properties of Ti2RhSn1-xSix, Ti2RhSn1-xGex, and Ti2RhGe1-xSix (x = 0, 0.25, 0.5, 0.75, and 1) quaternary Heusler alloys have been investigated using first-principles density functional theory within generalized gradient approximation (GGA) and local spin-density approximation with Hubbard-U corrections (LSDA+U). The calculations have been performed using the full-potential linearized augmented Plane wave plus local orbitals method. The crystal structures of Ti2RhSn1-xSix, Ti2RhSn1-xGex, and Ti2RhGe1-xSix were found to be cubic in (F-43m) symmetry for x = 0, 1 and cubic in (P-43m) symmetry for x = 0.25, 0.75, while tetragonal in (P-4m2) symmetry for x = 0.5. The results show that all Ti2RhSn1-xSix, Ti2RhGe0.75Si0.25, and Ti2RhGe alloys are half-metallic ferrimagnetic. These new materials are good candidates for potential applications in spintronic. [ABSTRACT FROM AUTHOR]

The structural, electronic, optical, and magnetic properties of the ternary mixed compound CsTexS1−x (x = 0.25, 0.50, and 0.75) with supercell 2 × 2 × 1-CsCl structure have been investigated using a first-principles method, considering that their pure binary compounds, such as CsS and CsTe, crystallize in CsCl phase. The main outcome of the study is that the lattice constants and energy bandgap for the majority spin all exhibit quasilinear variation with increase in the concentration of S ions. It was also determined that the magnetic moments per formula unit are mainly due to the magnetic moments of the p-orbitals of the S/Te anions. Interestingly, the ferromagnetism of the anion is found without the inclusion of transition-metal elements, representing a remarkable property of these materials. Furthermore, the optical properties of these magnetic systems show a quite similar tendency, and the high reflectivity at zero photon energy illustrates weak absorption for all the studied materials. It is therefore suggested that CsS and CsTe could be potential candidates for use in spintronic applications. [ABSTRACT FROM AUTHOR]

The mechanical stability and physical properties of Co2V1−xZrxGa (x = 0, 0.25, 0.50, 0.75, 1) have been predicted by using ab initio calculations based on density functional theory. The exchange-correlation potentials are treated within the generalized gradient approximation-Perdew-Burke and Ernzerhhof (GGA-PBE) and Hubbard coefficient (GGA+U). The investigated minimum lattice parameter of Co2VGa is 5.8030 Å, which is in excellent agreement with available experimental and theoretical data and for Co2V1−xZrxGa (x = 0.25, 0.50, 0.75, 1) are 5.9026, 5.9625, 6.0060 and 6.0021 Å, respectively, which are predicted for the very first time. The total magnetic moments decrease with increasing concentration of x in Co2V1−xZrxGa, in agreement with the Slater-Pauling rule. Band structure and density of states calculations show that the minority spin channel exhibits band gaps of 0.43, 0.46, 0.52, 0.54 and 1.01 eV for GGA+U scheme around the Fermi level confirming that all the studied composites are half-metallic in nature. In this study, we also studied the elastic constant and it is established that all the materials are mechanically stable and ductile in nature. The Co2VGa is stiffer than other materials and all the studied composites have anisotropic behaviour. Moreover, by using a quasi-harmonic Debye model and calculated elastic constant, the Debye temperature and temperature-dependent constant volume heat capacity have been investigated. [ABSTRACT FROM AUTHOR]

In this work, we use the full potential linearized augmented plane wave (FP-LAPW + lo) method under the framework of spin polarization density functional theory (SP-DFT) to study the structural properties of diluted magnetic semiconductors alloys, Mg1−xCrxSe (x = 0.25, 0.50 and 0.75), in the rock–salt ferromagnetic phase by using the WC-Cohen GGA approximation. To compute the electronic and magnetic properties of our compounds, we have used the Tran Blaha modified Becke–Johnson potential (TB-mBJ) combined with PBE approximation. The results of electronic properties show that our compounds have a half-metallic behavior with a spin polarization of 100% at the Fermi level. Moreover, at all concentrations, the magnetic moment has been estimated as equal to 4.0 (μB). Furthermore, to validate the effects resulting from the exchange splitting process, we calculate the values of the spin-exchange constants N0α and N0β, respectively. Finally, we present in detail the effects of the temperature and the pressure on some macroscopic thermodynamic parameters by using the quasi-harmonic Debye model. [ABSTRACT FROM AUTHOR]

The effects of spin polarization on the structure, magnetic, and optoelectronic properties of Cr-based series of double perovskites Sr2CrXO6 (X = La and Y) have been studied by using the full-potential linearized augmented plane-wave method (FP-LAPW), based on the density functional theory (DFT) as implemented in the Wien2k code, within the generalized gradient approximation (GGA), GGA + U, and GGA plus Trans-Blaha-modified Becke-Johnson (TB-mBJ) as the exchange correlation. Our results show a similar half-metallic ferromagnetic ground state for both materials. From the electronic properties, it is found that Sr2CrYO6 has a direct band gap at (Γ-Γ) direction and Sr2CrLaO6 has an indirect band gap at (Γ-W) direction. Furthermore, we have computed the optic and thermodynamic properties which are investigated for the first time. Consequently, the magnetic, optoelectronic, and thermodynamic properties show these compounds are promising for high technological applications, namely spintronic materials. [ABSTRACT FROM AUTHOR]

The electronic, magnetic, and thermoelectric properties of ZTi2O4 (Z = Mg, Zn, and Cd) spinel oxides are analyzed by applying DFT approach. The band structure (BS) and density of states (DOS) illustrate a ferromagnetic state due to the evident exchange splitting leading to the energy shift in the spin-polarized sub-bands. Furthermore, ferromagnetic state stability is also justified through the computed crystal field, Jahn-Teller, and exchange energies. The exchange energy exceeding the crystal field energy reveals that ferromagnetism is mediated due to electrons, which is also consistent with the computed negative indirect exchange energy. Using BoltzTraP code, thermoelectric investigation illustrate that Mg, Zn, and Cd cations can tune the optimum power factor to intermediate and higher temperatures, which suggests potential energy harvesting applications. [ABSTRACT FROM AUTHOR]

The structural, electronic, and magnetic properties I-II2-III-VI4 and I2-II-IV-VI4 are investigated firstly by using the first-principles calculations. The investigation was done using the ab initio full-potential linearized augmented plane wave (FPLAPW) method where the exchange-correlation potential was calculated with the frame of GGA and GGA+U. The theoretically predicted lattice parameters for I-II2-III-VI4 and I2-II-IV-VI4 alloys are in good agreement with existing experimental measurements. The possibility of half-metallic ferromagnetism in I-II2-III-VI4 and I2-II-IV-VI4 (I = Cu; II = Mn, Fe, Co; III = In; IV = Ge, Sn; VI = S, Se, Te) was analyzed by electronic band structure and density of states calculations. We found that Cu2CoGeS4, Cu2FeGeS4, Cu2FeSnS4, and CuMn2InSe4 compounds exhibit a complete half-metallic characteristic with a total spin moment of 3.00, 4.00, 4.00, and 10.00 μB and direct band gap of (Eg ↑ =  0.63 eV), (Eg ↑ =  0.90 eV), (Eg ↑ =  0.31 eV), and (Eg ↓ =  1.10 eV), respectively. These results may be of interest for spintronic applications. [ABSTRACT FROM AUTHOR]

Increasing the density of data storage is crucial to the future of inexpensive digital technology. The large majority of storage in the “Cloud” consists of magnetic hard-disk drives. The continued evolution of this USD$30 billion industry depends on the commercial introduction of heat-assisted magnetic recording (HAMR). This technology uses heat from a laser beam confined well below the diffraction limit, <50-nm wide, to write to media near 450°C with high magnetic anisotropy that would normally be unwriteable under available magnetic fields. This high anisotropy guarantees thermal stability even for grain sizes around 5-nm diameter, which are necessary for major increases in storage density. In this article and in the articles in this issue, we introduce HAMR requirements and discuss its numerous interdisciplinary materials challenges, including high-temperature/efficient plasmonic materials, low-loss optical materials, highly ordered/thermally anisotropic nanoscale magnetic grains, block copolymers for directed assembly below 10 nm, high-temperature nanometer-thick coatings/lubricants, materials/interfaces to control heat flow at nanometer length scales, and advanced spintronic materials. [ABSTRACT FROM PUBLISHER]

We report on the structural, mechanical, magneto-electronic and thermodynamic properties of cubic sodium based fluoro-perovskite NaXF3 (X $=$ V, Co) through density functional theory (DFT). The generalized gradient approximation of Perdew, Burke, and Ernzerh (GGA-PBE) and the Tran-Blaha modified Becke-Johnson potential (TB-mBJ) are used for modeling exchange-correlation effects. The calculated lattice parameters agree well with the experimental measurements. Elastic properties show that these compounds are mechanically stable. The results of spin-polarized band structure show a half metallic behavior of NaVF $_{3}$ and NaCoF $_{3}$ . The magnetic study shows that the nature of these compounds is ferromagnetic and the integer value of the total magnetic moment confirms the half metallicity for both materials. The thermodynamic characters are also investigated through quasi-harmonic approximation. [ABSTRACT FROM AUTHOR]

In this work, the electronic and magnetic properties of SnFeO spinel ferrite with various cation distributions (mixed, normal and inverse spinel phases) were studied. The calculations were performed by Korringa-Kohn-Rostoker (KKR)-coherent potential approximation (CPA) method with generalized gradient (GGA) approximation for the exchange and correlation functional. Our spin-polarized calculations give a half-metallic character for SnFeO inverse spinel phase and near half-metallic character for SnFeO mixed spinel phase and metal character for SnFeO normal spinel phase. These results, which contribute to understanding the effect of the cation distribution in SnFeO ferrite with spinel structure in the existence of gap states occupied by majority and minority spin electrons, the spin magnetic moments, the magnetization and the half-metallic behaviour. [ABSTRACT FROM AUTHOR]

The magnetic properties of FeO, with the presence of Fe and O vacancy atoms, were carried out using the KKR-CPA method in density functional theory (DFT) implemented in the MACHIKANYAMAv2009 package, by considering local density approximation (LDA) and local density approximation-self-interaction-correction (LDA-SIC) approximations. Our study presents total, atoms projected density of states (DOS), and magnetic moments of different atoms in FeO with and without vacancy atoms; we provide an atomic level insight for magnetite which is a necessary step to understand their electronic, half-metallicity, and magnetic properties. We also noticed that the half-metallic behaviors of FeO contribute to a better understanding of the utility of this material in spintronic applications. [ABSTRACT FROM AUTHOR]

We present a quantum-mechanical first-principle calculation of the structural, elastic, electronic, and magnetic properties of the full-Heusler compounds TiNi X ( X= Al, Ga, and In). The calculation uses the full-potential linearized augmented plane waves plus local orbital method to describe Ti-based Heusler alloys. The results show that these compounds exhibit half metallic characteristics over a wide range of mesh parameters and obey the Slater-Pauling rule, which states that the total magnetic moment per unit cell M = Z − 18 for half-Heusler compounds XYZ and M = Z − 24 for full-Heusler X YZ compounds. For these new alloys TiNi X ( X= Al, Ga, and In), we initially considered the two possible L2 structures AlCuMn and CuHgTi. However, two subsequent structural studies showed that only the CuHgTi-like structure is half metallic. Over a wide range of mesh parameters, the calculations give a total magnetic moment of 3.00 μ . These results suggest that TiNi X ( X= Al, Ga, and In) are promising materials for spintronic applications. [ABSTRACT FROM AUTHOR]

Using the first principles with local density approximation (LDA) and self-interaction-corrected local density approximation (SIC-LDA), the electronic structure of transition metal-doped copper indium sulfide chalcopyrite (CuInS) has been calculated and the effect of low-impurity concentration on magnetic structure has been carried out for both LDA and SIC-LDA; also, the magnetic transition temperature for Cr-doped CuInS was reported in the concentration range of 1-6 % with LDA and SIC-LDA. It is shown that the chalcopyrite semiconductor-doped transition metals (with low concentration) exhibit a high magnetic critical temperature and half-metallic behavior that could have a significant participation in spintronic applications. [ABSTRACT FROM AUTHOR]

Density functional theory based on the full-potential linearized augmented plane wave (FP-LAPW) method is used to investigate the structural, magnetic, electronic, and elastic properties of Heusler alloys CoYIn (Y = Ti, V). It is shown that the calculated spin magnetic moments using the local spin-density approximation (LSDA), generalized gradient approximation (GGA), LSDA + U, and Tran-Blaha (TB)-modified Becke-Johnson (mBJ)-local density approximations (LDA) are in good agreement with the Slater-Pauling rule. The obtained results with LSDA, GGA-PBE, and LSDA + U of the density of states illustrate that both compounds have a metal behavior; however, mBJ-LDA predicts CoVIn alloy to be a half metal. The band structure obtained with mBJ-LDA has an indirect band gap along the Γ- X symmetry with energy of 0.4 eV for CoVIn, and E lies in the middle of the gap; the electrons at the Fermi level are fully spin-polarized. The calculation of elastic properties indicates the stability of these compounds, and they have a ductile behavior. The 3D dependences of Young's modulus exhibit a strong anisotropic character. The high values of the elastic constant C reflect the strength of the bonding Ti (V)-In. [ABSTRACT FROM AUTHOR]

Quantum information and computing are at the forefront of computer science, but their implementation relies on significant developments in materials science. In particular, suitable, lattice-matched substrates for two promising approaches—electrostatically defined quantum dots in Si/SiGe heterostructures, and superconducting circuits containing Josephson junctions—do not exist. Instead, these approaches rely on metamorphic substrates. In this article, we focus on the general structure and requirements of SiGe quantum dot heterostructures, the demands they impose on the underlying substrate, and the impact that properties of the metamorphic substrate have on device performance. Superconductor Josephson junction materials are briefly discussed in a similar fashion, and opportunities for future developments in both systems are described. [ABSTRACT FROM AUTHOR]