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In this work, CeO 2 nanocrystals with a mixture of distinct morphologies were obtained using different solvents (acetone or ethanol). The (micro)structural, sensing mechanism, and magnetic properties, as well as first-principle calculations were evaluated. XPS reveals that the sample synthesized in acetone exhibited a diminished Ce4+ content (and heightened Ce3+ concentration) compared to the sample synthesized in ethanol. In the case of the syntheses at acetone, sphere-like nanoparticles and nanorods present a predominance of surfaces (111) and (220), while the syntheses with ethanol led to a predominance of surfaces (200) for the sphere-like nanoparticles. Theoretical simulations reveal the spin polarization of f electrons in Ce ions neighboring oxygen vacancies suggests that oxygen vacancies situated at the surface may engender a greater number of magnetic moments compared to those induced by an oxygen vacancy within the bulk. At room temperature, the M S of CeO 2 nanocrystals crystallized in acetone (66.20 emu-g) surpasses that of the CeO 2 nanocrystals obtained in ethanol (24.07 emu-g), which can be attributed to the differing morphologies of the samples. Our findings illustrate that, in addition to the solvent type, the size and morphology of the particles also play a significant role in influencing the sensing mechanism and magnetic properties. Films based on CeO 2 nanocrystals synthesized via MAS using acetone and ethanol revealed a fast response time of 9.6 s and 12 s, with a recovery time of 45.6 s and 87.6 s towards CO gas, respectively, these phenomena are attributed to the presence of oxygen vacancies, which facilitate the adsorption of CO. Our findings are key for facet engineering and may provide new strategies for producing CeO 2 based-materials to be applied in morphology-dependent technologies, such as carbon monoxide (CO) gas sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] • PtSe 2 monolayer is a non-magnetic indirect-gap semiconductor 2D material. • Either half-metallic or magnetic semiconductor natures are induced by doping with TMX n clusters. • Magnetic properties depend on the spin ordering in the incorporated clusters. • TMN n clusters act as charge gainers, meanwhile TMP n clusters lose charge. • Efficient methods to make new highly spin-polarized 2D materials towards spintronic applications are proposed. In this work, doping with TMX n (TM = Mn and Fe; X = N and P, n = 3 and 6) clusters is proposed to modify the electronic and magnetic properties of PtSe 2 monolayer. Pristine PtSe 2 monolayer is a non-magnetic two-dimensional (2D) semiconductor material with indirect band gap of 1.40(2.01) eV obtained from PBE(HSE06)-based calculations. PtSe 3 -type multivacancies lead to the monolayer magnetization with total magnetic moment of 0.54 μ B , where Pt and Se atoms around defect sites produce mainly the system magnetism. In contrast, no magnetism is induced by PtSe 6 -type multivacancies. The substitutional incorporation of TMX n clusters magnetizes significantly PtSe 2 monolayer, where both TM and X atoms originate mainly the magnetic properties. Depending on the spin orientation in the clusters, total magnetic moments between 0.00 and 8.00 μ B are obtained. All the doped D TMX n systems exhibit strong spin polarization around the Fermi level, which is derived mainly from the outermost TM- 3 d , N- 2 p , and P- 3 p orbitals. Consequently, either half-metallicity or magnetic semiconductor behavior can be induced, depending on the nature of TMX n cluster. Further, the Bader analysis indicates that TMN n clusters act as charge gainers due to the more electronegative nature of N atoms in comparison with Se atoms, meanwhile TMP n clusters transfer charge to the host PtSe 2 monolayer. Our study may introduce the cluster doping in PtSe 2 monolayer as efficient method to create new highly spin-polarized 2D materials towards spintronic applications. [ABSTRACT FROM AUTHOR]

Heusler alloys based on 4d-elements are relatively less explored though they are known to host interesting electronic/magnetic properties useful for future spintronics applications. Here, we report a comparative study of the structural and magnetic properties of FeRuVSi (FRVS) and FeRuVGe (FRVG) using experimental and theoretical tools. Magneto-transport measurements have also been carried out to probe the role of magnetism on their transport behaviour. Room temperature (T) X-ray diffraction data reveals cubic crystal structure (space group No. 216) with B 2 type antisite disorder between Fe and Ru sites in both the alloys. They show ferromagnetic behaviour below the Curie temperature (T C) 84 K for FeRuVSi and 57 K for FeRuVGe respectively. The field dependence of magnetization at low-T shows saturating (nearly saturating) behaviour for FRVS (FRVG). Transport measurements show metallic behaviour with a sharp reduction in the resistivity near T C. Ab-initio calculations predict nearly half metallic behaviour with ∼ 87 % and ∼ 89 % spin polarization for FRVS and FRVG in their ordered states. The inclusion of antisite disorder changes the magnetic configuration, leading to a visible decrease in the magnetic moment and spin polarization. The calculated net moment and the transport properties agree fairly well with those observed experimentally. These results confirm the importance of disorder in determining the intrinsic properties of these alloys. Such combined studies help in the identification of more novel quantum materials suitable for future spintronic applications. ● We present a comparative study of the magnetic, transport, and electronic properties of FeRuVZ (Z = Si, Ge) Heusler alloys. ● Disorder increases the symmetry of the FeRuVSi Heusler alloy to L 2 1 type, higher than that in FeRuVGe. ● The magnetization goes from saturating to nearly saturating behaviour when Si is changed to Ge. ● High spin polarization and nearly half metallic behaviour in the ordered state in both the alloys. [ABSTRACT FROM AUTHOR]

The weak magnetic properties of Ni 0.25 NbSe 2 are attributed to the delocalized nature of Ni-3 d electrons and hence poor spin polarization. [Display omitted] • Ni x NbSe 2 with x = 0, 0.05, 0.1, 0.15, 0.2 and 0.25 were synthesized and observed that Ni intercalation limit is 25 %, beyond which NiSe phase segregates. • A phase transition is observed beyond x = 0.20 in Ni x NbSe 2 with a 2 a o × 2 a o × 1 c o order superstructure. • Theoretical calculation on Ni 0.25 NbSe 2 shows that the magnetic spins are very weakly spin-polarized and the Ni-3 d states are more delocalized. • Magnetic measurements on Ni x NbSe 2 (x = 0.05, 0.1, 0.2, 0.25) shows very small magnetic moment at low temperature for all the compounds attributed to the delocalized nature of Ni-3 d electrons, which is conformed from the theoretical studies. The article presents the synthesis, structural and magnetic properties of Ni x NbSe 2 (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25). The intercalation limit of Ni in NbSe 2 is found to be 25 mol%, above which NiSe appears as a binary impurity phase. Single crystal X-ray diffraction studies show that all the compounds crystallize in the hexagonal P6 3 /mmc space group. However, there is a distinct phase transition beyond x = 0.20 with Ni intercalation in Ni x NbSe 2. The Ni x NbSe 2 compounds crystallized in the parent 2H phase with x value between 0 ≤ x ≤ 0.2. Subsequently, the phase transforms into the 2H(I) phase with an order superstructure of 2 a o × 2 a o × 1 c o for 0.20 ≤ x ≤ 0.25 in Ni x NbSe 2. The superstructure formation is attributed to the occupation of Ni at the alternate octahedral voids present in the van der Waals gap of the NbSe 2. The XPS results and theoretical analysis clearly show that the intercalation of Ni results in a more metallic character in Ni x NbSe 2. Magnetic measurements on Ni x NbSe 2 (x = 0.05, 0.1, 0.2, 0.25) shows very small magnetic moment at low temperature for all the compounds. Theoretical calculation on Ni 0.25 NbSe 2 shows that the Ni-3 d electrons are delocalized and are very weakly spin-polarized, which may be the reason for the experimentally observed weak magnetism in these compounds. [ABSTRACT FROM AUTHOR]

Rhenium-based double perovskite oxides (DPOs) are a particularly fascinating class of materials because of high carrier spin polarization, large magnetic anisotropy energy (MAE), and complex electrical behavior along with high Curie temperature (T C). Herein, we discussed the impact of biaxial ([110]) strain ranging from − 5% to ＋ 5% along the a b -plane on the electronic and magnetic properties of CaCuFeReO 6 (CCFRO) DPO using a b - i n i t o calculations. The unstrained system exhibits a ferrimagnetic (FiM) spin ordering as an energetically stable magnetic ground state due to electron hopping between Fe + 3 /Re + 5 t 2 g and Cu + 2 e g orbitals along with a metallic electronic state. Moreover, [010] (b -axis) is the magnetic easy axis that produces the MAE of 5.36 meV, giving a giant MAE constant of 1.97 × 1 0 7 erg/cm 3. The evaluated partial spin-magnetic moment on the Cu1/Cu2/Fe/Re ion is 0.14/0.44/4.04/ − 0. 64 μ B , where " − " sign on the Re moment means that its spin is antiparallel to the other ions, verifying the FiM ordering in the system. Also, the e g , t 2 g / e g , and t 2 g orbital characteristics of Cu + 2 , Fe + 3 , and Re + 5 ions are visible in the spin-magnetization density iso-surfaces plots, respectively. Using the classical Heisenberg model, the computed T C for the unstrained structure is 576 K, which is quite close to the experimentally reported value of 567 K. In addition, it is shown that the FiM metallic behavior in the motif is robust against biaxial ([110]) strain within the considered range. It has also been revealed that T C increased to 5.73%/3.30% for the considered range of − 5% compressive/＋5% tensile strain due to improved structural distortions. [Display omitted] • A ferrimagnetic (FiM) state is found the energetically stable one. • [010] (b-axis) is the magnetic easy axis having MAE of 5.36 meV, giving a giant MAE constant of 1.97 × 107 erg/cm 3. • T C increased to 5.73%/3.30% for the considered range of −5% compressive/+5% tensile strain. [ABSTRACT FROM AUTHOR]

We employed first-principles calculations to investigate the structural, electronic, and magnetic properties of carbon/boron nitride nanoribbons in different sizes and doping, using twenty-eight zigzag and armchair configurations. We note that the structures present dynamic stability, with formation energies slightly higher than those of the respective undoped nanoribbons. Our electronic calculations revealed that BN-doped armchair carbon nanoribbons exhibit narrow bandgap semiconductor behavior. Most of the zigzag carbon nanoribbons doped with BN exhibited metallic behavior, in addition to exhibiting non-zero spin polarization in these cases. However, carbon-doped boron nitride nanoribbons in both configurations – zigzag and armchair – exhibited wide-gap semiconductor behavior. We also observed that the energy gap in the band structure directly depends on the doping position. The incorporation of boron and nitrogen pairs into the center of the zigzag carbon nanoribbons does not significantly alter the magnetic properties of the nanoribbons. However, when performed at or near the edges, it results in significant changes in spin polarization. Therefore, based on these results, we can consider potential applications of these nanoribbons in electronic devices. • The studied structures exhibit dynamic stability. • Doping-induced semiconductor behavior. • Band structure is directly influenced by doping position. • Doping with boron and nitrogen in nanoribbons has little impact on magnetic properties. [ABSTRACT FROM AUTHOR]

Magnetic tunnel junctions are the core component of spintronic devices, and good magnetic tunnel junctions require high tunnel resistance, which is determined by the spin polarization of the thin films of ferromagnetic layers that make up their structure. Therefore, the design of ferromagnetic films with high spin polarization is a current research hotspot in this field. In the current study, we taken the half-metallic CrYCoAl as an object, and studied the influence of surface effect on the half-metallic behavior. Especially, we constructed the CrYCoAl (100), (110), and (111) surfaces to study their stability, electronic and magnetic properties. Results show that the YY and YAl (100) surfaces, and Co (111) surface retain the half-metallic behavior and structural stability of bulk, which provide a basis for CrYCoAl application as a thin films in magnetic tunnel junctions thus, they are likely to be used in the spintronic devices. • Stability of CrYCoAl (100), (110) and (111) surfaces are estimated by their phase diagrams. • Atomic relaxation and surface roughness are discussed. • Electronic and magnetic properties of CrYCoAl (100), (110) and (111) surfaces are studied. • The YAl and YY (100), and Co (111) termination surfaces maintain the half-metallic nature of bulk CrYCoAl. [ABSTRACT FROM AUTHOR]

• Highly ordered L2 1 type heusler alloy film on cu substrate. • Near stoichiometric Co 2 FeSn films by electrodeposition. • High magnetic moment, high T C and high effective anisotropy films. • Co 2 FeSn films (320 nm −1400 nm thick) with high crystalline order. • Minority band gap close (∼0.05 eV) to fermi level. Co 2 FeSn films have been electrochemically deposited on polycrystalline Cu substrates in potentiostatic mode. Processed films with thicknesses of 320 nm, 780 nm, and 1400 nm exhibited highly ordered L2 1 type crystal structure with saturation magnetizations of 1023.38 kA/m (5.08 ± 0.04 μ B /f.u.), 1035.31 kA/m (5.14 ± 0.04 μ B /f.u.) and 1044.34 kA/m (5.18 ± 0.04 μ B /f.u.) at 5 K and 965.00 kA/m (4.79 ± 0.04 μ B /f.u.), 967.75 kA/m (4.81 ± 0.04 μ B /f.u.), and 1003.52 kA/m (4.97 ± 0.04 μ B /f.u.) at 300 K, respectively. The soft ferromagnetic films possess coercivity of ∼ 15.92 kA/m (200 Oe) with a high effective anisotropy constant of ∼ 105 J/m3. Thermo-magnetization measurements yielded high Curie temperatures of 995 K, 1005 K, and 1123 K for films of thicknesses 320 nm, 780 nm, and 1400 nm, respectively. Tailoring the thickness from 320 to 1400 nm could be achieved by merely varying the electrodeposition time without appreciable departure from chemical stoichiometry or compromise in crystalline order or magnetic properties. This establishes a methodology to prepare high quality L2 1 ordered Co 2 FeSn films with a few hundred nanometers thickness by electrodeposition. Electrodeposited Co 2 FeSn films with high magnetic moment, high K e f f value, and high Curie temperature are potential candidates for fabricating nanomagnetic devices. [ABSTRACT FROM AUTHOR]

Spin-Polarized optical parameters for Sr 2 UFeO 6 double perovskite. [Display omitted] • The Sr 2 UFeO 6 is half-metallic having indirect energy band gaps. • The Sr 2 UFeO 6 to be anti-ferromagnetic with a major contribution from Fe+3. • The Sr 2 UNiO 6 , as ferromagnetic in nature with a major contribution from Ni+6. • The peaks in ε 2 ω are linked to various inter-band transitions. • These double perovskites show substantial absorption in UV region. The electronic, and magneto-optical properties of Sr 2 UXO 6 (X = Fe, & Ni) double perovskite materials, in the monoclinic structure, were calculated employing the full-potential Linearized augmented plane wave (FP-LAPW) approach based on the density functional theory (DFT). The results reveal that Sr 2 UFeO 6 is half-metallic and anti-ferromagnetic, whereas Sr 2 UNiO 6 is semiconducting and ferromagnetic. The spin-polarized linear optical features, including the dielectric functions, absorption coefficients, energy loss functions, reflectivity coefficient, and refractive indexes, have been calculated and analyzed in the energy range of 0–14 eV. The study reveals that both materials exhibit transmission at low energies, making them promising candidates for optoelectronic applications. Moreover, the presence of distinct absorption and reflectivity peaks suggests potential applications in tunable optical devices and sensors. The dispersion characteristics of the refractive index open up new possibilities for developing novel photonic materials. [ABSTRACT FROM AUTHOR]

• Property of multicomponent soft magnetic alloy was predicted by first-principles calculation. • Complex competition exists among Fe, Ni, and Cr in affecting physical properties. • Relatively high contents of Fe and Cr is expected for great electromagnetic performance. • Ni is beneficial to enhancing the system stability of the face-centered cubic structure. • This work give a strategy for accelerated design of multicomponent soft magnetic alloy. Multicomponent alloys (MCAs) exhibit excellent soft magnetic properties and other service performance, and are promising for high-end applications. However, their complicated effects of element mixture and low efficiency in research and development could limit their industrialization. Hence, in this work, first-principles calculation was conducted on the relative formation energy, magnetism and density of states of Fe-Ni-Cr-Si-P-B-C-Nb MCAs for predicting its alloy stability, saturation magnetization (B s) and electric resistivity (ρ). The calculation results mainly present the mixture effects among Fe, Ni and Cr. There is a complex competition among Fe, Ni, and Cr elements in affecting the physical properties of the MCAs. The magnetism of the MCAs is not only determined by composition of magnetic elements but also by the coordination environment around the magnetic atoms. To achieve both high B s and high ρ in the Fe-Ni-Cr-Si-P-B-C-Nb system, proper addition of Fe and Cr may be expected. The optimized MCA has a relatively high B s nearly equal to the Fe-Si-Al system, and exhibits higher ρ and higher spin polarization. This indicates that the proposed MCAs are promising for both power devices and spintronic applications. This work gives a strategy for the property prediction and accelerated design of MCAs by first-principles calculation. It has promising potential to explore other element systems as for high-performance soft magnetic MCAs. [ABSTRACT FROM AUTHOR]

Monolayer SnO has attracted extensive attention due to the unique electronic properties, which have potential applications in nanoelectronic and optoelectronic devices. Transition metal (TM) atoms are often used to modulate electronic structures and magnetic properties of two dimensional (2D) materials, which can facilitate the application of these materials in spintronic devices. The electronic structure and magnetic characteristics of 3 d TM (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) adsorbed SnO monolayer are predicted by first-principle calculations. The n -type doping in the SnO monolayer appears when Sc, Ti, V, Cr, Mn, Fe and Zn atoms are adsorbed. Co, Ni and Cu adsorptions induce the p -type doping in the SnO monolayer. In addition, the magnetic moments of SnO in the adsorption systems are in the range from −0.038 to 0.414 μ B , and that reach the maximum at the case of Ni-absorbed. It is also found that Fe, Co and Ni adsorbed SnO monolayers have a perpendicular magnetic anisotropy (PMA), while Ti, V, Cr and Mn adsorbed SnO monolayers have an in-plane magnetic anisotropy (IMA). Our results indicate that TM adsorbed SnO monolayers have the potential applications in spintronic devices. Unlabelled Image • n -Type doping in SnO monolayers appears when Sc, Ti, V, Cr, Mn, Fe and Zn are adsorbed. • Co, Ni and Cu adsorptions induce the p -type doping in SnO monolayer. • TM atoms adsorption can induce the spin polarization in monolayer SnO. • Fe, Co and Ni adsorbed SnO monolayers show perpendicular magnetic anisotropy. [ABSTRACT FROM AUTHOR]

[Display omitted] The quaternary Heusler alloys with composition LiAEFeSb have been studied in this manuscript (AE = Alkaline Earth elements Be, Mg, Ca, Sr and Ba) for their potential applications in spintronics. All the investigations have been performed by employing density functional theory. A systematic comparison of results obtained within local density approximation (LDA) and the generalized gradient approximation (GGA) done. Our calculations reveal that all the studied alloys have lowest energy in type-I arrangement of basis and exhibit interesting electronic and magnetic properties. All the alloys exhibit a stable ferromagnetic ground state. Fixed spin moment calculations rule out existence of any other local magnetic minima. The phonon dispersions show that all the alloys except LiBeFeSb are dynamically stable. Notably, LiSrFeSb and LiBaFeSb exhibit half-metallic electronic band structure and 100 % spin polarization making them suitable choice for promising spintronic applications such as spin filter and detectors. [ABSTRACT FROM AUTHOR]

• The magnetism of LaFe x Ni 1- x O 3 are investigated based on the first principles. • A detail discussion of magnetic performance of FM and AFM in LaFe x Ni 1- x O 3 system. • LaFe x Ni 1- x O 3 undergoes a magnetic transition from FM to AFM when x increases to 0.5. • The magnetic moment of O atom increases with the increase of Fe doping concentration. The effect of different Fe doping concentration (x = 0.125, 0.25, 0.375 and 0.5) on electronic structure and magnetic properties of LaNiO 3 (LNO) have been performed on the spin polarization calculations based on first principles. The calculation results show that with the increase of Fe dopant concentration, LaFe x Ni 1- x O 3 undergoes a magnetic transition from ferromagnetism (FM) to antiferromagnetism (AFM). The net magnetic moments of LaFe 0.125 Ni 0.875 O 3 , LaFe 0.25 Ni 0.75 O 3 , LaFe 0.375 Ni 0.625 O 3 and LaFe 0.5 Ni 0.5 O 3 in the FM ground state are found to be 12.00 µ B /supercell, 16.00 µ B /supercell, 20.06 µ B /supercell and 23.96 µ B /supercell, respectively. In the magnetic configuration of AFM of LaFe x Ni 1- x O 3 (x = 0.125 and 0.375) with the nearest doping position, the asymmetric magnetic structure leads to the symmetry of the spin-ordered AFM network is broken, resulting in the generation of net magnetic moment of -3.06 µ B and 3.87 µ B. The net magnetic moment in LaFe x Ni 1- x O 3 mainly originates from transition metals (TM) Fe, Ni and magnetized O atoms. [ABSTRACT FROM AUTHOR]

• DFT calculations were used to study the magnetic properties of the Fe 2 MnAs alloy. • The influence of point defects on these properties were investigated. • The formation energy, density of states, and magnetic moments, were computed. • The contraction of the lattice enhance the spin polarization of the Fe 2 MnAs alloy. • The defects of Mn As , Mn ↔ As, V As , and V Mn exhibit 100% spin polarization. First-principles calculations within the framework of the density functional theory were conducted using the FP-LAPW method to investigate the electronic and magnetic properties of the Full-Heusler Fe 2 MnAs alloy. The study encompassed the examination of its perfect structure as well as the variation of lattice constants around the ground state. The negative value of the calculated formation energy suggests that the alloy may form spontaneously. From a magnetic perspective, Fe 2 MnAs exhibit a ferromagnetic order. The alloy also shows a high spin-polarization that may be increased, transforming the alloy into a half-metal, with the contraction of the lattice constant. Furthermore, the investigation delved into the effect of point defect formation. The calculated formation energies for vacancies, antisite, and exchange defects suggest the likely occurrence of some of these defects within the Fe 2 MnAs compound. Significantly, certain defects contribute to the spin-polarization of the alloy, effectively rendering it a fully half-metallic material. [ABSTRACT FROM AUTHOR]

• An effect of oxygen vacancy on the electronic and magnetic properties of copper pyrophosphate compound was investigated using DFT calculations. • The vacancy presence reduced the gap width from 2.17 eV to 0.19 eV, changing its character from indirect to direct. • The oxygen vacancies slightly modify the spin polarization of d-orbitals of Cu atoms neighboring the vacancy, resulting in the non-zero total magnetic moment of 0.19 µB/FU. The effect of oxygen vacancies (V O) on the electronic and magnetic properties of copper pyrophosphate dihydrate Cu 2 P 2 O 7 *2H 2 O (CuPPD) semiconductors is studied employing the DFT-based ab initio pseudopotential method. Site preference for vacancy formation on the selected oxygen sublattices is analyzed. Investigations revealed that the V O vacancies led to narrow bands of hybridized Cu-3d and O-2p states within the energy gap of perfect CuPPD semiconductors, significantly reducing the gap width from 2.17 eV to 0.19 eV and changing its character from indirect to direct one. Calculations have shown that the vacancies have no significant influence on the ferrimagnetic structure of CuPPD. The magnetic properties are driven by local magnetic moments of Cu atoms pointed oppositely. The oxygen vacancies slightly modify the spin polarization of d-orbitals of Cu atoms neighboring the vacancy, resulting in the non-zero total magnetic moment of 0.19 µ B /FU (0.0 µ B /FU in perfect CuPPD). The study's main finding, which can be exploited in nanoelectronics, is that the controlled implementation of oxygen vacancies can regulate the energy gap of CuPPD semiconductors. [ABSTRACT FROM AUTHOR]

• A dynamical study at atomistic-scale on the behavior of non-collinear antiferromagnetic Mn 3 Pt driven by current-induced spin orbit torque. • Two different field-free magnetic excitation modes can be achieved in W/Mn 3 Pt heterostructures with varying crystalline direction. • Oscillation frequency depends on the injected current density as well as the antiferromagnetic layer's thickness. Current-induced spin–orbit torque (SOT) enables highly efficient manipulation of magnetic orders. Non-collinear antiferromagnets exhibit ultrafast spin dynamics by SOT with much higher oscillation frequency than ferromagnets, offering potential applications in terahertz spintronic devices. In this study, we used atomistic scale Landau-Lifshitz-Gilbert simulation approach to demonstrate different magnetic excitation modes in W/Mn 3 Pt heterostructures with varying crystalline direction. When the spin polarization is perpendicular to the Kagome plane of Mn 3 Pt, all the magnetic Mn atoms oscillate periodically within the Kagome plane around the normal direction. In contrast, when the spin polarization is parallel to the Kagome plane, only two neighboring Mn atoms rotate while another neighboring Mn atom remains immobile. Interestingly, both of these magnetic excitation modes have the same frequencies and occur in the terahertz range. Additionally, the frequency is proportional to current density and inversely proportional to the antiferromagnetic layer thickness. These findings provide a deeper understanding of magnetic excitation properties in non-collinear antiferromagnets, which can inform the design of terahertz spintronic devices. [ABSTRACT FROM AUTHOR]

• The effect of 3d TM dopants (12.5% doping concentration) in BiCoO 3 having C-type AFM arrangement has been studied using first principle calculation to study the structural, electronic and magnetic properties. • The defect states are introduced due to presence of 3d TM dopants in BCO. • The PDOS reveal that V, Ni and Zn doped BCO exhibit half metallic characteristics. • The net magnetization was found to arise due to TM doping at Co site which may be attributed to the uncompensated Co spins and is mainly localized on the TM dopant. • SSP model was used to explain the net magnetization in the system due to 3d TM dopants in BCO system. • Ti doped BCO system found to be most stable due to lowest formation energy as compared to other 3d TM doped BCO system. In this paper, the influence of 3d transition metal (TM) dopants in BiCoO 3 (BCO) having C-type antiferromagnetism has been studied using first principles calculation. The value of c/a ratio is found to improve for Sc, V, Mn, Fe, Ni, Cu and Zn doping in BCO which indicates an increase in the tetragonality ratio upon introduction of these dopants in BCO. The formation energy calculations pointed out that it is easier to incorporate the TM atoms having number of d atoms lesser than that of Co (d < 7) in BCO. The electronic, and magnetic properties were studied and it was found that the electron/hole traps are introduced due to the presence of 3d TM dopant in BCO. The partial density of states reveal that V, Ni and Zn doped BCO exhibit half metallic characteristics with a lower band gap value among the other TM doped BCO systems. It was interesting to note that the presence of states in both spins at Fermi level due to Cu doping leads to a transition of BCO towards metallic behaviour in contrast to pure BCO having a clear band gap of 1.77 eV. The net magnetization was found to arise due to TM doping at Co site which may be attributed to the uncompensated Co spins and is mainly localized on the TM dopant. Successive spin polarization model (SSP model) was used to explain the net magnetization in the system due to 3d TM dopants in BCO system. The electron localization function plots also reveal that for d < 5 the electrons are localised near the TM metal ions and for d > 5 the localization impacts the near neighbouring Co ions. From this study, it is suggested that the magnetic and electronic properties of BCO system, can be tuned by 3d TM doping which has vast potential in photovoltaic and magneto-electric applications. [ABSTRACT FROM AUTHOR]

We report a systematic experimental and theoretical study of half-metallic Heusler alloys Mn 2 V 1−x Co x Al (x = 0, 0.25, 0.5, 0.75, 1). In this study, using the arc-melting method and optimizing annealing temperatures, we succeed to synthesize Mn 2 V 1−x Co x Al (x = 0, 0.25, 0.5, 0.75, 1) alloys with evident L2 1 (or XA) order. A near compensated ferrimagnetic moment of 0.02 μB/f.u. at 5 K is observed with the Co concentration of 0.5 which is consistent with the S-P rule. In addition, we systematacially investigate the effects of Co concentration on electronic structure of Heusler alloys Mn 2 V 1−x Co x Al (x = 0, 0.25, 0.5, 0.75, 1) using first-principles calculations, and found that the half-metallic characteristic persists for all Co concentrations. In line with our experimental results, employing appropriate atomic site occupation, we obtained a full compensated ferrimagnetic moment of 0 μB/f.u. for stoichiometric Mn 2 V 0.5 Co 0.5 Al alloy. In addition, the robustness of half-metallic properties for compensated ferrimagnet Mn 2 V 0.5 Co 0.5 Al with the variation of atomic disorder are investigated and the results indicate that the Mn-Al swapping weakly destroys the half-metallic properties and the compensated ferrimagnet Mn 2 V 0.5 Co 0.5 Al alloy maintains the high spin polarization under the effect of B2 disorder. • Mn 2 V 1−x Co x Al (x = 0, 0.25, 0.5, 0.75, 1) alloys with evident L2 1 (or XA) order are fabricated successfully. • Magnetic properties can be regulated by component ratio of Co and V. • A full compensated ferrimagnetic moment of 0 μB/f.u. for stoichiometric Mn 2 V 0.5 Co 0.5 Al alloy is obtained. • Half-metallic properties of Mn 2 V 0.5 Co 0.5 Al is robust against atomic disorder. [ABSTRACT FROM AUTHOR]

We report the structural stability and half-metallicity of the half-Heusler alloy CoMnSe via the density functional theory (DFT). The γ -phase ferromagnetic of CoMnSe is more energetically stable than other phases. The electronic and magnetic properties show that the CoMnSe is a false half-metal ferromagnetic with 98.10% spin polarization and a total magnetic moment of 4 μ B . This value is in good agreement with the Slater-Pauling rule and available data using the GGA method, whereas the GGA+U method shows it is a ferrimagnetic metal with 95.73% spin polarization, and the total magnetic moment is 4.01 μ B. The effects of Bulk strain and axial strain demonstrate that the relative change of total magnetic moment M t o t and spin polarization P of CoMnSe is almost negligible, indicating that the half-metallicity is strong against Bulk strain and axial strain. Using Monte Carlo simulations, a transition ferromagnetic-paramagnetic response is also studied. • CoMnSe alloy is mechanically and thermodynamically stable. • CoMnSe does not undergo martensitic transformation. • CoMnSe is found to be falsely half-metallic using GGA, while it is metallic using GGA+U. • The high spin polarization and Curie temperature make CoMnSe suitable for spintronic. [ABSTRACT FROM AUTHOR]

[Display omitted] • The electronic and magnetic properties of pristine and defected sheets before and after Sc metal decoration are investigated. • The E g values are reduced in the order of pristine(2.01 eV) > 55-77 (1.90 eV) > 5–8-5(1.90 eV) > 4-55-7777(0.58 eV). • The Sc-1 metal decoration produces one unpaired electron to the complex which transforms it to the magnetic state. • The highest spin polarization of P = 4.15 in Pristine_A and P = 3.41 in the 4-55-7777_I complex is obtained. To scrutinize the electronic and magnetic properties of fluorinated pristine, stone wales, di-vacancy, and two stone wales defected graphene sheets by scandium (Sc) metal decoration, the density functional theory is used. The obtained maximum binding and interaction energy values confirm that the two Sc metals decorated on the direct top and bottom of pentagonal rings of the two stone wales graphene sheet have stronger interactions than others. To validate the interactions, natural population analysis and electron density difference map are performed, revealing that Sc metal is the electron donor in all complexes. After the formation of defects in the pristine sheet, energy gap values are reduced in the defected sheets. The density of states infers the shift in the fermi level of all complexes after defect formation and metal decoration. The ultraviolet–visible spectral analysis exposes the highest absorption peaks of all bare sheets at the UV region and after Sc metal decoration, the peaks get red shifted. The results show that Sc metal decorated on two stone wales graphene sheet interacts better with Sc metals than other complexes. The decoration of single Sc metal in all four bare sheets transforms the sheet from a non-magnetic to a magnetic state but when two Sc metals are decorated it became non-magnetic. The highest degree of spin polarization, P = 4.15 is obtained while decorating a single Sc metal on the hexagonal ring of the pristine sheet. The outcome of this work suggests that Sc metal decoration on pristine and defected graphene sheets has great potential to improve the electronic and magnetic properties of graphene for designing spintronic and data storage devices. [ABSTRACT FROM AUTHOR]

Silicon (Si) is the dominant material in the semiconductor industry with some novel properties, the introduction of germanium (Ge) and vacancies lead to special electronic and magnetic properties. In this work, the effects of spin-polarized electrons regulate the electronic and magnetic properties for substituted Ge in bulk crystalline Si (Ge Si) with vacancies and electrical charge states introduced are investigated based on first-principles calculations. It is found that the electron spin density of Ge-vacancy (GeV) and Ge-divacancy (GeV 2) complex structures is redistributed, the number of the defect energy levels is changed, and the magnetic moment on atoms appears when vacancies are introduced in Ge Si. In addition, the distribution of the defect energy levels in the band gap is affected by charge states (negative and neutral), resulting in changes in the degree of spin-splitting, orbital occupation and electron filling, energy levels degeneracy, and the magnitude of the magnetic moment. These results show that the spin polarization on Ge Si with vacancies and charge states, the number and the distribution of the vacancies around Ge, all play important roles in regulating the magnetic moments, magnetic properties, and the magnitude and distribution of defect energy levels. [ABSTRACT FROM AUTHOR]

In this study, the author theoretically investigates the effect of the external Rashba interaction on the properties of spin transport in a magnetic MoS 2 superlattice. The results show that the spin conductance of the magnetic MoS 2 superlattice heavily relied on the applied external magnetic field in the presence of more than one barrier. Moreover, the spin conductances with and without the spin-flip exhibited a gap, the size of which increased with the number of the barriers in the superlattice. The spin-dependent conductance in the magnetic MoS 2 superlattice could be controlled by changing the number of barriers to the superlattice and the strength of the Rashba interaction. The spin polarization exhibited oscillating behavior in terms of the energy of the incident electron and the strength of the Rashba interaction. Remarkably, full-spin polarization could be achieved by using an MoS 2 superlattice under an external magnetic field. The results of this study confirm that the magnetic MoS 2 under the Rashba interaction can be used in spintronics and electronics devices in the future. [Display omitted] • Transport properties were investigated in a magnetic MoS 2 superlattice. • The spin conductivity with and without spin flip has a gap. • Spin-dependent conductivity can be controlled by changing the number of barriers. • Direction and value of the spin polarization can be changed by magnetic field. • By a magnetic MoS 2 superlattice, the 100% spin polarization current can be obtained. [ABSTRACT FROM AUTHOR]

For the purposes of fitting the characteristics of the Magnesium sulfide (MgS) and, Magnesium selenide (MgSe) semiconductors in Spintronic applications, a theoretical ab-initio investigation of Transition metals (TM=Ti, V, Cr, Mn, Co, Ni) substitution is performed. The equilibrium properties have been studied in the zinc-blende phase of MgS and MgSe. The effects of temperature and pressure on the structural, electronic, thermodynamic, and magnetic properties of our systems are explored as well. It is found that the introduction of the TMs in MgS and MgSe brings out a half-metallic ferromagnetic behavior with 100% polarization around Fermi level in Ti, V, Cr, Co and Ni cases, contrary to the Mn case where the half-metallic feature does not appear. The double exchange mechanism was the mechanism responsible for magnetism in these systems. Finally, the high Curie Temperate (T c) of the ferromagnetic systems reveals that Ti, Cr and V substitutions could play a significant role in spintronic applications. • Electronics & magnetism merge, yielding Innovative materials & components for Spintronics. • Half-metallic magnets are 100% spin polarization; ideal for Spintronic apps. • Investigating transition metal substitutions (Ti, V, Cr, Mn, Co, Ni) in MgS and MgSe. • Half-metallic ferromagnetic found for Ti, V, Cr, Co, & Ni substitutions, except Mn. • High Curie temperature for Cr, V, and Ti substitutions above room temperature. [ABSTRACT FROM AUTHOR]

We present our work on the structural, electronic and magnetic properties of monolayer-CdS which was subjected to bi-axial strain and hydrogenation at possible adsorption sites using the first-principles calculations. The results show that both bulk-CdS and monolayer-CdS are non-magnetic direct (Γ − Γ) band-gap semiconductors. By applying a compressive strain up to −10 % the monolayer-CdS remain direct band-gap semiconductor with a maximum band gap value of 2.11 eV. In contrast, a semiconductor to metal transition occurred at 17 % applied tensile strain. Moreover, hydrogenation on all possible adsorption sites induces ferromagnetism and p -type conductivity in monolayer-CdS. Among all possible adsorption sites, H added on the Cd-top site is the most probable site showing strong ferromagnetism and half-metallicity. The strong ferromagnetism means 100 % spin polarization is retained up to applied bi-axial strain of −5 % to +15 %. Also, half-metallicity is robust under the bi-axial strain in the range of −4 % to +2 %. To determine the strength of the exchange-coupling parameter, the FM (ferromagnetic) and AFM (anti-ferromagnetic) coupling between added atoms was investigated under the bi-axial strain of −5 % to + 5 %. Our findings show that H added on the Cd-top site makes it ferromagnetic and half-metallic above room temperature. The maximum Curie temperature T c = 651.41 K is achieved at a strain of ɛ = −2 % of ferromagnetic state. This high Curie temperature has not been achieved for any 2D material to-date. The present work provides a route to harness the ferromagnetism and thermal stability of 2D monolayer-CdS for electronic and spintronic applications. [ABSTRACT FROM AUTHOR]

• The intrinsic magnetic properties can be modulated by geometrical configuration. • The spin degeneracy semiconducting ground state can be lifted by electric field. • The half-metallicity can be induced at critical electric field strength. It has been known for a long time that graphene flakes of certain geometries can develop spontaneous spin polarization. Here, it is studied what happens when two triangular graphene nanoflakes, possibly different sizes, are placed in close proximity with AB (Bernal) stacking. The results of first-principles calculations show that the magnetic ground state of the bilayer system depends on the different sizes of the two nanoflakes, and spin-related energy gap can be controlled with external electric fields. Under certain circumstances, the system even can be tuned into half-metallic nature, which might potentially be exploited in future spintronics applications. [ABSTRACT FROM AUTHOR]

In this study, the half-metallic behavior and magnetic properties of various (001) surfaces for Y 2 CrSn Heusler alloy were investigated using the spin-polarized first-principles method. The spin polarizations of the standard stable YSn-terminated and artificial stable SnSn-terminated (001) surfaces were −96.9% and −95.8%, respectively, using the generalized gradient approximation (GGA) method (−69.2% and −83.0% using the GGA + U method), and thus the two surfaces have potential use in spintronic devices. The spin polarizations of the standard YCr-terminated, artificial YY-terminated, and artificial CrCr-terminated (001) surfaces were only −43.0%, 29.3%, and −40.8%, respectively, using the GGA method (−63.2%, −67.9%, and −44.4% using the GGA + U method). The atomic magnetic moments (AMMs) of the Y and Cr atoms in the outmost layer changed greatly due to the surface states, but little change was found in the AMMs of atoms near the central layer. The average AMMs obtained for the Sn, Y, and Cr atoms using the GGA + U method were only slightly larger than the corresponding AMMs determined using the GGA method. Image 1 • Spin polarizations of stable YSn and SnSn-term (001) surfaces were high. • Spin polarizations of unstable YCr, YY, and CrCr-term (001) surfaces were low. • Atomic magnetic moments of Y and Cr atoms changed little in the outermost layer. • Little change in atomic magnetic moments of atoms near the central layer. [ABSTRACT FROM AUTHOR]

• Origin of the large saturate moment at 5 K in Fe 2 MnGe DO 19 phase was determined. • Phase stability of cubic and hexagonal Fe 2 MnGe was investigated. • "Why Fe 2 MnGe DO 19 phase is stable at room temperature" was discussed. • Information on electronic structure of Fe 2 MnGe DO 19 phase was presented. The electronic structure, phase stability and magnetic properties of cubic and hexagonal type Fe 2 MnGe were investigated and compared with the well-known Heusler alloy Fe 2 MnSi. Three different structures L2 1 , DO 3 and DO 19 were considered for them. In both alloys the cubic phase (L2 1 and DO 3) has a lower total energy comparing with the hexagonal DO 19 phase at 0 K. But in Fe 2 MnGe the energy difference between the DO 19 and L2 1 phases is much smaller than Fe 2 MnSi. The DO 3 disorder can lower the stability of the cubic phase further and make the total energies of hexagonal and cubic phases closer, this can help the DO 19 phase gain stability. Finally, in Fe 2 MnGe, the energy difference is 0.12 eV/f.u., much smaller than the 0.41 eV/f.u. in Fe 2 MnSi. That is the possible reason why Fe 2 MnGe DO 19 phase can be synthesized experimentally and Fe 2 MnSi cannot. L2 1 type Fe 2 MnGe is a half-metal with 100% spin polarization and has a total spin moment of 3μ B /f.u. The spin polarization ratio of DO 3 phase is also high. But for the DO 19 hexagonal phase, a normal ferromagnetic metal character is observed. The calculated total moment for DO 19 type Fe 2 MnGe is larger than 6μ B /f.u. This total moment comes mainly from the large and parallel coupled partial spin moments of Fe and Mn. [ABSTRACT FROM AUTHOR]

Highlights • We studied the structural, electronic and magnetic properties of transition-metal (TM) (Cr, Mn, Fe, Co, Ni and Cu) adatoms on WS 2 monolayer by performing first-principles calculations. • Based on the adsorption energy, TM atoms prefer to occupy the T W site, above the W atoms, for all the cases. • The results indicate that systems of Cr, Mn, Fe and Co adsorbed on WS 2 monolayer are magnetic, while in Ni and Cu atoms adsorbed don't have any magnetic properties. • The TM atoms are adsorbed chemically to the WS 2 layer. The obtained values of the total magnetic moment vary from 4 μ B to 1 μ B in case of Cr to Co adsorption, respectively, which agree with the Slater-Pauling rule. • Based on magnetic moment of 0.00 μ B , non-magnetic states are realized for Ni and Cu adsorption. More importantly, a high spin polarization of 100% at the Fermi level is achieved in the Cr, Mn, Fe and Co adsorption, which implies the potential for application in spintronic devices. Abstract Given the various applications of half-metals in the spintronics devises, we studied the structural, electronic and magnetic properties of transition-metal (TM) (Cr, Mn, Fe, Co, Ni, and Cu) adatoms on WS 2 monolayer by performing first-principles calculations. Based on the adsorption energy, TM atoms prefer to occupy the T W site, above the W atoms, for all the cases. The results indicate that systems of Cr, Mn, Fe, and Co adsorbed on WS 2 monolayer are magnetic, while in Ni and Cu atoms adsorbed don't have any magnetic properties. The TM atoms are adsorbed chemically to the WS 2 layer. The obtained values of the total magnetic moment vary from 4 μ B to 1 μ B in case of Cr to Co adsorption, respectively, which agree with the Slater-Pauling rule. Based on the magnetic moment of 0.00 μ B , non-magnetic states are realized for Ni and Cu adsorption. More importantly, the high spin polarization of 100% at the Fermi level is achieved in the Cr, Mn, Fe and Co adsorption, which implies the potential for application in spintronic devices. [ABSTRACT FROM AUTHOR]

This manuscript reports the theoretical results on the magnetic and electronic properties of the new rare-earth element based LuCoVGe equiatomic quaternary Heusler (EQH). To investigate the magnetic and electronic properties of this compound, we used the both Methods: The first-principles calculations using Quantum Espresso and the Monte Carlo simulations (MCS). The good properties of LuCoVGe alloys that is, large half-metallic gaps and 100% spin polarization fulfill the requirements of the candidate materials for diverse applications especially in spintronics. A clear behavior of half-metallicity appearing in the First principles calculations when to investigate the density of states (DOS) and band structure of the Heusler compound LuCoVGe. On the other hand, for non-null temperature values, the behavior of the total magnetizations are presented as a function of the temperature, exchange coupling interactions, crystal field and the external magnetic field. Finally, we outlined and talked about the hysteresis loops as a function of the external magnetic field, when settling the values of the examined physical parameters. • The Heusler LuCoVGe is studied. • DFT and Monte Carlo simulations are used. • The hysteresis loops are presented. [ABSTRACT FROM AUTHOR]

Abstract The structural, mechanical, electronic and magnetic properties of quaternary Heusler ZrTiRhGa alloy have been investigated by using the first-principles calculations within the generalized gradient approximation GGA. The results of our calculations show that the type (I) of ZrTiRhGa, with the ferromagnetic (FM) state, is the most stable configuration among three possible configurations. The GGA + U calculations, where U is on-site Coulomb interaction correction, are performed to investigate the relationship between band gap and Hubbard potential. The calculated results showed that ZrTiRhGa compound is half-metallic material (HMM) with complete spin polarization around the Fermi level. The total magnetic moment is 2 μB per formula unit and follows the Slater-Pauling rule μt = Zt−18. The calculated elastic constants, cohesive and formation energy, for ZrTiRhGa compound, were analyzed in detail and reveal the mechanical stability. In addition, we investigated the sensitivity of the half-metallicity with two structural-type changes: hydrostatic and tetragonal deformation. Our calculations show that the half-metallicity can be preserved with lattice constants from 5.74 Å to 7.12 Å, under the influence of hydrostatic strain and in the range of the c/a ratio from −8% to 12% with the effect of the tetragonal strain. For ZrTiRhGa, since there is no available experimental data, our calculations are considered as first predictions. Highlights • The quaternary Heusler ZrTiRhGa alloy has HM nature at the equilibrium volume. • The calculated Mtot of quaternary Heusler ZrTiRhGa alloy is 2 µB, which is in agreement with Slater- Pauling rule. • ZrTiRhGa alloy maintains the HM nature when the values of lattice constant are included between 5.74 Ǻ -7.12 Ǻ. • The quaternary Heusler ZrTiRhGa alloy maintains the HM nature, in the range of the c/a ratio from 0.81 to 1.2. [ABSTRACT FROM AUTHOR]

Abstract The electronic structures and magnetic properties of 6H-SiC doped with N, C vacancies (V C), Si vacancies (V Si) and Al are studied by first principles calculations. The results indicate that the N substituting C in 6H-SiC cannot order magnetism but V Si can introduce magnetic moments effectively. Ferromagnetism coupling is obtained in (N, 2 V Si)-codoped 6H-SiC. The ferromagnetism can be mainly attributed to the interactions between the 2 p orbitals of C atoms around Si vacancies. More interestingly, substituting Si with Al can enhance the ferromagnetic states in 6H-SiC in neutral states. We also studied the effect of charge on magnetic properties and provide an effective method of tuning magnetism in 6H-SiC. Highlights • The doping with N Si , V Si and (N C , V Si) can induce ferromagnetism in 6H-SiC crystal. • Ferromagnetism can be enhanced by Al substituting and charge. • The spin polarization is proposed as the origin of ferromagnetism. [ABSTRACT FROM AUTHOR]

Abstract The inverse Heusler alloy Zr 2 RhAl is investigated using first-principles calculations. The calculations are carried out using the full-potential linearized augmented plane wave plus local orbital (FP-LAPW + lo) method that is employed in the WIEN2k package. The structural, electronic, magnetic, and thermoelectric properties are studied. It is found that the ferromagnetic phase of Zr 2 RhAl is the most stable with lattice parameter 6.6328 Å. The calculations showed that there is an energy gap in the spin down channel whereas the spin up channel is metallic, resulting in a 100 % spin polarization at Fermi level. This is an obvious characteristic of half-metallic materials. The calculated total magnetic moment of Zr 2 RhAl is found to be 2 μ B which follows the generalized Slater-Pauling rule. The Curie temperature is estimated to be 607 K using the mean field approximation. Transport properties are studied using the Boltzmann theory with constant relaxation time approximation. The variation of transport properties with temperature is investigated using the two current model. Highlights • The ferromagnetic phase of Zr 2 RhAl is the most stable magnetic phase. • The Zr 2 RhAl have metallic behavior for spin–up channel and a semiconducting behavior for the spin down channel with band gap 0.50635 eV. • The Curie temperature of Zr 2 RhAl was found to be 607 K within the mean field approximation. • The transport properties for the spin-down channel show promising future for thermoelectric applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Structural, magnetic and optical properties of Mg-doped CeO 2 (1 1 1) surface were investigated. • The doped CeO 2 (1 1 1) surface systems exhibit different bonding character. • The doped surface and subsurface systems result in local and scattered spin atmosphere. • The incorporation of Mg can lead to the red shift of absorption edge. Abstract The electronic structure, magnetic and optical properties of Mg-doped CeO 2 (1 1 1) surface have been investigated by first-principles calculations. In this paper, the doping case is actively favorable to process under O-rich conditions than under Ce-rich conditions. The distortion of doping systems of Mg replacing Ce of surface is larger than that of subsurface. The covalent character is getting weaker and the ionic character is gradually obvious for Mg O bond from surface to subsurface doping. The results show that the existence of defect states with O 2 p orbital character makes spin splitting, causing the local and scattered magnetic moments for surface and subsurface doping of Ce, respectively. And the 9 and 12 atomic layers doping systems exhibit magnetic ground states with different magnetic moments. In particular, the calculated Curie temperature (about 434, 483, 1200 K) is higher than room temperature (RT), therefore, the theoretical results showed that Mg-doped CeO 2 (1 1 1) thin films would can be obtained stable room temperature ferromagnetism (RTFM), which is beneficial to practical application. In addition, the optical properties show that all doped systems are capable of enhancing effective absorption of visible and near-infrared light. [ABSTRACT FROM AUTHOR]

• We performed a computational and theoretical study of FeCrTiAl. • Our calculations indicate that this material undergoes several band structure transitions. • Another interesting feature of FeCrTiAl is that its spin polarization changes sign from negative to positive under pressure. • At the largest considered lattice parameters, this compound exhibits nearly 100% spin polarization. Spin-gapless semiconductors (SGS) represent a new type of compounds with potential applications in novel spintronic devices. Here, we performed a comprehensive computational and theoretical study of FeCrTiAl, a quaternary Heusler compound that was recently predicted to exhibit nearly SGS properties. Our calculations indicate that this material undergoes several band structure transitions from essentially semimetallic phase at smaller lattice constants to nearly type-II SGS at the ground state, then to nearly type-III SGS and further to nearly type-I SGS, as the lattice parameter is increased. Another interesting feature of FeCrTiAl is that its spin polarization changes sign from negative to positive as the volume of the cell increases. At the largest considered lattice parameters, this compound exhibits nearly 100% spin polarization. The mechanical expansion discussed in this text may be achieved, in principle, either by applying an epitaxial strain in thin-film geometry, or by chemical substitution, for example with non-magnetic element of larger atomic radius. We hope that the presented results may provide guidance for further research on mechanical strain induced manipulation of electronic and magnetic properties of spin-gapless semiconductors. [ABSTRACT FROM AUTHOR]

In this paper, we study the structural, electronic, magnetic, mechanical and thermal properties of Half-Heusler CoMnTe, using the Density Functional Theory (DFT) with the generalized gradient approximation (GGA) and GGA plus the Hubbard correction (GGA+U). The obtained results show that the compound is more stable in γ -phase with the ferromagnetic (FM) configuration than the nonmagnetic (NM) among the three considered structural phases (α , β , γ) and there is no possibility of martensitic transformation under the tetragonal distortion effect. The computed total magnetic moments of CoMnTe by GGA and GGA+U are 4 μ B and 4.13 μ B , respectively, arising mainly from the Mn atom. The obtained density of states and band structures using GGA approach show that the compound exhibits half-metallic behavior with 100% spin polarization. As the Hubbard is added, the electronic properties show an electronic phase transition from half-metallic to metallic behavior with 68% spin polarization. While the thermal and mechanical properties show very small changes, confirming that the studied compound is mechanically and dynamically stable. • CoMnTe compound is more stable in γ -phase with the ferromagnetic configuration. • CoMnTe compound is mechanically and thermodynamically stable. • CoMnTe compound is promising for spintronic applications. [ABSTRACT FROM AUTHOR]

The density functional theory (DFT) studies are made to calculate the electronic, magnetic, and transport characteristics of potassium lanthanide KXO2 (X = Pr, Nd, and Pm) oxides have been studied by using the WIEN2K code. Perdew Burke Ernzerhof-Generalized Gradient approximation (PBE-GGA) is used for the exchange-correlation energy of the crystal structures in the hexagonal phase. However, the volume-optimized graphs depict that these compounds are energetically stable in the ferromagnetic state. Moreover, the studies of the spin-up channels of the band structure and density of states (DOS) reveal their metallic behavior whereas semiconductor nature has been noticed through spin-channels. Therefore, studied materials have half metallicity nature with 100% spin polarization at the Fermi level (EF). Total and partial magnetic moments of KXO2 (X = Pr, Nd, and Pm) and individual atoms exist due to unpaired 4f electronic states of the lanthanide ions, present at the EF. The energy difference between anti-ferromagnetism and ferromagnetism versus the volume optimization curve gives the curie temperature (Tc). The volume optimization curves show a flat region where both magnetic states have similar energies. This means the material can exist at the equilibrium volume in either state. Finally, thermoelectric properties are calculated by the BoltzTraP code. Our results unveil that these potassium-based lanthanide oxides are potential materials for devising spintronics devices and lifting future practical applications. • Studied materials have half metallicity nature with 100% spin polarization at E F. • Total and partial magnetic moments of KXO 2 and individual atoms exist due to unpaired 4 f states of La. • Energy difference between anti-ferromagnetism and ferromagnetism energy vs volume optimization curve gives value of T C. • The figure of merit is higher for KPmO2, KNdO2 as compared to KPrO2. [ABSTRACT FROM AUTHOR]

Spin-polarized, first-principles total energy calculations have been performed to investigate the structural, electronic and magnetic properties of the chromium nitride (0 0 1) surface. Different approximations were used to treat the non-classical exchange correlation energy: LDA, GGA, LDA + U (3 eV ≤ U ≤ 5 eV) and GGA + U (1 eV ≤ U ≤ 4 eV). It was found that LDA + U with U = 4 eV describes correctly the structural, electronic and magnetic properties of bulk CrN. The CrN (0 0 1) surface has been investigated, employing the surface formation energy (SFE) formalism. For the surface in the cubic phase, three different structures were found to be stable: an ideally terminated surface, one with no nitrogen atoms in the second layer, and one with half of the nitrogen atoms missing in the second layer. In the case of the orthorhombic surface, only the ideal surface is stable in all the range of the chemical potential. Density of States (DOS) calculations show a metallic behavior for all the stable surface structures, with the main contribution around the Fermi level coming from Cr-d orbitals. The effect of nitrogen vacancies is clearly observed with an increase in the metallic behavior in the structures having less nitrogen atoms. [ABSTRACT FROM AUTHOR]

Effect of Cr doping on the magnetic structure and electronic properties of Fe 2 VSi has been investigated by experimental measurement and first-principles calculations. In Fe 2 V 1-x Cr x Si, ferromagnetism can be stabilized with 10% Cr substitution. The Curie temperature T C increases rapidly with increasing Cr content and reaches 365K when x = 0.4. The saturation magnetization M s also increases with increasing Cr content. A small amount of A15 secondary phase is observed with increasing Cr content at x = 0.4, indicating that the solid solubility of Cr in Fe 2 VSi has been reached. In Fe 2 V 1-x Cr x Si, high spin polarization ratio is predicted when x ≥ 0.25, and half-metallic character is observed when x = 0.5, 0.75 and 1.0. The calculated total spin moment M t also increases with increasing x. When x is larger than 0.2/0.25, the experimental/theoretical total moment gets close to the Slater-Pauling curve of M = Z - 24 for half-metallic Heusler alloys. All this makes Fe 2 V 1-x Cr x Si promising candidates for spintronic applications. [ABSTRACT FROM AUTHOR]

In this paper, using first-principles calculations based on density-functional theory, the electronic structures, magnetic properties, and half-metallicity in the bulk and (001) surface of quaternary Heusler alloy CoNbMnSi are studied. For the bulk, the CoNbMnSi compound shows half-metallicity with a band gap of 0.5 eV in the down-spin direction at a equilibrium lattice constant of 5.88 Ǻ. At a similar equilibrium lattice constant, the half-metallicity confirmed in the bulk CoNbMnSi, is ruined at both NbSi- and MnCo-terminated (001) surfaces and subsurfaces. Based on the magnetic property calculations, the magnetic moments of Mn and Nb atoms at the (001) surfaces increase with respect to the corresponding bulk values, while the magnetic moment of Co and Si atoms decreases. The spin-polarization ratio clearly decreases below 75% for (001) surfaces and subsurfaces of the CoNbMnSi alloy. [ABSTRACT FROM AUTHOR]

On the basis of first principles calculations, the electronic structures and magnetic properties of quaternary Heusler alloys RbCaNZ (Z = O, S, and Se) were studied. The negative formation energies indicated that all these compounds were thermodynamically stable and thus may be experimentally synthesized at appropriate conditions in the future. The results showed that Y I structure was the most favorable configuration among the three possible structures. All compounds were found to be half-metallic ferromagnets. The characteristic of energy bands and origin of half-metallicity were also verified. The total magnetic moments of RbCaNZ (Z = O, S, and Se) compounds were obtained 2 μ B per formula unit, which were in an agreement with Slater-Pauling rule ( M tot = 12  −  Z tot ). Half-metallicity was preserved at ranges of 5.06–8.36 Å, 5.96–8.81 Å, and 6.13–8.73 Å for RbCaNO, RbCaNS, and RbCaNSe compounds, respectively, which show that these quaternary Heusler compounds may be potential candidates in spintronic applications. [ABSTRACT FROM AUTHOR]

Aim of this study is to investigate spin transportation in double quantum ring (DQR). We developed an array of DQR to measure the transmission coefficient and analyze the spin transportation through this system in the presence of Rashba spin-orbit interaction (RSOI) and magnetic flux estimated using S-matrix method. In this article, we compute the spin transport and spin-current characteristics numerically as functions of electron energy, angles between the leads, coupling constant of the leads, RSOI, and magnetic flux. Our results suggest that, for typical values of the magnetic flux ( ϕ / ϕ 0 ) and Rashba constant ( α R ), such system can demonstrates many spintronic properties. It is possible to design a new geometry of DQR by incoming electrons polarization in a way to optimize the system to work as a spin-filtering and spin-inverting nano-device with very high efficiency. The results prove that the spin current will strongly modulate with an increase in the magnetic flux and Rashba constant. Moreover it is shown that, when the lead coupling is weak, the perfect spin-inverter does not occur. [ABSTRACT FROM AUTHOR]

The structural, electronic, and magnetic properties of (ZnO) 12 clusters doped with Cr atoms have been investigated by using spin-polarized first-principles calculations. The exohedral a3 isomer is favorable than endohedral a2 isomer. The isomer a1 and a5 respectively have the narrowest and biggest gap between highest unoccupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO) of 0.473 and 1.291 eV among these five monodoped isomers. The magnetic moment may be related to the local environment around the Cr atom that the a2 isomer whose total magnetic moment is 6 μ B while the other monodoped isomers which all isomers have nearly total magnetic moments 4 μ B . For Cr-doped (ZnO) 12 on a1 or a3 isomer, the DOS of spin-up channel cross the Fermi level E F showing a finite magnitude near the Fermi level which might be useful for half metallic character. For the bidoped cases, the exohedral isomers are found to be most favorable. Including all bipoed isomers of substitutional, exohedral and endohedral bidoped clusters, the total magnetic moment of the ferromagnetic (antiferromagnetic) state is 8 (0) μ B and the HOMO-LUMO gap of antiferromagnetic state is slightly larger than that of ferromagnetic state. The magnetic coupling between the Cr atoms in bidoped configurations is mainly governed by the competition between direct Cr and Cr atoms antiferromagnetic interaction and the ferromagnetic interaction between two Cr atoms via O atom due to strong p-d hybridization. Most importantly, we show that the exohedral bidoped (ZnO) 12 clusters favor the ferromagnetic state, which may have the future applications in spin-dependent magneto-optical and magneto-electrical devices. [ABSTRACT FROM AUTHOR]

The electronic structures and magnetic properties for Cr doped LiZnP system are studied by first principles calculations. The results indicate that Cr doped LiZnP structures with Cr concentration 6.25 at.% favors spin polarized ground states and the system should be magnetic. The magnetic coupling results show that the system exists in the ferromagnetic (FM) stable state and the FM interactions in the Cr-Cr pair can be attributed to the p-d exchange interactions as Cr↑-P↓-Cr↑. V Li act as donor in Li(Zn,Cr)P host, which increasing the carrier concentration and thus lead to the FM state more stable. V Zn has less influence on FM stability, and V P weakens FM stability of the system. [ABSTRACT FROM AUTHOR]

Using the first-principles periodic boundary density functional theory along with the Grimme function, this study investigated the vacancy formation in the neck area of a 3-D pillared graphene structure. Three different possible configurations of the monovacancy defect formation were studied on a 3-D pillared graphene in order to explore the role of the monovacancy defect in the structural, electronic, and magnetic properties of each configuration. The density of state (DOS), projected DOS and spin polarization of the defected structures were calculated in order to determine which monovacancy site could have a significant impact on the magnetization of the 3-D pillared graphene. The obtained results at the GGA/revPBE level with a DZP basis set revealed that the influence of changing the position of the monovacancy defects from the graphene sheet to the nanotube part of the 3-D pillared graphene could give rise to greater magnetization. In particular, the monovacancy defects on the graphene (sheet) and nanotube (pillar) parts of the 3-D pillared graphene yielded less magnetization and greater magnetization, respectively. Moreover, the simulation results indicated that the px and pz orbitals had a substantial contribution to the spin polarization in these structures. [ABSTRACT FROM AUTHOR]

A new prototype tunnel junction with AgBr based barrier is proposed in this study. Electronic and magnetic properties of Fe/AgBr/Fe (001) heterostructures are investigated on the basis of first-principles and ballistic conductance calculations. The interlayer exchange coupling and electronic transport properties are analyzed as functions of the AgBr barrier thickness. The results show that Fe magnetism at Fe/AgBr (001) interfaces is enhanced as compared with the bulk material. A very strong direct tunnelling of Fe Δ 1 states is observed. The minority-spin channel is characterized by resonant tunnelling of interfacial states that are forming at Fe/AgBr (001) interfaces. Spin-polarization of the tunnelling current is positive and can exceed 99%. Tunnelling magnetoresistance ratios of about 8000% are evidenced for the junctions with clean interfaces. Fe/AgBr (001) coherent interfaces could act as nearly ideal symmetry-filters. In the presence of interfacial disorder the tunnelling magnetoresistance ratios decrease dramatically. The exchange coupling between Fe electrodes oscillates as a function of the barrier thickness. [ABSTRACT FROM AUTHOR]

The mechanical, structural, electronic and magnetic properties of s -triazine sheet ( C 6 N 6 ) with embedded Mn atom ( Mn – C 6 N 6 ) is investigated under the influence of external environment (symmetric deformation and perpendicular electric field) using density-functional theory (DFT) with the spin polarized generalized gradient approximation (GGA) and Hubbard U correction ( GGA + U ). Our results show that Mn – C 6 N 6 system is structurally and mechanically stable. The binding energy of Mn embedded in C 6 N 6 sheet can be modulated under the influence of external environment. Moreover, the semiconducting and magnetic properties of the Mn – C 6 N 6 systems under external fields are preserved. We also explore the geometries, electronic and magnetic properties of Mn – C 6 N 6 with adsorbed atoms and molecules. The Mn – C 6 N 6 with adsorbed O atom and O 2 molecule systems shows half-metallic character whereas the remaining systems preserve their semiconducting property. The total magnetic moment per unit cell in most of the systems is found to reduce as compared to that of the Mn – C 6 N 6 sheet. The reduction in the magnetic moment can be related to the strong interactions among the Mn atom and the surrounding atoms which lead to the formation of low-spin configurations. Overall, our results indicate that the Mn – C 6 N 6 systems with and without adsorbed atoms and molecules can serve as potential candidates for future spintronics and catalysis applications. [ABSTRACT FROM AUTHOR]

The discovery of different two-dimensional (2D) materials both theoretically and experimentally, can change the scenario of the current electronic industry because of their intriguing properties. Among the 2D materials, the first one which was discovered experimentally was graphene. In this work we have studied the electronic and magnetic properties of a new allotrope of disordered graphene, which is not hexagonal, rather possesses tetragonal symmetry known as T-graphene (TG). Density functional theory (DFT) has been thoroughly employed to study the relevant electronic properties. In previous works, it has been reported that pristine TG is non-magnetic. It is also known that, introducing transition metal (TM) atoms is a feasible way to control the electronic and magnetic properties. Here we have reported the relevant properties of four TM atoms i.e. Sc, V, Cr and Mn doped TG. From the defect formation energy study, it has been noticed that all the structures are endothermic in nature. For each case, we have found appreciable amount of magnetic moment. With increasing atomic weight of the dopant atom, the magnitude of the magnetic moment also increases. We have tried to explain this magnetic ordering with the help of spin-polarized partial density of states (PDOS). Controlling spin degrees of freedom is important for building spintronic devices. From that point of view, we hope this study will be useful to build TG based spintronic devices. [ABSTRACT FROM AUTHOR]

This study investigated the structural, elastic, electronic, thermal, magnetic, and optical behavior of GeGa 2 O 4 , FeGa 2 O 4 , GeFe 2 O 4 , and FeFe 2 O 4 spinel oxides based on ab -initio calculations. The results showed that the non-magnetic spinel oxide GeGa 2 O 4 exhibited remarkable physical properties due to Fe occupancy at different lattice sites within the spinel lattice. The Fe containing spinel oxides (FeGa 2 O 4 , GeFe 2 O 4 , and FeFe 2 O 4) were found to be stable in the magnetic phase in contrast to the host GeGa 2 O 4 spinel oxide. The spin polarizations of FeGa 2 O 4 , GeFe 2 O 4 , and FeFe 2 O 4 oxides were calculated as 98.5%, 98.4%, and 100%, respectively. Analysis of the elastic and mechanical properties showed that all of the spinel oxides followed the Born and Huang criteria for mechanical stability. The highest Debye temperature (θ D = 663.77 K) was determined for the FeGa 2 O 4 spinel oxide. For GeGa 2 O 4 , FeGa 2 O 4 , GeFe 2 O 4 , and FeFe 2 O 4 oxides, the calculated structural parameters (cation–anion bond lengths and average values of tetrahedral and octahedral radii) predicted the following cation distributions among the A and B atomic sites: (G e 2 +) [ G a 2 3 + ] O 4 − 2 , (F e 2 +) [ G a 2 3 + ] O 4 − 2 , (G e 4 +) [ F e 2 2 + ] O 4 − 2 , and (F e + 2) [ F e 2 3 + ] O 4 − 2 . The calculated electronic structures indicated that the host GeGa 2 O 4 spinel oxide and FeFe 2 O 4 spinel ferrite were semi-conducting and half-metallic ferromagnetic, respectively, whereas FeGa 2 O 4 and GeFe 2 O 4 oxides exhibited semi-metallic behavior. The GeFe 2 O 4 spinel oxide was found to have the highest saturation magnetization (185.79 emu g−1) and total magnetic moment (8.26 Σ B fu −1). The calculated optical properties indicated the suitability of these oxides for use in optical filters and sensors. The electronic and magnetic characteristics of these spinel oxides with excellent thermal and elastic stability suggest that they have potential uses in diluted magnetic semiconductor devices. [Display omitted] • Effects on physical properties of GeGa 2 O 4 with Fe occupancy are observed. • GeGa 2 O 4 , FeGa 2 O 4 , GeFe 2 O 4, and FeFe 2 O 4 spinels exhibit mechanical anisotropy. • Presence of Fe at A, B, and/or both sites reduces electronic, and optical bandgap. • GeFe 2 O 4 shows semi-metallic behavior with m t o t = 8.26 μ B /f.u and M S = 185.79 emu/g. • The oxides containing Fe have less threshold electronic transition energy. [ABSTRACT FROM AUTHOR]

Employing first principles calculations within the Density Functional Theory, the influence of Se dopants on electronic structure, magnetic and optical characteristics of CoNiFe 2 O 4 (CNFO) spinel ferrites (SFs) is elucidated. The role of Se dopants replacing the O atoms in the supercell is revealed by means of spin-asymmetric density of states, magnetic moment, and optical spectra. The findings suggest that electronic structure, magnetism and optical properties are determined by both Se content and atomic arrangment due to doping sites. It is shown that the energy band gap declines with increasing Se concentration and that, based on site occupation, a half metallic characteristic can be achieved. An appreciable spin polarization and relevant data on optical characteristics demonstrate that Se doped CNFO SFs are promising candidates for prospective spin dependent applications and visible light photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Se bivacancy cause semiconductor-half-metal transition with 100% spin polarization. • The direction of easy magnetization axes remain unchanged with Se vacancies. • MAE and Curie temperatures of Se vacancy defective monolayers increase with strain. • The direction of easy magnetization axes remains unchanged under strain. • A larger doping range is obtained by Se vacancies for pure spin-polarized current. • Defective VSe 2 monolayer is highly promising for new spintronic nanodevices. As a room-temperature van der Waals intrinsic ferromagnetic semiconductor, monolayer VSe 2 was studied extensively for both fundamental research and potential low-dimensional semiconductor spintronic applications. Defects are inevitably encountered and can affect the electronic, magnetic, and transport properties during the experimental synthesis of VSe 2 monolayer. However, the study of defects in VSe 2 monolayer is still lacking at the atomic level. Here, the electronic, magnetic, and transport properties of VSe 2 monolayer with Se vacancies are investigated by first-principles density-functional method. With the direction of easy magnetization axes unchanged, introducing Se vacancies results in the decrease of magnetic anisotropy energy and Curie temperature, which can be further increased by applying in-plane biaxial strain. After Se vacancies are introduced, the conductivity of the system decreases, while the larger doping range is obtained for pure spin-polarized current. The transition from semiconductor to half-metal with 100% spin polarization can be realized by introducing Se bivacancy in VSe 2 monolayer, which is highly promising for next-generation spin filter, spin injection and spin transport nanodevices. PACS: 61.72.jd; 73.20.At; 75.50.Pp; 75.70.Ak [ABSTRACT FROM AUTHOR]