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Revealing the magnetic coupling nature of boundary defects is crucial for in-depth understanding of the behavior and properties of magnetic materials and devices. Here, magnetite (i.e., Fe3O4) thin films were grown epitaxially on (100) SrTiO3 single-crystal substrates by pulsed laser deposition. Atomic-scale scanning transmission electron microscopy characterizations reveal that three types of antiphase boundaries (APBs) are formed in the Fe3O4 thin film. They are the (100) APB that is formed on the (100) plane with a crystal translation of (1/4)a[01 1 ¯ ], the type I and type II (110) APBs that are both formed on the (110) plane with the same crystal translation of (1/4)a[101] but different terminated atomic planes. The type I (110) APB is terminated at the atomic plane with mixed tetrahedral- and octahedral-sites Fe atoms, the type II (110) APB is terminated at the octahedral-site Fe plane. First-principles calculations reveal that the (100) APB and the type I (110) APB tend to form the ferromagnetic coupling that will not decrease the spin polarization of Fe3O4 films, while the type II (110) APB prefers to form the antiferromagnetic coupling that will degrade the magnetic properties. The magnetic coupling modes of the APBs are closely related to the Fe-O-Fe bond angles across the boundaries.

A mesoscopic multi-terminal superconducting Nb strip with a spin injection terminal has been developed. We investigate the influence of the spin polarization on the relaxation process of the quasiparticle in the superconducting Nb. The position dependence of the nonlocal voltage provides the quasiparticle relaxation length. The relaxation length for the spin-polarized quasiparticle is found to show 12.5 percent increase from that for the un-polarized quasiparticle. This demonstration opens a new avenue for utilization of the the spin current in a superconducting device.

A large variety of recently predicted and synthesized 2D materials significantly broaden capabilities of magnetic interfaces design for spintronics applications. Their diverse structural and electronic properties allow finely adjust interfacial interaction between electrode and spacer materials providing robust and effective spin transport. Based on recent experimental results, here we present a theoretical study of novel interfaces formed by half-metallic Co2FeGe1/2Ga1/2 (CFGG) substrate with h-BN or MoSe2 monolayer on its top. By means of DFT approach structural, magnetic and electronic properties are studied for Co- and FeGeGa termination of CFGG surface. Found large spin polarization in the vicinity of the interface and robust magnetization support a promise of 2D materials/Heusler alloy heterostructures for spintronics needs.

The ferroelectric material In2Se3 is currently of significant interest due to its built-in polarisation characteristics that can significantly modulate its electronic properties. Here we employ density functional theory to determine the transport characteristics at the metal-semiconductor interface of the two-dimensional multiferroic In2Se3/Fe3GeTe2 heterojunction. We show a significant tuning of the Schottky barrier height as a result of the change in the intrinsic polarisation state of In2Se3: the switching in the electric polarization of In2Se3 results in the switching of the nature of the Schottky barrier, from being n-type to p-type, and is accompanied by a change in the spin polarization of the electrons. This switchable Schottky barrier structure can form an essential component in a two-dimensional field effect transistor that can be operated by switching the ferroelectric polarization, rather than by the application of strain or electric field. The band structure and density of state calculations show that Fe3GeTe2 lends its magnetic and metallic characteristics to the In2Se3 layer, making the In2Se3/Fe3GeTe2 heterojunction a potentially viable multiferroic candidate in nanoelectronic devices like field-effect transistors. Moreover, our findings reveal a transfer of charge carriers from the In2Se3 layer to the Fe3GeTe2 layer, resulting in the formation of an in-built electric field at the metal-semiconductor interface. Our work can substantially broaden the device potential of the In2Se3/Fe3GeTe2 heterojunction in future low-energy electronic devices.

Half-Heusler alloys are prominent material for spintronics devices as these materials usually exhibit high spin polarization. But this spin polarization is severely affected by various disorders and distortions which ultimately hinders their practical applications. This paper examines the effect of the uniaxial strain as well as the tetragonal strain on the electronic and magnetic properties of half-Heusler FeCrAs alloy. This work is carried out by using the first-principles density functional theory calculations using the Wein2k software. The results of our study show that FeCrAs alloy exhibiting AFM and FM characteristics in u- strain while showing only FM characteristics in t- strain. The Half metallicity of the FeCrAs is sensitive in negative u-strain while it is quite robust in positive u-strain and t-strain the FeCrAs. The maximum value of band gap at 0% tetragonal-strain is about 1.04 eV. The FeCrAs Heusler alloy preserve the 100% spin polarization for whole studied range of tetragonal-strain (−10% to 10%). This property may make this system a promising candidate for spin transfer torque application.

Summary The photomagnetic effect is known to be related only to transition metal atoms with empty orbitals and spin-state changes. In general, noble metals with high electron density cannot be used as photomagnetic materials because of the absence of spin polarization. However, here, we found that photomagnetic-chiral anisotropy (PM-ChA) was generated in chiral nanostructured Au films (CNAFs), and opposite photomagnetic fields (PMFs) were created in the antipodal CNAFs under unpolarized irradiation. The PM-ChA was speculated to arise from directional alignment of opposite spins polarized by the asymmetric spin-orbit coupling due to the opposite effective magnetic fields induced by electron motion in the antipodal helical structure. PM-ChA can be applied in enantiomeric quantification, probably because of the spin polarization coupling between CNAFs and enantiomers. PM-ChA of noble metals generated by directional spin control in helical nanostructures could provide new strategies in quantum technology and theories in magnetophysics.

Recently prepared layered MoSi2N4 exhibits excellent stability and semiconductor properties, adding building blocks for two-dimensional families. In this research, we present the spin-orbit coupling and valley-related properties of monolayer WSi2N4 family. Better than transition metal dichalcogenides, the structural symmetry of WSi2N4 monolayer can be different by changing the stacking of three parts in the monolayers, resulting in a Rashba spin-orbit field. The vertical and horizontal polarization will lift the degeneration of the in-plane and out-of-plane polarized spin, respectively. The gradient of potential energy and the proportion of d orbitals play dominant roles. The in-plane orbitals contribute to the out-of-plane spin polarization, while the out-of-plane orbitals contribute to the in-plane spin polarization. The characteristics of a Rashba semiconductor can be utilized in spin/valley Hall effects, as well as the regulation of the spin direction of the valley electrons, promoting the manipulation of multiple degrees of freedom of electrons in monolayer materials.

This article introduces and develop a new area of transparent conducting material by doping GaN with two rare earth (RE) impurities (Eu, Sm). Our theoretical calculations confirm that the co-doped compound exhibits half-metallic ferromagnet (HMF) with 100% spin polarization at the Fermi level using GGA and mBJ. To determine which magnetic configuration is the most stable one, we compared the energy of ferromagnetic and antiferromagnetic states. Our results suggest that the ferromagnetic state is the most stable ground state. The exchange splitting energy and exchange constants $$N_{0} \alpha$$ and $$N_{0} \beta$$ are calculated. Additionally, we determined the electron specific heat ‘c’. It has a high optical transmittance and conductivity. These properties make GaN doped with double rare-earth impurities a potential material in optoelectronic and solar cell applications. For the calculations of mechanical, optical, and transport properties, the generalized gradient approximation + Hubbard U (GGA + U) and the modified Becke–Johnson (GGA-TB-mBJ) approximations were used.

In this study, we investigated the electronic and magnetic properties of pure and Cr-doped $$Li_{2}O$$ semiconductor within the framework of density functional theory (DFT) with the Korringa-Kohn-Rostoker method combined with the coherent potential approximation (KKR-CPA). The pure $$Li_{2}O$$ compound proved to be an intrinsic semiconductor with an indirect band gap of 4.74 eV. However, Cr-doped $$Li_{2}O$$ ( $$Li_{2}O_{1-x}Cr_{x})$$ showed the characteristics of a metal with a spin polarization at the Fermi level less than 100%. $$Li_{2}O_{1-x}Cr_{x}$$ exhibits a ferromagnetic stable phase originating from strong hybridization existing between the d-orbitals of Cr and that of Oxygen and total magnetic moments ranging from −0.383 $$\mu _{B}$$ to −0.912 $$\mu _{B}$$ for a concentration in the interval between 10% and 25%, respectively. The formation energy was also been calculated to study the stability of the pure and doped compound. Finally, the value of the Curie temperature, which reaches 780 (K), exceeds the ambient temperature, revealing the potential use of this doped material for new spintronic devices.

The spintronic properties of molecules are essential for the development of multifunctional organic spintronic devices. Here, the spin polarization of bis-(8-hydroxyquinoline) zinc (Znq2) molecule upon electron and hole injection has been theoretically studied by using density-functional theory calculations. It is found that both the injected excess electrons and holes are highly spin polarized in Znq2, leading to an approximately linearly increased magnetic moments with the amount of the charge injected. Our calculation also reveals that the spin polarization upon excess electron and hole injection may attribute to the exchange splitting of lowest unoccupied molecular orbital (LUMO)-related p states of N and C atoms of pyridyl rings and the highest occupied molecular orbital (HOMO)-related p states of O and C atoms of the phenoxide rings, respectively. The d0 ferromagnetism in the charge-injected Znq2 molecule is quite promising for organic spintronic devices.

As cathodes, iron-series (Fe, Co, Ni) clusters supported by carbon materials exhibit outstanding electrocatalytic reduction activities in many electrocatalytic applications. To date, this general characteristic of iron-series clusters that should be related to the inherent attributes of these electrodes has not been fully understood from the perspectives of thermodynamics and electronic structure alone. Electron transport is a necessary process in electrocatalysis, and therefore, the study of the change of the electronic state in electron transport is beneficial for understanding this general characteristic of iron-series cluster catalysts. In this work, the electron transport properties, including the conductivity and transport spin-polarization at the Ni-cluster/graphene interface are carefully investigated as an example of carbon-supported iron-series electrodes. Using first-principles calculations within the framework of the nonequilibrium Green’s function density functional theory (NEGF-DFT), we reveal that the electronic transport states of the coupled Ni-cluster/graphene are strongly changed compared to those of their isolated Ni-cluster and graphene component. It is found that graphene dominates the overall conductivity of the interface, while the morphology of Ni-clusters controls the spin polarization efficiency. High spin polarization can lead to the self-excitation effect of the electrons that raises the energy of the electronic system, improves the thermodynamics of the reduction reaction and promotes catalytic activity. Our work hints that iron-series elements (Fe, Co, Ni) based electrodes may generally show transport polarization that is likely to give rise to a high electrocatalytic reduction activity and such transport polarizability can be used as a new factor in the further exploration and design for electrocatalytic materials.

Production of single-phase materials with multifunctional properties is still a challenge faced by material scientists. In addition, obtaining high spin polarization efficiency in the materials that exhibit multifunctional properties is a big issue. A novel approach is suggested in this work for obtaining multifunctionality and spin polarization in the same material. This approach has combined the effect of microwave radiations and aluminum (Al) doping in iron oxide thin films during synthesis. Combined effect of microwave radiations and Al doping results in controlling / tuning the structural transitions in iron oxide thin films. Pristine and 2–10 wt% Al doped iron oxide thin films are prepared and studied in detail. Raman analysis shows that 2 and 4 wt% Al concentration results in γ-Fe2O3 + Fe3O4 phase with 71.3% and 64.5% of γ-Fe2O3 content, respectively. XRD and Raman analyses confirm the transition from γ-Fe2O3 to Fe3O4 thin films at Al concentrations of 6–10 wt%. Structural transformation shows that microwave radiations catalyzes that Al3+ions to occupy the vacancies on B sites of iron oxide thus, lead to the formation of Fe3O4. Observation of Verwey transition ~ 126 K also supports the transition in phases of iron oxide with increase in saturation magnetization from 251.3emu/cm3 (pristine films) to 405.6emu/cm3 (8 wt% Al concentration). High dielectric constant of ~ 135.5 (log f = 5.0) is observed for 8 wt% Al concentration. Conductivity and detailed impedance & modulus analyses depict Mott’s hopping phenomenon along with presence of different relaxation times. Coupling between magnetic and dielectric properties is observed at room temperature. Magnetoresistance curves indicate spin polarization efficiency of ~24%.

Sputtered Tb/Cr/Fe structures with a Cr layer (tCr) thickness ranging from 0 to 4 nm were prepared. The coercivity (Hc) of Tb/Cr (tCr)/Fe films with tCr ≥ 1 nm is consistent with that of the corresponding Cr(tCr)/Fe films. At the same time, the addition of the Tb layer results in a large saturation magnetization field (Hs) and even oscillatory relations of Hs on tCr, which might indicate an oscillatory indirect exchange coupling mediated by the spin polarization of the spacer Cr layer. Consistent oscillations are observed in anisotropic magnetoresistance (AMR) originating in spin–orbit coupling and magnetoresistance (MR) associated with interlayer exchange coupling as tCr in Tb/Cr/Fe films increases. The oscillatory MR demonstrates antiferromagnetic coupling, which also implies that it is not ordinary MR, although it is of the same magnitude as a result of the nonsharp interfaces. The value of the antiferromagnetic exchange coupling J as a function of tCr is estimated. Consistent oscillations with those in MR and AMR versus tCr are found, accompanied by a gradually flattened oscillation for films with tCr ≥ 2.5 nm resulting from weak coupling as the thick spacer Cr layer. Compared with the curves of MR, AMR, and J versus tCr, the opposite oscillations observed in the curve of Hc/Hs versus tCr further confirm the oscillatory interlayer exchange coupling in the studied structure, which provides theoretical basis for the adjustment of magnetic properties in spintronics by rare earth elements.

Heteroatom doped atomically dispersed Fe1 -NC catalysts have been found to show excellent activity toward oxygen reduction reaction (ORR). However, the origin of the enhanced activity is still controversial because the structure-function relationship governing the enhancement remains elusive. Herein, sulfur(S)-doped Fe1 -NC catalyst was obtained as a model, which displays a superior activity for ORR towards the traditional Fe-NC materials. 57 Fe Mossbauer spectroscopy and electron paramagnetic resonance spectroscopy revealed that incorporation of S in the second coordination sphere of Fe1 -NC can induce the transition of spin polarization configuration. Operando 57 Fe Mossbauer spectra definitively identified the low spin single-Fe3+ -atom of C-FeN4 -S moiety as the active site for ORR. Moreover, DFT calculations unveiled that lower spin state of the Fe center after the S doping promotes OH* desorption process. This work elucidates the underlying mechanisms towards S doping for enhancing ORR activity, and paves a way to investigate the function of broader heteroatom doped Fe1 -NC catalysts to offer a general guideline for spin-state-determined ORR.

Low efficient transfer of photogenerated charge carriers to redox sites along with high surface reaction barrier is a bottleneck problem of photocatalytic H2O overall splitting. Here, in the absence of cocatalysts, H2O overall splitting has been achieved by single-atomic S vacancy hexagonal CdS with a spin polarization electric field (PEF). Theoretical and experimental results confirm that single-atomic S vacancy-induced spin PEF with opposite direction to the Coulomb field accelerates charge carrier transport dynamics from the bulk phase to surface-redox sites. By systematically tuning the spin PEF intensity with single-atomic S vacancy content, common pristine CdS is converted to a photocatalyst that can efficiently complete H2O overall splitting by releasing a great number of H2 bubbles under natural solar light. This work solves the bottleneck of solar energy conversion in essence by single atom vacancy engineering, which will promote significant photocatalytic performance enhancement for commercialization.

Spin-dependent charge transmission or the so-called chirality-induced spin selectivity (CISS) effect was demonstrated in self-assembled chiral coordinated monolayers. Distinct from the previous CISS phenomenon observed mainly on pure biomolecules, here we expanded this effect to the coordinated complex of chiral biomolecules and metal cations, specifically, cysteine-Cu2+-alanine (Cys/Cu/Ala), in which the complex itself was redox-active. However, the coordinated self-assembled monolayers of cysteine-Cu2+-cysteine did not show any spin-dependent effect. In addition, this phenomenon was explained by developing a theoretical model with spin-orbit coupling. The alanine molecules contributed to multiple transport pathways, leading to experimentally observable spin polarization. Finally, this CISS effect in Cys/Cu/Ala complex was demonstrated to amplify the sensing signal. The enantioselective discrimination efficiency could be improved by controlling the orientation of the external magnetic field.

Nodal monoloop, enjoying the cleanest scenario with a single loop, is recognized as the basic building block of intricate linked loops including chains, nets, and knots. Here, we explore the interplay of magnetic ordering and band topology in one system by introducing a brand-new quantum state, referred to as Weyl monoloop semi-half-metal, which is characterized by a single loop at the Fermi level stemming from the same spin channel. Such a nodal line Fermion, yielding 100% spin polarization, is protected by mirror ( M z ) symmetry. As a prominent example, a realistic rutile-type metal fluorides LiV2F6 achieves the hitherto unmaterialized state, featuring fully spin-polarized ultraflat surface states. More interestingly, LiV2F6 has a "soft" ferromagnetic property, which is one of the desired systems to control the anomalous Hall effect by rotating the magnetization direction. Our findings offer a promising candidate for exploring the topology and magnetism with intriguing effects.

In this paper, we investigate the structural, the electronic and the magnetic properties of the equiatomic quaternary Heusler alloy CoRuMnGe using the first-principle calculations. In fact, we appl...

Magnetic fields are known as clean, economic, and effective tools to modify band and magnetic structures of materials. When coupled with catalytic processes such as the hydrogen evolution reaction ...

In this article, for the first time, we propose a silicene-based spin filter having a TFET configuration. The device portrays a voltage-dependent spin polarization and achieves a “spin polarization” as high as 98% at a minimal “operating voltage” (0.35 V). The operation of the device is based on the “spin-polarized edge states” in a silicene nanoribbon. The “spin polarization” of the output current can be tuned by modifying the bandgap of the spin-up and spin-down states via an in-plane perpendicular “electric field” generated by two “lateral gates.” The device features high spin polarization apart from its expected integration with Si-based technology. The proposed device has a simple construction, wherein a single layer of Si atoms achieves such a high value of spin polarization at a minimal operating voltage. The operation of the proposed device is demonstrated by using the first-principles quantum transport simulations.

2D materials offer the ability to expose their electronic structure to manipulations by a proximity effect. This could be harnessed to craft properties of 2D interfaces and van der Waals heterostructures in devices and quantum materials. We explore the possibility to create an artificial spin polarized electrode from graphene through proximity interaction with a ferromagnetic insulator to be used in a magnetic tunnel junction (MTJ). Ferromagnetic insulator/graphene artificial electrodes were fabricated and integrated in MTJs based on spin analyzers. Evidence of the emergence of spin polarization in proximitized graphene layers was observed through the occurrence of tunnel magnetoresistance. We deduced a spin dependent splitting of graphene's Dirac band structure (∼15 meV) induced by the proximity effect, potentially leading to full spin polarization and opening the way to gating. The extracted spin signals illustrate the potential of 2D quantum materials based on proximity effects to craft spintronics functionalities, from vertical MTJs memory cells to logic circuits., This work has received funding from the European Union’s H2020 Future and Emerging Technologies “Graphene Flagship” (Grant Core3 No. 881603), “SINFONIA” (No. 881603) projects and a Grant Agreement Marie Skłodowska Curie “ITN Spinograph” (No. 697904), as well as from EPSRC (EP/P005152/1, EP/K016636/1). This research is supported by a public grant overseen by the French National Research Agency (ANR) as part of the “Investissements d’Avenir” program Labex NanoSaclay (ANR-10-LABX-0035), as well as grants STEM2D (ANR-19-CE24-0015), MIXES (ANR-19-CE09-0028), and by the Flag-ERA JTC 2019 project “SOGraphMEM” (ANR-19-GRFI-0001-07). This work has also received fundings from the “Spanish ministry of Science and Innovation” through “Severo Ochoa” (CEX2019-000917-S) and “OXISOT” (PID2021-128410OB-I00)., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

Lithium-sulfur batteries (LSBs) are still limited by the shuttle of lithium polysulfides (LiPS) and the slow Li-S reaction. Herein, we demonstrate that when using cobalt sulfide as a catalytic additive, an external magnetic field generated by a permanent magnet can significantly improve the LiPS adsorption ability and the Li-S reaction kinetics. More specifically, the results show both experimentally and theoretically how an electron spin polarization of Co ions reduces electron repulsion and enhances the degree of orbital hybridization, thus resulting in LSBs with unprecedented performance and stability. Under an external magnetic field, LSBs with 0.0084 % per cycle decay rate at 2 C during 8150 cycles are produced. Overall, this work not only demonstrates an effective strategy to promote LiPS adsorption and electrochemical conversion in LSBs at no additional energy cost but also enriches the application of the spin effect in the electrocatalysis fields., This work was supported by the National Natural Science Foundation of China (Grant Nos.: 51572118 and 21975123) and partially by the Fundamental Research Funds for the Central Universities (Grant Nos.: lzujbky-2021-it33). C. Y. Zhang, C. Q. Zhang, and L. Gong thank the China Scholarship Council for the scholarship support. A. Cabot thanks financial support from the Combenergy project (PID2019-105490RB-C32) from the Spanish Ministerio de Ciencia e Innovación. The authors also greatly acknowledge the support supported by the Supercomputing Center of Lanzhou University, China., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

Over the past few decades, development of electrocatalysts for energy applications has extensively transitioned from trial-and-error methodologies to more rational and directed designs at the atomic levels via either nanogeometric optimization or modulating electronic properties of active sites. Regarding the modulation of electronic properties, nonprecious transition metal-based materials have been attracting large interest due to the capability of versatile tuning d-electron configurations expressed through the flexible orbital occupancy and various possible degrees of spin polarization. Herein, recent advances in tailoring electronic properties of the transition-metal atoms for intrinsically enhanced electrocatalytic performances are reviewed. We start with discussions on how orbital occupancy and spin polarization can govern the essential atomic level processes, including the transport of electron charge and spin in bulk, reactive species adsorption on the catalytic surface, and the electron transfer between catalytic centers and adsorbed species as well as reaction mechanisms. Subsequently, different techniques currently adopted in tuning electronic structures are discussed with particular emphasis on theoretical rationale and recent practical achievements. We also highlight the promises of the recently established computational design approaches in developing electrocatalysts for energy applications. Lastly, the discussion is concluded with perspectives on current challenges and future opportunities. We hope this review will present the beauty of the structure-activity relationships in catalysis sciences and contribute to advance the rational development of electrocatalysts for energy conversion applications. Ministry of Education (MOE) This work was financially supported by the AcRF Tier 1 (Grant RG105/19) provided by Ministry of Education in Singapore.

International audience; The nitrogen-vacancy (NV) center in 3C-SiC, the analog of the NV center in diamond, has recently emerged as a solid-state qubit with competitive properties and significant technological advantages. Combining first-principles calculations and magnetic resonance spectroscopy we provide thorough insight in its magneto-optical properties. By applying resonantly excited electron paramagnetic resonance spectroscopy, we identified the zero-phonon absorption line of the 3 A 2 → 3 E transition at 1289 nm (within the telecom Oband) and measured its phonon sideband, the analysis of which reveals a Huang-Rhys factor of S = 2.85 and a Debye-Waller factor of 5.8 %. The low temperature spin-lattice relaxation time was found to be exceptionally long (T 1 = 17 s at 4 K). All these properties make NV in 3C-SiC a strong competitor for qubit application. In addition, the strong variation of the zero-field splitting in the range of 4K to 380K allows its application for nanoscale thermal sensing.

In this paper, we present the results obtained from our study on the heat current across double quantum dots in serial coupled to ferromagnetic leads (FM-DQDs-FM), when the leads magnetic moments are in antiparallel configuration. This study was done by using nonequilibrium Green's function method in the linear response regime. Our results are calculated in weak interdot coupling regime by taking all the parameters that affect the system such as intradot Coulomb correlation energy, spin–spin exchange interaction, and spin polarization on the leads. These results are accomplished as a function of temperature gradient as well as quantum dots energy levels. According to our results, it is noticed that the values of intradot Coulomb correlation energy and the spin–spin exchange interaction have significant impact on increasing the heat current that flows through our system. It is concluded that increasing or decreasing the magnitude of heat current in negative or positive thermal bias is ideal for designing high-efficiency heat diode.

The first-principle calculations of density functional theory were used to study the structural, electronic, magnetic, mechanic, and half-metallic behavior of Y2MnZ (Z = Al, Ga, In) within the spin generalized gradient approximation. These compounds can be experimentally synthesized due to their negative values of the calculated formation energies. Our calculations indicate that they are more stable in Cu2MnAl-type structure. The Hg2CuTi-type structure displays half-metallic characteristic with 100% spin polarization at the Fermi level. The value of calculated magnetic moment has an integer value of 2μB for Y2MnZ (Z = Al, Ga, In) in the Hg2CuTi-type structure which well matches with magnetic moments predicted from Slater–Pauling rule. Therefore, the Y2MnZ (Z = Al, Ga, In) in the Hg2CuTi-type structure is predicted to be a candidate for possible spintronics applications.

Organic molecule/half-metallic oxide interfaces play essential roles in recent molecular spintronics devices, yet factors governing the spin polarization of the hybridized interface state (HIS) formed there remain unclear because of the lack of direct spectroscopic evidence for it. Here, we present a spin-polarized metastable deexcitation spectroscopy (SPMDS) experiment, which is sensitive to the topmost surface, showing that the adsorption of pyridine on H-terminated Fe3O4(100) at 100 K produces a highly spin-polarized HIS, while no such HIS forms on a bare Fe3O4(100) surface. A density functional theory calculation has predicted the formation of half-metallic HIS, which is consistent with the SPMDS results. This can be understood on the basis of the interface chemical bonding formed by the coordination of the nitrogen end of pyridine to the surface Fe atom where half-metallic conduction electrons are distributed.

The electrocatalytic activity of transition-metal (TM)-based catalysts is correlated with the spin states of metal atoms. However, developing a way to manipulate spin remains a great challenge. Using first-principles calculations, we first report the crucial role of the spin of exposed Mo atoms around an S-vacancy in the electrocatalytic dinitrogen reduction reaction on defective MoS2 nanosheets and propose a novel strategy for regulating the electronic spin moments by tuning a single-atom promoter (SAP). Single TM atoms adsorbed on a defective MoS2 basal plane serve as SAPs via a noncontact interaction with an exposed Mo active site, inducing a significant spin polarization that promotes N2 adsorption and activation. Interestingly, by changing only the adsorption site of the TM atom, we are able to change the spin moments of the Mo atom, over a wide range of tunable values. The spin moments can be tuned to largely improve the catalytic activity of MoS2 toward the reduction of N2 to NH3.

The mechanism of spin polarization transfer from a photogenerated spin-correlated radical pair to a stable radical was studied in a covalent donor-chromophore-acceptor-stable radical (D-C-A-R•) system, where the donor (D) is 4-methoxyaniline (MeOAn), the chromophore (C) is 4-(N-piperidinyl)-naphthalene-1,8-dicarboximide (ANI), the acceptor (A) is naphthalene-1,8:4,5-bis(dicarboximide) (NDI) and the stable radical (R•) is (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO). Experiments probed the effect of the spin–spin exchange interaction between D•+ and A•− as well as the charge recombination dynamics of D•+-C-A•− on spin polarization transfer from the D•+-C-A•− SCRP to R• as a function of the dielectric environment in glassy media at cryogenic temperatures. The results show that spin polarization on R• is generated by asymmetry in the charge recombination pathways rather than variations in the spin–spin exchange interaction between D•+ and A•−. These results inform design criteria for using an SCRP to spin polarize a third spin for potential applications in quantum information science.

Three different contributing mechanisms have been considered to calculate the magnetization (M) of p-type Pb1-xMnxSe for a hole density of p = 5 × 1018 cm−3and n-type Pb1-xMnxS for an electron density of n = 6 × 1018 cm−3.The first mechanism comes from the valence band diamagnetism which is calculated in a frame of the two-band model. The second mechanism which we consider arises from the spin densities of holes and electrons and we use a six-level $$\vec{k}.\vec{\pi }$$ theory in second-order perturbation theory in the effective mass representation. The third mechanism is the impurity Mn+2 ions contribution, and we consider small clusters consisting of one, two and three spins to evaluate it. The three spin clusters include both open and closed types. It has been observed that the former two mechanisms contribute very little to the magnetization compared to the latter one. However, their importance cannot be ignored because they provide a deeper understanding of the underlying physical mechanisms involved with carrier spin polarization and orbital diamagnetism of the host matrix, in which the Mn+2 spins are embedded. Good agreement of our theory with experiment is the other interesting and distinct feature of this work.

A new scheme is presented for obtaining a pure spin state for the one-determinant wave function built on Hartree–Fock or Kohn–Sham orbitals. In this scheme, the unrestricted determinant is expanded in restricted determinants constructed in the basis set of spin-paired orbitals. Using spin projection, one can determine spin density components corresponding to pure spin states and estimate the weight of spin contaminants in the spin density. The efficiency of this approach is demonstrated on the example of methane oxidation. It is shown that self-consistent solutions of Hartree–Fock or Kohn–Sham equations with broken spin symmetry are not an artifact of one-determinant approximation. The equations reflect real spin polarization that creates negative spin density in some parts of the molecular system.

Half-metallic materials are theoretically predicted to be metallic and insulating, which have not been confirmed experimentally, and the predictions are still in doubt. We report the resistance-chiral anisotropy (R-ChA), i.e., chirality-dependent electrical conductivity, in chiral mesostructured Fe3 O4 films (CMFFs) grown on the substrates via a hydrothermal method using amino acids as symmetry-breaking agents. Two levels of chirality exist in the CMFFs: primary distortion of the crystal lattice forms twisted nanoflakes, and secondary helical stacking of nanoflakes forms fan-shaped nanoplates. At temperatures below 30 K, the CMFFs exhibited metallic conductivity and insulation for one handedness and the other, respectively. The chirality-dependent effective magnetic fields were speculated to stabilize the opposite spin in the antipodal chiral frame, which led to the free transport of electrons in one handedness of the chiral structure and immobility for the other handedness.

The quaternary Heusler LuCoTiSi, LuCoTiGe, and LuCoTiSn compounds' physical properties have been investigated using the GGA approximation based on the density functional theory. These compounds are stable in the ferromagnetic phase and semi-stable in the non-magnetic phase. Elastic studies show that these compounds are quite stable and belong to the category of ductile materials. Phonon calculations also show that these two combinations are quite stable, and the phonon levels in the band structure are all in the positive region. The LuCoTiSi, LuCoTiGe, and LuCoTiSn compounds are half-metallic with 100% spin polarization with 2.0µB 3.0 µB, and 2.0µB, respectively. The maximum value of their Seebeck (S) coefficient occurred at 130 K. The figure of merit (ZT) coefficient of these compounds at 100 K equals one and decreased to room temperature with a gentle slope, indicating their thermoelectric efficiency at low and room temperatures. All compounds have accessible regions that referred to their thermodynamic stability. The LuCoTiGe case has a more extensive accessible region than other cases of the thermodynamic phase diagram.

In this work, theoretical investigation in coherent manipulation throughout local density of states calculation for serially coupled double quantum dots embedded between ferromagnetic leads (FM-QD1-QD2-FM) by using the non-equilibrium Green's function approach. Since the local density of states are formulated incorporating the spin polarization and the type of spin configuration on the leads. Our model incorporates the inter-dot hopping, the intra-dot Coulomb correlation, the spin exchange energy and the coupling interactions between the quantum dots and leads. The results concerned to the parallel configuration at strong inter-dot coupling regime shows that the spin down electrons in the quantum dots may be more coupled coherently if the regime is tuned. The local density of states of the two dots for spin up electrons shows a broad hump with small splitting i.e. the case is decoherent for spin up electrons. In the case of weak interdot coupling it is obvious that the spin dependent density of states on the quantum dots show that the resonances are not well splitted. For the antiparallel configuration in the strong coupling regime, the spin dependent density of states of the double quantum dots show four peaks but with broaden and overlapping. In the case of weak coupling regime, the total spin dependent density of states, which have two peaks with certain board, one can conclude that the states are not coupled coherently. The case of the antiferromagnetic nature of the spin exchange interaction, our calculations for the parallel and antiparallel configurations (in strong and weak regimes) show a decoherence state.

Electric field control of magnetic properties has been achieved across a number of different material systems. In diluted magnetic semiconductors (DMSs), ferromagnetic metals, multiferroics, etc., electrical manipulation of magnetism has been observed. Here, we study the effect of an electric field on the carrier spin polarization in DMSs ( GaAsMn ); in particular, emphasis is given to spin-dependent transport phenomena. In our system, the interaction between the carriers and the localized spins in the presence of electric field is taken as the main interaction. Our results show that the electric field plays a major role on the spin polarization of carriers in the system. This is important for spintronics application.

Some nitrogen-based gases (NO, $${\text {NO}}_{2}$$ , $${\text {NH}}_{3}$$ and $${\text {N}}_{2}$$ O) generate from the burning of fossil fuels and biomass, as well as from agricultural-related processes. They are directly related to both the deterioration of environment and human health. Research on two-dimensional materials as cores for sensing these types of harmful gases has attracted great interest; motivated by the fact that the interaction with those gases produces changes in their structural, electronic, magnetic and optical properties. In this work, investigation on the adsorption of those gases onto different blue phosphorene oxide species was carried out with the use of density functional theory, including Van der Waals interaction through KBM exchange-correlation functional. In the calculation, different positions and modes of molecule adsorption on the oxides were taken into account. The results obtained show that the interaction varies with both the nature of the molecule chemical composition and the oxide structure, resulting in different values of charge transfer, and leading to greater or lesser values of the adsorption energy of the gases. In some cases, spin polarization was observed, producing noticeable changes in the electronic structure and the optical spectrum of the nanosurfaces for each of the systems. The gases that produce the greatest change are $${\text {NH}}_3$$ and NO, while those with the lowest optoelectronic responses on the different oxides are $${\text {N}}_2$$ O and $${\text {N}}_2$$ . The changes observed in the electronic structure as well as the short recovery time of gases would confirm the possibility of using these oxides for sensing applications, as it has been verified for other 2D nanomaterials.

Molecular spintronics may boost the development of nanoscale devices with improved performance and enhanced functionality, which is very promising for the next generation of electronic devices. Here, we design a new type of spintronics device based on the novel 2D material C3N. Using nonequilibrium Green’s function in combination with the density functional theory, we systematically study the spin-dependent transport properties in four different magnetic configurations of the C3N junction, and the perfect spin filter efficiency and giant magnetoresistance effects are achieved. The calculated results clearly demonstrate that the transport properties of the C3N junction are sensitive to the magnetic configuration of the electrodes. The calculated spin-resolved transmission spectra of the proposed ferromagnetic coupling C3N junctions exhibit a robust spin filtering effect, where the conductance is mainly governed by the spin-down electrons. Under the small bias voltage, the transport properties are mainly determined by the spin-down channel and exhibit a large spin polarization. The conductance of three antiferromagnetic coupling states is nearly zero at the Fermi level. These theoretical results indicate that the novel 2D C3N monolayer is promising for molecular spintronics devices in the near future.

Hyperons production and decays are studied with using 1310.6 × 106 J/ψ and 448.1 × 106 ψ(3686) events collected with the BESIII experiment. The recent achievements in BESIII are report. The spin polarization of Σ+ and Σ ‾ − is observed in J/ψ and ψ(3686) decays for the first time. The spin of Ω− is determined to be 3/2 unambiguously with helicity amplitude analysis method. The SU(3)-flavor violating decay J / ψ → Ξ ( 1530 ) − Ξ ‾ + + c.c. is studied with the evidence for the radiative decay Ξ(1530)− → γΞ− of a significance of 3.9σ. The branching fractions of the decays χ c J → Σ − Σ ‾ + are measured for the first time using the final states n n ‾ π + π − .

The effect of supercell size in the ribbon model of molybdenum disulfide edge on the cell electronic structure and specific energy was investigated, with and without spin polarization. The differences found were discussed in terms of electron count. Diagnostic criteria for the model applicability and the effect of opposite edge were discussed.

The linear properties of magnetosonic waves are studied by using the separated spin evolution quantum hydrodynamic equations in which each electron and positron are treated as two different fluids. At the perpendicular propagation, we have only one magnetosonic wave which is affected by both spin polarization and concentration of positron. In the case of oblique propagation, we solve dispersion numerically and found that three wave solutions are obtained without taking into account separate spin evolution (SSE), but the oblique propagation with SSE gives five wave solutions, two of them are electron and positron spin-dependent wave solutions and have been reported for the first time. It is noted that the spin polarization and positron concentration reduce the phase velocities of the obliquely propagating spectra. Moreover, it is seen that the obliqueness effect enhances the frequency of all waves. Finally, the comparison with earlier reported results is also presented. For numerical analysis, we choose parameters relevant to astrophysical environments.

The Curie temperature of electron-doped Sr2FeMoO6 can be optimized significantly due to the band-filling effect, but accompanying an almost absent low-field magnetoresistance (LFMR), which is unfavorable to applications in the magnetoresistive devices operated at room-temperature. Our previous works confirmed that, a remarkable enhanced LFMR was observed in Sr2FeMoO6 by modifying the grain boundary with insulating organic small molecules (glycerin, CH2OHCHOHCH2OH). However, in this work, modifying the grain boundary strength of the La0.5Sr1.5FeMoO6 with the insulating organic macromolecules (oleic acid, CH3(CH2)7CH=CH(CH2)7COOH) or small molecules (glycerin), both of them have negligible functions on the magnetoresistance behavior in La0.5Sr1.5FeMoO6. Contrary to the glycerin-modified Sr2FeMoO6, Sr2FeMoO6/oleic acid composites don’t exhibit an obviously increased magnetoresistance property. Based on the above experimental results and the related works, it is proposed that, maintaining high spin polarization of the carriers at the Fermi level and improving the tunneling process across the grain boundary by using the suitable organic materials are decisive factors for optimizing the magnetoresistance behavior in the similar electron-doped double perovskites.

Manipulating heterogeneous electrified interfaces with an external magnetic field (Hₑₓₜ) explicitly mandates the constant presence of Hₑₓₜ for achieving magnetoelectrocatalytic kinetic enhancements. Here, we demonstrate the highest kinetic enhancement of 650% in electrocatalytic hydrogen evolution reaction (HER), without the mandatory presence of Hₑₓₜ. A synergistic interface created in nanostructured hard carbon florets (NCF) decorated with ferro–paramagnetic nanoparticles (Co₃O₄, Co, and Ni–Co) is demonstrated to be critical for both (a) prominent enhancement in HER-kinetics when Hₑₓₜ = 200 mT and (b) sustaining the rapid HER when Hₑₓₜ = 0 mT. Significant lowering of magnetoresistance (22%) and magnetocharge-transfer resistance (84.8%) using a weak Hₑₓₜ = 100 mT leads to a 2.5-fold volumetric increment in hydrogen generation driven by 7% enhancement in electrokinetic activity. Furthermore, all such enhancements are strongly correlated with the magnetic coercivity of the catalyst, implying the role of interfacial mechanistic modulation of the HER by Hₑₓₜ. Additionally, microscopic dimensional enlargement of the structurally flexible NCF promotes such a long-term effect leading to larger magnetocurrent as compared to other carbon-based supports. Our work demonstrates the importance of spin polarization in magnetically active electrocatalytic interfaces and thereby offers a general practical strategy for energy-efficient hydrogen production.

We theoretically investigate the dwell time for electrons in an antiparallel double $\delta $ -magnetic-barrier nanostructure, which is constructed on the surface of the InAs/Al x In1- x As heterostructure by patterning two ferromagnetic (FM) stripes. It is shown that the dwell time is dependent on electron spins due to the spin–field interaction between spins and magnetic fields. It is also shown that both magnitude and sign of the spin polarization in the dwell time can be modulated by the structural width or magnetic-strength difference between two magnetic barriers, which may give rise to a controllable temporal spin splitter for spintronics device applications.

Non-stationary spin-dependent transport through the interacting single-level quantum dot coupled to ferromagnetic leads with non-collinear magnetizations has been analyzed theoretically. The non-stationary transport is investigated within the theoretical approach based on kinetic equations for the electron occupation numbers with different spins taking into account high order correlation functions for the localized electrons. It has been demonstrated that spin polarization, direction and amplitude of the non-stationary currents could be effectively changed in a rather simple system by varying the relative directions of the magnetic moments in the leads. The degree of the currents spin polarization also changes following the direction of magnetic moments in the leads. The results open a possibility for spin polarization control in nanoscale systems and are very promising in the sense of spin filtering.

We review recent studies of the spin-dependent tunneling transport via an Aharonov–Bohm interferometer (ABI) formed by helical edge states. We focus on the experimentally relevant case of relatively high temperature, T, as compared to level spacing, Δ. The tunneling conductance of helical ABI is structureless in ballistic case but shows sharp periodic antiresonances as a function of magnetic flux with the period $$hc{\text{/}}2e$$ in presence of magnetic impurities. The incoming unpolarized electron beam acquires finite polarization after transmission through the helical ABI provided that the edges contain at least one magnetic impurity. The finite polarization appears even in the fully classical regime and is therefore robust to dephasing. There is also a quantum contribution to the polarization, which shows sharp identical resonances as a function of magnetic flux with the same period as conductance. This polarization survives at relatively high temperature. The interferometer can be described in terms of ensemble of $$\mathcal{N} \simeq T{\text{/}}\Delta $$ flux-tunable qubits giving equal contributions to conductance and spin polarization. Hence, with increasing the temperature number of active qubits participating in the charge and spin transport increases. These features of tunneling helical ABI open a wide avenue for applications in the area of quantum computing.

Graphene/hematene heterostructure is an interesting 2D van der Waals material with exciting and valuable features of both graphene and hematene. Our density functional theory calculations reveal that the resulting heterostructure preserves a long-range ferromagnetic character of pristine hematene monolayer and behaves as a half metal with 100% spin polarization unlike individual graphene and hematene monolayers which act like non-magnetic semi-metal and ferrimagnetic semiconductor, respectively. This transition to the half metal mainly arises due to charge transfer from C atoms of graphene to O atoms of hematene monolayer. These results manifest that the proposed heterostructure will attract the experimentalists highly and serve as a powerful candidate in spintronics and magnetic memory-based storage devices in near future.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful method to study the molecular structure and dynamics of materials. The inherently low sensitivity of NMR spectroscopy is a consequence of low spin polarization. Hyperpolarization of a spin ensemble is defined as a population difference between spin states that far exceeds what is expected from the Boltzmann distribution for a given temperature. Dynamic nuclear polarization (DNP) can overcome the relatively low sensitivity of NMR spectroscopy by using a paramagnetic matrix to hyperpolarize a nuclear spin ensemble. Application of DNP to NMR can result in sensitivity gains of up to four orders of magnitude compared to NMR without DNP. Although DNP NMR is now more routinely utilized for solid-state (ss) NMR spectroscopy, it has not been exploited to the same degree for liquid-state samples. This Review will consider challenges and advances in the application of DNP NMR to liquid-state samples. The Review is organized into four sections: (i) mechanisms of DNP NMR relevant to hyperpolarization of liquid samples; (ii) applications of liquid-state DNP NMR; (iii) available detection schemes for liquid-state samples; and (iv) instrumental challenges and outlook for liquid-state DNP NMR.