Search

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]

The present study explored the impacts of dysprosium (Dy³⁺) doping on the structure, optical, and magnetic characteristics of CuDy x Fe 2-x O 4 nanospinel ferrites synthesized via a hydrothermal method. X-ray diffraction revealed a tetragonal spinel matrix with increasing Dy³⁺ content, accompanied by a secondary Dy 2 O 3 phase at higher dopant levels for x ≥ 0.1. Crystallite size and microstrain increased with doping, while infrared spectroscopy confirmed the spinel structure and distinct vibrational modes. Interestingly, saturation magnetization displayed a non-monotonic trend, first rising due to spin polarization and cation redistribution, then decreasing with higher Dy³⁺ content attributable to the Dy 2 O 3 phase and larger grains. Coercivity exhibited a maximum at x = 0.2, reflecting the interplay between magnetocrystalline anisotropy, canting angles, and domain wall pinning. These findings highlight the complex interplay between Dy³⁺ doping and the resulting properties, paving the way for tailored CuDy x Fe 2-x O 4 nanospinel ferrites functionalities.. Further research involving advanced techniques and targeted dopant levels holds promise for optimizing properties for diverse technological applications such as magnetic storage, microwave devices, sensors, and hyperthermia treatment. [ABSTRACT FROM AUTHOR]

Fe-based catalysts have a good prospect in oxygen reduction reaction (ORR) in fuel cells. However, the catalytic activity of Fe-based catalysts requires further improvement to satisfy the demand in industrial application and the working mechanism is still shrouded in ambiguity. Here, a ferromagnetic catalyst with nitrogen-doped carbon supported FeCoNi alloy was synthesized by impregnation-pyrolysis method. The micromorphology and structure of the catalyst was analyzed by XRD, SEM, TEM, XPS, BET and Raman spectroscopy. The trimetallic catalyst showed high ORR activity in 0.1 M KOH with a half-wave potential of 0.908 V and a limiting current density of 6.153 mA cm−2, which was superior to 20 % Pt/C. The synergistic effect of FeCoNi alloy regulated the spin polarization and the regulated spin state improved ORR performance by facilitating the adsorption of O 2 molecules and the conversion of the activated intermediates. [Display omitted] • FeCoNi@NC is derived from C 3 N 4 by impregnation-pyrolysis method. • FeCoNi@NC is highly active for oxygen reduction reaction. • The spin polarization is regulated by the synergistic effect of Fe, Co and Ni. [ABSTRACT FROM AUTHOR]

In this study, we investigate the effects of doping with ∼10 at% of Si, Al, Sn, and Bi on the atomic order, microstructure, and magnetic properties of CoMnSb samples prepared using the arc-melting method. X-ray diffraction, scanning electron microscopy, and magnetometry techniques were employed to derive the structural and magnetic parameters. The samples demonstrate a superstructure with an Fm -3 m space group. They exhibit a saturation moment of 3.71–4.71 μ B per formula unit at 5 K and a Curie temperature ranging from 474 to 507 K. Rietveld refinement performed on the XRD data revealed a possible occupation of magnetic atoms in the vacant 32 f (x ', x ', x ') sites and atomic swapping, both of which may affect the magnitudes of the magnetic moment and Curie temperature. The electrical measurement results show that the grain boundaries and voids govern the conductivity of the samples. The spin polarization of the Si-doped sample was determined based on the grain-boundary magnetoresistance effect, which showed that this sample has a high degree of atomic order, consistent with the low magnetic moment, Curie temperature, and lattice constant. [ABSTRACT FROM AUTHOR]

The single-phase bismuth ferrite BiFeO 3 (BFO) has garnered significant interest due to its spintronic-based switching properties observed at room temperature. The first-principles calculations were executed to examine the spin-polarized electronic, dielectric, and structural characteristics of co-doped BFO with lanthanum (La) at A-site and cobalt (Co), nickel (Ni) at B-site in its hexagonal phase (Bi 1-α La α Fe 1-β Ni β O 3 with α = β = 0.04) with generalized gradient approximation (GGA-PBE). The highest value (1.01 × 10−11 A) of total current observed in La Ni co-doped BFO, featuring a distinct spin current of the same magnitude, attributed to spin polarization at the Fermi level (100 %). Additionally, Co-doped BFO exhibits the highest observed spin current density (1.05 × 109A/m2) and charge current density (1.03 × 10−5A/m2). In case of dielectric switching properties, the Ni-doped BFO displays the lowest values of linear dielectric polarization (6.00 × 10−2 C/m2), polarization charge at its interface (1.27 × 10−17 C), capacitance (4.23 × 10−15 F), and switching energy (3.81 × 10−19 J), which is particularly lower than the reported switching energy (1.92 aJ) of multiferroic capacitor. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ferromagnetic-assisted FeCoO x /Mo:BiVO 4 photoanode was prepared. • Fe−Co dual-site as catalytic center reduces the barrier energy for water oxidation. • Ordered spin polarization can optimize PEC performance. • OER activity can be enhanced under a magnetic field. Photoelectrochemical (PEC) devices could play a significant role in efficient solar-to-fuel production for a sustainable economy. Herein, we report a significant enhancement of PEC water splitting via rational tailoring of ferromagnetic ordered oxygen evolution cocatalysts (OECs) iron-cobalt oxide on the Mo-doped BiVO 4 (Mo:BiVO 4) surface. The Fe3+ and Co2+ tend to form an optimal electron-filled arrangement, contributing to lower barriers for the oxygen evolution reaction (OER). Benefiting from the Fe/Co dual-site as the catalytic center, the prepared FeCoO x /Mo:BiVO 4 photoanode achieves 4.55 mA·cm−2 at 1.23 V vs reversible hydrogen electrode (RHE) with a lower starting potential for OER, outperforming the FeO x /Mo:BiVO 4 (2.71 mA·cm−2) and CoO x /Mo:BiVO 4 (3.48 mA·cm−2). Importantly, ferromagnetic iron-cobalt oxide as the spin polarizer can optimize the OER kinetics. Under spin-related effects, a magnetic stimulation strategy can further enhance the spin alignment. The corresponding photocurrent of FeCoO x /Mo:BiVO 4 is increased up to 5.15 mA·cm−2 under a magnetic field, with η Sep and η Trans reaching 89 % and 91 %, respectively. Specifically, the spin-polarization process will be helpful for the production of O(↓)O(↓)H intermediates, preferring to produce O 2. Hence, this study provides a new pathway for designing highly efficient PEC water splitting systems on magnetic-assisted photoelectrodes. [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]

The effect of the Rashba spin-orbit interaction on the shot noise, spin/valley polarization in 8- Pmmn borophene-based superlattice are studied theoretically, by applying the transfer-matrix approach. The spin-dependent transmission probability can be easily controlled by the number of superlattice barriers, the strength of the Rashba, and the incident electron angle. The Fano factor without spin rotation as well as with spin rotation shows an oscillatory pattern versus the strength of the Rashba, and the oscillatory behavior becomes more pronounced as the number of barriers increases. Also, the Fano factor shows a strong dependence on the superlattice direction and number of barriers. The spin and valley polarizations can be easily controlled by the number of barriers and the direction of superlattice. Our findings in this work could provide useful for valleytronics/spintronics systems based on the 8- Pmmn borophene. [ABSTRACT FROM AUTHOR]

Spintronics is an emerging field that has the potential to replace conventional electronics due to their comparatively high speed, low power consumption, and infinite endurance. The phenomena of ferromagnetism with high spin polarization in double perovskites make them the desired materials for spintronics. In the present work, the structure of Cs 2 CuCrX 6 (X = Cl and Br) and their magnetic and optoelectronic properties were studied by utilizing density functional theory (DFT). For the calculations of exchange-correlation potential, PBE-sol approximation was utilized while for the accurate measurement of electronic band structure and density of states (DOS), we employed mBJ potential. Both materials exhibit cubic structure and are thermodynamically stable as confirmed by volume optimization and negative formation energy respectively. Spin-based energy-volume optimization and values of exchange constants reveal the ferromagnetic nature of materials. It has been observed that 3-d states of Cr are responsible for ferromagnetism and have the major contribution to the net magnetic moment caused by exchange splitting. Furthermore, investigations of band structure and electronic density of states showed that both Cs 2 CuCrCl 6 and Cs 2 CuCrBr 6 were indirect bandgap (E g) semiconductors with the E g values of 1.2 eV and 0.33 eV respectively. The optical spectra of materials showed strong absorption in the ultraviolet region. Lastly, the transport and thermoelectric properties (TE) of materials were investigated in the range of temperature 300 K–800 K by using the BoltzTrap code. The transport parameter which included the electrical conductivity (σ/τ) and thermal conductivity (κ e /τ) of the materials showed a decreasing trend with temperature whereas the Seebeck coefficient (S) and Power factor (P.F) showed an increasing trend for Cs 2 CuCrCl 6 while decreases in case of Cs 2 CuCrBr 6. Furthermore, a high figure of merit (ZT) with values of 0.75 and 0.64 was obtained for Cs 2 CuCrCl 6 and Cs 2 CuCrBr 6 respectively. The results of this work are encouraging and show the capabilities of the discussed materials in the fields of spintronics, thermoelectric, and optoelectronics. [Display omitted] • This manuscript presents a comprehensive theoretical investigation into the magnetic, optoelectronic, and thermoelectric properties of Cs 2 CuCrX 6 (X = Cl and Br) double perovskites. • Through rigorous theoretical analysis, the manuscript unveils the spintronic potential of Cs 2 CuCrX 6 double perovskites, shedding light on their intrinsic magnetic properties and their suitability for spin-based electronic applications. This insight opens avenues for innovative spintronics device designs. • Delving into the optoelectronic characteristics, the manuscript elucidates the optical properties of Cs 2 CuCrX 6 double perovskites, offering valuable insights into their light-matter interaction mechanisms. • By examining the thermoelectric properties of Cs 2 CuCrX 6 double perovskites, the manuscript assesses their potential for thermoelectric applications, highlighting their ability to efficiently convert heat into electrical energy. This exploration paves the way for dual-functionality devices coupling data storage with energy harvesting capabilities. [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]

[Display omitted] • We study conductance and polarization in borophene magnetic junctions, theoretically. • The transmission probability can be is zero for most angles of incident electron. • Spin/valley polarization can be easily changed by the external magnetic field. • An 8- Pmmn borophene magnetic junctions can be used as an effective spin filter. • Full valley polarization can be achieved in an 8- Pmmn borophene magnetic junctions. Conductance, spin and valley polarizations through 8- Pmmn borophene barriers in the presence of external Rashba spin–orbit interaction (RSOI) and magnetic field are investigated theoretically. The spin-dependent conductance shows a strong dependence on the direction of the 8- Pmmn borophene barriers, the strength of RSOI and value of the magnetic field strength. For two barriers unlike to one barrier, the spin-dependent conductance exhibits a prominent oscillatory behavior. For the parallel configuration, the dependence of conductance on the magnetic field is more than for the antiparallel configuration. Transmission probability without and with spin rotation decreases drastically with the increase in the value of the magnetic field, so that for sufficiently large magnetic fields, the transmission probability is zero for most electron incidence angles. The size and direction of the spin and valley polarization can be tuned by the strength of RSOI, direction of the 8- Pmmn borophene barriers, size of the magnetic field and type of parallel or antiparallel configuration. In certain conditions, full valley polarization can be achieved in the proposed structure. [ABSTRACT FROM AUTHOR]

The intrinsic activity of single-atom catalysts is influenced by the local electronic structures of metal centers, with existing modulation strategies limited to adjacent atomic coordination. However, the impacts of support surface geometry on local bonding environment, and thus electronic structures of single-atom centers have rarely been known. Here, we prepared highly curved B,N co-doped carbon-supported ruthenium catalyst with an ultra-low Ru loading of 0.4 wt%, which exhibited an ultrahigh turnover frequency (TOF) of 10 H 2 s−1 (38 times that of Pt/C) and superior stability in alkaline hydrogen evolution reaction (HER). We found that curving support surface induced the strain, resulting in 1.5% compressed Ru-N and 4% stretched Ru-B bonds, leading to the accumulation of positive charge and quenching of spin polarization at Ru sites, thereby achieving the optimal binding of H* and enhanced performance for HER. This work highlights the significant support effects upon the structural design of active sites. [Display omitted] • Two types of B, N co-doped carbon-supported Ru site catalysts with and without support surface curvature were synthesized. • Curving the support surface induces strain and thereby changes the local bond length at the Ru sites. • Regulating bond length increases the aggregation of positive charges and suppresses spin polarization at the Ru sites. • The B, N co-doped carbon-supported Ru site catalyst with curvature achieves optimal H* binding strength for HER. • The turnover frequency of Ru sites with curvature is significantly higher than those without surface curvature. [ABSTRACT FROM AUTHOR]

For the application of the spintronics devices, large Rashba spin splitting and Zeeman spin splitting are required. However, the absence of spin splitting in the non-polar MXene Lu 2 CT 2 (T = F, OH) with mirror symmetry limits the functionality of the spintronics applications. In this paper, by the density functional theory calculation, the effect of the electric field on the electronic properties along with the spin polarization of MXene Lu 2 CT 2 (T = F, OH) are investigated. For Lu 2 CF 2 , the electric field can effectively regulate the energy band structures resulting in the indirect-direct band gap transition and semiconductor-metal transition. The spin splitting and spin polarization that are not observed in the situation of the intrinsic systems are established due to the breaking of the mirror symmetry by a suitable external electric field, which is sufficient to support the spintronics functionality. Furthermore, the electric field can effectively control the in-plane Rashba spin splitting and out-of-plane Zeeman spin splitting. The parameters of Rashba and the warping coefficients are comprehensively studied by using the effective k · p model. Therefore, our results provide a possible way to induce and tune Rashba spin splitting and Zeeman spin splitting in the MXene by an external electric field, which is useful for spintronic devices. [Display omitted] • We offer a possible way to induce and tune Rashba effect in no-polar MXene by an external electric field for spintronic devices. • The parameters of Rashba and the warping coefficients are comprehensively studied by using the effective k · p model. • We offer a possible way to induce and tune Rashba effect in no-polar MXene by an external electric field for spintronic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] In recent years, Dion-Jacobson (D-J) perovskite has been extensively studied. In order to further study the application of D-J perovskite materials in spin-optoelectronic multifunctional devices, this paper is based on CsSbCl 3 Br and CsMnBr 4 , a zero-band gap semi-metallic material with the same ferromagnetic ground state and the same crystal structure. In this paper, put forward with transverse CsMnBr 4 /CsSbCl 3 Br/CsMnBr 4 heterojunction optoelectronic devices. The characteristics of photocurrent are discussed using parallel configuration (PC) and anti-parallel configuration (APC) magnetoelectric poles under two conditions: vertical incidence of linearly polarized light and elliptically polarized light utilizing density functional theory and the non-equilibrium Green's function method. The results reveal that the device can achieve complete spin polarization photocurrent, pure spin current, perfect spin filtering effect, and excellent spin valve effect, with high extinction ratios. Under linearly polarized light, the maximum extinction ratio reaches 2747 for the PC configuration and 5200 for the APC configuration. For elliptically polarized light, the extinction ratio is 739 for the PC configuration and reaches a maximum of 240 for the APC configuration. These results indicate that the lateral CsMnBr 4 /CsSbCl 3 Br/CsMnBr 4 heterojunction has broad multi-functional application prospects in the field of optoelectronics and spintronics. [ABSTRACT FROM AUTHOR]

The electronic and magnetic properties of KCaN 2 /KCl(001) heterojunction have been studied within the framework of density functional theory using the full-potential linear augmented plane waves plus local orbital approach. There are two possible interface layers depending on the crystal structure of KCaN 2. The results demonstrate that the half-metallicity nature remains in both possible interfaces, i.e., KCl/KCa and KCl/NN. Spin polarization in both interfaces is complete, % 100, and the interface effects do not affect half-metallicity. The Schottky barrier height, band offsets, valence band maximum, and conduction band minimum to these interfaces were calculated and compared with the other half-metal/semiconductor heterostructures. • Half-metallicity preserves at the both KCl/KCa and KCl/NN interfaces. • There are two types of band alignment for different interfaces: staggered type for NN/KCl and straddling type for KCa/KCl interfaces. • Potential lineups are obtained, Δ V KCa/KCl =0 18 eV and Δ V NN/KCl =1.05 eV. [Display omitted] [ABSTRACT FROM AUTHOR]

A new experimental method to measure muon polarization using a scintillating material has been proposed. One of the key issues for this measurement is the choice of scintillation materials which can maintain the μ + spin polarization for several μ + lifetimes. Thus far, a CeF 3 scintillating crystal has been known to be only a possible candidate and it is highly preferable to find other scintillators whose performance is nearly equivalent to CeF 3. The residual μ + polarization in a 2% cerium-doped LaF 3 scintillating crystal was measured at the J-PARC Material and Life Science Facility (MLF) by applying the longitudinal field (LF) to the LaF 3 material. The polarization was obtained to be 83 and 87 % with LF = 100 and 140 Gauss, respectively, which is high enough to measure the μ + polarization in various experiments. [ABSTRACT FROM AUTHOR]

• Thin film of a composite α″-Cd 3 As 2 (metastable) + MnAs phases were obtained. • The negative magnetoresistance value increased to 5.35 %. • The crystallite's sizes decreased with decreasing substrate temperature. Two types of Cd 3 As 2 –MnAs composite films were synthesized by vacuum-thermal evaporation technique on substrates held at 300 and 427 K. According to X-ray diffraction data, studied films contained α″-Cd 3 As 2 (P4 2 /nmc) and MnAs (P6 3 /mmc) crystalline phases, traces of the amorphous phase were also detected. Stabilization of the metastable α″-phase suggested the formation of (Cd 0.92 Mn 0.08) 3 As 2 ternary compound crystallites in studied films. The average crystallite size is higher for films obtained at higher substrate temperatures (427 K). However, the results of Magnetic Force Microscopy (MFM) studies suggested that the spatial distribution of relevant phases is more homogeneous in films deposited at lower substrate temperatures (300 K). According to the results of MFM studies and electromagnetic measurements, films under study demonstrate ferromagnetic properties and metallic-type conductivity. The films were characterized by negative magnetoresistance, the amplitude of which depended on the substrate temperature and saturated around 0.14 T (1.4 kOe) with maximum value of 5.35 % observed for the film obtained at 300 K. The presence of negative magnetoresistance in studied films suggested the appearance of carrier spin polarization. The linear character of the temperature dependence of resistivity of studied films makes them promising for applications as temperature and magnetic field sensors. [ABSTRACT FROM AUTHOR]

Doping magnetic elements into semiconductors is an effective strategy for manipulating spin-polarized electrons in photocatalysis. This work indicates that the introduction of spin-polarized electrons into BiOCl ultrathin sheets remarkably boosts the efficiency of photocatalytic CO 2 reduction by doping BiOCl with magnetic Co. The Co-doped BiOCl (Co-BiOCl) photocatalyst selectively converts CO 2 into CH 4 and C 2+ products with a hydrocarbon selectivity of 76.9 %, which is not available for pristine BiOCl. The spin-polarized electrons generated from Co-BiOCl promote CO adsorption, stabilize the key CO* intermediate, and significantly reduce the kinetic barrier to CH 2 * formation, tuning the subsequent hydrogenation and C−C coupling into hydrocarbons. The regulatory effect of spin polarization on photocatalytic CO 2 reduction can also be observed for Fe-, Ni- or non-magnetic element Cu- doped BiOCl. Hence, this work provides new insight into the regulation of the photoreduction of CO 2 to hydrocarbon products by spin-polarized electrons. [Display omitted] • Co doping introduces spin-polarized electrons in BiOCl ultrathin sheets. • Co-BiOCl selectively converts CO 2 into CH 4 and C 2+ products. • Spin-polarized electrons generated from Co-BiOCl promote CO adsorption. • Spin-polarized electrons benefit for stabilizing the reaction intermediates. • The regulatory effect is also observed on Fe-, Ni- or Cu- doped BiOCl. [ABSTRACT FROM AUTHOR]

Restraining the fast recombination of electrons and holes is an essential method to enhance the photocatalytic reaction efficiency, which could be attempted by modulating the electron spin polarization except for energy band structures. Herein, we synthesized manganese zinc ferrite (Mn x ZFO) photocatalysts with spin polarization effect by doping Mn cation into ferromagnetic semiconductor ZnFe 2 O 4 (ZFO). X-ray diffraction (XRD) characterization confirmed the successful preparation of ZFO and gradient Mn doping Mn x ZFO samples. In addition, the vibrating sample magnetometry (VSM) results of Mn 0.6 ZFO displayed a stronger magnetization property than ZFO, which was beneficial for the modulation via a magnet. In photodegradation experiments, Mn 0.6 ZFO exhibited a remarkable enhancement of about 30% for tetracycline (TC) removal with an external magnet. The improvement of TC photodegradation efficiency by Mn 0.6 ZFO and a magnetic field could be attributed to the spin polarization of materials. In detail, the opposite spin states of numerous light-induced electrons with the holes suppressed the rapid recombination of charge carriers, thus boosting the TC degradation performance. The DFT calculation indicated that Mn doping could realize the electron spin polarization of ZFO, while Mn 0.6 ZFO exhibited the most obvious spin polarization among the nearby compositions of Mn x ZFO and ZFO. Additionally, the antibacterial experiments of TC degradation products analyzed by LC-MS were carried out to determine the biotoxicity of TC intermediates. Specifically, the biotoxicity of the TC solution progressively declined as the reaction progressed. Moreover, the photocurrent implied Mn 0.6 ZFO with electron spin polarization behaved with a better charge separation ability than ZFO without spin polarization. This work would extend the strategy for tailoring the electron spin polarization in ferromagnetic photocatalysts by metal doping engineering. Mn-doped ZnFe 2 O 4 shows an excellent photodegradation activity enhancement with the presence of an external magnetic field, which is ascribed to the successful introduction of electron spin polarization. [Display omitted] • Electron spin polarization manipulated by an external magnetic field inhibited the recombination of charge carriers. • The DFT results indicated Mn 0.6 ZFO exhibited the strongest electron spin polarization. • LC-MS and biotoxicity tests revealed that the toxicity of the TC solution declined along with the photodegradation. • A possible mechanism based on electron spin polarization was proposed. [ABSTRACT FROM AUTHOR]

The FP-LAPW method is used to examine the physical properties of Fe–Pd binary intermetallic compounds. The calculated formation enthalpies indicate that FePd and FePd 3 compounds are thermodynamically stable in L1 0 and L1 2 phases, respectively, and the ferromagnetic Fe 3 Pd can be formed in a tetragonal Z1 structure with a small negative formation enthalpy. The elastic coefficients and their related parameters show that all compounds are mechanically stable and ductile in nature. The FePd-L1 0 is the harder compound and Fe 3 Pd-Z1 exhibits the highest anisotropy. The band structure, the TDOS profile and the charge density distribution show that these compounds are ferromagnetic with a metallic character and covalent-metallic bonds. The PDOS shows that the Pd- 4d and Fe- 3d states are dominant, and the asymmetry of Fe- 3d states is behind the system strong spin polarization. The calculated magnetic moments agree well with previous theoretical results. The thermodynamic parameters are determined using the quasi-harmonic Debye model. [ABSTRACT FROM AUTHOR]

[Display omitted] Incorporating magnetic species, magnetic functional groups or additives, into polymer hosts is an effective method for synthesizing magnetic polymers. Polymers can gain magnetic moments not solely through magnetic coupling but also via the induction of Coulombic excitation. Attachment of the magnetic side-groups to the polymer backbone increases orbital localization in repeat units. This will bring two competing effects. The orbital localization will increase the intra-site Coulomb interaction, which increases magnetic moments in repeat units. Oppositely, the orbital localization also increases the energy splitting between orbitals on the polymer backbone and on side-groups, suppressing thus the magnetic moments of repeat units. However, a preference for low-spin states in the polymer units emerges when a substantial split in orbital energy occurs due to a strong coupling, consequently suppressing the magnetic moment. On the contrary, a minimal split in orbital energy within the polymer units can readily induce a high-spin state and generate a magnetic moment. However, in such cases, the Coulomb interaction triggered by the interconnected magnetic moieties might be too weak to produce a magnetic moment in the polymer. To explore this trade-off, we have proposed a theoretical two-level model aimed at elucidating the decision-making process of experimentalists during the synthesis of magnetic polymers. We also found that the dimerization of the polymer backbone together with the phonon dependence of spin–spin interaction between near-neighbor repeat units increases magnetic moments. As the magnetic responses arising from Coulombic interactions in polymers are intricately linked to carrier density, properties of the magnetic polymers acting as an active layer of a field-effect transistor can be tuned by the gate field, which controls the charge carrier density in the transistor transport channel. [ABSTRACT FROM AUTHOR]

• We explore 2D systems with a type of spin-polarized nodal loop that are robust under SOC and characteristic an hourglass type dispersion. • γ -structure VCl 2 , which bridges hourglass loop materials and spintronics, exhibits many unique properties including large spin polarization and robust topological properties. • Most importantly, hourglass loop is intrinsic and do not require any external conditions in experiments such as strain, magnetic field, or electric field. Hourglass loop in two-dimensional (2D) systems is typically vulnerable against spin–orbit coupling (SOC). Here, we explore 2D systems with a type of spin-polarized nodal loop that is robust under SOC and characteristic of an hourglass-type dispersion. Through first-principles calculations, we identify the monolayer VCl 2 materials as a realistic material platform to realize an hourglass loop. There exist three phases, all of which are dynamically stable. For the γ -structure, as a new single spin hourglass loop material. It shows semiconducting and gapless properties in spin down and spin up channels, respectively. Moreover, it always exhibits an hourglass loop property in the absence and presence of SOC. It indicates that the hourglass has strong against SOC. Our work suggests a realistic material platform for investigating the novel physics associated with band crossings in 2D systems. [ABSTRACT FROM AUTHOR]

• Spin transport properties in bilayer graphene on a Cr 2 X 2 Te 6 monolayer (where X = Ge, Si, or Sn). • Employment of a Hamiltonian model to describe carrier motion in the bilayer graphene/ Cr 2 X 2 Te 6 system. • Study of spin transport, demonstrating the modulation of spin polarization from 0% to 100% by varying gate voltage. • Perfect spin polarization switching from −100 % to + 100 % through gate voltage adjustment, achieving complete spin filtering. • Unique spin conductance curve splitting under perpendicular electric field, showing potential for spintronic applications. We investigate the spin transport properties of bilayer graphene grown on a monolayer Cr 2 X 2 Te 6 hybrid structure. Here, X can be Ge, Si, or Sn, all of which are van der Waals layered materials with magnetic properties. Our results show that the magnetism in bilayer graphene is layer-dependent, affecting the spin-dependent energy gap and Fermi level. Focusing specifically on the X = Ge case, we reveal that pure spin currents can be precisely controlled by applying gate voltage and a perpendicular electric field across the barrier. By varying these parameters, we achieve perfect switching of pure spin current from spin-down to spin-up due to the system's layer-dependent magnetism. Moreover, due to differing gaps between spin-up and spin-down electrons, spin polarization can sharply jump from 0 % to 100 % with changes in gate voltage. The splitting of spin conductance curves, creating a fully functional spin-filtering junction, is also predicted under a varying perpendicular electric field. This model can be extended to cases where X is Si or Sn due to their similar electronic band structures. Our research demonstrates the potential of bilayer graphene on Cr 2 X 2 Te 6 hybrid structures, which exhibit distinctive layer-dependent magnetism ideal for spintronic applications. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the electronic, magnetic, and optical properties of scandium based ternary oxides perovskite YScO 3 (Y = Ni, Pd, Pt). We employ the Tran and Blaha modified Becke-Johnson approximation to calculate spin polarization using the density functional theory. Based on the formation energy, we found that our materials are thermodynamically stable (−0.76 eV, −1.3 eV and −1.65 eV for NiScO 3 , PdScO 3 and PtScO 3 , respectively). The densities of states and spin polarized band structures for spin up (↑) and spin down (↓) channels reveal the half-metallic nature for all studied compounds with Ni/Pd/Pt-d orbitals playing a major role in the valence band. Additionally, all perovskites exhibit ferromagnetic behavior with magnetic moments approximately equal to 3 μ B. Moreover, we calculate several optical parameters such as the dielectric constants, refractive index, reflectivity, extinction and absorption coefficients for these compounds. The results suggest that these perovskites might be promising candidates for optical and spintronic devices. • YScO3 (Y = Ni, Pd, and Pt) are thermodynamically stable. • Exhibits half-metallic ferromagnetism with 100% spin polarization. • The structural, electronic, magnetic, and optical properties were investigated using density functional theory. • Promising candidates for spintronic applications. [ABSTRACT FROM AUTHOR]

The global spin alignment of the vector meson has been observed in relativistic heavy ion collisions, but its theoretical origin is still on hot debates. Here we propose to apply the light front framework to explain this phenomenon since the light front form explicitly describes the hadron spin including both the quark spin and the orbital angular momentum. After applying the light front spinor, we find that the spin alignment in the polarization of vector mesons with ρ 00 > 1 / 3 can be naturally manifested and in particular, the obtained spin alignment for ϕ meson is in good agreement with the experimental data. This implies that to explain the spin alignment it is important to properly include the contribution from the gluon interactions that are presented in terms of the orbital angular momentum of the hadron bound state. [ABSTRACT FROM AUTHOR]

The strong interaction between graphene and elemental ferromagnetic transition metals results in considerable shifts of the graphene π band away from the Fermi level. At the same time, a weakly-dispersing single-spin conical band feature is found in the proximity of the Fermi level at the K ̄ point in the surface Brillouin zone of epitaxially-aligned graphene/Co(0001). Here, the robustness of this electronic state against twisting angles at the interface is experimentally and theoretically demonstrated by showing the presence of similar band features also in the case of rotated graphene domains on Co(0001). Spin-resolved reciprocal space maps show that the band feature in rotated graphene has similar Fermi velocity and spin polarization as its counterpart in epitaxially-aligned graphene. Density functional theory simulations carried out for the experimentally observed graphene orientations, reproduce the highly spin-polarized conical band feature at the graphene K ̄ point, characterized by a hybrid π -d orbital character. The presence of the conical features in the rotated domains is attributed to the unfolding of the superstructure K ̄ point states exclusively to the K ̄ point of the graphene primitive cell. The similarities found in the electronic character for different graphene orientations are crucial in understanding the magnetic properties of realistic graphene/Co interfaces, facilitating their implementation in spintronics applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Extreme structure and spin states of doped and undoped perforated bigraphenes was studied using DFT simulations. It was found that folded nanopores possess extremely high curvature of 0.34 Å−1. Dramatic structural deformation causes severe changes of the chemical properties of carbon atoms localized at the nanopores converting the folded edges to local oxidative fragments. It was found that asymmetrical coordination of either Li, Ca, or Al to the nanopores is coupled with electron transfer from metal to edge carbon atoms and breakdown of local inversion symmetry. Li-, Ca-, and Al-doped perforated AA bigraphene revealed ferromagnetic spin ordering with magnetic moments of 0.38, 0.14, and 0.32μ B /unit cell, respectively, and spin polarization energy gain of 0.037eV for Ca-doped superlattice. It was shown that ferromagnetic spin ordering of bigraphene nanopores contradicts to the Nagaoka's theorem, which excludes strong electron correlations as a reason of spin polarization. Spontaneous lift of spin degeneracy was interpreted in terms of perturbing intense local electrostatic fields from extra electron charges localized at the nanopore edges, coupled with breakdown of space inversion and local translation invariances. It was shown that spin energy splitting is proportional to the matrix elements calculated on Bloch states with opposite wavevectors and perturbing electrostatic fields. [Display omitted] [ABSTRACT FROM AUTHOR]

Cost-effective oxygen evolution reaction (OER) electrocatalysts play a key role in electrocatalytic water splitting process. Here, a facile and scalable strategy was applied to synthesize the bimetallic metal-organic frameworks (MOFs) with high OER activity, and the effects of AC magnetic field on OER was also investigated. Results shows that the bimetallic MOFs (Co 0.4 Ni 0.6 -MOF-74) exhibited a three-dimensional flower-like morphology, and possessed a higher BET specific area of 905.39 m2 g−1 as well as a smaller median pore size of 0.49 nm as compared to single metal MOFs; It owned a lowest overpotential of 314 mV at 10 mA cm−2 and Tafel slope of 79.39 mV dec−1, both are much lower than these of single metal MOFs, being due to the high specific area and more active sites derived from the distorted crystal structure; When AC magnetic field strength equaled to 5.50 mT, overpotential at 10 mA cm−2 for Co 0.4 Ni 0.6 -MOF-74 reached minimum value of 201 mV, reduced by about 36% as compared to that without magnetic field, indicated that AC magnetic field could greatly improve OER process. These improvements resulted from the spin polarization effect, magnetohydrodynamic (MHD) convection and improved active point temperature. • Co 0.4 Ni 0.6 -MOF-74 owned a lowest OER overpotential of 314 mV at 10 mA cm−2. • η 10 of Co 0.4 Ni 0.6 -MOF-74 is reduced by up to 36% under AC magnetic field. • Spin polarization, magnetic heating effect and MHD convection improved OER activity. [ABSTRACT FROM AUTHOR]

The spin-dependent conductance and spin polarization are investigated theoretically in a phosphorene superlattice in the presence of external magnetic field and Rashba interaction. It is demonstrate that, the spin-dependent conductance with and without spin-flip as well as spin polarization can be effectively controlled by changing the magnetic field strength and the number of the superlattice barriers. For small magnetic field strength, the conductance for with and without spin-flip shows an oscillating behavior as increasing the strength of the Rashba interaction, and by increasing the number of barriers, the oscillating behavior becomes prominent. Further, when the magnetic field is greater than a limit value, the spin conductance will be zero. The size of the spin-dependent transmission window in the phosphorene superlattice under external magnetic field decreases drastically. The magnitude, sign and behavior of the spin polarization can be tuned by the amount of the external magnetic field. [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 dope paramagnetic iron ions (Fe2+) into colloidal metal halide perovskite nanocrystal (PNC). • Incorporating a magnetic dopant and applying an external magnetic field induce spin polarization. • The spin polarized photo-excited electrons enhance the photocatalytic CO 2 reduction efficiency. • Applying an external magnetic field with Fe-doped PNCs, we achieve a CO 2 reduction rate of 133.04 μmol g−1. • This shows a 1.68-fold increase in CO 2 reduction rate compared to magnetic field-free Fe-doped PNCs. Spin manipulation offers an effective strategy to enhance photocatalytic activity in metal halide perovskites by suppressing the recombination of photo-excited electrons. However, the scope of the magnetic dopant inducing spin polarization is still limited. Here, we introduce synergetic strategies to polarize the spin in photo-excited electrons and boost their photocatalytic activity for CO 2 reduction. We dope iron cation (Fe2+) into CsPbBr 3 perovskite nanocrystals (PNCs). Fe ions induce paramagnetism, fostering spin polarization within the Fe-doped CsPbBr 3 PNCs (Fe-CsPbBr 3 PNCs) under magnetic fields. The magnetic compositions in PNC tend to stabilize the spin polarized electrons within the PNC, mitigate the recombination of photo-excited electrons and enhance the redox reaction for photocatalytic CO 2 reduction. The synergistic effects of magnetic element doping and the application of magnetic fields resulted in a photocatalytic CO 2 reduction of 133.04 μmol g−1, which is 1.68-fold increase compared to the Fe-PNC without a magnetic field. This work provides a simple and environmentally friendly approach to CO 2 reduction based on PNCs. [ABSTRACT FROM AUTHOR]

This study employs density functional theory (DFT) using Wien2k to comprehensively analyze the essential properties of two half-Heusler alloys, KCrSi and KCrGe. Our findings demonstrate that the ferromagnetic Type 2 configuration exhibits superior stability over non-magnetic and antiferromagnetic states for all KCrZ (Z = Si, Ge) alloys. These alloys exhibit complete spin polarization and half-metallic character, with calculated magnetic moments of 3 μB for both KCrSi and KCrGe. The Curie temperature (T C) is determined using the mean field approximation. Mechanical stability is assessed through second-order elastic constants (SOECs), and electronic properties are analyzed using local spin density approximation (LSDA), Perdew-Burke Generalized Gradient Approximation (PBE-GGA), and Tran-Blaha modified Becke-Johnson (TB-mBJ) schemes, confirming the retention of the half-metallic nature. The negative enthalpy of formation (ΔH) suggests material stability. The use of semi-classical Boltzmann theory, incorporated through the sophisticated scheme of BoltzTraP, explores transport coefficients. High pressures and temperature discrepancies in thermodynamics are considered by implementing the quasi-harmonic Debye approximation to illustrate stability. Finally, optical properties are summarized to assess the applicability of this alloy for optoelectronic applications. The overall characteristics of these particular alloys suggest potential applications in sustainable thermoelectric and optoelectronic features. • The stability in cubic structure is established with the help of structural optimization, and mechanical stability criteria. • The high Seeback coefficient and low thermal conductivity yield a high figure of merit ZT at 900 K. • The alloy has potential applications in thermoelectric technology and optoelectronic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Be 2 CrH 6 , and Be 2 CrH 6 have hydrogen storage capacities 7.9 wt%, and 7.6 wt%, • Spintronic and energy harvesting applications. • The ferromagnetism by electron spin instead of magnetic ion clustering. • The Half-metallic ferromagnetism ensures 100% spin polarization. • Large power factor and least lattice thermal conductivity. Metal hydrides are highly significant for hydrogen storage because of high gravimetric and kinetic factors. Therefore, the double perovskites hydrides Be 2 XH 6 (X = Cr and Mn) have outstanding hydrogen storage capability with gravimetric hydrogen densities of 7.9 wt% and 7.6 wt%, respectively. Moreover, the DFT-based PBE-GGA and TB-mBJ potential have been implemented to systematically analyze the electronic, Curie temperature, and magnetic characteristics of Be 2 XH 6 (X = Cr and Mn). The tolerance factor and formation energy analysis indicate the structural and thermodynamic stabilities. The band structures, density of states and Curie Weiss law ensure the above room temperature half metallic ferromagnetism with complete spin polarization. The ultralow lattice thermal conductivity and high thermoelectric performance also significantly increase their importance. Finally, the mechanical and thermodynamic behavior have also been addressed in detail. These conclusions are significant for future hydrogen storage growth increases in metal hydrates. [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]

The investigation focused on examining the spin polarization and thermal spin polarization transport characteristics of dual rhenium phthalocyanine (Re2PC2) molecular junctions. This analysis was conducted using first-principles density-functional theory and the non-equilibrium Green's function approach. Calculations were performed on molecular junctions in two configurations: one at a non-magnetic electrode (Au) and the other at a magnetic electrode (Ni). A comparison of the spin transport properties of the two electrodes shows significant differences. The magnetic electrode has a notable effect on the spin-polarization and thermal spin-polarization transport properties of the devices. In contrast, the nickel electrode bis-phthalocyanine rhenium molecular device exhibits perfect spin/thermal spin-filtering efficiencies in a parallel structure. The properties of the dual phthalocyanine rhenium molecular devices were significantly affected by the nature of the electrodes. This makes dual rhenium phthalocyanine molecular junctions have great potential for the development of high-performance multifunctional spintronic and spin caloritronic devices. • The nickel electrode Re2PC2 molecular device showed perfect spin/thermal SFE at parallel structure. • PDOS revealed that the transport properties of Re2PC2 molecules were strongly influenced by the magnetic electrode. • Changing the direction of the magnetic moments of the molecules and electrodes can alter the device's characteristics. [ABSTRACT FROM AUTHOR]

In this work we report on the systematic characterization of a rare-gas moderated magnetically-transported continuous positron beam based on a 22Na radioactive source. The characterization was performed with three different rare-gas solid moderators: Ne, Ar, and Kr. Each moderator was deposited and then thermal annealed at temperature ∼ 35 % and ∼ 30 % lower than the melting point, respectively. Tests of moderation/magnetic transport efficiency of the apparatus have shown a maximum efficiency of 1.8 10-3, 2.0 10-3 and 0.6 10-3 for Ne, Ar, and Kr, respectively. The average longitudinal kinetic energy of positrons was found to be ∼ 0.95 eV, ∼1.25 eV, and ∼ 0.45 eV for Ne, Ar, and Kr moderator, respectively. The spin polarization measurement of moderated positrons was performed by using the Doppler broadening of the annihilation γ-rays from positronium formed in oxidized nanochanneled silicon positron/positronium converters. Polarization values of 0.30 ± 0.01, 0.29 ± 0.01 and 0.29 ± 0.01 were found for Ne, Ar, and Kr moderator, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • The coupling effect of the BCC-B2 transition and Mn occupancies has been studied. • The BCC-B2 transition intensified the magnetic interaction between Fe and Mn atoms. • The increased covalent bonding component and Peierls stress enhanced the brittleness. • VEC, spin polarization, and Mn content correlate with the contradictory relationship. The magnetism-ductility contradictory relationship presents a significant challenge in the development of magnetic alloys. The impact of the BCC-B2 transition, along with Mn site occupancy, on magnetism and ductility have been investigated by using first-principles calculations. The calculations involved the evaluation of magnetic moments, density of states (DOS), phase stability and ductility of FeCoMn alloys. The results of binary alloys confirm the enhancement of magnetism due to the BCC-B2 transition. Furthermore, the ordering phase transition can strengthen the magnetic interaction between Fe and Mn atoms, which is associated with minimal variations in the density of states of Fe and Mn in the B2 structure. Regarding the ductility of FeCoMn alloys, two factors contribute to increased brittleness. Firstly, the increased covalent component in bonding, as a result of the strong hybridization between different elements, leads to an increased brittleness. Secondly, the increased Peierls stress provides a larger resistance to dislocation motion, which also contributes to the increased brittleness. Finally, the Pearson correlation coefficients and data analysis indicate that VEC, spin polarizations and Mn content provide major contributions to the contradictory relationship between magnetism and ductility. [ABSTRACT FROM AUTHOR]

The structure and the thermophysical properties of δ -UZr 2 are investigated using 0 K density functional theory and ab initio molecular dynamics (AIMD). Modeling the true paramagnetic state of this intermetallic compound has been challenging using first-principles calculations. For the first time, we find that the generalized gradient approximation method without applying an on-site Coulomb interaction term (Hubbard U) can result in a ground state that is antiferromagnetic (AFM). We believe that this weak AFM ground state is the closest to the real paramagnetic state. We found that structure optimization at finite temperatures using AIMD is necessary to achieve this ground state instead of the non-magnetic and ferromagnetic states previously reported in the literature. Our findings indicate that applying the Hubbard U on uranium f -orbitals in this metallic system is unnecessary and not recommended, as it leads to a large overestimation of the volume and introduces an unphysical strong spin polarization. Our approach results in atomic volume, thermal expansion, and heat capacities that have strong agreement with experiments. [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]

Spintronics is a rapidly developing field in advanced technology. It focuses on manipulating the spin of electrons to achieve high-speed data transfer, handling, and storage in order to enhance its capabilities. We conducted a systematic investigation of the ferromagnetism, electronic, and thermoelectric characteristics of spinel compounds LiFe 2 (O/S) 4. Our analysis for optimization demonstrates that ferromagnetic states exhibit great energy release compared to the antiferromagnetic states, indicating the presence of ferromagnetic behavior in the studied compounds. To evaluate the presence of ferromagnetism above room temperature, we employ the Heisenberg model to calculate the Curie temperature and spin polarization to evaluate the presence of ferromagnetism above room temperature. Additionally, a concise overview of the nature of ferromagnetism, including band structures, density of states, exchange energies and constants, hybridization double exchange model, and crystal-field energy, is provided in this research. The absorption of a shift in magnetic moment from Fe to the Li and O/S sites suggests that the ferromagnetic behavior is primarily due to the spin of electrons. Furthermore, we explore the impact of the thermal parameters on the electro-spin as well as the thermoelectric characteristics for both spin-down and spin-up states, providing insights into the energy-harvesting potential. • Half-metallic ferromagentic spinels LiFe 2 (O/S) 4. • Elastic constant are investigated for structural stability. • Electronic and magnetic properties for spintronic applications. • Magnetic moments are discussed for both compounds. • The electronic and lattice thermal conductivity are calculated for thermoelectric characteristics. [ABSTRACT FROM AUTHOR]

Optically pumped atoms have essential applications in magnetic sensing, physics research, and inertial navigation. The polarization gradient caused by light absorption dramatically influences the performance of quantum sensors based on optical pumping. This paper presents a novel approach to address the trade-off between polarization gradient and sensitivity by introducing the pulsed optical pumping method. The interplay of pulsed optical pumping, relaxation, and diffusion processes leads to a more homogeneous distribution of electron spin. Experimental results indicate that the pulsed optical pumping technique increases the optically pumped magnetometer (OPM) signal strength by 12.8% and increases the nuclear spin coherence time by 12.29% in optically pumped co-magnetometer (OPCM). This technology has broad applications in sensors based on the optical pumping effect, such as OPM, OPCM, and nuclear magnetic resonance gyroscope, and holds immense promise for future advancements in the optical pumping field. • Novel Approach: Pulsed optical pumping for homogeneous polarization. • Improved Performance: Improved Performance: Increases OPM signal strength and nuclear spin coherence time. • Broad Applications: Applicable to OPMs, OPCMs, NMRGs, et al. [ABSTRACT FROM AUTHOR]

• The spin-dependent electronic transport properties of zigzag phosphorene nanoribbons (ZPNRs);. • The electronic transport through the ZPNRs shows apparent spin polarization;. • The spin polarization is tightly dependent on the absorbing manners;. • Negative differential resistance characteristic can be observed on current-voltage curves. Based on density functional theory (DFT) and non-equilibrium Green's function (NEGF) method, we have investigated spin-dependent electronic transport properties of zigzag phosphorene nanoribbons (ZPNRs) coupled with chromium triiodide (CrI 3) molecules. Three different adsorption models have been considered: CrI 3 molecule is placed on ZPNR surface (C-type), and CrI 3 molecule is lateral adsorbed on the edge of ZPNR with its molecule panel vertical (V-type) or parallel (P-type). We discovered that ZPNR's electrical transport clearly displays spin polarization, owing to the coupling between ZPNR and CrI 3 molecules. And spin-polarization is tightly dependent on the absorbing manners. Moreover, the negative differential resistance (NDR) characteristics can be observed from current-voltage curves and modulated by absorbing molecules. Furthermore, we also discovered that CrI 3 is vertically adsorbed on the surface of the ZPNRs has a better spin-polarization efficiency than the other two cases. [ABSTRACT FROM AUTHOR]

The ability of organic radicals to maintain their open-shell feature in the device environment directly determines whether they can act as spin filters. Based on the recently synthesized stable VR-1 radical, we have designed two molecular devices with symmetric and asymmetric molecule-electrode connections and investiaged their spin-polarized transport properties using density functional theory and non-equilibrium Green's function methodology. The results show that the presence of unpaired electron in VR-1 radical is not a sole requirement for causing spin polarization and the molecular-electrode connection mode plays a decisive role in the transport characteristics. VR-1 can be used as a spin filter in the asymmetric connection mode, while it loses its open-shell feature in the symmetric connection mode. Moreover, VR-1 with the asymmetric connection mode exhibits obvious spin-rectifying effect. The results are analyzed by the spin-resolved frontier molecular orbitals and eigenstates, Mulliken population analysis, transmission spectra and transmission eigenstates. [ABSTRACT FROM AUTHOR]

• The formation energy of Fe2+ in the β-Ga 2 O 3 matrix is lower than that of Fe3+, and the system is more stable when the Ga or O vacancies (V Ga or V O) are adjacent to the Fe lattice position. • The β-Ga 31 Fe2+/3+O 47 and β-Ga 30 Fe2+/3+O 48 systems all exhibit ferromagnetism with above-room-temperature Curie temperature. Ga 30 Fe2+/3+O 48 has more spin-polarized O atoms in the same direction. • The magnetism originates from the double-exchange interaction of the coupling and hybridization of the Fe-3d state of Fe3+ and the O-2p state. • Ga 30 Fe3+O 48 system achieves semi-metallization with 100 % hole spin polarization. Induced by the spin-polarized double-exchange interaction between the 3d orbitals of Fe atoms and O-2p orbitals near the O/Ga vacancy complexes, the origin of magnetism in β-Ga 2 O 3 is investigated by using geometry optimization and energy calculation based on the first-principles generalized gradient approximation Hubbard + U method of density-functional theory. The results show that the formation energy of Fe2+ in the β-Ga 2 O 3 matrix is lower than that of Fe3+, and the system is more stable when the Ga or O vacancies (V Ga or V O) are adjacent to the Fe lattice position. It is found that the β-Ga 31 Fe2+/3+O 47 and β-Ga 30 Fe2+/3+O 48 systems all exhibit ferromagnetism with above-room-temperature Curie temperature. β-Ga 30 Fe2+/3+O 48 (i.e., with Fe2+/3+ and V Ga) has more spin-polarized O atoms in the same direction. The magnetism originates from the double-exchange interaction of the coupling and hybridization of the Fe-3d state of Fe3+ and the O-2p state, which increases the magnetic moment of the β-Ga 30 Fe3+O 48 system. This study provides a theoretical reference for designing and preparing new β-Ga 2 O 3 -based dilute magnetic semiconductors and related spintronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chiral-induced spin selectivity effect used for enhancing electrocatalytic properties. • overpotential decreased by 197 mV and there is a three-fold increase in the current density due to the spin effect in the oxygen evolution reaction. • Threefold increase and fourfold decrease in the current density and overpotential respectively for the hydrogen evolution reaction. • The formation of H 2 O 2 is retarded significantly due to the spin effect. • The combination of Al and chiral molecules influences the water-splitting process. The spin-polarized electrons, generated due to the chiral-induced spin selectivity (CISS) effect, play a critical role in enhancing the catalytic behavior during oxygen evolution reaction (OER). In this research, we have designed and investigated the electrocatalytic performance of a chiral bilayer hybrid structure utilizing D-Phenylalanine-coated Ni/Al bilayer thin film. Subsequently, spin-dependent electrochemical measurement reveals that there is a nearly two-fold increase in the spin polarization (of electrons) value to 9 %, when the D-Phenylalanine molecule is anchored onto to Al overlayer of Ni/Al electrodes than on the Ni itself. Accordingly, the overpotential decreased by 197 mV and there is a three-fold increase in the current density value to 39 mAcm−2 in OER for D-Phenylalanine-coated Ni/Al electrodes than that coated on Ni surface. Moreover, the same electrode also demonstrated excellent hydrogen evolution reaction (HER). The faradaic efficiency calculated for the D-Phenylalanine-coated Ni/Al bilayer hybrid structure is 88.7 % and 96 % for OER and HER respectively. This chiral bilayer hybrid architecture presents an innovative way of enhancing the spin polarizability with superior catalytic activity for both OER and HER. [ABSTRACT FROM AUTHOR]

An investigation is carried on a quantum system featuring a MoS 2 zigzag nanoribbon employing double magnetic barriers. This study aims to overcome a valley polarization limitation observed in systems using a uniform magnetic field or a single magnetic barrier. A magnetic field breaks the degeneracy of the K and K ′ valleys owing to the valley Zeeman effect, but reversing the direction of the magnetic field is required to invert the valley polarization. In a double magnetic barrier system, interplay between the Fano resonance (arising from the quantum interference between the continuum state of the magnetic barrier and the Landau level) and the resonant tunneling (arising from the quantum states between two barriers) indicates the potential for achieving selective spin and valley polarization by adjusting the strength and width of the magnetic barrier. This can enhance the degree of valley polarization and enable the existence of four distinct spin and valley currents. Obtaining full spin and valley polarization is shown with the optimized parameters of this system. The experimental realization of this system should enable the control of carrier valley and spin degrees of freedom in future devices. [Display omitted] • Three-band tight-binding model using three d orbitals (dx 2 , dx2−y2, and dz2) of Mo atoms. • Double magnetic barrier is used to enhance valley and spin polarization. • Resonant tunneling effect in the K valley and Fano resonance effect in the K ′ valley. • The MoS 2 zigzag nanoribbon system with double magnetic barriers along the same direction has great advantages compared with a single magnetic barrier. [ABSTRACT FROM AUTHOR]

We study spin- and valley-dependent transport properties in a n-p–n junction of 8-pmmn borophene monolayer. We show that an exchange magnetic field can generate spin polarization in the system and a gate voltage, as a potential barrier, induces valley polarization. The valley polarization, induced by the gate voltage, is due to the anisotropic and tilted Dirac cones of borophene structure. This property is the advantage of borophene over the other 2D materials with isotropic and non-tilted Dirac cones such as graphene in which a gate potential cannot induce valley polarization. We also show that the proposed device (borophene-based n-p–n junction) can work as perfect spin and perfect valley filters. The spin and valley filters can be controlled by changing the gate voltage and/or Fermi energy. The results of this study show that borophene has a suitable potential to be used in spintronic and valleytronic devices. • Our npn junction can work as perfect spin and perfect valley filters. • Spin-up filter changes to the spin-down filter and vice versa via gate voltage. • Valley filtering by applying gate voltage is due to tilted Dirac cones. • Above property cannot occur in 2D materials with isotropic and non-tilted cones. • Borophene shows a great potential for use in spintronic and valleytronic devices. [ABSTRACT FROM AUTHOR]

Asymmetric coordination effect is an important concept in heterogeneous catalysis where both catalytic activity and product selectivity are serious influenced. However, this effect has rarely been understood because of the difficult in characterizing detailed coordination information. Here, by employing a theoretical study on electrocatalytic CO 2 reduction reaction (ECO 2 RR) towards HCOOH over Ti 3 C 2 O 2 -based NS/NN co-coordinated transition metal single atom catalysts (TM-NS/NN-Ti 3 C 2 O 2 SACs), we show that asymmetric coordination environments have great impact on the electronic structure of the active center. Both electron transferring ability and spin polarization of the active center are vital to optimize the adsorption and hydrogenation of key intermediates. As a result, both catalytic activity and product selectivity can be maximized. V-NN-Ti 3 C 2 O 2 are predicted to promote high-throughput HCOOH generation process at operation applied potential of −0.32 with considerable electrochemical stability, surpassing most reported catalysts. This work demonstrates V-NN-Ti 3 C 2 O 2 as high-performance ECO 2 RR catalysts, and highlights that the introduction of the concept of asymmetric coordination effect may offer a new insight into the rational design of more efficient SACs. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] One-dimensional (1D) gapless hinge states are predicated in the three-dimensional (3D) higher-order topological insulators and topological semimetals, because of the higher-order bulk-boundary correspondence. Nevertheless, the topologically protected property of the hinge states is still not demonstrated so far, because it is not accessible by conventional methods, such as spectroscopy experiments and quantum oscillations. Here, we reveal the topological nature of hinge states in the higher-order topological semimetal Cd 3 As 2 nanoplate through spin potentiometric measurements. The results of current induced spin polarization indicate that the spin-momentum locking of the higher-order hinge state is similar to that of the quantum spin Hall state, showing the helical characteristics. The spin-polarized hinge states are robust up to room temperature and can nonlocally diffuse a long distance larger than 5 μ m , further indicating their immunity protected by topology. Our work deepens the understanding of transport properties of the higher-order topological materials and should be valuable for future electronic and spintronic applications. [ABSTRACT FROM AUTHOR]