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The investigation of two-dimensional (2D) intrinsic ferromagnetic material is important in the field of spintronics. In this study, the Mn2Ge2Te6 monolayer (ML) with intrinsic ferromagnetism was fabricated by using the density functional theory (DFT). The Mn2Ge2Te6 ML is a half metal (HM) with a spin-β bandgap of 1.462 eV. Biaxial strain could be applied to tune the electronic and magnetic properties of Mn2Ge2Te6. The magnetic moment (MM), magnetic exchange parameter (J), band structures, and magnetic anisotropy energy (MAE) could be effectively controlled by the biaxial strains (ε). This modulation originates that the states near the Fermi level mainly come from the contribution of in-plane atomic orbitals. The MM of Mn monotonously increases as the tensile strains increase. The energy difference between different magnetic orders (Δ E) and J also change with the strains. The antiferromagnetic-stripy order always has the lowest energy under the strains. As the strains change, Δ E and J monotonously change as the direct exchange and super-exchange interactions between Mn atoms vary. As the tensile strain decreases and compressive strain increases (− 2.1 % < ε < 8 %) , the gap of spin-β electrons monotonously decreases. The Mn2Ge2Te6 ML changes from a HM to a normal spin-unpolarized metal under larger compressive strains (ε > − 2.1 %). When the tensile strains are applied, the MAE monotonously increases to the largest value of −22.3 meV (ε = 12 %). As the compressive strains increase, the MAE monotonously decreases. Last, the Mn2Ge2Te6 ML changes from an in-plane magnetic anisotropy into a perpendicular magnetic anisotropy under a larger compressive strain (− 11 %). The change of MAE direction origins that the contribution of hybridization between Te's py and pz orbitals is changed when the strain changes. Our results offer crucial insights into the potential of strain modulation in a 2D Mn2Ge2Te6 ML, paving the way for future advancements in this field. [ABSTRACT FROM AUTHOR]

Intrinsic defects can have an effect on the microstructure of semiconductor materials, which can change the electronic structure of the material and ultimately alter its optical and magnetic properties. In this study, first-principles calculations are performed to demonstrate that the defect formation energies of VTe and ZnCd + VTe are lower under Cd-rich conditions. Conversely, under Te-rich conditions, with the exception of Tei, the defect formation energies for TeCd, VCd, ZnCd+ TeCd, and ZnCd+ VCd are lower, indicating that these defects exhibit greater stability within the system. Furthermore, it is demonstrated that VCd, CdTe, and TeCd introduce magnetic moments into the CdTe system, with VCd contributing the largest magnetic moment. Additionally, composite defects formed by ZnCd and VCd, CdTe, and TeCd also induce spin polarization and introduce magnetic moments. However, the synergistic effect of ZnCd on CdTe defects is significant, reducing the magnetic moment introduced by the CdTe defects. Moreover, ZnCd + VTe composite defects, VTe + VCd composite defects, and VTe, Cdi, and Tei do not introduce magnetic moments into the system. For the CdTe and ZnCd + CdTe defect systems, there is a notable impact on the optical properties, such as the refractive index and reflectance, compared to the perfect CdTe system. When CdTe defects are present, defect energy levels are introduced within the bandgap, affecting electronic transitions between energy bands, which, in turn, influences the magnetic and optical properties of the system. Additionally, it is found that the optical properties of CdTe systems containing intrinsic or composite defects are isotropic, exhibiting weak absorption in the visible light range. However, VTe and TeCd defects can enhance the absorption of visible light to some extent. [ABSTRACT FROM AUTHOR]

A magnon junction consisting of ferromagnetic/antiferromagnetic/ferromagnetic insulators can manipulate the transmission of magnon current through adjusting magnetic moment alignment, offering potential for ultra-low power magnon circuits. This study employs density functional theory calculations and atomic simulations to investigate the strain-dependent modulation of magnon current transport in CoF e 2 O 4 / NiO / CoF e 2 O 4 junctions induced by bulk acoustic waves. Our results demonstrate that strain significantly alters the magnetic anisotropy energy of both NiO and CoF e 2 O 4 , with NiO favoring in-plane magnetic anisotropy under various strains and CoF e 2 O 4 exhibiting a transition from in-plane to perpendicular magnetic anisotropy. Additionally, controlling the magnetic anisotropy energy of NiO and CoF e 2 O 4 allows for the regulation of magnon current transmission, providing a novel approach to optimize magnonic device performance. These findings highlight the potential of strain as a tunable parameter in the design of advanced magnonic devices. [ABSTRACT FROM AUTHOR]

The electron electric–dipole–moment (eEDM) is a powerful tool for exploring new particles. The candidates for eEDM search are heavy atoms and their molecules, which are well known for the obvious relativistic effect. Lead atom is considered to be the most ideal relativistic atom [Park et al., Nat. Commun. 11(1), 815 (2020)]. PbH molecule is an important representative of the Pb compound and is considered a cold candidate molecule due to the high diagonal Franck–Condon factors. We systematically investigated the (eEDM) searches of PbH using a two-component approach. The parity- and time-reversal symmetry violation constants of ground and excited states, including internal effective electric field Eeff, electron–nucleon scalar–pseudoscalar interaction constant WP,T, and nuclear magnetic quadrupole moment, were obtained and compared to other molecules. In addition, we designed two experimental methods to measure the sensitivity of the eEDM, indicating that the Faraday rotation method could greatly improve its sensitivity. [ABSTRACT FROM AUTHOR]

The present study probes the effect of cation distributions in the structural, optical, electronic, and magnetic properties of mixed-valent inverse-spinel NiCo2O4 (NCO) nanoparticles (NPs). NCO NPs were prepared using the sol–gel combustion method and the grain size was obtained in the magnetic exchange length range assumed to be from single-ion anisotropy. The Raman and photoluminescence spectroscopies confirm the presence of an inverse-spinel structure with different oxidation states, and vibrating sample magnetometry clarifies the existence of ferromagnetism with the presence of magnetic anisotropy among the cations. These NPs annealed at a higher grain-growth temperature accumulate ferrimagnetic properties and produce magneto-crystalline anisotropy making NCO an assuring material for spintronic applications. A detailed x-ray absorption spectroscopy and x-ray magnetic circular dichroism studies reveal an indestructible correlation between the distribution of the present cations and the element-specific origin of ferrimagnetic behavior. Ni is found to be accountable for the magnetic moment and electronic conduction, whereas Co is associated mainly with the generation of the magnetic anisotropy even in the polycrystalline NP form. This describes the anti-ferromagnetic coupling between Co and Ni ions that is pivotal in demonstrating the exchange interaction between these cations. The above result signifies the site-dependent cation valence states for the magnetic properties, and the extent of growing conditions are related to such cation-site dysfunction. This depicts further tunability in NCO as a functional oxide material. [ABSTRACT FROM AUTHOR]

Magnetic force microscopy (MFM) is long established as a powerful tool for probing the local stray fields of magnetic nanostructures across a range of temperatures and applied stimuli. A major drawback of the technique, however, is that the detection of stray fields emanating from a sample's surface rely on a uniaxial vertical cantilever oscillation, and thus are only sensitive to vertically oriented stray field components. The last two decades have shown an ever-increasing literature fascination for exotic topological windings where particular attention to in-plane magnetic moment rotation is highly valuable when identifying and understanding such systems. Here, we present a method of detecting in-plane magnetic stray field components, by utilizing a split-electrode excitation piezo that allows the simultaneous excitation of a cantilever at its fundamental flexural and torsional modes. This allows for the joint acquisition of traditional vertical mode images and a lateral MFM where the tip–cantilever system is only sensitive to stray fields acting perpendicular to the torsional axis of the cantilever. [ABSTRACT FROM AUTHOR]

Spin waves, collective perturbations of magnetic moments, are both fundamental probes for magnetic physics and promising candidates for energy-efficient signal processing and computation. Traditionally, coherent propagating spin waves have been generated by radio frequency (RF) inductive Oersted fields from current-carrying electrodes. An alternative mechanism, spin–orbit torque (SOT), offers more localized excitation through interfacial spin accumulation but has been mostly limited to DC to kHz frequencies. SOT driven by RF currents, with potentially enhanced pumping efficiency and unique spin dynamics, remains largely unexplored, especially in magnetic insulators. Here, we conduct a comprehensive theoretical and computational investigation into the generation of coherent spin waves via RF-SOT in the prototypical yttrium iron garnet. We characterize the excitation of forward volume, backward volume, and surface modes in both linear and nonlinear regimes, employing single and interdigitated electrode configurations. We reveal and explain several unique and surprising features of RF-SOT compared to inductive excitation, including higher efficiency, distinct mode selectivity, and directional symmetry, a ∼ 3 π / 4 phase offset, reduced anharmonic distortion in the nonlinear regime, and the absence of second harmonic generation. These insights position RF-SOT as a promising new mechanism for future magnonic and spintronic applications. [ABSTRACT FROM AUTHOR]

The burgeoning fields of spintronics and topological electronics require materials possessing a unique combination of properties: ferromagnetism, metallicity, and chemical stability. SrRuO3 (SRO) stands out as a compelling candidate due to its exceptional combination of these attributes. However, understanding its behavior under tensile strain, especially its thickness-dependent changes, remains elusive. This study employs machine-learning-assisted molecular beam epitaxy to investigate tensile-strained SRO films with thicknesses from 1 to 10 nm. This work complements the existing focus on compressive-strained SRO, opening a new avenue for exploring its hitherto concealed potential. Using soft x-ray magnetic circular dichroism, we uncover an intriguing interplay between film thickness, electronic structure, and magnetic properties. Our key findings reveal an intensified localization of Ru 4d t2g-O 2p hybridized states at lower thicknesses, attributed to the weakened orbital hybridization. Furthermore, we find a progressive reduction of magnetic moments for both Ru and O ions as film thickness decreases. Notably, a non-ferromagnetic insulating state emerges at a critical thickness of 1 nm, marking a pivotal transition from the metallic ferromagnetic phase. These insights emphasize the importance of considering thickness-dependent properties when tailoring SRO for next-generation spintronic and topological electronic devices. [ABSTRACT FROM AUTHOR]

The composition-dependent spin exchange interaction in a perovskite-structured Pb(Fe0.5−xNix)Nb1/2O3 system has been studied to understand its multiferroicity at room-temperature. Special emphasis was paid to the magnetic behavior in terms of magnetic moment, interatomic distance, and atomic ordering because they play a key role in the modulation of magnetic multiferroic behavior. We observed that 10 mol. % Ni incorporation led to multiferroic behavior with considerable ferrimagnetic properties (saturation magnetization of 0.6 emu/g and a coercive field of 20 Oe) coupled with the inherent properties of displacive ferroelectricity (spontaneous polarization of 20 μC/cm2). A subsequent increase in the Ni substitution degree degraded the ferroelectricity due to a phase transition from a non-centrosymmetric rhombohedral to a centrosymmetric cubic system. We have shown that magnetic spins with a pronounced magnetic moment along the [001] direction are ferrimagnetically arranged when the interatomic distance between the magnetic transition metals at the octahedral site is less than 4 Å, resulting in significant magnetic properties The objective of this study is to provide a general methodology for modulating magnetic orders in ferroelectric perovskite oxides. [ABSTRACT FROM AUTHOR]

The composition-dependent spin exchange interaction in a perovskite-structured Pb(Fe0.5−xNix)Nb1/2O3 system has been studied to understand its multiferroicity at room-temperature. Special emphasis was paid to the magnetic behavior in terms of magnetic moment, interatomic distance, and atomic ordering because they play a key role in the modulation of magnetic multiferroic behavior. We observed that 10 mol. % Ni incorporation led to multiferroic behavior with considerable ferrimagnetic properties (saturation magnetization of 0.6 emu/g and a coercive field of 20 Oe) coupled with the inherent properties of displacive ferroelectricity (spontaneous polarization of 20 μC/cm2). A subsequent increase in the Ni substitution degree degraded the ferroelectricity due to a phase transition from a non-centrosymmetric rhombohedral to a centrosymmetric cubic system. We have shown that magnetic spins with a pronounced magnetic moment along the [001] direction are ferrimagnetically arranged when the interatomic distance between the magnetic transition metals at the octahedral site is less than 4 Å, resulting in significant magnetic properties The objective of this study is to provide a general methodology for modulating magnetic orders in ferroelectric perovskite oxides. [ABSTRACT FROM AUTHOR]

We conducted spin Hall magnetoresistance (SMR) measurements to investigate the Ru-doping effect on the Morin transition of α-Fe2O3(0001) films, which is the transition from the low-temperature antiferromagnetic state with c-axis magnetic moments to the high-temperature weak ferromagnetic state with c-plane magnetic moments, under a thickness of 6–100 nm. We clarified that the Morin temperature of the 2.6 at. % Ru-doped α-Fe2O3 film was greater than 400 K when the thickness was 100 nm and decreased with a decrease in thickness. Our results demonstrated that SMR measurements are a valid verification method for the Morin transition of very thin α-Fe2O3 films down to several nm. [ABSTRACT FROM AUTHOR]

Density functional approximations to the exchange–correlation energy can often identify strongly correlated systems and estimate their energetics through energy-minimizing symmetry-breaking. In particular, the binding energy curve of the strongly correlated chromium dimer is described qualitatively by the local spin density approximation (LSDA) and almost quantitatively by the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA), where the symmetry breaking is antiferromagnetic for both. Here, we show that a full Perdew–Zunger self-interaction-correction (SIC) to LSDA seems to go too far by creating an unphysical symmetry-broken state, with effectively zero magnetic moment but non-zero spin density on each atom, which lies ∼4 eV below the antiferromagnetic solution. A similar symmetry-breaking, observed in the atom, better corresponds to the 3d↑↑4s↑3d↓↓4s↓ configuration than to the standard 3d↑↑↑↑↑4s↑. For this new solution, the total energy of the dimer at its observed bond length is higher than that of the separated atoms. These results can be regarded as qualitative evidence that the SIC needs to be scaled down in many-electron regions. [ABSTRACT FROM AUTHOR]

The effect of the YBCO superconducting (SC) state on the magnetic properties of as-grown YBCO/Co/IrMn heterostructures has been systematically studied using magnetometry and ferromagnetic resonance. The obtained data showed that the superconductivity of the YBCO substrate strongly affects the ferromagnetic properties of the deposited Co layer deeper (up to 50 nm) than the coherence length of the YBCO (≃ 4 nm) by an exchange interaction between the Co magnetic moments and the superconducting pairs at the YBCO/Co interface. The interfacial exchange interaction, switched on while the YBCO enters the SC state, pins Co spins and yields an enhancement of the Co magnetic properties. [ABSTRACT FROM AUTHOR]

VO2 is renowned for its electric transition from an insulating monoclinic (M1) phase, characterized by V–V dimerized structures, to a metallic rutile (R) phase above 340 K. This transition is accompanied by a magnetic change: the M1 phase exhibits a non-magnetic spin-singlet state, while the R phase exhibits a state with local magnetic moments. Simultaneous simulation of the structural, electric, and magnetic properties of this compound is of fundamental importance, but the M1 phase alone has posed a significant challenge to the density functional theory (DFT). In this study, we show none of the commonly used DFT functionals, including those combined with on-site Hubbard U to treat 3d electrons better, can accurately predict the V–V dimer length. The spin-restricted method tends to overestimate the strength of the V–V bonds, resulting in a small V–V bond length. Conversely, the spin-symmetry-breaking method exhibits the opposite trends. Each of these two bond-calculation methods underscores one of the two contentious mechanisms, i.e., Peierls lattice distortion or Mott localization due to electron–electron repulsion, involved in the metal–insulator transition in VO2. To elucidate the challenges encountered in DFT, we also employ an effective Hamiltonian that integrates one-dimensional magnetic sites, thereby revealing the inherent difficulties linked with the DFT computations. [ABSTRACT FROM AUTHOR]

VO2 is renowned for its electric transition from an insulating monoclinic (M1) phase, characterized by V–V dimerized structures, to a metallic rutile (R) phase above 340 K. This transition is accompanied by a magnetic change: the M1 phase exhibits a non-magnetic spin-singlet state, while the R phase exhibits a state with local magnetic moments. Simultaneous simulation of the structural, electric, and magnetic properties of this compound is of fundamental importance, but the M1 phase alone has posed a significant challenge to the density functional theory (DFT). In this study, we show none of the commonly used DFT functionals, including those combined with on-site Hubbard U to treat 3d electrons better, can accurately predict the V–V dimer length. The spin-restricted method tends to overestimate the strength of the V–V bonds, resulting in a small V–V bond length. Conversely, the spin-symmetry-breaking method exhibits the opposite trends. Each of these two bond-calculation methods underscores one of the two contentious mechanisms, i.e., Peierls lattice distortion or Mott localization due to electron–electron repulsion, involved in the metal–insulator transition in VO2. To elucidate the challenges encountered in DFT, we also employ an effective Hamiltonian that integrates one-dimensional magnetic sites, thereby revealing the inherent difficulties linked with the DFT computations. [ABSTRACT FROM AUTHOR]

In the present work, gadolinium (Gd) doping on ZnFe 2 O 4 nanoparticles and analysing its structural, optical, dielectric and magnetic properties synthesized via a co-precipitation method. From structural analysis, it confirms that prepared nanoparticles are cubic spinel structure and reduced crystallite size which indicates lattice distortion. The synthesized nanoparticles are spherical shape morphology with agglomerated from FESEM and HR TEM analysis. From SAED pattern confirms that the nanoparticles are polycrystalline in nature and corresponding d-spacing's values are calculated. The optical band gap values are ranging from 1.96 to 2.15 eV with varying Gd concentration, suggesting potential applications in optoelectronics. The elements such as Gd, Zn, Fe and O are presented in the prepared samples confirmed via EDS analysis which ensuring the purity of the samples. Magnetic studies revealed a shift from paramagnetic behavior at lower Gd concentrations to ferro-canting at higher levels, further supported by density functional theory (DFT) calculations, which showed enhanced magnetic moments in Fe atoms due to Gd substitution. Dielectric analysis indicated a decrease in dielectric properties with temperature, though a slight increase is observed with increased Gd concentration. These findings suggest that Gd-doped ZnFe₂O₄ nanoparticles possess tunable properties, making them promising candidates for applications in energy, environmental, and advanced magnetic technologies. [Display omitted] • Gd doping ZnFe 2 O 4 shifts XRD peaks, reducing crystallite size and increasing lattice constant. • TEM shows agglomerated nanoparticles (25–30 nm), reflects the d-spacing value. • Optical band gap extends from 1.96 eV to 2.15 eV with Gd incorporation. • Magnetic transition from paramagnetic to ferro-canting at higher Gd doping levels. • DFT reveals increased magnetic moment in Fe atoms upon Gd substitution. [ABSTRACT FROM AUTHOR]

The composite material based on the ferrihydrite nanoparticles (5Fe 2 O 3 · 9H 2 O) encapsulated in SiO 2 matrix was synthesized. Synthesized sample has been characterized by transmission electron microscopy, room-temperature 57Fe Mössbauer spectroscopyand X-ray photoelectron spectroscopy. The data obtained have shown (i) the presence of isolated ferrihydrite nanoparticles with an average size of ∼4.3 nm in the SiO 2 matrix and (ii) the complete absence of the nanoparticles binding with the SiO 2 matrix. The temperature dependences of the ac and dc magnetization, as well as the temperature evolution of the Mössbauer spectra point out only the occurrence of the superparamagnetic blocking with decreasing temperature. The analysis of the relaxation time of particle magnetic moments have shown no magnetic interactions in the investigated system. A detailed examination of the magnetization curves has revealed that the non-interacted ferrihydrite nanoparticles formed by two magnetic subsystems: paramagnetic surface spins and the magnetically ordered core. Such magnetic morphology results in the significantly decrease of the anisotropy constant (K = 18 ∙ 105 erg/cm3) compared to interacted nanoparticles. At the same time, a decisive role in the magnetic behavior of the material is played by the subsystem of free spins, which involves about half of all iron atoms on the particle surface. [ABSTRACT FROM AUTHOR]

Reduction of free-base trithiadodecaazahexaphyrin, H3Hhp, by potassium graphite in the presence of cobalt(II) acetylacetonate and cryptand[2.2.2] produces {Cryptand[2.2.2](K+)}2{(Co I2 CoIIO)2+(Hhp˙4−)}2−·2C6H4Cl2 (1). Co atoms in Co3O have square-planar geometry with short Co–N and Co–O bonds of 1.852–1.898(3) Å length. A nearly planar shape of Hhp macrocycles in 1 with equal Nmeso–C bonds indicates the aromatic character of Hhp˙4−. Magnetic measurements show the presence of two weakly interacting paramagnetic Hhp˙4− and CoII centers with the S = 1/2 spin states below 100 K providing an effective magnetic moment of 2.50μB and separate EPR signals characteristic of these species. Magnetic moment reversibly increases above 100 K reaching a value of 3.68μB at 300 K. We attributed this increase to a population of the excited state which is separated from the ground state by 490 K energy gap. This is also accompanied by growth of a new broad EPR signal at g = 2.11–2.03 above 100 K (the estimated gap is 497 K). According to the calculations, the excited state can be populated due to electron transfer from CoI to Hhp˙4− accompanied by the formation of {(CoICo II2 O)3+(Hhp5−)}2− with a triplet Hhp5− macrocycle. As a result, the S = 1/2 + 1/2 + 1 spin system is formed in the excited state. Coupling between CoII ions and triplet Hhp5− can provide one broad EPR signal with a g-factor value that is intermediate between those of individual species. Salt 1 shows a broad absorption band at 1770 nm (5500 cm−1), which is attributed to a symmetry-allowed low-energy d–π transition at the absorption of the light quantum. [ABSTRACT FROM AUTHOR]

This study explores unusual magnetic coupling between two metal centers in dimers bridged by a tetrazine ring. Computational analysis was performed to understand how a radical perturbation on the bridging ligand influences the magnetic properties of previously synthesized cobalt (Co) and nickel (Ni) dimers. We applied broken-symmetry density functional theory (BS-DFT) functionals to gain deeper insights into the magnetic interactions. This approach provided a comprehensive quantitative picture of the coupling nature of the metal centers. To study the effect of the radical, the two dimers are studied in two oxidation states of bridging tetrazine: the neutral state and the radical state. The radical state was achieved by reducing the tetrazine ring through one-electron transfer. This approach allowed us to monitor the alterations in magnetic properties due to monoradical perturbation. For the dimers in their oxidized form, we observed ferromagnetic coupling between the Ni(II) centers, in contrast to the corresponding neutral Co(II) dimers, which exhibited strong antiferromagnetic coupling. Concerning the radical species, in both Co and Ni dimers, the magnetic calculations aligned with experimental measurements. This alignment demonstrated that the magnetic coupling between the metal and the radical led to robust ferromagnetic coupling. These results were further validated through orbital Mulliken spin density analysis. To support our findings, we developed an in-house code that generated temperature-dependent magnetic moment diagrams, coupled with energy-dependent spin-coupled states. These diagrams provided evidence of the ferromagnetic nature of the two radical dimers. [ABSTRACT FROM AUTHOR]

Reduction of free-base trithiadodecaazahexaphyrin, H3Hhp, by potassium graphite in the presence of cobalt(II) acetylacetonate and cryptand[2.2.2] produces {Cryptand[2.2.2](K+)}2{(Co I2 CoIIO)2+(Hhp˙4−)}2−·2C6H4Cl2 (1). Co atoms in Co3O have square-planar geometry with short Co–N and Co–O bonds of 1.852–1.898(3) Å length. A nearly planar shape of Hhp macrocycles in 1 with equal Nmeso–C bonds indicates the aromatic character of Hhp˙4−. Magnetic measurements show the presence of two weakly interacting paramagnetic Hhp˙4− and CoII centers with the S = 1/2 spin states below 100 K providing an effective magnetic moment of 2.50μB and separate EPR signals characteristic of these species. Magnetic moment reversibly increases above 100 K reaching a value of 3.68μB at 300 K. We attributed this increase to a population of the excited state which is separated from the ground state by 490 K energy gap. This is also accompanied by growth of a new broad EPR signal at g = 2.11–2.03 above 100 K (the estimated gap is 497 K). According to the calculations, the excited state can be populated due to electron transfer from CoI to Hhp˙4− accompanied by the formation of {(CoICo II2 O)3+(Hhp5−)}2− with a triplet Hhp5− macrocycle. As a result, the S = 1/2 + 1/2 + 1 spin system is formed in the excited state. Coupling between CoII ions and triplet Hhp5− can provide one broad EPR signal with a g-factor value that is intermediate between those of individual species. Salt 1 shows a broad absorption band at 1770 nm (5500 cm−1), which is attributed to a symmetry-allowed low-energy d–π transition at the absorption of the light quantum. [ABSTRACT FROM AUTHOR]

The influence of incorporating iron on the electronic structure, magnetic and optical properties of zigzag (10,0) boron nitride nanotubes (BNNTs) was investigated using first-principles calculations. The structures were incorporated with Fe according to B1−xFe xN at various (x) contents (0.10, 0.20 and 0.30). Our calculations exhibited that adding additional Fe atoms reduced the energy gap of the structure. Incorporating more iron atoms creates additional sharp peaks within Fermi levels that come from the contribution of Fe-3d states. Doping with (Fe) also introduced magnetic moments in the BNNT structure. The optical parameters of the Fe-incorporated boron nitride nanotube are calculated. The real part of the dielectric function of pristine BNNT started to increase up to the middle of the UV region and then rapidly decreased between the wavelength range of 310–390 nm. Also, the pure boron nitride nanotube has no absorption in the visible light range and only detects UV radiation. The optical calculations showed that incorporating Fe shifted the absorption peaks of BNNTs into risky UV radiations, which helps researchers develop a vision for controlling and developing advanced materials for various electronic applications. [ABSTRACT FROM AUTHOR]

Small adjustments in atomic configurations can significantly impact the magnetic properties of matter. Strain, for instance, can alter magnetic anisotropy and enable fine-tuning of magnetism. However, the effects of these changes on nanoscale magnetism remain largely unexplored. In particular, when strain fluctuates at the nanoscale, directly linking structural changes with magnetic behavior poses a substantial challenge. Here, we develop an approach, LA-Ltz-4D-STEM, to map structural information and magnetic fields simultaneously at the nanoscale. This approach opens avenues for an in-depth study of structure-property correlations of magnetic materials at the nanoscale. We applied LA-Ltz-4D-STEM to image strain, atomic packing, and magnetic fields simultaneously in a deformed amorphous ferromagnet with complex strain variations at the nanoscale. An anomalous magnetic configuration near shear bands, which reside in a magnetostatically high-energy state, was observed. By performing pixel-to-pixel correlation of the different physical quantities across a large field of view, a critical aspect for investigating industrial ferromagnetic materials, the magnetic moments were classified into two distinct groups: one influenced by magnetoelastic coupling and the other oriented by competition with magnetostatic energy. The authors present an approach to simultaneously map local magnetization, strain, atomic structure at nanoscale. It provides direct visualization of strainmagnetic coupling in ferromagnetic materials, opening avenues for studying nanomagnetism. [ABSTRACT FROM AUTHOR]

In this study, a new evaluation method was investigated for the magnetic properties of the amorphous alloys by comparing the experimental results with the theoretical calculations. First, The (Fe 7 0 Co6P 4. 8 Si 9. 6 B 9. 6 ) 1 0 0 − x Cux (x = 0 –0.5) amorphous ribbons were prepared by melt spinning method. Then, the magnetic properties of the prepared amorphous alloys were measured as 165.86–147.04 emu/g, respectively. On the other side, we analyzed the valence electron structure and obtained the magnetizations as 159.92–158.77 emu/g by calculating the magnetic moments of unit cells based on empirical electron theory (EET) of solids and molecules. Through comparing the magnetic properties of the calculations with the measurements, we found that the differences between the calculations and the measurements are less than 12% for all samples, meeting the first approximation requirement. Moreover, with the addition of Cu, the change trends both in the calculated and measured magnetic properties are also consistent. These results prove that it is feasible to calculate the magnetic property of the amorphous alloy from the valence electron level using EET, which provides a new method to investigate the soft magnetic property of the amorphous alloy instead of the real measurement. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of cost-effective, highly active, and stable electrocatalysts for water splitting to produce green hydrogen is crucial for advancing clean and sustainable energy technologies. Herein, we present an innovative in-situ synthesis of FeOOH nanorods@NiOOH nanosheets on nickel foam (FeOOH@NiOOH/NF) at an unprecedentedly low temperature, resulting in a highly efficient electrocatalyst for overall water splitting. The optimized FeOOH@NiOOH/NF sample, evaluated through time-dependent studies, exhibits exceptional oxygen evolution reaction (OER) performance with a low overpotential of 261 mV at a current density of 20 mA cm−2, alongside outstanding hydrogen evolution reaction (HER) activity with an overpotential of 150 mV at a current density of 10 mA cm−2, demonstrating excellent stability in alkaline solution. The water-splitting device featuring FeOOH@NiOOH/NF-2 electrodes achieves a voltage of 1.59 V at a current density of 10 mA cm−2, rivalling the state-of-the-art RuO 2 /NF||PtC/NF electrode system. Density functional theory (DFT) calculations unveil the efficient functionality of the Fe sites within the FeOOH@NiOOH heterojunction as the active OER catalyst, while the Ni centres are identified as the active HER sites. The enhanced performance of OER and HER is attributed to the tailored electronic structure at the heterojunction, modified magnetic moments of active sites, and increased electron density in the dx2-y2 orbital of Fe. This work provides critical insights into the rational design of advanced electrocatalysts for efficient water splitting. [ABSTRACT FROM AUTHOR]

In this manuscript we study the magnetic MAOX phases (M = Mn, Cr; A = Ga, Al, X = C) obtained by the replacement of the A-layer in the parent MAX phase by the AO2 layer. The screening analysis of the magnetic and electronic properties of Mn- and Cr-based MAOX phases is performed using DFT calculations. All MAOX are thermodynamically stable. It was found that in MAOX phases Cr magnetic moments are pronounced increased in compare to corresponding MAX phase. Moreover, drastically changes in the electronic structure arise in Cr2AlO2C and Cr2GaO2C MAOX phases. The metal behavior in Cr2GaC MAX phase changes for the near to half-metallic behavior with 90% spin polarization at the Fermi energy in Cr2GaO2C MAOX phases. We have found that in Cr2AlO2C, the change in the electronic structure leads to the formation of the spin-gapless semiconductor state under slight extension in the ab plane. The obtained results make Cr2GaO2C and especially Cr2AlO2C prospective candidates for application as functional elements of electronics and spintronics. [ABSTRACT FROM AUTHOR]

This paper investigates the tunable properties of two-dimensional spintronics and optoelectronics through V- and Fe-doping, alongside strain engineering. Using density functional theory, we focus on the impact of V- and Fe-doping and (V, Fe) co-doping, as well as strain engineering, on the electronic and optical properties of SnSe2. V and Fe atoms exhibit significant local magnetic moments of 2.86 µB and 3.20 µB, respectively. Our findings reveal that (V, Fe) co-doped SnSe2 is an indirect bandgap semiconductor with a bandgap of 0.367 eV. The ferromagnetic (FM) state, driven by the interaction between V and Fe 3d orbitals and Se 4p orbitals, is notably more stable, with a relative energy difference of − 388.30 meV. Additionally, 2% biaxial strain enhances the formation and stability of this FM state. The study also identifies a red-shift in the visible absorption spectrum, coupled with a weakening of intensity, resulting from the combined effects of doping and strain. These results demonstrate a promising strategy for the development of spintronic devices based on (V, Fe) co-doped SnSe2. [ABSTRACT FROM AUTHOR]

In this work, we will investigate structural, electronic, magnetic, and thermodynamic properties using density functional theory (DFT) and the quasi-harmonic Debye model. We consider ferromagnetic (FM) and non-magnetic (NM) states for L21 and Hg2CuTi-type crystal structures. The best stability is obtained for ferromagnetic Rh2MnGa in a Cu2MnAl structure with a lattice parameter of 6.07 Å and a total magnetic moment of 4.11 μB. The compressive strain range from −6% to +4% tensile strain maintains the ferromagnetic nature and enhances the magnetic moment up to 4.39 μB. The formation energy confirms the inherent stability of Rh2MnGa. Other important thermodynamic parameters such as the expansion coefficient (α), heat capacity (CV), Debye temperature (θD) and Grüneisen constant (γ) are also estimated in this work. [ABSTRACT FROM AUTHOR]

We conduct a systematic investigation of the role of Hubbard U corrections in electronic structure calculations of two-dimensional (2D) materials containing 3d transition metals. Specifically, we use density functional theory (DFT) with the PBE and PBE+U approximations to calculate the crystal structure, band gaps, and magnetic parameters of 638 monolayers. Based on a comprehensive comparison to experiments we first establish that the inclusion of the U correction worsens the accuracy for the lattice constants. Consequently, PBE structures are used for subsequent property evaluations. The band gaps show a significant dependence on U. In particular, for 134 (21%) of the materials the U parameter induces a metal-to-insulator transition. For the magnetic materials we calculate the magnetic moment, magnetic exchange coupling, and magnetic anisotropy parameters. In contrast to the band gaps, the size of the magnetic moments shows only weak dependence on U. Both the exchange energies and magnetic anisotropy parameters are systematically reduced by the U correction. On this basis we conclude that the Hubbard U correction will lead to lower predicted Curie temperatures in 2D materials. All the calculated properties are available in the Computational 2D Materials Database (C2DB). [ABSTRACT FROM AUTHOR]

In this investigation, we successfully synthesized an asymmetrical N, N, N, O tetradentate Schiff base ligand (L) through the condensation reaction between 1-phenylbutane-1,3-dione and 2,6-diaminopyridine. Subsequently, this ligand was used to form a new Cr(III) complex (LMC) by reacting with Cr(NO3)3·9H2O. The synthesis of the ligand and the complex was confirmed using various techniques, including elemental analysis, magnetic susceptibility, molar conductance, FTIR, UV–visible, 1H-NMR, mass spectrometry, and thermogravimetric analysis. The FTIR spectra indicated that L acted as a dibasic tetradentate ligand, coordinating with the metal ion through multiple binding sites: the oxygen atom of the carbonyl group, the nitrogen atoms of the imine and amine groups, and the pyridine nitrogen atom. The molar conductance values suggested that the LMC possessed electrolytic properties. Analysis of electronic spectra and magnetic moments further supported the assignment of an octahedral geometry to the LMC complex. Furthermore, the complex was integrated into a chitosan (Cs) matrix using an acidic solution method, resulting in the formation of polymer composites denoted as Cs/LMC. These composites exhibit enhanced optical properties. Specifically, the optical bandgap of the composite decreased from 5.2 to 1.85 eV, while the refractive index increased from 1.29 to 1.341. This innovative approach holds promise for enhancing the optical characteristics of chitosan-based materials, rendering them suitable for various applications. [ABSTRACT FROM AUTHOR]

To develop new devices based on synthetic ferrimagnetic heterostructures, understanding the material's physical properties is pivotal. Here, the induced magnetic moment (IMM), magnetic exchange coupling, and spin textures are investigated in Pt(1 nm)/Co(1.5 nm)/Gd(1 nm) multilayers using a multiscale approach. The magnitude and direction of the IMM are interpreted in the framework of both X-ray magnetic circular dichroism and density functional theory. The IMM transferred by Co across the Gd paramagnetic thickness leads to a nontrivial flipped spin state (FSS) within the Gd layers, in which their magnetic moments couple antiparallel/parallel with the ferromagnetic Co near/far from the Co/Gd interface, respectively. The FSS depends on the magnetic field, which, on average, reduces the Gd magnetic moment as the field increases. For the Pt, in both Pt/Co and Gd/Pt interfaces, the IMM follows the same direction as the Co magnetic moment, with negligible IMM in the Gd/Pt interface. Additionally, zero-field spin spirals were imaged using scanning transmission X-ray microscopy, whereas micromagnetic simulations were employed to unfold the interactions, stabilizing the ferrimagnetic configurations, where the existence of a sizable Dzyaloshinskii-Moriya interaction is demonstrated to be crucial. Magnetic heterostructures are a platform to realize magnetic ordering that differs from the component layers, a prime example being synthetic ferrimagnets. Here, the authors use X-ray magnetic circular dichroism supported with a multiscale approach (density functional theory, atomistic spin dynamics and micromagnetic simulations) to investigate the induced magnetic moment, magnetic exchange-coupling and spin textures in the ferrimagnetically coupled Pt/Co/Gd heterostructures. [ABSTRACT FROM AUTHOR]

We use Density Functional Theory and Monte Carlo simulation to investigate the structural, electronic, and magnetic properties of the ferromagnetic inverse Heusler alloys Fe2RhSi and Fe2RhGe. The metallic nature of both alloys is confirmed using GGA, GGA+U, and meta-GGA methods. The calculated magnetic moments are 5.017μB for Fe2RhSi and 5.177μB for Fe2RhGe, aligning well with experimental findings. Spin polarization calculations yield 70% for Fe2RhSi and 53.03% for Fe2RhGe using the GGA method, while other methods produce values below 30%. Additionally, GGA+U calculations indicate a martensite transition at approximately c∕a=1.08 for both alloys without affecting their magnetic state. The Curie temperatures are around 900K for Fe2RhGe and Fe2RhSi, which closely match experimental data. The high spin polarization and Curie temperature make Fe2RhSi a promising candidate for spintronic applications. [ABSTRACT FROM AUTHOR]

Inspired by recent advancements in the field of single-atom magnets, particularly those involving rare-earth (RE) elements, we present a theoretical exploration employing DFT+U calculations to investigate the magnetic properties of selected 4f atoms, specifically Eu, Gd, and Ho, on a monolayer of the transition-metal dichalcogenide WSe2 in the 1H-phase. This study comparatively examines RE with diverse 4f orbital fillings and valence chemistry, aiming to understand how different coverage densities atop WSe2 affect magnetocrystalline anisotropy. We observe that RE lacking 5d occupation exhibit larger magnetic anisotropy energies at high densities, while those with outer 5d electrons show larger anisotropies in dilute configurations. Additionally, even half-filled 4f shell atoms with small orbital magnetic moments can generate substantial energy barriers for magnetization rotation due to prominent orbital hybridizations with WSe2. Open 4f shell atoms further enhance anisotropy barriers through spin-orbit coupling effects. These aspects are crucial for realizing stable magnetic information units experimentally. [ABSTRACT FROM AUTHOR]

Theoretical study on the structure and electronic properties of small Nin (n ≤ 15) clusters has been carried out in the framework of density functional theory. The equilibrium geometries, the bond length, average binding energy, and magnetic moment per atom of these clusters were calculated in detail. The clusters constitute an intermediate state of matter between the isolated atoms and the massive condensed phase, and they do not mimic the bulk structure and shows significant geometrical changes with size. The binding energy per atom increases monotonically with size, and the magnetic moment oscillates with the size. The more stable structures are closed structures with inter atomic distances between 2.13 and 2.76 Å. The Ni2, Ni7, Ni9, Ni12, and Ni14 clusters are more stable than their neighboring clusters, and the most favorable channel for nickel clusters is the Ni14 cluster. [ABSTRACT FROM AUTHOR]

Assembling antiferromagnetic (AFM) clusters is perhaps an effective way to construct AFM materials to meet the increasing demand for micro/nano spintronic devices, which promotes the exploration of AFM clusters. Herein, we unveil the structural evolution, electronic, and AFM properties of Cr2Pbn (n = 3–20) clusters based on density functional theory (DFT) calculations. It is found that the Cr impurities prefer the central axis positions of the skeleton in these Cr2Pbn (n = 3–20) clusters. For sizes n ≤ 6, their structures are exohedral structures with the two Cr atoms exposed outside, endohedral Cr@Pbn configuration with one Cr atom interior appears at size 7, and the resulting endohedral structure is then gradually covered by the additional Pb atoms to form endohedral Cr2@Pbn structures for n = 15–20. All Cr2Pbn clusters are antiferromagnets, except for the ferrimagnetic Cr2Pb11 with a net magnetic moment of 2 μB. The discovered stable Cr2Pb17 cluster can assemble into dimers and trimers while maintaining its geometric structure and AFM properties, indicating the potential of becoming structural units for cluster‐assembled AFM materials. [ABSTRACT FROM AUTHOR]

The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe2 is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry Y and T points and disperse along the crystallographic b ̂ -axis. In applied magnetic fields to at least μ0H = 11 T along the c ̂ − axis , the magnetism is found to be field-independent in the (hk0) plane. The scattering intensity is consistent with that expected from U3+/U4+ f-electron spins with preferential orientation along the crystallographic a ̂ -axis, and a fluctuating magnetic moment of μeff=1.7(5) μB. We propose interband spin excitons arising from f-electron hybridization as a possible origin of the magnetic excitations in UTe2. [ABSTRACT FROM AUTHOR]

Actuation powered by a rotating magnetic field is a promising method of controlled steering of micro(nano)metric synthetic propellers through fluids. Such actuation relies on a magnetic torque, which is a product of the driving field and a dipolar magnetic moment possessed by the micro-/nanopropeller of nontrivial shape allowing for rotation–translation coupling. While ferromagnetic (permanently magnetized) microbots have been studied extensively, superparamagnetic (susceptible to magnetization, not possessing remanent magnetization) did not get as much focus. Here, we present a general theory of torque-driven actuation and steering of magnetically polarizable micropropellers. The steady torque-driven rotation regimes and their stability are considered for microbots assuming cylindrical rotational anisotropy and for arbitrary geometry and orientation of the magnetization easy axis. Furthermore, we study in detail the dynamics of planar microbots made of isotropic superparamagnetic material, for which the magnetic anisotropy is being controlled entirely by the geometry. Planar geometry is interesting from a fundamental point of view (i.e., to establish the minimal requirements for steering of polarizable microbots) and for practical reasons due to easy of microfabrication via standard photolithography. It is demonstrated that stable torque-driven rotation resulting in net propulsion would require high degree of geometric and magnetic asymmetry, e.g., the L-shaped planar propeller with unequal arms, with a shorter arm made of superparamagnetic material, can be efficiently steered by a rotating magnetic field. [ABSTRACT FROM AUTHOR]

We start with the 50-component relativistic matrix equation for a hypothetical spin-2 particle in the presence of external electromagnetic fields. This equation is hypothesized to describe a particle with an anomalous magnetic moment. The complete wave function consists of a two-rank symmetric tensor and a three-rank tensor that is symmetric in two indices. We apply the general method for performing the nonrelativistic approximation, which is based on the structure of the 50 × 50 matrix Γ 0 of the main equation. Using the 7th-order minimal equation for the matrix Γ 0 , we introduce three projective operators. These operators permit us to decompose the complete wave function into the sum of three parts: one large part and two smaller parts in the nonrelativistic approximation. We have found five independent large variables and 45 small ones. To simplify the task, by eliminating the variables related to the 3-rank tensor, we have derived a relativistic system of second-order equations for the 10 components related to the symmetric tensor. We then take into account the decomposition of these 10 variables into linear combinations of large and small ones. In accordance with the general method, we separate the rest energy in the wave function and specify the orders of smallness for different terms in the arising equations. Further, after performing the necessary calculations, we derive a system of five linked equations for the five large variables. This system is presented in matrix form, which has a nonrelativistic structure, where the term representing additional interaction with the external magnetic field through three spin projections is included. The multiplier before this interaction contains the basic magnetic moment and an additional term due to the anomalous magnetic moment. The latter characteristic is treated as a free parameter within the hypothesis. [ABSTRACT FROM AUTHOR]

Herein, two barium‐based double perovskites, Ba2DyTaO6 and Ba2DyBiO6, have been investigated using density functional theory with the modified Becke–Johnson potential to explore their geometric, magnetic, and optoelectronic attributes. The calculations, including formation enthalpies and tolerance factors, confirm structural and thermodynamic stability of both compounds. The results reveal half‐metallic behavior, with a bandgap present in spin‐up channel and metallic bands in the spin‐down channel for both materials. Specifically, Ba2DyTaO6 exhibits a spin‐up bandgap of 4.60 eV, while Ba2DyBiO6 has 3.0 eV in the spin‐up channel, indicating their semiconducting nature in this spin orientation. Magnetic properties are dominated by the Dy‐4f states, yielding a stable ferromagnetic nature with a magnetic moment around 5.0 μB. Both compounds display strong absorbance in the UV spectrum, regarding these double perovskites as promising contenders for optical devices, UV filters, and spintronic applications. The study highlights the potential of these materials in combining optical and magnetic properties for multifunctional device applications. [ABSTRACT FROM AUTHOR]

Nanocrystalline CoTb y Fe 2-y O 4 (0 ≤ y ≤ 0.025) ferrites were prepared through the citrate-gel combustion method. X-ray diffraction confirmed the formation of a single-phase spinel structure with crystalline sizes ranging between 19 and 48 nm. The experimental and theoretical lattice parameters correlated well and were found to be ranging between 8.510 and 8.367 Å. SEM images revealed a large aggregation of spherical-shaped nanoparticles with non-uniform shape and distribution. Magnetization measurements revealed the dependance of both M s , Mr, and H C with increasing Tb3+ content. The evolution of M S and H C upon reducing the measuring temperature indicates the thermal instability of the blocked magnetic moments, which increased for the different compositions. The dielectric properties obtained for CoTb y Fe 2-y O 4 as a function of frequency. The Tb-doped cobalt ferrite catalysts exhibit superior photocatalytic efficiency for crystal violet (CV) degradation as compared to cobalt ferrite nanoferrite catalysts. [ABSTRACT FROM AUTHOR]

This study investigates the properties of the double perovskite compound Ba2BTaO6 (B = Gd, Yb) using the "full-potential linearized augmented plane wave method (FP-LAPW) based on density functional theory (DFT)" with various exchange-correlation potentials (GGA, GGA+U, and mBJ-GGA). The structural, electronic, magnetic, optical, and thermoelectric properties are explored. Ba2GdTaO6 is found to be a ferromagnetic half-semiconductor with two spin-dependent energy gaps, exhibiting stability in the ferromagnetic phase and possessing an integral magnetic moment of 7μB. On the other hand, Ba2YbTaO6 is ferrimagnetic. It shows half-metallic behavior with a semiconductor nature in the spin-up state and metallic in the spin-down state, having an integral magnetic moment of 1μB. The optical characteristics suggest their potential use in UV optoelectronic systems, including UV sensors, photodetectors, and efficient UV reflectors. Additionally, the investigated thermoelectric properties, such as the Seebeck coefficient, electrical conductivity, and Figure of merit, indicate that Ba2BTaO6 (B = Gd, Yb) materials have promising potential for practical thermoelectric applications. [ABSTRACT FROM AUTHOR]

This study investigates the magnetic, structural, and optical properties of CoxCd1−xFe2O4 ferrite microparticles that were produced using the co-precipitation method. The FTIR spectroscopy shows two distinct and significant absorption bands that are associated with the permanent stretching vibrations of metals at tetrahedral and octahedral sites. The results of Raman scattering disclose that a rise in the Co content intensifies the local disorder at both sublattices (octahedral and tetrahedral sites). The powder XRD results revealed the formation of single-phase cubic spinel ferrite with a crystallite size in the 35–77 nm range. The optical properties were analyzed, and a Tauc plot was produced to determine the optical band gap, which is higher for the x=1 sample (2.73 eV). The study further examined the influence of Co2+ substitution on Mössbauer parameters, such as line width, quadrupole splitting, isomer shift, and the hyperfine magnetic field. Surface morphology images were studied by AFM and SEM, while the elemental and magnetic characteristics were studied with EDS and magnetic hysteresis (M-H). Here, the Co (x = 1)-doped sample has shown the increment in magnetic moment (2.9809 µB), which further complements the previous results. [ABSTRACT FROM AUTHOR]