Search

Spin pumping from canted antiferromagnets is a cutting-edge topic in modern spintronics. The interest for fundamental and applied research that these materials arouse is related to their unusual structure, namely, with a small canting of the magnetic sublattices, which is explained by the presence of the Dzyaloshinskii–Moriya interaction. Through this effect, it becomes possible to experimentally study quasi-ferromagnetic resonance spectra and spin pumping in the range of tens of GHz at room temperature. In this paper, an experimental and theoretical investigation of spin pumping from an antiferromagnet with weak ferromagnetism, α -Fe 2 O 3 , is carried out. The conversion of the precession of the magnetization vector, excited by an alternating magnetic microwave field, into a constant voltage is realized using the inverse spin Hall effect in the hematite/heavy metal structure. Using a constant magnetic field up to 5 kOe, the resonant frequency of such a detector is tunable over a wide range up to 32 GHz with potential sensitivity reaching 10.1 μ V/W. Confirmation of the measurement of the spin current is the change in the sign of V sp when the polarity of the constant magnetic field alters. We believe that these studies will make a major contribution to the understanding of the physics of the spin-pumping effect from antiferromagnets and will also help in the development of devices for quantum technologies and next-generation communication technologies. [ABSTRACT FROM AUTHOR]

By using first-principles calculations and micromagnetic simulations, we investigate the electronic structure, magnetic properties, and skyrmions in two-dimensional Janus Cr 2 XYTe 6 (X,Y = Si, Ge, Sn, X ≠ Y) monolayers. Our findings reveal that the Cr 2 XYTe 6 monolayers are ferromagnetic semiconductors with a high Curie temperature (T c). The bandgap and T c can be further increased by applying tensile strain. In addition, there is a transition from the ferromagnetic to the antiferromagnetic state at a compressive strain. Both Cr 2 SiSnTe 6 and Cr 2 SiGeTe 6 exhibit a large magnetic anisotropy energy, which are mainly associated with the significant spin–orbit coupling of the nonmagnetic Te atoms rather than that of the magnetic Cr atoms. Interestingly, the Cr 2 SiSnTe 6 monolayer exhibits a significant Dzyaloshinskii–Moriya interaction of 1.12 meV, which facilitates the formation of chiral domain walls and skyrmions. Furthermore, under tensile strain, chiral DWs can be transformed into skyrmions if applying an external magnetic field. These findings suggest that Janus Cr 2 XYTe 6 monolayers hold promise for spintronic nanodevice applications. [ABSTRACT FROM AUTHOR]

Two-dimensional ferromagnetic materials hold great promise to develop energy-efficient magnetoelectric memory devices and next-generation spintronics. However, one of the crucial challenges for these materials is the realization of tunable magnetocrystalline anisotropy (MCA) to balance thermal stability and energy efficiency. Here, we systematically study the adsorption effects of 3d transition metals (3d-TMs) on the electronic structure and magnetic property of the Fe3GeTe2 (FGT) monolayer. The adsorption systems exhibit different ground state configurations depending on the adatoms, while the controlled perpendicular magnetic anisotropy has also been achieved. Notably, the Mn/FGT system can maintain the out-of-plane magnetic orientation with a changing amplitude of MCA energy up to 3.057 erg/cm2 as the external strain varies from −4% to 1%. In contrast, the Fe/FGT structure undergoes spin reorientation from in-plane to out-of-plan magnetization with a distinct modification behavior of MCA. We elucidate that the underlying atomistic mechanism mainly arises from the alteration of Fe-derived 3d-orbital states in response to the strain effect, leading to competitive changes in the different coupling states. These findings can not only provide useful guidance to optimize two-dimensional magnets for fundamental research but also reveal the promising potential of TMs/FGT materials for the development of ultra-low energy spintronic devices. [ABSTRACT FROM AUTHOR]

Magnetic semiconducting materials offer tremendous prospects for spin electronics but is challenging to achieve room-temperature ferromagnetism with unambiguous origin. Herein, a non-stoichiometry strategy is proposed to induce tunable magnetization in MoSe2−x nanoflowers via vacancy-controlled 2H–1T phase transition. The resultant MoSe2−x exhibits robust room-temperature ferromagnetism with significant positive correlation to the content of 1T phase and 2H–1T interfaces. Significant magnetic hysteresis and Curie transition above room temperature have been achieved, confirming the ferromagnetic feature of MoSe2−x. To examine the origin of ferromagnetism, formation energy and spin-polarized calculations have been conducted, indicating that the Se vacancy is beneficial for the formation of the 1T phase and interfacial spin polarization. Localized magnetic moments induced at the 2H–1T interfaces exhibit enhanced magnetism as compared to the net moments from the 1T orbital splitting, giving rise to strong coupling bound magnetic polarons. This work not only advances the understanding on the origin of magnetism in magnetic semiconductors, but also provides an effective route to generate ferromagnetism by defect and/or interface engineering that could be applied to multiferroics, spintronics, and valleytronics. [ABSTRACT FROM AUTHOR]

This paper describes the contributions made by Władysław (Władek) Walukiewicz and his colleagues to the field of ferromagnetic semiconductor (FMS) alloys, such as (Ga,Mn)As. We focus on two key accomplishments. First, this team has predicted the formation of Mn interstitials in these materials, which have a profound effect on ferromagnetism in semiconductors. Additionally, identifying the conditions at which interstitials form has provided grounds for optimizing their ferromagnetic properties. Second, by applying the approach of band anticrossing to ferromagnetic semiconductors, this team has mapped out the properties of an Mn-derived impurity band in these materials. This is of particular importance in the field, because holes, which reside in the Mn-derived impurity band, are the very mechanism responsible for ferromagnetic order in FMSs. We discuss the effect that these accomplishments have on our understanding of FMSs and how they have contributed to progress in this area. We then describe the pathways that these achievements have opened up toward further progress in both basic and applied fronts of ferromagnetism in semiconducting systems; and we present our perspective on where additional work along the lines initiated by Władek Walukiewicz should be extended to further benefit this field. [ABSTRACT FROM AUTHOR]

We synthesized La2NiO4 nanostructures using the cationic surfactant-based reverse micellar route and reported on the effect of the size and shape of the La2NiO4 nanostructures on their magnetic and photoelectrochemical properties. We satisfactorily refined the powder X-ray diffraction data in the tetragonal space group, I4/mmm. Magnetic susceptibility measurements were performed on all samples within the range of 5–300 K. The Curie–Weiss law determines the magnetic susceptibility of bulk La2NiO4, and a negative value for the Weiss temperature indicates antiferromagnetic exchange. The field-dependent magnetization curves of bulk La2NiO4 suggest a canted antiferromagnetic behaviour. The Mott–Schottky plot demonstrates that La2NiO4 is a p-type semiconducting material with holes as the primary charge carriers. Chronoamperometric measurements for these nanomaterials demonstrate excellent photostability of photocurrent. [ABSTRACT FROM AUTHOR]

The exploration of magnetism in two-dimensional layered materials has attracted extensive research interest. For the monoclinic phase CrI3 with interlayer antiferromagnetism, finding a static and robust way of realizing the intrinsic interlayer ferromagnetic coupling is desirable. In this work, we study the electronic structure and magnetic properties of the nonmagnetic element (e.g., O, S, Se, N, P, As, and C) doped bi-and triple-layer CrI3 systems via first-principles calculations. Our results demonstrate that O, P, S, As, and Se doped CrI3 bilayer can realize interlayer ferromagnetism. Further analysis shows that the interlayer ferromagnetic coupling in the doped few-layer CrI3 is closely related to the formation of localized spinpolarized state around the doped elements. Further study presents that, for As-doped tri-layer CrI3, it can realize interlayer ferromagnetic coupling. This work proves that nonmagnetic element doping can realize the interlayer ferromagnetically-coupled few-layer CrI3 while maintaining its semiconducting characteristics without introducing additional carriers. [ABSTRACT FROM AUTHOR]

In spintronics, transverse anomalous transport properties have emerged as a highly promising avenue surpassing the conventional longitudinal transport behaviors. Here, we explore the transverse transport properties of monolayer and bilayer Fe3−xCoxGaTe2 (x = 0.083, 0.167, 0.250, and 0.330) systems. All the systems exhibit ferromagnetic ground states with metallic features and also have perpendicular magnetic anisotropy. Besides, the magnetic anisotropy is substantially enhanced with increasing Co-doping concentration. However, unlike magnetic anisotropy, the Curie temperature is suppressed by increasing the Co-doping concentration. For instance, the monolayer and bilayer Fe2.917Co0.083GaTe2 hold a Curie temperature of 253 K and 269 K, which decreases to 163 K and 173 K in monolayer and bilayer Fe2.67Co0.33GaTe2 systems, respectively. We find a giant anomalous Nernst conductivity (ANC) of 6.03 A/(K·m) in the monolayer Fe2.917Co0.083GaTe2 at −30 meV, and this is further enhanced to 11.30 A/(K·m) in the bilayer Fe2.917Co0.083GaTe2 at −20 meV. Moreover, the bilayer Fe2.917Co0.083GaTe2 structure has a large anomalous thermal Hall conductivity (ATHC) of −0.14 W/(K·m) at 100 K. Overall, we find that the Fe3−xCoxGaTe2 (x = 0.083, 0.167, 0.250, and 0.330) structures have better anomalous transverse transport performance than the pristine Fe3GaTe2 system and can be used for potential spintronics and spin caloritronics applications. [ABSTRACT FROM AUTHOR]

The reaction of MnCl2·4H2O with HL ((1-methyl-1H-imidazol-2-yl)methanol) and pdH2 (1, 3 propanediol) in a basic MeCN solution results in the formation of a mixed-valence [Mn20] cationic cluster and two [MnIICl4] counter anions. The metallic skeleton of the cluster describes two geometrically equivalent mixed-valent, linked [MnIII6MnII4] supertetrahedra in which nearest-neighbor metal ions have a different oxidation state. Magnetic susceptibility, magnetization data and heat capacity measurements support evidence of predominant ferromagnetic correlations, leading to a s = 22 spin ground state for the [MnIII6MnII4] supertetrahedra, which are pair-linked by a weak antiferromagnetic coupling. The properties are discussed in the context of the magnetocaloric effect and the potential application of this compound in cryogenic refrigeration. [ABSTRACT FROM AUTHOR]

The reaction of MnCl2·4H2O with HL ((1-methyl-1H-imidazol-2-yl)methanol) and pdH2 (1, 3 propanediol) in a basic MeCN solution results in the formation of a mixed-valence [Mn20] cationic cluster and two [MnIICl4] counter anions. The metallic skeleton of the cluster describes two geometrically equivalent mixed-valent, linked [MnIII6MnII4] supertetrahedra in which nearest-neighbor metal ions have a different oxidation state. Magnetic susceptibility, magnetization data and heat capacity measurements support evidence of predominant ferromagnetic correlations, leading to a s = 22 spin ground state for the [MnIII6MnII4] supertetrahedra, which are pair-linked by a weak antiferromagnetic coupling. The properties are discussed in the context of the magnetocaloric effect and the potential application of this compound in cryogenic refrigeration. [ABSTRACT FROM AUTHOR]

Ferromagnetism in the two‐dimensional limit has become an intriguing topic for exploring new physical phenomena and potential applications. To induce ferromagnetism in 2D materials, intercalation has been proposed to be an effective strategy, which could introduce lattice distortion and unpaired spin into the material to modulate the magnetocrystalline anisotropy and magnetic exchange interactions. To strengthen the understanding of the magnetic origin of 2D material, Cu was introduced into a 2D WO3 through chemical intercalation in this work (2D Cu/WO3). In contrast to the diamagnetic nature of Cu and WO3, room‐temperature ferromagnetism was characterized for 2D Cu/WO3. Experimental and theoretical results attribute the ferromagnetism to the bound magnetic polaron in 2D Cu/WO3, which is consist of unpaired spins from W5+/W4+ with localized carriers from oxygen vacancies. Overall, this work provides a novel approach to introduce ferromagnetism into diamagnetic WO3, which could be applied for a wider scope of 2D materials. [ABSTRACT FROM AUTHOR]

Ferromagnetism in the two‐dimensional limit has become an intriguing topic for exploring new physical phenomena and potential applications. To induce ferromagnetism in 2D materials, intercalation has been proposed to be an effective strategy, which could introduce lattice distortion and unpaired spin into the material to modulate the magnetocrystalline anisotropy and magnetic exchange interactions. To strengthen the understanding of the magnetic origin of 2D material, Cu was introduced into a 2D WO3 through chemical intercalation in this work (2D Cu/WO3). In contrast to the diamagnetic nature of Cu and WO3, room‐temperature ferromagnetism was characterized for 2D Cu/WO3. Experimental and theoretical results attribute the ferromagnetism to the bound magnetic polaron in 2D Cu/WO3, which is consist of unpaired spins from W5+/W4+ with localized carriers from oxygen vacancies. Overall, this work provides a novel approach to introduce ferromagnetism into diamagnetic WO3, which could be applied for a wider scope of 2D materials. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials with inherent magnetism have attracted considerable attention in the fields of spintronics and condensed matter physics. The anomalous Hall effect (AHE) offers a theoretical foundation for understanding the origins of 2D ferromagnetism (2D-FM) and offers a valuable opportunity for applications in topological electronics. Here, we present uniform and large-size 2D Cr7Te8 nanosheets with varying thicknesses grown using the chemical vapor deposition (CVD) method. The 2D Cr7Te8 nanosheets with robust perpendicular magnetic anisotropy, even a few layers deep, exhibit a Curie temperature (TC) ranging from 180 to 270 K according to the varying thickness of Cr7Te8. Moreover, we observed a temperature-induced reversal in the sign of the anomalous Hall resistance, correlating with changes in the intrinsic Berry curvature. Additionally, the topological Hall effect (THE) observed at low temperatures suggests the presence of non-trivial spin chirality. Our findings about topologically non-trivial magnetic spin states in 2D ferromagnets provide a promising opportunity for new designs in magnetic memory spintronics. [ABSTRACT FROM AUTHOR]

Bilayer thin films of GdFeO3/Fe97Si3 have been synthesized by RF–magnetron sputtering at different thicknesses of GdFeO3. A pure phase polycrystalline growth of GdFeO3 and Fe97Si3 has been confirmed by XRD measurements. Stress-induced room-temperature magnetocrystalline anisotropy has been confirmed in all the bilayer thin films. A high magnetic moment has been induced in antiferromagnetic GdFeO3 thin films resulting in the ferromagnetic character of all the samples. The ferromagnetic moment was found to be enhanced with increasing thickness of the GdFeO3 layer. The maximum value of the room- temperature magnetic moment has been observed as Ms ~ 9.3 emu/ml in 170-nm-thick GdFeO3 film. Dielectric measurements confirmed the induced magnetocapacitance due to grain boundary accumulation of charge carriers. Magnetic field control of capacitance and current–voltage measurements of these thin films represents a strong potential for the existence of magnetoelectric coupling in GdFeO3/Fe97Si3 films. A maximum 30% rise in magnetocapacitance and a 95.6% increase in tunneling current in an applied 1-kOe magnetic field was obtained for 170-nm-thick GFO thin film. These thin films possess applications in spintronic devices due to the presence of room- temperature magnetocrystalline anisotropy and magnetic control of the electric properties. [ABSTRACT FROM AUTHOR]

We report the influence of oxygen impurities in generating ferromagnetism in GaN doped with Mn, Fe, and Cr through superexchange involving Mn–O–Mn, Fe–O–Fe, and Cr–N–Cr atomic configurations. Density Functional Theory (DFT) calculations demonstrated that these configurations originate within V Ga - O N complex defects by incorporating Mn2+, Fe2+, and Cr3+ ions into gallium vacancies ( V Ga ) sites promoted by the presence of oxygen as a substitutional impurity ( O N ). These co-doped GaN microstructures were synthesized using the thermal evaporation method. Cathodoluminescence (CL) and photoluminescence (PL) measurements confirmed the presence of V Ga - O N complex defects in all GaN-grown samples. X-ray photoelectron spectroscopy (XPS) measurements confirmed the successful incorporation of Mn2+, Fe2+, and Cr3+ ions in GaN samples. SQUID measurements demonstrated room-temperature ferromagnetism with respective saturation magnetization (Ms) and coercive field (Hc) values of ± 1.5 × 10−5 emu and 4 mT for GaN:O,Mn, ± 4.4 × 10−5 emu and 2.6 mT for GaN:O,Fe, and ± 1.7 × 10−5 emu and 2.6 mT for GaN:O,Cr. [ABSTRACT FROM AUTHOR]

In this article, we have investigated the electronic structure and magnetic properties of Sm2MgMnO6 prepared through auto-combustion method. The first principles of the density-functional theory have been applied to study of the electronic structure. The oxidation states of Mn and Mg are Mn3+/Mn4+ and Mg2+, respectively. The existence of Mn3+ is higher than Mn4+. The magnetic study reveals the sample shows ferromagnetic to paramagnetic transition at around 13.5 K which is followed by an antiferromagnetic ordering at 8.3 K. Antiferromagnetic and ferromagnetic ordering have been identified at 8.3 K and higher temperature, respectively. Sm2MgMnO6 shows a maximum magnetic entropy change of 1.25 J kg-1K-1 and relative cooling power of 86.9 J/kg for a field variation of 70 kOe near 25 K. The values are comparable to many double perovskites reported previously. This study highlights that Sm2MgMnO6 is a potential material for magnetocaloric refrigerant at low temperature. [ABSTRACT FROM AUTHOR]

The effect of Nb doping concentration (0, 1, 2, and 4 at. %) on donor defect‐induced ferromagnetism in ZnO thin films is investigated. The films are deposited on Si(111) substrates utilizing the radio frequency magnetron sputtering. X‐ray diffraction pattern unveils that the films show a pronounced orientation along the (002) direction. The relative intensities of defect‐related bands with that of the ultraviolet band from photoluminescence (PL) spectra show that 2 at. % Nb doping results in a greater number of donor defects (Zni+ and VO+) in the ZnO lattice. The parameters extracted from the electron paramagnetic resonance spectra follow a similar trend. The results from vibrating sample magnetometer measurement indicate that pure ZnO displays diamagnetic nature, whereas Nb‐doped ZnO exhibits a ferromagnetic nature. The saturation magnetization value is found highest for 2 at. % Nb doping, which correlates with the presence of a greater number of donor defects, as supported by the PL and electron paramagnetic resonance results. Images obtained from atomic force microscopy show that the surface roughness of the ZnO thin film reduces upon Nb doping. X‐ray photoelectron spectroscopy validates that Nb is doped in 2 at. % Nb‐doped ZnO thin film with Nb oxidation state of +5. [ABSTRACT FROM AUTHOR]

It is well known that the properties of a crystal evolve as it increases in size from a single atomic plane to that of the bulk. Such size‐dependent transitions can stem from many different origins and depend on minute changes to crystal bonding and composition. A model example is that of LaCoO3, which is non‐magnetic in the bulk but can display ferromagnetism at the nanoscale. Here, the evolution of structure‐property relationships is studied in the LaCoO3−δ/SrTiO3 (001) system as the thickness of LaCoO3−δ is increased from a single plane to 10 unit cells. In situ synchrotron X‐ray studies are performed during and post‐deposition to probe changes in the interactions between structure, stoichiometry, and magnetic behavior. Structural quantification indicates that the oxygen octahedral rotation pattern evolves with thickness, due to inherent differences in crystal symmetry between the film and substrate. The change in rotation modifies the required energy barrier for the spin state transition via the Co–O bond length and Co–O–Co bond angle, affecting the appearance of ferromagnetism. Our results highlight the contributions of high spin Co2+ and/or high spin Co3+ to respective weak and robust ferromagnetism and the evolution of properties with size in ultrathin LaCoO3−δ heterostructures. [ABSTRACT FROM AUTHOR]

Cubic, perovskite‐structure ABO3‐ and A1−xA'xBO3‐type oxides have been investigated extensively while their hexagonal structure versions have not, even though they are multiferroic and can form heterostructures with hexagonal 2D materials. In particular, multiferroic 2D epilayers may lead to strong magnetoelectric coupling. Hexagonal RFeO3 ferrites, where R is a rare‐earth element (Lu, Yb, etc.), are excellent candidates, but their ferromagnetism is weak. In this work, density‐functional‐theory (DFT) calculations are employed and first show that heavy electron doping of hexagonal LuFeO3 (h‐LFO), namely Lu1−xHfxFeO3 (h‐LHFO), leads to spin‐disproportionation of the Fe sublattices and, especially for x = 1/2 and 2/3, to robust, room‐temperature, out‐of‐plane, collinear ferrimagnetism that is stabilized by a Jahn–Teller metal‐to‐insulator transition. h‐LHFO/h‐2D heterostructures are then shown, where h‐2D is the FE/FM monolayer MnSTe, to stabilize skyrmions without an external magnetic field and their chirality is controlled by an external electric field through the h‐LHFO polarization, opening up a new realm for magnetoelectric applications. [ABSTRACT FROM AUTHOR]

Here we report the structural, optical and magnetic properties of La0.4Pr0.25NaxSr0.35−xMnO3 (x = 0, 0.05, and 0.1) synthesized using ball milling method. After milling, the precursors are calcinated at 1,200 °C for 12 h. The phase purity, crystal structure, lattice parameter, and crystallite size of the samples were determined using X‐ray diffraction (XRD). The peaks from XRD provide the perovskite hexagonal structure with an R 3 ‾ c space group. Surface morphology shows the recreation of spherical structure to nanoflakes/layered structures. The ultraviolet-visible diffused reflectance spectroscopy (UV–vis DRS) study indicates that the decrease in the band gap is observed with the increase of Na content. The intensity of the luminescence peak decreases progressively with the increase of Na doping. The room temperature (RT) magnetization of the samples reveals weak ferromagnetism and shows a novel vertical shift in magnetization at room temperature. [ABSTRACT FROM AUTHOR]

The study of exchange bias in various types of systems received great attention due to widespread applications in numerous magnetoelectronic devices and, in particular, understanding and controlling exchange bias in single layer films becomes crucial in advancing the spintronics field. With this connection, we here present a study on the origin of the exchange bias in the Fe3O4 (t nm) films with a polycrystalline structure fabricated via magnetron reactive sputtering directly onto a Si(100) substrate at ambient conditions and its correlation with thickness of the films and cooling fields. Structural and morphological studies reveal single phase polycrystalline Fe3O4 films and the average roughness increases with increasing thickness of the films. Magnetic properties show typical ferromagnetic behavior in Fe3O4 film, but interestingly, a considerable exchange bias (EB) of 550 Oe is noticed in 30 nm thick Fe3O4 film at 10 K when subjected to field cool. In addition, Fe3O4 (30 nm) film exhibits a spontaneous exchange bias without any external applied field. These observations can be understood from the magnetic exchange coupling at the interfaces between the ferromagnetic Fe3O4 and antiferromagnetic FeO, and the existence of a FeO can be validated from the magnetic anomalies in thermomagnetization data. Furthermore, the magnetic anomalies fade out at higher film thicknesses due to reduced (increased) volume of FeO (Fe3O4), causing suppression in the EB effect. The variation of EB with cooling field and film thickness demonstrates the tunability of EB in single layer Fe3O4 film and its suitability for possible applications in spintronics. [ABSTRACT FROM AUTHOR]

Conventional solid-state reaction method has been cautiously employed to prepare the Ba0.75Sr0.25Ti1−xMnxO3 ceramic where Sr was firmly doped at the Ba site and Mn was doped with different densities at the Ti site. Since the performance of materials varies with frequency, electric field, and temperature, we have elucidated the various features of the synthesized samples for the sake of scientific benefit in the fields of microelectronics, telecommunications, and spintronics. Structural and morphological features of the ready samples were examined by X-ray diffraction and scanning electron microscopy (SEM). The crystal's tetragonal behavior was verified by XRD analysis, and with the increment of Mn content, the volume of the unit cell is little changed. It is clear from the SEM images that the grain size of the prepared samples increases with Mn doping. The dielectric properties of Ba0.75Sr0.25Ti1−xMnxO3 were measured by dielectric constant and AC conductivity in a wide range of frequency from 1 kHz to 10 MHz. This result also explores that the dielectric constant rises with the concentration of Mn, most significantly for the 20% Mn substitution with Ti. We also found from the experimental result that the dielectric constant is high in the frequency range of 1–10 kHz. The magnetic permeability of the prepared sample increased with 10% and 20% of Mn replacement. Ferromagnetic features with a weak coercive field and the increased ferromagnetic order with rising Mn concentrations of the prepared samples were confirmed by VSM data analysis. The developed multiferroic materials can be employed in future spintronic devices like spin transistors, sensors, spin diodes, and memory devices. [ABSTRACT FROM AUTHOR]

We calculate the conductance of a junction between a disordered superconductor and a very strong half-metallic ferromagnet admitting electrons with only one spin projection. A usual mechanism of Andreev reflection is strongly suppressed in this case since Cooper pairs are composed of electrons with opposite spins. However, this obstacle can be overcome if we take into account spin-orbit scattering inside the superconductor. Spin-orbit scattering induces a fluctuational (zero on average) spin-triplet component of the superconducting condensate, which is enough to establish Andreev transport into a strong ferromagnet. This remarkably simple mechanism is quite versatile and can explain long-range triplet proximity effect in a number of experimental setups. One particular application of the suggested effect is to measure the spin-orbit scattering time τ SO in disordered superconducting materials. The value of Andreev conductance strongly depends on the parameter Δ τ SO and can be noticeable even in very disordered but relatively light metals like granular aluminum. [ABSTRACT FROM AUTHOR]

We present a systematic investigation of the detailed structural, optical and magnetic properties of ZnO thin films deposited by pulsed laser deposition as a function of varying Al doping from 0% to 5%. The observed features can be associated with strain introduced into the ZnO lattice by the incorporation of Al. Enhanced optical transmittance values close to 95% were achieved in Al-doped ZnO epitaxial films deposited on sapphire substrates. In addition, these films exhibit robust ferromagnetic properties at room temperature with saturation magnetization that varies from 143 to 63 emu/cm3 for Al dopant concentrations from 0% to 5%. It is demonstrated that the saturation magnetization is related to the strain introduced into the lattice with increased Al doping. [ABSTRACT FROM AUTHOR]

The magnetoelectric (ME) response of laminated composites consisting of BaFe12O19 and Pb(Zr,Ti)O3 ceramics is systematically investigated. A butterfly-shaped curve of a magnetoelectric coefficient emerges in both three-layer and multilayer composites. We show that the appearance of a 7 ppm residual strain in the BaFe12O19 layer after magnetization is the main reason for this special curve. We also observe the self-biasing effect of the composites and a maximum ME response from 0.6 to 5 mV/(Oe cm) in laminated composites with magnetic and ferroelectric layers of different thicknesses that can be measured at a zero-bias magnetic field. The repeatable and stable maximum and minimum values of the magnetoelectric coefficient can be obtained under periodically applied biasing magnetic fields, which is important for a practical device application. An electric-field control of ferromagnetism, evidenced by a 17%–19% enhancement in the magnetization of the BaFe12O19 layer after Pb(Zr,Ti)O3 is polarized, is observed in the composites, implying potential applications in memory devices for the composites. Our work indicates that both magnetic field-controlled polarization and electric-field-controlled magnetization exist in BaFe12O19/Pb(Zr,Ti)O3 laminated composites. [ABSTRACT FROM AUTHOR]

Improper ferroelectricity and canted ferromagnetism in antiferromagnetically ordered hexagonal ferrites with A2-type spin configuration have been intensely studied due to their potential for room-temperature multiferroicity with strong magnetoelectric couplings. However, the subtle interplay between the magnetic structure and trimer structural distortion, which is a critical ingredient for ferroelectricity, has not been clearly verified in experiments due to the lack of control over trimer distortion. In this study, we report on Lu0.6In0.4FeO3, which exhibits weaker trimer distortion primarily related to the smaller tilting of the FeO5 bipyramids. The reduced vertical displacement of the equatorial oxygen of FeO5 located at the center of the trimer lowers the magnitude of the in-plane Dzyaloshinskii–Moriya vector component, resulting in the absence of canted ferromagnetism with the planar A1-type spin configuration, rather than the canted A2-type observed in other hexagonal ferrites. Our findings demonstrate that the degree of trimer distortion plays an important role in determining the spin configuration in related hexagonal systems. [ABSTRACT FROM AUTHOR]

The tunable magnetism and reversible phase transformation between SrCoO2.5 (SCO) and HSrCoO2.5 (HSCO) have attracted vast research interest; however, the physical origin of the weakly ferromagnetism of the hydrogenated phase is still unclear. Various point defects, especially H related ones, may play important roles in the magnetic order of SCO and HSCO. In this study, we performed first-principles calculations combined with bond orbital model analysis to investigate the stabilities and magnetic effects of these defects and their complexes in both phases. We find that Hi, VO, CoSr, and Oi are relatively stable in SCO, while VH, CoSr, Hi, and Oi are relatively stable in HSCO. Additionally, these defects show significant differences of formation energy in these two phases because the charge transfer mechanisms from defects to nearby Co atoms are different. The different mechanisms also lead to different local reconstructions and crystal field splitting of the Co 3d states, affected by the interaction between Co–O bond orbital and surrounding bonding environment. Single defects of VH, Hi, and CoSr contribute significantly to the total magnetic moment of the system for HSCO or SCO. However, a ferromagnetic coupling is discovered in the two VH configurations only in HSCO, which may explain the experimental observation of the weakly ferromagnetism of HSCO. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van der Waals (vdW) magnets are crucial for ultra-compact spintronics. However, so far, no vdW crystal has exhibited tunable above-room-temperature intrinsic ferromagnetism in the 2D ultrathin regime. Here, we report the tunable above-room-temperature intrinsic ferromagnetism in ultrathin vdW crystal Fe3+xGaTe2 (x = 0 and 0.3). By increasing the Fe content, the Curie temperature (TC) and room-temperature saturation magnetization of bulk Fe3+xGaTe2 crystals are enhanced from 354 to 376 K and 43.9 to 50.4 emu·g−1, respectively. Remarkably, the robust anomalous Hall effect in 3-nm Fe3.3GaTe2 indicates a record-high TC of 340 K and a large room-temperature perpendicular magnetic anisotropy energy of 6.6 × 105 J m−3, superior to other ultrathin vdW ferromagnets. First-principles calculations reveal the asymmetric density of states and an additional large spin exchange interaction in ultrathin Fe3+xGaTe2 responsible for robust intrinsic ferromagnetism and higher TC. This work opens a window for above-room-temperature ultrathin 2D magnets in vdW-integrated spintronics. [ABSTRACT FROM AUTHOR]

Topological semimetals, possessing topologically non-trivial band structures, serve as excellent platforms for realizing topological superconductivity through hard point-contact experiments. In this study, we successfully induce superconductivity in the three-dimensional Dirac semimetal, cubic PtBi2, using ferromagnetic and paramagnetic tips in hard point contact experiments. The induced superconductivity is proven to be insensitive to ferromagnetism and exhibits unconventional features in the point-contact spectra. The highest superconducting transition temperature ( T c ) reaches approximately 5.1 K, and the T c values are proven to have a positive correlation with the coupling between the tip and the sample. Furthermore, we extend our point-contact experiments to trigonal PtBi2, a material possessing a type-I Weyl semimetal band structure and triply degenerate points proximate to the Fermi level. Utilizing both ferromagnetic Ni tips and paramagnetic Ag tips, we successfully enhance superconductivity with a T c of up to 3.0 K in this material. The findings from point-contact measurements reveal that the enhanced superconductivity is compatible with ferromagnetism and the magnetism of the tip can affect the symmetry of the enhanced superconducting state. Given that the lattice structure remains stable under pressure up to 51.2 GPa for cubic PtBi2 and 12.9 GPa for trigonal PtBi2, the emergent superconducting states observed in these two PtBi2 materials could inherit their topological nontrivial nature and be promising candidates for topological superconductor. [ABSTRACT FROM AUTHOR]

We study the effect of hole doping on the Kitaev spin liquid (KSL) and find that for ferromagnetic (FM) Kitaev exchange K the system is very susceptible to the formation of a FM spin polarization. Through density matrix renormalization group simulations on finite systems, we uncover that the introduction of a single hole, corresponding to ≈1% hole doping for the system size we consider, with a hopping strength of just t ~ 0.28K is enough to disrupt fractionalization and polarize the spins in the [001] direction due to an order-by-disorder mechanism. Taking into account a material relevant FM anisotropic exchange Γ drives the polarization towards the [111] direction via a transition into a topological FM state with chiral magnon excitations. We develop a parton mean-field theory incorporating fermionic holons and bosonic magnons, which accounts for the doping induced FM phases and topological magnon excitations. We discuss experimental implications for Kitaev candidate materials. [ABSTRACT FROM AUTHOR]

For temperatures below and beyond the Curie temperature, the stochastic Landau-Lifshitz-Bloch equation describes the evolution of spins in ferromagnetic materials. In this work, we consider the stochastic Landau-Lifshitz-Bloch equation driven by a real valued Wiener process and show Wong-Zakai type approximations for the same. We consider non-zero contribution from the helicity term in the energy. First, using a Doss-Sussmann type transform, we convert the stochastic partial differential equation into a deterministic equation with random coefficients. We then show that the solution of the transformed equation depends continuously on the driving Wiener process. We then use this result, along with the properties of the said transform to show that the solution of the originally considered equation depends continuously on the driving Wiener process. [ABSTRACT FROM AUTHOR]

A facile method has been employed to synthesize pristine and Cr-doped SnS2 (Cr: SnS2) nanoplates (Sn1-xCrxS2, here x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) and Cr: SnS2 nanoplates (NPs) were successfully synthesized via hydrothermal method. The nanoplates' structure was hexagonal, with a preference for orientation along the (001) plane; there was no evidence of additional undesirable phases. FTIR and EDX were used to observe the existence of functional groups in the samples where Sn-S bonds were present in each of the produced pristine and Cr: SnS2 nanoplates. XPS measurements demonstrated the existence of Sn, S, and Cr. FESEM revealed that the morphological properties of the nanoplates included several hexagonal grains. Magnetic characterizations showed that with increasing doping concentration of Cr, SnS2 nanoplates become superparamagnetic from ferromagnetic. The band gap values for the pristine and Cr: SnS2 nanoplates calculated from the absorbance spectra decreased from 2.53 to 2.08 eV with an increase in doping concentration. The photoluminescence spectra of the pristine SnS2 and Cr: SnS2 nanoplates exhibit two strong emission peaks at around 562 and 666 nm for an excitation wavelength of 420 nm. The Cr: SnS2 nanoplates have demonstrated the resistive behavior of the sample. The Cr: SnS2 nanoplates have shown good photocatalytic activity towards the decolorization of rhodamine B under visible irradiation.Article highlights: Hydrothermally synthesized pristine SnS2 and Cr: SnS2 nanoplates exhibit hexagonal crystal structures and the hexagonal shape of layered nanoplates is apparent in both cases. The ferromagnetic order is introduced by Cr doping in SnS2 which increases the formation of dilute magnetic semiconductors that can therefore be used in spintronic devices. The Sn0.6Cr0.4S2 photocatalyst shows the highest photocatalytic activity and a degradation efficiency of 71%, which is 3.4 times higher than the pure SnS2 catalyst. [ABSTRACT FROM AUTHOR]

During the last two decades, researchers have been making efforts to find the most suitable metal oxides to be utilized for spintronics applications, magneto-optical devices, quantum dots, etc. Thus current research has examined the microstructural, optical, dielectric, and magnetic behavior of co-doped (Cr, Fe) tin oxide (Sn1−2xCrxFexO2−δ) nanoparticles. The Cr and Fe-doped (Sn1−xCrxO2−δ), (Sn1−xFexO2−δ) and co-doped (Cr, Fe) tin oxide (Sn1−2xCrxFexO2−δ) for x = 0.1 have been synthesized by solid-state reaction method from the tin oxide, chromium oxide, and ferric oxide prepared by co-precipitation method. Powder x-ray diffraction reveals the formation of pure rutile type tetragonal phase of samples and average crystalline size was found to be in the range of 45–54 nm. The electronic state of elements Sn, Cr, and Fe was observed to be 4+, 6+, and 3+, respectively, from x-ray photoelectron spectroscopy. The shape and size of the particles were observed to be cubic and in the range of 52–70 nm by scanning electron microscope. On the other hand, transmission electron microscopic reveals the grain size of 25–36 nm. The optical band gap determined from UV–visible absorption spectroscopy was found to be widened by doping. The maximum dielectric loss (5.3) was observed for pristine SnO2 and low loss (0.78) for co-doped (Cr, Fe) tin oxides from P–E measurement. The vibrating sample magnetometer studies show the transition from diamagnetism to ferromagnetism after co-doping. We found improvement in ferromagnetism and ferroelectricity due to co-doping, therefore the sample is suitable for high-frequency optoelectronic applications. [ABSTRACT FROM AUTHOR]

Using state-of-the-art first-principles electronic-band-structure calculations alongside density functional theory, we investigated the structural, elastic, electronic, and magnetic properties of LiMnZ2 (Z = Se, Te) compounds with a trigonal structure. Initially, we determined the equilibrium lattice structure and atomic positions, which aligned well with experimental values. Ferromagnetism was shown to be more favorable than the non-magnetic state. The elastic constants, cohesive energies, and formation energies indicated that the studied compounds were mechanically stable in the experimentally determined trigonal lattice. The analysis of spin-polarized band structures and density of states revealed that both LiMnZ2 compounds exhibited perfect half-metallic characters. The total spin magnetic moment per formula unit adhered to the Slater–Pauling rule, being exactly 4 μΒ, mainly concentrated at the Mn atoms due to the strong spin polarization of the Mn d orbitals. We anticipate that our results will prompt further experimental and computational studies for the application of these layered materials in practical devices. [ABSTRACT FROM AUTHOR]

Here, by using angle-resolved photoemission spectroscopy, we showed that Bi2−xCrxSe3 single crystals have a distinctly well-defined band structure with a large bulk band gap and undistorted topological surface states. These spectral features are unlike their thin film forms in which a large nonmagnetic gap with a distorted band structure was reported. We further provide laser-based high resolution photoemission data which reveal a Dirac point gap even in the pristine sample. The gap becomes more pronounced with Cr doping into the bulk of Bi2Se3. These observations show that the Dirac point can be modified by the magnetic impurities as well as the light source. [ABSTRACT FROM AUTHOR]

Thin films of FePtCo ternary alloy with 100 nm thickness have been deposited on an Si substrate using a DC magnetron sputtering system by co-sputtering of Co metal target and Fe40Pt60 alloy target in three different conditions, i.e. as-deposited at room temperature, annealed at 400 °C ${}_{}^ \circ C$ ∘ C , and deposited on the seed- layer. The effects of target sputtering power, leading to different compositions and various deposition conditions on surface roughness of films and magnetic properties, were studied. The average surface roughness of the as-deposited films decreases with the increase in the sputtering power of the Co target. For the annealed and seed-layered films, an increase in Co sputtering power resulted in an increased in roughness. Moreover, the annealed films possess smallerlower roughness due to an increase in the surface mobility. On the other hand, the Cu seed- layer decreases the roughness by preventing the diffusion of the film into the substrate. The room -temperature M-H measurement shows that the films exhibit soft ferromagnetism with coercivity in the order of ${10^3}$ 10 3 A/m and large saturation magnetizationmagnetisation of the order ${10^6}$ 10 6 A/m. The saturation magnetizationmagnetisation decreases with the increase in the sputtering power and is not influenced by the film surface roughness. On the other hand, riseincrease in surface roughness leads to decrease in coercivity of the films. HIGHLIGHTS: Thin films of FePtCo ternary alloy have been deposited by co-sputtering of Co metal target and Fe40Pt60 alloy target. The effects of surface roughness of films on magnetic properties were studied. The room-temperature M-H measurement shows that the films exhibit soft ferromagnetism. The saturation magnetisation decreases with sputtering power and is not influenced by the film surface roughness. On the other hand, increase in surface roughness leads to decrease in coercivity of the films. [ABSTRACT FROM AUTHOR]

Here, we show that the ferro(para)magnetic and non-collinear antiferromagnetic interfaces contribute to oscillating signals observed in the magnetoresistance. We associate the effect with the fact that the spins on the surface of IrMn 3 produce instability in the surface magnetoresistance of the material, which is sensitive to the magnetic field. We carried out experiments using bilayers of IrMn 3 under permalloy (Py) and IrMn 3 under platinum (Pt). The oscillations were intensely evident at the Py/IrMn 3 interface and less explicit at the Pt/IrMn 3 interface. We carried out the experiments using pulsed current, with a square pulse width of 1 μ s and amplitudes of I AC = 20 μ A to 20 mA. The oscillating signals are proportional to the crystallographic direction of the material, the ferromagnetism of the material adjacent to IrMn 3 , and sensitive to the amplitude of the pulsed current. We believe that observation is a way of transmitting encoded information through magnetoresistance. [ABSTRACT FROM AUTHOR]

Perovskite LaCoO3 is a subject of extensive and ongoing investigation due to the delicate competition between high‐spin (HS) and low‐spin (LS) states of Co3+. On the other hand, their indistinct free energy boundary poses a significant challenge to annihilate the magnetically/electrically inert LS Co3+ for yielding fully HS state. Here, electronic transformation from the conventional isovalent mixed HS/LS state (La[CoHS3+,CoLS3+]O3${\mathrm{La}}[ {{\mathrm{Co}}_{HS}^{3 + },{\mathrm{Co}}_{LS}^{3 + }} ]{{{\mathrm{O}}}_3}$) into an unprecedented aliovalent fully HS state (La[CoHS3+,CoHS2+]O3${\mathrm{La}}[{\mathrm{Co}}_{HS}^{3 + },{\mathrm{Co}}_{HS}^{2 + }]{{{\mathrm{O}}}_3}$) is demonstrated in monolayer LaCoO3 confined by 5d SrIrO3 slabs via atomically constructing SrIrO3/LaCoO3 superlattices. Excitingly, this emergent fully HS La[CoHS3+,CoHS2+]O3${\mathrm{La}}[ {{\mathrm{Co}}_{HS}^{3 + },{\mathrm{Co}}_{HS}^{2 + }} ]{{{\mathrm{O}}}_3}$ monolayer exhibits not only remarkable 2D ferromagnetism beyond the Mermin–Wagner restriction, but also larger magnetization (≈1.8µB/Co) and higher Curie temperature (above 100 K) than that of conventional La[CoHS3+,CoLS3+]O3${\mathrm{La}}[ {{\mathrm{Co}}_{HS}^{3 + },{\mathrm{Co}}_{LS}^{3 + }} ]{{{\mathrm{O}}}_3}$ thick film and any previously reported oxide‐based monolayer ferromagnets. Furthermore, Ir/Co hybridization driven orbital reconstruction with polarization beyond standard crystal field expectations is observed, which is supported by DFT calculations. The findings not only expand the electronic phase domains of LCO into fully HS state, but also provide a fresh platform for investigating the 2D magnetic physics under strongly spin‐orbit coupled regime and developing new 2D spintronic devices. [ABSTRACT FROM AUTHOR]

In this work, we have used the full-potential linearized augmented plane wave (FP-LAPW) method implemented in the WIEN2k code combined with the generalized gradient approximation (GGA) of the density functional theory (DFT) to study the structural, elastic, mechanical, electronic, magnetic, and thermodynamic properties of the parent ternary inverse Heusler compounds based on Titanium and Cobalt Ti2CoGa, Ti2CoCu in the Hg2CuTi-type structure and their quaternary alloys Ti2CoGa 1 − x Cux (x = 0. 2 5 , 0.5, 0.75) for the chosen concentrations using a supercell with 16 atoms. We have calculated the structural properties, such as the lattice parameters, bulk modulus, and its first derivative, which are in good agreement with those that have been obtained based on other published theoretical methods. Also, we calculated the elastic constants of the studied Heusler alloys, and we found that these materials are elastically stable, ductile, and anisotropic. Therefore, the electronic and magnetic properties indicate that Ti2CoGa exhibits a half-metallic (HM) ferromagnetic behavior, while Ti2CoCu shows a metal and a non-magnetic (NM) character. Their quaternary alloys are found to be nearly HM ferromagnetic materials, with a magnetic moment mainly due to the atom Ti. Furthermore, the quasi-harmonic Debye model, which incorporates the lattice vibrations, was used to estimate the thermodynamic effects on some macroproperties of the Ti2CoGa 1 − x Cux alloys. Successful results were achieved for the variations of the primitive cell volume, bulk modulus, heat capacities, and Debye temperature with pressure and temperature, respectively, in the ranges of 0–30 GPa and 0–1400 K. To our knowledge, no analogous investigations on the mechanical and thermodynamic properties of the Ti2CoGa 1 − x Cux (x = 0. 2 5 , 0.5 and 0.75) alloys have been performed to date. As a result, it is predicted that Ti2CoGa 1 − x Cux Heusler alloys will be promising candidates for actual applications in spintronic devices. [ABSTRACT FROM AUTHOR]

Indium sulfide (In2S3) is a promising candidate material for spintronic applications. In this article, undoped In2S3 nanoparticles with varying sizes were fabricated via a gas–liquid phase chemical method and annealing process. The In2S3 nanoparticles with small particle sizes are subjected to annealing treatment in a nitrogen atmosphere for the purpose of adjusting the surface-to-volume ratio of the nanoparticles and avoiding magnetic doping. Magnetic measurements indicate that these nanoparticles clearly exhibit a room temperature ferromagnetic behavior, which decreases with increasing size due to annealing. Intrinsic defects are believed to be responsible for the observed ferromagnetism, which is fully elucidated in terms of the bound magnetic polarons (BMPs) mechanism. Notably, the defect-related d0 ferromagnetism of the samples can be conveniently modulated by controlling the particle size. First principles calculations reveal that the p–d exchange interaction between unpaired S 3p electrons induced by the In vacancies and In 4d electrons is the primary origin of ferromagnetism in In2S3. The size-dependent magnetic properties of pure In2S3 nanoparticles not only suggest potential applications in future spintronics and magneto-optics, but also propose a novel strategy for the exploration of pure diluted magnetic semiconductors (DMSs). [ABSTRACT FROM AUTHOR]

In this paper, we establish the existence of global-in-time weak solutions for the Landau–Lifschitz–Gilbert equation with magnetostriction in the case of mixed boundary conditions. From this model, we derive by asymptotic method a two-dimensional model for thin ferromagnetic plates taking into account magnetostrictive effects. [ABSTRACT FROM AUTHOR]

Herein we report the existence of room temperature ferromagnetic ordering in pristine cuprous oxide nanocrystals mediated by native point defects present in the material. To demonstrate defect‐induced magnetism, cuprous oxide nanocrystals were synthesized in a simple and sustainable route employing hydroxylamine as the reducing agent. The crystalline phase of the as‐synthesized nanocrystals was investigated and was found to have crystallized in cuprite crystal structure. The optical absorption characteristics exhibits absorption features in the visible region between 400 and 600 nm signifying the presence of optically active defects. The morphology of the sample was examined, which reveals the shape to be corner‐truncated rhombic dodecahedral and the size to be in the range of 200–250 nm. The field‐dependent magnetization measurement at room temperature indicates the presence of collective ferromagnetism with hysteresis behavior (Ms = 210 memu g−1, Mr = 43 memu g−1, Hc = 16.37 mT) due to exchange interaction between the uncompensated spin moments present on the surface of the material. [ABSTRACT FROM AUTHOR]

The regularities of changes in the atomic, electronic, and magnetic subsystems in ferrites of variable composition MnxZnyFezO4 related to the formation of clusters differing in the composition of cations are studied using the methods of X-ray diffraction analysis, X-ray spectroscopy, and theoretical physics. Experimentally detected clusters appearing in the X-ray diffraction patterns as a halo are characterized by a certain superposition of ion states, the magnetic moment of which depends not only on the spin of the electron, but also on its orbital moment and the spin of the nucleus. In a mesoscopic cluster structure, a phase transition from manganese-containing clusters stipulated by the interaction of trivalent manganese ions with oxygen ions to clusters with a predominance of divalent and trivalent manganese ions with oxygen ions is discovered. It is found that the clustered structure of manganese-zinc ferrites is responsible for the appearance of extreme magnetic properties; the maximum corresponds to a change in the dominant type of clusters. It is found that with an increase in mass density, a repopulation of energy states occurs: a decrease in the number of states of the low-energy electron group and their increase in the high-energy group in the form of a Fermi-surface saddle point. It is established that the peculiarities of condensation of the basic and soft modes of complexes (clusters) containing manganese and oxygen ions result in changes in the physical parameters of the samples. [ABSTRACT FROM AUTHOR]

The combustion process was used to create pure and Zn2+ substituted MgFe2O4 nanoparticles. XRD analysis is used to determine the structure of magnesium ferrite samples. The average crystallite size ranges from 26 to 14 nm. FE-SEM images were used to investigate the shape of spinel nanoparticles. The EDX is utilised to confirm the presence of elements, and the tau'c relation was used to calculate the band gap values of 2.08, 2.06, 1.90, and 1.80 eV. The band at 433 and 584 cm−1, which correspond to the stretching vibration of the tetrahedral site (Fe3+ –O2−) and octahedral site (Mg2+ –O2−), respectively, confirms the presence of the magnesium spinel structure. The magnetic characteristics Hc, Mr, and Ms were identified from the hysteresis loops and behave ferromagnetic. Additional study is conducted on the obtained samples' dielectric properties and AC conductivity. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) analyses were carried out to study electronic structures and magnetic properties of Mn- and Cu-doped GaNNS. To investigate the influence of transition metal atoms (TM) on magnetic properties, we substituted Ga atoms with Mn and Cu atoms in different concentrations. Investigation shows that TM leads to electronic structural reconstruction which changes their properties in this way, and plays a significant role in spin polarization. Although the pure nanosheet is a nonmagnetic semiconductor, the doped atoms induce magnetism in the structure. The band gap changes monotonically depending on the concentration of TM atoms. The observed good half-metal ferromagnetism GaNNS:Mn, allows them to be a potential candidate for use in spintronics. The local magnetic moment calculated from Mulliken analyses for the Mn atom is approximately 4.05 μ B. By choosing the appropriate concentration of impurity atoms one can obtain a magnetic semiconductor and is half-metal. Thus, Mn-atoms may induce half-metallic ferromagnetism in GaN nanosheet, which makes it a potential candidate for spintronics device applications. Also observed, was weak ferromagnetism in Cu-doped GaNNS is not suitable for use in spintronics. [ABSTRACT FROM AUTHOR]

The effects of 180, 210, and 230°C reaction temperatures on the structural and magnetic properties of synthesized iron sulfide nanoparticles were studied. The Rietveld refinement analysis result of the X‐ray diffraction data indicated that greigite was the dominant phase in all samples. The sample was prepared at 210°C for 18 h and had a greater wt% ratio of the greigite phase. The crystallite and particle sizes increased with increasing reaction temperatures. Scanning electron microscope images confirmed the presence of aggregation of synthesized rod‐shaped nanoparticles. The magnetic hysteresis curves of all samples showed ferromagnetic behavior at room temperature. The magnetic saturation of three samples increases with increased reaction temperature, but the coercive force has the opposite behavior. Antioxidant activity and cytotoxicity of the sample synthesized at 210°C were investigated. This sample killed cancer cells at relatively moderate and high concentrations with high viability of normal cells, demonstrating the sample's suitability for use in killing cancer cells while avoiding normal cells. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered materials have been studied in depth during the past two decades due to their unique structure and properties. Transition metal (TM) intercalation of layered materials have been proven as an effective way to introduce new physical properties, such as tunable 2D magnetism, but the direct growth of atomically thin heteroatoms-intercalated layered materials remains untapped. Herein, we directly synthesize various ultrathin heteroatoms-intercalated 2D layered materials (UHI-2DMs) through flux-assisted growth (FAG) approach. Eight UHI-2DMs (V1/3NbS2, Cr1/3NbS2, Mn1/3NbS2, Fe1/3NbS2, Co1/3NbS2, Co1/3NbSe2, Fe1/3TaS2, Fe1/4TaS2) were successfully synthesized. Their thickness can be reduced to the thinnest limit (bilayer 2D material with monolayer intercalated TM), and magnetic ordering can be induced in the synthesized structures. Interestingly, due to the possible anisotropy-stabilized long-range ferromagnetism in Fe1/3TaS2 with weak interlayer coupling, the layer-independent magnetic ordering temperature of Fe1/3TaS2 was revealed by magneto-transport properties. This work establishes a general method for direct synthesis of heteroatom-intercalated ultrathin 2D materials with tunable chemical and physical properties. The intercalation of heteroatoms has been demonstrated to be an effective approach to introduce new physical properties in 2D layered materials (2DMs). Here, the authors report a flux-assisted growth method to synthesize various ultrathin heteroatoms-intercalated 2DMs, showing evidence of anisotropy-stabilized long-range ferromagnetism in Fe1/3TaS2. [ABSTRACT FROM AUTHOR]

Although extensive work has already been done on bulk La1−xSr1+xCoO4 layered oxides, there is very limited studies on their nano-crystalline nature, particularly for those with a higher Sr level (x ≥ 0.4), which may exhibit interesting magnetic properties and in particular photocatalytic properties because of their enhanced surface area. Moreover, the phases with higher Sr doping levels can be formed only at higher temperatures, which otherwise contain significant amounts of impurities. In order to synthesize them in a nanocrystalline form in the pure state at the lowest possible temperature, we applied a glycine nitrate combustion method using excess fuels for the synthesis of nanocrystalline La1−xSr1+xCoO4 (x = 0.0, 0.2, 0.4 and 0.6) layered perovskite oxides. Efforts were also made to synthesize phases with x > 0.6 but remained unsuccessful. The prepared nanophases were thoroughly characterized using PXRD, XPS, SEM, SQUID VSM and UV-DRS to examine the structural, morphological, optical, magnetic and photocatalytic properties. All the phases exhibit mixed valence states of +3 and +4 of Co, as confirmed by XPS analysis, which has a remarkable effect on various physical properties, especially magnetic and photocatalytic properties. An abrupt transition in magnetic behaviour from antiferromagnetic for x = 0 and 0.2 phases to ferromagnetic in case of x = 0.4 and 0.6 was observed. The optical band gap values (Eg) of all the synthesized nanophases obtained from DRS are in the visible range (1.57 to 1.47 eV), which make them suitable and reliable photocatalysts for dye degradation. Moreover, the synthesized nanophases were assessed for their photocatalytic activity by employing rhodamine B (RhB) dye as a model contaminant. The results revealed that the La0.4Sr1.6CoO4 photocatalyst efficiently and swiftly degraded RhB within 60 min. Considering the performance of the La0.4Sr1.6CoO4 photocatalyst, the study was expanded to include the degradation of other organic dye pollutants, namely, methyl orange (MO), methylene blue (MB) and a ternary combination of these contaminants (RhB + MB + MO). [ABSTRACT FROM AUTHOR]

Femtosecond laser excitation of materials exhibiting magnetic spin textures promises advanced magnetic control via the generation of non‐equilibrium spin dynamics. Ferrimagnetic [Fe(0.35 nm)/Gd(0.40 nm)]160 multilayers are used to explore this approach, as they host a rich diversity of magnetic textures from stripe domains at low magnetic fields, a dense bubble/skyrmion lattice at intermediate fields, and a single domain state for high magnetic fields. Using femtosecond magneto‐optics, distinct coherent spin wave dynamics are observed in this material in response to a weak laser excitation, enabling an unambiguous identification of the different magnetic spin textures. Moreover, employing strong laser excitation, versatile control of the coherent spin dynamics via non‐equilibrium transformation of magnetic spin textures becomes possible by both creating and annihilating bubbles/skyrmions. Micromagnetic simulations and Lorentz transmission electron microscopy with in situ optical excitation corroborate these findings. [ABSTRACT FROM AUTHOR]

The rapidly emerging field of 2D magnetic materials has garnered significant attention due to its fascinating physical properties and wide‐ranging potential applications. This review highlights the importance of magneto‐optical interactions as a crucial tool for both studying and modulating 2D magnets. It offers a comprehensive survey of current research concerning magneto‐optical interactions in 2D magnetic materials, encompassing the magneto‐optical Kerr effect, reflection magnetic circular dichroism, second‐harmonic generation, photoluminescence, inelastic light scattering, and time‐resolved spectroscopy. This review discusses how these techniques provide insights into the properties of 2D magnets, enabling exploration of magnetic phase transitions, lattice alterations, spin dynamics, as well as their responses to external fields. Moreover, it emphasizes the modulation of magnetic properties by photo‐stimulation and offers a brief outlook on this swiftly developing field. [ABSTRACT FROM AUTHOR]