Long-range Ferromagnetic Order Research Articles

Magnetic irreversibility and magnetization processes in Ni5Al3/NiO core/shell nanoparticle system.

This work brings out many interesting facets of magnetism in the Ni5Al3/NiO core/shell nanoparticle system. The weak and strong magnetic irreversibility lines (TWI(H) and TSI(H)) reproduce the previously reported H - T phase diagram at fields H ≤ 30 Oe, but strong departures occur for H > 30 Oe. Comparison with the theoretically predicted H - T phase diagram allows us to identify TWIwith TCG+SG, where the paramagnetic (PM)-chiral glass (CG) and PM-spin glass (SG) phase transitions occur simultaneously, and TSIwith TSG, the temperature at which transition to the replica symmetry breaking SG state takes place. The TSI(H) transition line abruptly ends at the point (H ≃ 30 Oe, T ≃ 90 K). As H exceeds 30 Oe, a new transition appears, which gets completely suppressed at fields H > 1 kOe, where the magnetic irreversibility ceases to exist. No intrinsic long-range ferromagnetic ordering exists, but fields as low as 3 kOe suffice to induce long-range ferromagnetic order. At fixed temperatures, the magnetocrystalline anisotropy fluctuations essentially govern the 'approach-to-saturation' in magnetization for fields in the range 3 - 70 kOe. The present nanocrystalline system behaves as an isotropic system with a random easy axis in which the magnetization reversal occurs through the coherent rotation of the magnetizations of weakly-interacting single-domain Ni5Al3particles. Saturation magnetization, like M(T) at H ≥ 2 kOe, exhibits an anomalous upturn at temperatures below ≈ 30 K. This upturn is associated with the anomalous softening of spin-wave modes, which results in the thermal excitation of a large number of non-equilibrium (finite lifetime) magnons. At sub-Kelvin temperatures, these magnons undergo Bose-Einstein condensation.&#xD.

Molecular beam epitaxy growth and doping modulation of topological semimetal NiTe2

In this study, high-quality thin films of the topological semimetal phase NiTe2 were prepared using the molecular beam epitaxy technique, confirmed through x-ray diffraction with pronounced Laue oscillations. Electrical transport experiments reveal that thick films have properties similar to bulk materials. By employing co-deposition, we introduced either magnetic or non-magnetic elements during the growth of thinner films, significantly altering their electrical properties. Notably, the magnetic element Cr induces long-range ferromagnetic ordering, leading to the observation of a significant anomalous Hall effect in NiTe2 thin films. The Hall conductivity remains nearly constant well below the Curie temperature, indicating the correlation with the intrinsic topological nature of the band structure. Theoretical first principles band calculations support the generation of the Weyl semimetal state in the material through magnetic doping. These findings pave the way for exploring more magnetic Weyl semimetals and related low-dimensional quantum devices based on topological semimetals.

Enhanced Electron Delocalization Induced by Ferromagnetic Sulfur doped C 3 N 4 Triggers Selective H 2 O 2 Production.

For the 2D metal-free carbon catalysts, the atomic coplanar architecture enables a large number of pzorbitals tooverlap laterally,thus formingπ-electron delocalization, and the delocalization degree of the central atom dominates the catalytic activity. Herein, designing sulfur-doped defect-rich graphitic carbon nitride (S-Nv-C3N4) materials as a model, we proposea strategy to promote localized electronpolarization by enhancing the ferromagnetism of ultra-thin 2D carbon nitride nanosheets.The introduction of sulfur (S)further promotes localized ferromagnetic coupling,thereby inducing long-range ferromagnetic ordering and accelerating the electron interface transport. Meanwhile, the hybridization of sulfur atoms breaks the symmetry and integrity of the unit structure, promoteselectron enrichment and stimulating electron delocalization at the active site. This optimization enhances the *OOH desorption, providing a favorable kinetic pathway for the production of hydrogen peroxide (H2O2). Consequently, S-Nv-C3N4exhibits high selectivity (>95%)and achieves a superb H2O2production rate,approaching4374.8ppm duringcontinuous electrolysisover 300-hour. According to theoreticalcalculationand in-situspectroscopy,the ortho-S configurationcan provide ferromagnetic perturbation incarbon active centers, leading to the electron delocalization, which optimizes the OOH* adsorption during the catalytic process.

Magnetic properties and magnetoresistance of hybrid multilayer nanostructures {[(Co40Fe40B20)34(SiO2)66]/[ZnO]}n

The structural, electrical, magnetic, magneto-optical properties and magnetoresistance of {[(Co40Fe40B20)34(SiO2)66]/[ZnO]}n multilayer structures, where n = 50 is the number of bilayers (Co40Fe40B20)34(SiO2)66 nanocomposite and ZnO have been studied. The thicknesses of (Co40Fe40B20)34(SiO2)66 nanocomposite layers as well as ZnO spacers were varied in a wide range. The samples were synthesized by ion-beam sputtering onto glass ceramic substrates. The (Co40Fe40B20)34(SiO2)66 composite have an amorphous structure and the semiconductor ZnO interlayers have a hexagonal crystalline structure with the p63mc symmetry group. The nanocomposite layers containing a ferromagnetic component far from the percolation threshold are in a superparamagnetic state. The presented in the paper data of magnetization, magneto-optical transverse Kerr effect and magnetoresistance indicates that long-range ferromagnetic order does not form down to 77 K both for references ZnO films and studied multilayers with thin and thick ZnO interlayers. An increase in the magneto-optical signal in multilayers compared to references (Co40Fe40B20)34(SiO2)66 composite films has been detected at 1.2 eV. The magnetoresistance of {[(Co40Fe40B20)34(SiO2)66]/[ZnO]}n multilayers with thick (>32 nm) ZnO interlayers is lower than in reference (Co40Fe40B20)34(SiO2)66 nanocomposite, while at thin ZnO interlayers magnetoresistance is significantly higher and reaches 12 % at temperatures of 77 К. Possible mechanisms of ferromagnetic and antiferromagnetic ordering, enhancement of the magneto-optical response and magnetoresistance in {[(Co40Fe40B20)34(SiO2)66]/[ZnO]}n multilayer nanostructures are discussed.

Coexistence of Ferromagnetism and Superconductivity at KTaO3 Heterointerfaces.

The coexistence of superconductivity and ferromagnetism is a long-standing issue in superconductivity due to the antagonistic nature of these two ordered states. Experimentally identifying and characterizing novel heterointerface superconductors that coexist with magnetism presents significant challenges. Here, we report the observation of two-dimensional long-range ferromagnetic order in a KTaO3 heterointerface superconductor, showing the coexistence of superconductivity and ferromagnetism. Remarkably, our direct current superconducting quantum interference device measurements reveal an in-plane magnetization hysteresis loop persisting above room temperature. Moreover, first-principles calculations and X-ray magnetic circular dichroism measurements provide decisive insights into the origin of the observed robust ferromagnetism, attributing it to oxygen vacancies that localize electrons in nearby Ta 5d states. Our findings suggest KTaO3 heterointerfaces as time-reversal symmetry breaking superconductors, injecting fresh momentum into the exploration of the intricate interplay between superconductivity and magnetism enhanced by the strong spin-orbit coupling inherent to the heavy Ta in 5d orbitals.

Correlation between the structural phase transition and magnetic properties of sol-gel synthesized nanoparticles

The La2CoFeO6 (LCFO) nanoparticles were synthesized using the sol-gel method and calcined at 600 , 800 , and 1000 . The X-ray diffraction data confirm the successful formation of LCFO nanoparticles. The crystallite size was observed to increase from ∼13 nm to ∼26 nm as the calcination temperature rose. Detailed Rietveld analysis revealed the coexistence of both orthorhombic (Pnma: S.G. 62) and rhombohedral ( : S.G. 167) phases in the LCFO samples. A two-phase Rietveld refinement demonstrated a structural phase transition (from Pnma to ) as the calcination temperature increased. FESEM micrographs exhibited a granular morphology for the LCFO nanoparticles, and the grain size was observed to increase with the elevated calcination temperature. Magnetization curves illustrated an increase in magnetization with a decrease in crystallite size or a reduction in calcination temperature for LCFO nanoparticles. At higher calcination temperatures, the rhombohedral phase displayed significant antisite disorder, resulting in the disruption of long-range ferromagnetic ordering in the material and a subsequent decrease in maximum magnetization.

Coexistence of Ferroelectricity and Ferromagnetism in Atomically Thin Two-Dimensional Cr2S3/WS2 Vertical Heterostructures.

Two-dimensional (2D) heterostructures with ferromagnetism and ferroelectricity provide a promising avenue to miniaturize the device size, increase computational power, and reduce energy consumption. However, the direct synthesis of such eye-catching heterostructures has yet to be realized up to now. Here, we design a two-step chemical vapor deposition strategy to growth of Cr2S3/WS2 vertical heterostructures with atomically sharp and clean interfaces on sapphire. The interlayer charge transfer and periodic moiré superlattice result in the emergence of room-temperature ferroelectricity in atomically thin Cr2S3/WS2 vertical heterostructures. In parallel, long-range ferromagnetic order is discovered in 2D Cr2S3 via the magneto-optical Kerr effect technique with the Curie temperature approaching 170 K. The charge distribution variation induced by the moiré superlattice changes the ferromagnetic coupling strength and enhances the Curie temperature. The coexistence of ferroelectricity and ferromagnetism in 2D Cr2S3/WS2 vertical heterostructures provides a cornerstone for the further design of logic-in-memory devices to build new computing architectures.

Spin glass state in Co doped NdMnO3

The temperature-dependent ac susceptibility studies of in-phase component (χ′ac) and out of phase component (χac″) was done on a single phase polycrystalline NdMn0.6Co0.4O3 sample. The measurements were conducted in 4 Oe ac field and 0 Oe dc field at frequencies of 111, 311, 1011, and 1311 Hz. As the frequency increases, the magnitude of χ′ac decreases, and its peak position, corresponding to Tf, moves towards higher temperatures. This strongly suggests the presence of a spin glass (SG) state and the absence of long-range ferromagnetic ordering. The value of relative shift in freezing temperature (δTf) is found to be δTf = 0.0089, which suggests the existence of canonical SG state in NdMn0.6Co0.4O3 sample. To confirm it the ac susceptibility data was further analyzed using Arrhenius, Vogel Fulcher, and Power–law.

Colossal Magnetoresistance in Layered Diluted Magnetic Semiconductor Rb(Zn,Li,Mn)4As3 Single Crystals

Diluted magnetic semiconductors (DMSs) with tunable ferromagnetism are among the most promising materials for fabricating spintronic devices. Some DMS systems have sizeable magnetoresistances that can further extend their applications. Here, we report a new DMS Rb(Zn1−x−yLiyMnx)4As3 with a quasi-two-dimensional structure showing sizeable anisotropies in its ferromagnetism and transverse magnetoresistance (MR). With proper charge and spin doping, single crystals of the DMS display Curie temperatures up to 24 K. Analysis of the critical behavior via Arrott plots confirms the long-range ferromagnetic ordering in the Rb(Zn1−x−yLiyMnx)4As3 single crystals. We observed remarkable intrinsic MR effects in the single crystals (i.e., a positive MR of 85% at 0.4 T and a colossal negative MR of −93% at 7 T).

Robust multiferroic in interfacial modulation synthesized wafer-scale one-unit-cell of chromium sulfide

Multiferroic materials offer a promising avenue for manipulating digital information by leveraging the cross-coupling between ferroelectric and ferromagnetic orders. Despite the ferroelectricity has been uncovered by ion displacement or interlayer-sliding, one-unit-cell of multiferroic materials design and wafer-scale synthesis have yet to be realized. Here we develope an interface modulated strategy to grow 1-inch one-unit-cell of non-layered chromium sulfide with unidirectional orientation on industry-compatible c-plane sapphire. The interfacial interaction between chromium sulfide and substrate induces the intralayer-sliding of self-intercalated chromium atoms and breaks the space reversal symmetry. As a result, robust room-temperature ferroelectricity (retaining more than one month) emerges in one-unit-cell of chromium sulfide with ultrahigh remanent polarization. Besides, long-range ferromagnetic order is discovered with the Curie temperature approaching 200 K, almost two times higher than that of bulk counterpart. In parallel, the magnetoelectric coupling is certified and which makes 1-inch one-unit-cell of chromium sulfide the largest and thinnest multiferroics.

Structural, magnetic and dielectric properties of green synthesized Ag doped NiFe2O4 spinel ferrite

Ag-doped nano NiFe2O4 spinel ferrites were successfully synthesized using an environmentally friendly sol-gel technique. Comprehensive characterization of the obtained samples was carried out, employing techniques such as X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy. The results from XRD and FTIR analyses unequivocally confirmed that the synthesized samples were of high purity and in a well-defined phase. Furthermore, examination of the samples through Field Emission Scanning Electron Microscopy (FESEM) revealed the formation of spherical grains, with an average grain size of 50 nm for pure NiFe2O4 nanoparticles and an increased size of 72 nm for the Ag-doped NiFe2O4 nanoparticles. Moreover, the investigation delved into the electrical conductivity and optical properties of these nanoferrites. It was noteworthy that the electrical conductivity demonstrated a significant enhancement in the case of Ag-doped NiFe2O4, further indicating the potential for improved performance. Magnetic analysis revealed a coercivity value (Hc) of 2.27 A/m for NiFe2O4, while the Ag-doped NiFe2O4 nanoparticles exhibited long-range ferromagnetic ordering. Additionally, optical absorption experiments disclosed an energy band gap of 1.75 eV for NiFe2O4, whereas the Ag-doped NiFe2O4 showcased a reduced energy band gap of 1.256 eV. These findings collectively contribute to a better understanding of the properties and potential applications of these materials in various technological domains.

Experimental investigation of the effect of topological insulator on the magnetization dynamics of ferromagnetic metal: and heterostructure

We have studied the spin-pumping phenomenon in ferromagnetic metal (FM) ()/topological insulator (TI) () bilayer system to understand magnetization dynamics of FM in contact with a TI. TIs embody a spin–momentum-locked surface state that spans the bulk band gap. Due to this special spin texture of the topological surface state, the spin-charge interconversion efficiency of TI is even higher than that of heavy metals. We evaluated the parameters like effective damping coefficient (), spin-mixing conductance () and spin current density () to demonstrate an efficient spin transfer in heterostructure. To probe the effect of the topological surface state, a systematic low-temperature study is crucial as the surface state of TI dominates at lower temperatures. The exponential increase of for all different thickness combinations of FM/TI bilayers and the enhancement of effective damping coefficient () with lowering temperature confirms that the spin chemical potential bias generated from spin-pumping induces spin current into the TI surface state. Furthermore, low-temperature measurements of effective magnetization () and magnetic anisotropy field (Hk ) showed anomaly around the same temperature region where the resistivity of TI starts showing metallic behavior due to the dominance of conducting TI surface state. The anomaly in Hk can result from the emerging exchange coupling between the TI surface state and the local moments of the FM layer at the interface without any long-range ferromagnetic order in TI at the interface.

Lanthanide atoms doped arsenene monolayer: Enhanced magnetic anisotropies, huge magnetic moments and significant strain-modulated effects

Employing the spin-polarized density functional theory (DFT), we investigated the magnetic and optical properties of buckled arsenene (β-As) after doping a whole series of lanthanide (Ln) atoms. Our results demonstrate that Ln atoms can be stably doped into the single layer arsenene. Upon doping Ln atoms, La, Ce, Pr, Nd, Gd, Dy and Lu@arsenene behave dilute magnetic semiconductor (DMS) properties, while the Pm, Sm, Eu, Ho, Er and Tm@arsenene show half metallic characteristics. Most of Ln@arsenene systems favor the long-range ferromagnetic ordering. The maximum of Ln-doped systems' magnetic moments and magnetic anisotropy energy (MAE) can reach 8 μB and 7.48 meV, respectively. The doping of Ln atoms into arsenene improves the optical responses in visible and infrared regions. Strain can alter the magnetic coupling between Sm and the neighboring As atoms and reduce the system's magnetic moment. Besides, strain can improve the MAE of these systems, accompanied by the change of the easy magnetization of Sm@arsenene. Furthermore, compressive and tensile strains effectively improve the optical responses in visible and ultraviolet region, respectively. Based on the obtained results, we believe that the Ln@arsenene monolayer has application prospects in photoelectronics and spintronics such as high-density memory devices.

Texture, electronic and magnetic states of Mn atoms in polycrystalline MnSi thin films facing a c-sapphire substrate studied by soft X-ray magnetic circular dichroism

Polycrystalline MnSi is a highly efficient magnetic skyrmionic material and information carriers for future spintronic devices, deposited on a c-cut sapphire substrate by magnetron sputtering with a low base pressure. Due to their fascinating crystal structures and spin textures these Mn-based silicides are most extensively studied now a days. In order to study the appearance of any impure phases like MnxSiy, hysteresis behavior and the inception of ferromagnetic/superparamagnetic domains present in the MnSi film, we have performed X-ray diffraction (XRD), XRD pole figures in stereographic projection, vibrating sample magnetometry and powerful element specific X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism techniques. The room temperature hysteresis curve points towards the phenomenon of long-range ferromagnetic ordering. The Mn L2,3 edge XAS spectra did not show a Mn2+-like multiplet structure. The overall magnetization increases with the increase in applied magnetic field from 0.1 T to 2 T on MnSi thin film. The observed spin and orbital magnetic moments ∼ 0.03 ̶ 0.1 μB and 0.01 to 0.04 μB, respectively.

Controllable high Curie temperature through 5d transition metal atom doping in CrI3

Two-dimensional (2D) CrI3 is a ferromagnetic semiconductor with potential for applications in spintronics. However, its low Curie temperature (T c) hinders realistic applications of CrI3. Based on first-principles calculations, 5d transition metal (TM) atom doping of CrI3 (TM@CrI3) is a universally effective way to increase T c, which stems from the increased magnetic moment induced by doping with TM atoms. T c of W@CrI3 reaches 254 K, nearly six times higher than that of the host CrI3. When the doping concentration of W atoms is increased to above 5.9%, W@CrI3 shows room-temperature ferromagnetism. Intriguingly, the large magnetic anisotropy energy of W@CrI3 can stabilize the long-range ferromagnetic order. Moreover, TM@CrI3 has a strong ferromagnetic stability. All TM@CrI3 change from a semiconductor to a half-metal, except doping with Au atom. These results provide information relevant to potential applications of CrI3 monolayers in spintronics.

Intrinsic Ferromagnetic Semiconductors with High Saturation Magnetization from Hybrid Perovskites.

Ferromagnetic semiconductors (FMS) enable simultaneous control of both charge and spin transport of charge carriers, which have emerged as a class of highly desirable but rare material for applications in spin field-effect transistors and quantum computing. Organic-inorganic hybrid perovskite with high compositional adjustability and structural versatility can offer unique benefits in the design of FMS but has not been fully explored. Here we demonstrate a series of molecular FMSs based on two-dimensional organic-inorganic hybrid perovskite structure, namely (2ampy)CuCl4 , (3ampy)CuCl4 and (4ampy)CuCl4 , which exhibits high saturation magnetization, dramatic temperature-dependent conductivity change and tunable ferromagnetic resonance. Magnetic measurements revealed high saturation magnetization up to 18.56 emu/g for (4ampy)CuCl4 , which is one of the highest value among reported hybrid FMSs to date. Conductivity studies of the three FMSs demonstrate that the smaller adjacent octahedron distance in the two-dimensional layer results in higher conductivity. Systematic ferromagnetic resonance investigation shows that the gyromagnetic ratio and Landau factor values are strongly dependent on the types of organic cations used. This work demonstrates that two-dimensional hybrid perovskite materials can simultaneously possess both tunable long-range ferromagnetic ordering and semiconductivity, providing a straightforward strategy for designing and synthesizing high-performance intrinsic FMSs. This article is protected by copyright. All rights reserved.

Structural, thermoelectric, and magnetic properties of pure and Ti-doped Ca3Co4O9 ceramic compounds

The effect of the Ti element on the incommensurately layered thermoelectric oxide material Ca3Co4O9 is investigated. This study compares the structural, morphological, thermoelectric, and magnetic properties of Ca3(Co3.7Ti0.3)O9 composition to the pristine Ca3Co4O9. No significant enhancement of the Seebeck coefficient compared to Ca3Co4O9 is observed in the Ti-doped sample. The magnetic properties of the pristine and Ti-doped Ca3Co4O9 are detailed, and the possible correlations between pristine and Ti-doped Ca3Co4O9 are established. In M-H measurements, the effect of Ti in low temperatures revealed a magnetic phase transition due to two sublattices exhibiting wavy behavior. For each sample, magnetic inhomogeneity in the long-range ferromagnetic ordering, which is clear almost before 19 K, is observed through FC and ZFC curves. The findings on the physical properties of both samples are discussed, considering the previously published results.

Response of DC biased magnetoelectric coupling in 0–3 type particulate lanthanum modified PZT-CFO composites

Magnetoelectric effect (ME) has been investigated in particulate ferroelectric (FE)-ferrimagnetic (FM) composites in the present work. The composition of ceramic composites has been tailored in terms of (1 - x) Pb0.4La0.6Zr0.6Ti0.4O3 (PLZT) – (x)CoFe2O4 (CFO) [x = 0, 0.2, 0.4, 0.6 and 1] in order to observe the magnetoelectric coupling. The FE-FM (PLZT-CFO) composites prepared using solid state route were investigated in terms of structural, morphological, dielectric, ferroelectric and magnetic properties. Well crystallized PLZT-CFO composites were observed with binary rhombohedral (R3m) and cubic (Fd3m) phase of PLZT and CFO, respectively, along with well-defined grains for both parent phases. The appearance of relaxor behaviour in prepared composites was revealed from temperature dependent dielectric study. The saturation (Ps) and remnant (Pr) polarizations were observed to be vary from 45µC/cm2 to 10µC/cm2 and 36µC/cm2 to 7 µC/cm2, with the increment in the CFO content from 0 % to 80 %, respectively. The emergence of long-range ferromagnetic ordering is revealed from M-H curves. It is evident from magnetization and polarization studies that each composite exhibits exceptional sensitivity to both the electric and magnetic fields. The magnetoelectric coefficient, is found to be initially rise with x and achieved maximal value of 450 µV/cm.Oe for 40 % CFO content. The obtained results indicate that almost equal number of weight proportion is required for achieving maximum strain transfer between FE-FM phases which is beneficial for future FE-FERAM devices. It is also perceptible that these novel composites may provide knowledge pathway for development of ME multifunctional device miniaturization.

Strain Engineering of Intrinsic Ferromagnetism in 2D van der Waals Materials.

Since the discovery of the low-temperature, long-range ferromagnetic order in monolayers Cr2Ge2Te6 and CrI3, many efforts have been made to achieve a room temperature (RT) ferromagnet. The outstanding deformation ability of two-dimensional (2D) materials provides an exciting way to mediate their intrinsic ferromagnetism (FM) with strain engineering. Here, we summarize the recent progress of strain engineering of intrinsic FM in 2D van der Waals materials. First, we introduce how to explain the strain-mediated intrinsic FM on Cr-based and Fe-based 2D van der Waals materials through ab initio Density functional theory (DFT), and how to calculate magnetic anisotropy energy (MAE) and Curie temperature (TC) from the interlayer exchange coupling J. Subsequently, we focus on numerous attempts to apply strain to 2D materials in experiments, including wrinkle-induced strain, flexible substrate bending or stretching, lattice mismatch, electrostatic force and field-cooling. Last, we emphasize that this field is still in early stages, and there are many challenges that need to be overcome. More importantly, strengthening the guideline of strain-mediated FM in 2D van der Waals materials will promote the development of spintronics and straintronics.

Room temperature two-dimensional ferromagnetic Ni-doped Fe5GeTe2 with tunable Tc for enhanced oxygen evolution reaction

Improving the Curie temperature and catalytic performance of two-dimensional magnetic materials through elemental doping is a feasible strategy. In this study, Ni-doped (Fe1−xNix)5GeTe2 (0 ≤ x ≤ 0.3) single crystals were grown via chemical vapor transport method and the amount of Ni doping could be precisely controlled. As the amount of Ni doping increases, the long-range ferromagnetic ordering temperature increased, and (Fe0.7Ni0.3)5GeTe2 exhibited the highest Curie temperature Tc = 492.73 K. The improvement of Tc can be attributed to the occupancy of the Fe1 site by Ni atoms. The oxygen evolution reaction (OER) activities of liquid phase exfoliated (Fe1−xNix)5GeTe2 nanoflakes were enhanced by doping Ni atoms, and the overpotential decrease to 464 mV at 10 mA/cm2 with a small Tafel slope of 41 mV/dec for the (Fe0.9Ni0.1)5GeTe2 nanoflakes. Based on the density functional theory calculations, when half of the Fe1 sites were replaced by Ni atoms, the number of enhanced OER active sites (Fe1-Te sites) reached maximum, and then, (Fe0.9Ni0.1)5GeTe2 exhibited the best catalytic performance. The experimental and theoretical calculation results indicate that replacing Fe1 site with Ni in two-dimensional magnetic Fe5GeTe2 can effectively increase the Curie temperature and enhance OER activity.