Journal of Magnetism and Magnetic Materials最新文献_第9页

Complex spin structure in co-trimer-chain Li2Co3Se4O12 共三聚体链Li2Co3Se4O12的复杂自旋结构

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-14 DOI: 10.1016/j.jmmm.2026.173840

Jie Xing , Feng Ye , Daniel Duong , Sai Mu , Max T. Pan , Rongying Jin

Complex magnetic materials are extremely attractive for revealing unconventional spin states and novel magnetic excitations. Here, we report the structural, thermodynamic, and magnetic properties of a novel magnetic material Li₂Co₃Se₄O₁₂ based on x-ray and neutron diffraction, specific heat, magnetization, and x-ray photoelectron spectroscopy measurements. X-ray and neutron diffraction refinements reveal two Co sites Co (1) and Co (2) even though both are in the octahedral environment. While they are not connected along the b and c directions, these octahedra are edge-shared forming the Co (2) – Co (1) – Co (2) trimer chain along the a direction. The magnetic susceptibility exhibits the Curie-Weiss (CW) temperature dependence at high temperatures (above ∼50 K) with the negative CW temperature, a dip centered at T^⁎ ∼ 8.0 K, and an antiferromagnetic transition at T_N = 3.3 K. The specific heat confirms that there is a phase transition at T_N and a hump at T^⁎. The long-range magnetic transition at T_N implies that, in addition to the intra-chain interaction, there is strong inter-chain interaction, which is likely due to polarized SeO₃ bridging between chains. Single crystal neutron diffraction refinement reveals a complex magnetic structure with the angle between Co (1) and Co (2) moments ∼105°. Within the Co (2) – Co (1) – Co (2) trimer, two Co (2) moments are parallelly aligned. Surprisingly, the Co (1) moment (1.92μ_B) is only half of the Co (2) moment (3.96μ_B). There is likely the spin-state change for Co (1) from the high-spin state at T > T^⁎ to the low-spin state at T < T^⁎, causing a dip in the magnetic susceptibility and a hump in the specific heat. When the magnetic field is applied, multiple metamagnetic transitions are found in all directions, implying field-driven magnetic excitations. Our results demonstrate rich magnetic properties of Li₂Co₃Se₄O₁₂ that are sensitive to the external stimuli such as the magnetic field.

复杂的磁性材料在揭示非常规的自旋态和新的磁激发方面具有极大的吸引力。在这里，我们报告了一种新型磁性材料Li2Co3Se4O12的结构，热力学和磁性基于x射线和中子衍射，比热，磁化和x射线光电子能谱测量。x射线和中子衍射的细化显示了两个Co位Co(1)和Co(2)，尽管它们都在八面体环境中。虽然它们不沿b和c方向连接，但这些八面体沿a方向形成Co (2) - Co (1) - Co(2)三聚体链。磁化率在高温（高于~ 50 K）表现出居里-魏斯（CW）温度依赖性，负CW温度，在T ~ 8.0 K处有一个倾斜，在TN = 3.3 K处有一个反铁磁跃迁。比热证实了在TN处有一个相变，在T _处有一个峰。TN处的长程磁跃迁表明，除了链内相互作用外，链间也存在很强的相互作用，这可能是由于链间的极化SeO3桥接。单晶中子衍射细化显示出Co(1)和Co(2)矩夹角为~ 105°的复杂磁结构。在Co (2) - Co (1) - Co(2)三聚体中，两个Co(2)矩平行排列。令人惊讶的是，Co(1)矩（1.92μB）只有Co(2)矩（3.96μB）的一半。Co(1)的自旋态可能从T >； T的高自旋态转变为T >； T的低自旋态，导致磁化率下降和比热峰。当施加磁场时，在各个方向上都发现了多个超磁跃迁，这意味着磁场驱动的磁激励。我们的研究结果表明，Li2Co3Se4O12具有丰富的磁性能，并且对磁场等外部刺激敏感。

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引用次数: 0

Grain-orientation engineering enables dual-functionality in (Mn,Fe)2(P,Si)/epoxy composites: Colossal negative thermal expansion and anisotropic magnetocaloric effect 晶粒取向工程使（Mn,Fe）2(P,Si)/环氧复合材料具有双重功能：巨大的负热膨胀和各向异性磁热效应

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-02 DOI: 10.1016/j.jmmm.2025.173809

Yong Gong , Zhubing Yan , Francesco Cugini , Fengjiao Qian , Jiawei Lai , Xuefei Miao , Jun Liu , Zhixiang Qi , Yuanyuan Gong , Feng Xu , Luana Caron

The 〈001〉 − oriented (Mn,Fe)₂(P,Si)/epoxy composites were fabricated via magnetic field-assisted dynamic self-assembly. These textured composites demonstrate remarkable adaptability for diverse applications that require either substantial coefficients (α_l) of negative thermal expansion (NTE) or broad NTE temperature windows (ΔT_NTE). A two-dimensional NTE with a colossal α_l of −144.37 × 10⁻⁶ K⁻¹ is realized between 280 and 360 K in the composite displaying a first-order phase transition (FOPT). The ΔT_NTE can be significantly extended to 190 K (120−310K) in the composite exhibiting a second-order phase transition (SOPT), while preserving a large α_l of −23.89 × 10⁻⁶ K⁻¹. Besides that, anisotropic MCE is observed in the textured composites. The FOPT composite exhibits a maximum entropy change of 7.18 Jkg⁻¹ K⁻¹ under a magnetic field of 1 T applied perpendicular to the texture direction, which is 34 % higher than the parallel field configuration. Consequently, our study demonstrates that grain-orientation engineering can be effectively employed to explore NTE and achieve anisotropic magnetocaloric properties.

采用磁场辅助动态自组装法制备了< 001 >−取向（Mn,Fe）2(P,Si)/环氧复合材料。这些纹理复合材料表现出卓越的适应性，适用于需要大量负热膨胀（NTE）系数（αl）或宽NTE温度窗（ΔTNTE）的各种应用。在280 ~ 360 K范围内实现了αl为−144.37 × 10−6 K−1的二维NTE，显示了一阶相变（FOPT）。在复合材料中，ΔTNTE可以明显扩展到190 K (120 ~ 310K)，表现出二级相变（SOPT），同时保持了较大的αl （- 23.89 × 10 ~ 6 K−1）。此外，在织构复合材料中观察到各向异性的MCE。在垂直于织构方向的1 T磁场下，FOPT复合材料的最大熵变为7.18 Jkg−1 K−1，比平行磁场配置高34%。因此，我们的研究表明，晶粒取向工程可以有效地用于探索NTE并获得各向异性磁热性能。

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引用次数: 0

Engineering MgFe2O4 nanoparticles to enhance magnetic, optical, and dielectric performance 工程MgFe2O4纳米粒子提高磁性，光学和介电性能

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-11 DOI: 10.1016/j.jmmm.2026.173833

Muhammad Luqman Hashmi , Fabio Scaffidi Muta , Gianluca Deninno , C. Parmar , R. Verma , F. Mazaleyrat , Shashank N. Kane , Salil Modak , V.R. Reddy , Paola Maria Tiberto , Marco Coïsson

This research investigated the effects of solution pH during synthesis and annealing on the structural, magnetic, optical, and dielectric properties of MgFe₂O₄ synthesised using the citric acid-assisted sol-gel auto-combustion method. Structural data showed that crystallinity, lattice parameters, and cation distribution were strongly influenced by both pH and annealing temperature. Optimal morphology and crystallinity were achieved at pH 7 and an annealing temperature of 550 °C for 3 h, under which cation ordering and defect reduction were effectively achieved. Magnetic characterisation revealed a significant improvement in saturation magnetisation (20.6 emu/g) under optimal conditions, attributed to increased super-exchange interactions. The optical bandgap was modulated by more than 11% (2.04 to 2.30 eV) by adjusting pH-mediated surface chemistry and subsequent defect states. The sample synthesised at pH 9 exhibited the highest values of ε’, ε”, and σ_ac. These results conclusively demonstrate that accurate control of synthesis pH and annealing enables the design of multifunctional properties in MgFe₂O₄ nanoparticles, providing a solid foundation for their application in high-end magnetic, optical, and electronic devices.

本研究考察了合成和退火过程中溶液pH对柠檬酸辅助溶胶-凝胶自燃烧法合成的MgFe2O4的结构、磁性、光学和介电性能的影响。结构数据表明，pH值和退火温度对结晶度、晶格参数和阳离子分布有很大影响。在pH为7、550℃退火3 h的条件下，得到了最佳的形貌和结晶度，有效地实现了阳离子有序和缺陷减少。磁性表征显示，在最佳条件下，由于超交换相互作用的增加，饱和磁化强度显著提高（20.6 emu/g）。通过调节ph介导的表面化学和随后的缺陷状态，光学带隙被调制了11%以上（2.04 ~ 2.30 eV）。在pH为9时合成的样品ε′、ε′和σac值最高。这些结果最终表明，精确控制合成pH和退火可以设计出多功能的MgFe2O4纳米颗粒，为其在高端磁性，光学和电子器件中的应用提供了坚实的基础。

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引用次数: 0

Modulation of spin transport in CrBr3|WS2|CrBr3 magnetic tunnel junctions via point defects 通过点缺陷调制CrBr3|WS2|CrBr3磁隧道结的自旋输运

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-14 DOI: 10.1016/j.jmmm.2026.173837

Yongsheng Zhao , Yuxin Zhang , Haishan Zhang, Juan Lyu, Jian Gong, Shaoqiang Guo

Two-dimensional (2D) magnetic tunnel junctions (MTJs) based on van der Waals heterostructures, as core spintronics devices, offer high storage density and fast information processing capabilities. However, the influences of intrinsic point defects on their Tunneling Magneto-resistance (TMR) effects as well as physical mechanisms remain underexplored. Here, we design a Cu(111)|CrBr₃|WS₂|CrBr₃|Cu(111) MTJ utilizing first-principles calculations combined with the nonequilibrium Green's function method. The perfect MTJ exhibits near 100% spin polarization and an ultrahigh TMR of 4312.77%; it maintains TMR above 1000% and high spin filtering efficiency within a bias voltage range from −0.5 to 0.5 V. To investigate the factors contributing to the low TMR in experimentally fabricated MTJs, we systematically investigated the impact of point defects (intrinsic vacancies/substitutions) on CrBr₃|WS₂|CrBr₃ MTJ performance. Spin-polarized electron transport channels are modified by point defects. S and Br vacancies show negligible effects on TMR. While W and Cr vacancies enhance spin-down electron transmission in parallel magnetization configurations, thereby reducing TMR. Substituting S atoms with Br atoms significantly improves TMR to 6916.36%. The work highlights defect engineering as a viable approach to optimize 2D MTJ performance, offering theoretical insights for designing high-efficiency spintronic devices with enhanced stability and tunability.

基于范德华异质结构的二维磁隧道结（MTJs）作为核心自旋电子学器件，具有高存储密度和快速信息处理能力。然而，本征点缺陷对其隧穿磁阻效应的影响及其物理机制尚不清楚。本文利用第一性原理计算结合非平衡格林函数方法设计了Cu(111)|CrBr3|WS2|CrBr3|Cu(111) MTJ。完美的MTJ表现出接近100%的自旋极化和4312.77%的超高TMR；在−0.5 ~ 0.5 V的偏置电压范围内，TMR保持在1000%以上，自旋滤波效率高。为了研究实验制备的MTJ中导致低TMR的因素，我们系统地研究了点缺陷（固有空位/取代）对CrBr3|WS2|CrBr3 MTJ性能的影响。点缺陷修饰了自旋极化电子输运通道。S和Br空位对TMR的影响可以忽略不计。而W和Cr空位在平行磁化构型下增强自旋向下电子传输，从而降低TMR。用Br原子取代S原子显著提高TMR至6916.36%。这项工作强调了缺陷工程作为优化二维MTJ性能的可行方法，为设计具有增强稳定性和可调性的高效自旋电子器件提供了理论见解。

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引用次数: 0

Quantitative stress modeling in full-scale pipelines via dual-probe differential magneto-mechanical coupling technique 基于双探头差分磁-力耦合技术的全尺寸管道应力定量建模

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-12 DOI: 10.1016/j.jmmm.2026.173834

Hanji Zhu , Baoming Gong , Yunfeng Zhao , Caiyan Deng , Yong Liu

In this study, full-scale hydrostatic experiments were performed on a pipeline to investigate the behavior of the magnetic flux under varying internal pressures and sensor lift-off distances. Full-field strain distribution with finite element modeling was used to characterize the stress–strain condition at the girth weld. A comprehensive investigation was conducted into the behavior of triaxial magnetic flux signals and their mechanical responses. A novel magnetic parameter, B_eff, was proposed based on correlation analysis of multiple signal types and was experimentally validated. The influence of lift-off distance on B_eff was discussed, and the underlying mechanism behind environmental magnetic interference was uncovered. Building upon these findings, a robust empirical model was proposed for the quantitative assessment of stress states in buried pipelines. The results are instructive for the application of metal magnetic memory (MMM) technology in non-contact pipeline health monitoring.

在本研究中，在管道上进行了全尺寸流体静力实验，以研究不同内压和传感器上升距离下磁通量的行为。采用有限元模拟的全场应变分布方法对环焊缝应力-应变状态进行了表征。对三轴磁通信号的特性及其力学响应进行了全面的研究。基于多信号类型的相关性分析，提出了一种新的磁参量Beff，并进行了实验验证。讨论了离体距离对环境磁干扰的影响，揭示了环境磁干扰的潜在机制。在这些发现的基础上，提出了一个可靠的经验模型，用于地埋管道应力状态的定量评估。研究结果对金属磁记忆技术在非接触式管道健康监测中的应用具有指导意义。

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引用次数: 0

Tailoring electronic and magnetic properties of edge-functionalized silicene–germanene nanoribbons through first-principles simulations 通过第一性原理模拟剪裁边缘功能化硅锗纳米带的电子和磁性能

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-16 DOI: 10.1016/j.jmmm.2026.173854

Koussai Lazaar , Mohamed Barhoumi , Wissem Dimassi , Moncef Said

We systematically investigated the structural, electronic, and magnetic properties of zigzag silicene–germanene nanoribbons (zSiGeNRs) with various edge modifications using first-principles density functional theory. The results reveal that the ground-state properties of zSiGeNRs are highly sensitive to both the chemical composition and the symmetry of edge terminations. Homogeneous symmetric modifications (e.g., 2Cl–zSiGeNR–2Cl, 2F–zSiGeNR–2F, 2H–zSiGeNR–2H) exhibit antiferromagnetic metallic behavior, whereas homogeneous asymmetric ones (e.g., 2F–zSiGeNR–1F, 2Cl–zSiGeNR–1Cl) induce robust half-metallicity. Heterogeneous edge functionalizations further enhance tunability: symmetric configurations display narrow-gap semiconducting characteristics, while asymmetric ones yield half-metallic states, with the direction of edge asymmetry determining the metallic spin channel. The application of a transverse electric field enables reversible transitions between metallic, semiconducting, and half-metallic phases, demonstrating strong electric-field control. Certain asymmetric systems preserve half-metallicity under high fields, indicating excellent stability for spintronic applications. Additionally, width-dependent analysis demonstrates that quantum confinement and edge interactions govern electronic evolution, with asymmetric systems such as 2F–zSiGeNR–1F retaining half-metallicity across a broad width range (

N_{z} = 6 - 14

). The Si–Ge hybridization provides enhanced tunability compared to single-element nanoribbons, enabling band gap and spin polarization control via simple edge chemistry. These findings highlight that combining edge modification, external electric fields, and width engineering offers an effective route for tailoring the properties of zSiGeNRs. The observed field-tunable half-metallicity and Si-based compatibility make these nanoribbons promising candidates for next-generation spintronic and nanoelectronic devices.

利用第一性原理密度泛函理论，系统地研究了具有不同边缘修饰的之字形硅锗纳米带（zSiGeNRs）的结构、电子和磁性能。结果表明，zSiGeNRs的基态性质对化学成分和边缘端点的对称性都非常敏感。均匀对称修饰（例如，2Cl-zSiGeNR-2Cl, 2F-zSiGeNR-2F, 2H-zSiGeNR-2H）表现出反铁磁性金属行为，而均匀不对称修饰（例如，2F-zSiGeNR-1F, 2Cl-zSiGeNR-1Cl）则产生强大的半金属性。异质边缘功能化进一步增强了可调性：对称结构显示窄间隙半导体特性，而不对称结构产生半金属态，边缘不对称的方向决定了金属自旋通道。横向电场的应用使金属相、半导体相和半金属相之间的可逆转变成为可能，证明了强电场控制。某些不对称体系在高场下保持半金属性，表明自旋电子应用具有优异的稳定性。此外，宽度相关分析表明，量子约束和边缘相互作用控制着电子演化，不对称系统如2F-zSiGeNR-1F在很宽的宽度范围内（Nz=6−14）保持半金属丰度。与单元素纳米带相比，硅锗杂化提供了更强的可调性，可以通过简单的边缘化学来控制带隙和自旋极化。这些发现表明，结合边缘修饰、外加电场和宽度工程为定制zsigenr的性能提供了有效的途径。观察到的场可调谐半金属丰度和硅基兼容性使这些纳米带成为下一代自旋电子和纳米电子器件的有希望的候选者。

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引用次数: 0

Effects of laser cutting and post-processing on the microstructure and properties of thin sintered Nd-Fe-B magnets 激光切割和后处理对烧结Nd-Fe-B薄磁体组织和性能的影响

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-14 DOI: 10.1016/j.jmmm.2026.173838

Lichun Zhan , Wenyu Pan , Ruihua Du , Weiqiang Liu , Zan Long , Shengli Jia , Qifeng Wei , Xiongfei Wu , Ming Yue

Laser cutting, recognized for its narrow kerf, high efficiency, and adaptability to complex geometries, is increasingly employed in the machining of thin sintered Nd–Fe–B magnets. This work systematically evaluates the influence of laser cutting versus conventional multi-wire cutting combined with grinding on the microstructure, mechanical strength, and magnetic properties of magnets under black, chamfered, and pickled conditions. Laser cutting induces stepped demagnetization curves, lowers intrinsic coercivity and mechanical properties compared to conventional multi-wire cutting combined with grinding method. Results indicate that chamfering improves the three-point bending force of laser-cut samples by approximately 31.4% on average. After pickling, the specific magnetic moment of laser-cut samples is only 0.13% lower, and the irreversible flux loss is merely 0.08% higher than that of ground specimens. Microstructural analysis reveals that laser-cut surfaces contain a resolidified layer, micropores, and networked microcracks, which contribute to the degradation in mechanical and magnetic properties. Magnetic domain observations further demonstrate that laser-cut black samples exhibit blurred domain boundaries and maze domains, whereas chamfered specimens show a marked reduction in maze domains and improved domain alignment. Under identical reverse magnetic fields, domain reversal occurs more readily in black samples than in chamfered ones. In summary, through appropriate parameter selection and post-processing, such as chamfering and pickling, the mechanical and magnetic performance of laser-cut thin Nd-Fe-B magnets can closely match that of ground magnets, offering valuable guidance for process optimization in thin magnet manufacturing.

激光切割以其窄切口、高效率和对复杂几何形状的适应性而被越来越多地应用于烧结钕铁硼薄磁体的加工。本研究系统地评估了在黑色、倒角和酸洗条件下，激光切割与传统多线切割结合磨削对磁体微观结构、机械强度和磁性能的影响。激光切割产生阶梯退磁曲线，与传统的多线切割结合磨削方法相比，具有较低的内在矫顽力和力学性能。结果表明，倒角可使激光切割样品的三点弯曲力平均提高约31.4%。经酸洗处理后，激光切割样品的比磁矩仅比地面样品低0.13%，不可逆磁通量损失仅比地面样品高0.08%。显微结构分析表明，激光切割表面含有再凝固层、微孔和网状微裂纹，这些都导致了机械性能和磁性能的下降。磁畴观察进一步表明，激光切割的黑色样品显示出模糊的畴边界和迷宫畴，而倒角样品显示出迷宫畴的显著减少和改进的畴对齐。在相同的反向磁场下，黑色样品比倒角样品更容易发生畴反转。综上所述，通过适当的参数选择和倒角、酸洗等后处理，激光切割的Nd-Fe-B薄磁体的机械性能和磁性能可以与地面磁体的机械性能和磁性能接近，为薄磁体制造的工艺优化提供了有价值的指导。

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引用次数: 0

Spin nematic with anisotropic exchange interaction in an external magnetic 外磁场中自旋向列与各向异性交换相互作用

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-22 DOI: 10.1016/j.jmmm.2026.173863

O.A. Kosmachev, E.O. Fadeeva, Yu.A. Fridman

Using the mean field approximation, the influence of the magnetic field on the phase states and excitation spectra of a spin nematic with anisotropic bilinear exchange interaction was studied. It is established that in the case of easy-plane exchange anisotropy, depending on the ratio of exchange integrals and the external field perpendicular to the easy plane, three phase states are realized in the system: nematic collinear phase with a nonzero value of the average magnetic moment, angular ferromagnetic phase, and collinear ferromagnetic phase. It is established that in the case under consideration, the angular nematic phase is energetically unfavorable. The case of easy-axis interionic anisotropy and Ising-like bilinear exchange interaction is also considered. The spectra of elementary excitations in all phases are determined, phase diagrams are constructed.

利用平均场近似，研究了磁场对具有各向异性双线性交换作用的自旋向列相的相态和激发谱的影响。在易平面交换各向异性的情况下，根据交换积分与垂直于易平面的外场的比值，系统可以实现三种相态：平均磁矩非零的向列共线相、角铁磁相和共线铁磁相。确定了在所考虑的情况下，角向列相在能量上是不利的。还考虑了易轴离子间各向异性和伊辛类双线性交换相互作用的情况。确定了各相的初等激发谱，构造了相图。

引用次数: 0

Magnetic phase transition and magnetocaloric effect in rare-earth-free high entropy alloys MnCoNiFeCu 无稀土高熵合金MnCoNiFeCu的磁相变和磁热效应

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2025-12-29 DOI: 10.1016/j.jmmm.2025.173793

Yulin Pan, Yong Li

In this paper, the structural characteristics, magnetic properties and magnetocaloric performance of a series of high-entropy alloys (HEAs) Mn₂₀Co₂₀Ni₂₀Fe_26+xCu_14-x (x = 0, 2, 4) have been experimentally determined and theoretically analyzed. The results showed that these alloys have a disordered FCC crystal structure. The Fe concentration determines the temperature range within which the ferromagnetic behavior and Curie temperatures can be adjusted. In particular, it decreases from 274 K for Fe₂₆Cu₁₄ to 242 K for Fe₃₀Cu₁₀. In addition, the maximum magnetic entropy change values are obtained in the magnetic field change of 7 T for 1.37, 1.28 and 1.33 J/kgK were obtained for x = 0, 2 and 4, respectively. Compared to other transition metal-based high-entropy alloys reported in the literatures, the present material shows comparable or superior performance. The experimental characterization results are in good agreement with the theoretical predictions and affords an extensive series of rare-earth-free HEAs exhibiting pronounced magnetocaloric properties.

本文对Mn20Co20Ni20Fe26+xCu14-x （x = 0,2,4）系列高熵合金（HEAs）的结构特征、磁性能和磁热性能进行了实验测定和理论分析。结果表明，这些合金具有无序的FCC晶体结构。铁浓度决定了铁磁行为和居里温度可调节的温度范围。特别是Fe26Cu14的274k， Fe30Cu10的242k。另外，在7 T磁场变化时，x = 0、2和4时的最大磁熵变化值分别为1.37、1.28和1.33 J/kgK。与文献报道的其他过渡金属基高熵合金相比，本材料表现出相当或更好的性能。实验表征结果与理论预测很好地吻合，并提供了一系列具有明显磁热特性的无稀土HEAs。

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引用次数: 0

Probing the local atomic structure and magnetism in Iron and manganese co-doped indium oxide Nanocubes using XAS and DFT 利用XAS和DFT探测铁锰共掺杂氧化铟纳米立方的局部原子结构和磁性

IF 3 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2026-03-01 Epub Date: 2026-01-06 DOI: 10.1016/j.jmmm.2026.173814

Manikandan Dhamodaran , Rahul Kumar Yadav , N. Raja , Ramesh Karuppannan , Rajeev Gupta

We examine the impact of iron and manganese co-doping on the local atomic environment in hydrothermally synthesized In₂O₃ using synchrotron X-ray absorption spectroscopy analysis, correlating the findings with the observed magnetic properties. The results revealed that manganese is mainly present in the +3-valence state with a dilute contribution from the +4 state. These oxidation states indicate the formation of oxygen vacancies resulting from charge imbalance. The effective co-substitution of iron and manganese atoms in the In₂O₃ was established, accompanied by specific changes in bond lengths. Additionally, the bond length of MnO slightly increased for In_1.94Fe_0.02Mn_0.04O₃, and subsequently, decreased for the higher Mn-doped samples. Density functional theory calculations revealed that the FeO bond length decreases from 2.194 to 2.141 Å upon the introduction of oxygen vacancies, indicating enhanced FeO interactions. Conversely, the MnO bond increased from 2.140 to 2.210 Å, reflecting the weakened local bonding environment and reduced lattice integration of Mn atoms. Magnetic investigations revealed a room-temperature ferromagnetism in In_1.94Fe_0.02Mn_0.04O₃, characterized by an enhanced coercivity and saturation magnetization. Density functional theory calculations show that oxygen vacancy formation stabilizes the high magnetic moments 3.85 μ_B for Fe and 4.23 μ_B for Mn, driven by FeO and MnO hybridization and increased d-electron localization around the transition metal centers. These findings offer new insights into the local micro-environment and magnetic characteristics of iron and manganese-codoped indium oxide.

我们利用同步x射线吸收光谱分析研究了铁和锰共掺杂对水热合成In2O3中局部原子环境的影响，并将这些发现与观察到的磁性能联系起来。结果表明，锰主要以+3价态存在，+4价态的贡献较小。这些氧化态表明由于电荷不平衡而形成的氧空位。在In2O3中建立了铁和锰原子的有效共取代，并伴随着键长的特定变化。此外，在In1.94Fe0.02Mn0.04O3中，MnO的键长略有增加，随后在mn掺杂较高的样品中，MnO的键长减小。密度泛函理论计算表明，引入氧空位后，FeO键长从2.194减小到2.141 Å，表明FeO相互作用增强。相反，MnO键从2.140增加到2.210 Å，反映了局部键合环境的减弱和Mn原子晶格积分的降低。磁学研究表明，In1.94Fe0.02Mn0.04O3具有室温铁磁性，具有增强的矫顽力和饱和磁化。密度泛函理论计算表明，氧空位的形成稳定了Fe （3.85 μB）和Mn （4.23 μB）的高磁矩，这是由FeO和MnO杂化和过渡金属中心周围d电子局域化的增加所驱动的。这些发现为铁锰共掺杂氧化铟的局部微环境和磁性特性提供了新的见解。

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