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

Ferrimagnetic half metals TaMnZ (Z = As, Sb, Bi) for thermoelectric and spintronic applications – Material computations 用于热电和自旋电子应用的铁磁性半金属 TaMnZ（Z = As、Sb、Bi） - 材料计算

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-30 DOI: 10.1016/j.jmmm.2024.172564

Klinton Brito K., D. Shobana Priyanka, M. Srinivasan, P. Ramasamy

Half metals possess coupling behavior of metals and semiconductors with wide heat transport and spin transport properties. This research article covers the structural, mechanical, electronic, magnetic and thermoelectric properties of the half Heusler alloys TaMnZ (Z = As, Sb, Bi). The equilibrium lattice constants and corresponding ground state energies show that the studied alloys are stable in the ferrimagnetic cubic phase. The band dispersion plots suggest that the compounds TaMnAs, TaMnSb and TaMnBi are half metals with indirect band gap having the band gap energies of 1.13 eV, 1.24 eV and 1.12 eV respectively in the spin down channel. As the materials have 100 % spin polarization with an integer magnetic moment of −1 μ_B_, they are suitable for making spintronic devices such as spin transistors and spin-flip flops. The temperature-dependent thermoelectric properties of the alloys have been studied by classical Boltzmann theory. The materials have low lattice thermal conductivity which was confirmed by Slack’s equation. The obtained thermoelectric figure of merit for p-type TaMnAs, TaMnSb and TaMnBi is 0.7, 0.6 and 0.8 respectively at 1200 K. Similarly, the figure of merit obtained for n-type TaMnAs, TaMnSb and TaMnBi is 0.6, 0.64 and 0.8 respectively at the same temperature. The favourable heat and spin transport properties of these alloys show that they are the potential characters to figure out better thermoelectric and spintronic performance.

半金属具有金属和半导体的耦合行为，具有广泛的热传输和自旋传输特性。本文研究了半 Heusler 合金 TaMnZ（Z = As、Sb、Bi）的结构、机械、电子、磁性和热电特性。平衡晶格常数和相应的基态能表明，所研究的合金在铁磁立方相中是稳定的。带色散图表明，TaMnAs、TaMnSb 和 TaMnBi 化合物是具有间接带隙的半金属，在自旋向下通道的带隙能量分别为 1.13 eV、1.24 eV 和 1.12 eV。由于这些材料的自旋极化率为 100%，整数磁矩为 -1 μB，因此适合制造自旋晶体管和自旋翻转器等自旋电子器件。经典玻尔兹曼理论研究了这些合金随温度变化的热电特性。这些材料具有较低的晶格热导率，这一点已通过斯拉克方程得到证实。在 1200 K 的温度下，p 型 TaMnAs、TaMnSb 和 TaMnBi 的热电功值分别为 0.7、0.6 和 0.8；同样，在相同温度下，n 型 TaMnAs、TaMnSb 和 TaMnBi 的热电功值分别为 0.6、0.64 和 0.8。这些合金有利的热量和自旋传输特性表明，它们是具有更好热电和自旋电子性能的潜在材料。

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引用次数: 0

The energy of 180° domain walls of uniaxial crystals with the different magnetocrystalline anisotropy type 不同磁晶各向异性类型单轴晶体 180° 域壁的能量

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-29 DOI: 10.1016/j.jmmm.2024.172560

A.I. Sinkevich, M.B. Lyakhova, E.M. Semenova

The main aim of the present work is to analyze the magnetocrystalline anisotropy (MCA) energy function of uniaxial crystals and to derive analytical expressions for the domain wall (DW) energy taking into account two MCA constants. Thus, the article presents a detailed analysis of the magnetocrystalline anisotropy energy function of uniaxial crystals taking into account two MCA constants (K₁, K₂). The values of the MCA energy extremes and the position of the easy magnetization directions (EMD) and hard magnetization directions (HMD) were determined. The MCA diagram was plotted in “K₁”-“K₂” coordinates. Six types of MCA have been found for uniaxial crystals. Two of them are simple with one maximum and one minimum of the E_A(θ) function, and four are complex with two absolute and one local extreme for each. It is shown that E_A(K₁, K₂) function has the smallest difference between the maximum and minimum values equal to |K₁|/4 and the smallest angle between EMD and HMD equal to π/4 when the K₁ + K₂ = 0 condition is met. Analytical expressions for the 180° Bloch domain wall energy surface density (γ) were derived for uniaxial crystals with each MCA type. It is found that the γ(K₁, K₂) function has a minimum, equal to

γ = 2 \sqrt{A | K_{1} |}

when the relation K₁ + K₂ = 0 between MCA constants is satisfied. The derived analytical expressions are useful for a detailed spin-reorientation transition analysis. To illustrate this, examples of the application of the obtained results to MCA analyses of real crystals and DW energy calculations are given.

本研究的主要目的是分析单轴晶体的磁晶各向异性（MCA）能量函数，并在考虑两个 MCA 常量的情况下推导出畴壁（DW）能量的分析表达式。因此，文章详细分析了考虑两个 MCA 常量（K1、K2）的单轴晶体磁晶各向异性能量函数。确定了 MCA 能量极值以及易磁化方向（EMD）和硬磁化方向（HMD）的位置。MCA 图以 "K1"-"K2 "坐标绘制。在单轴晶体中发现了六种类型的 MCA。其中两种是简单的，EA(θ) 函数只有一个最大值和一个最小值；四种是复杂的，各有两个绝对极值和一个局部极值。结果表明，当 K1 + K2 = 0 条件满足时，EA(K1, K2) 函数的最大值和最小值之差最小，等于 |K1|/4，EMD 和 HMD 之间的夹角最小，等于 π/4。针对每种 MCA 类型的单轴晶体，推导出了 180° 布洛赫畴壁能量表面密度 (γ)的分析表达式。结果发现，当 MCA 常量之间的关系 K1 + K2 = 0 满足时，γ(K1, K2) 函数有一个最小值，等于 γ=2A|K1|。推导出的分析表达式有助于进行详细的自旋取向转变分析。为了说明这一点，我们举例说明了所获结果在实际晶体的 MCA 分析和 DW 能量计算中的应用。

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引用次数: 0

Magnetic interaction induced splitting of bands in hexagonal RMnO3 (R = Lu, Y, and Sc) compounds 六方 RMnO3（R = Lu、Y 和 Sc）化合物中磁性相互作用引起的带分裂

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-28 DOI: 10.1016/j.jmmm.2024.172558

D.M.S. Brito, A.F. Lima

In this work, calculations using non-collinear spin density functional theory were performed to study the electronic band structures for different antiferromagnetic orders in hexagonal RMnO₃ (R = Lu, Y, and Sc) compounds. These are an important class of multifunctional materials with interesting properties for various applications. By comparing the band structure of different magnetic configurations, it is observed that some of them exhibit band splitting that can be attributed to ferromagnetic interplane coupling. The energy splitting is significantly larger (331 meV) for the ScMnO₃ compound, which probably has a higher interplane magnetic interaction. In addition, we report that the spin–orbit coupling also induces a splitting of bands in some regions of the Brillouin zone for those magnetic configurations with a weak magnetic moment along the hexagonal c-axis. These findings offer an intriguing insight into the topological characteristics of hexagonal manganites’ band structure, which was previously unexplored in existing literature. This discovery opens avenues for future investigations in this field.

在这项研究中，利用非共线自旋密度泛函理论进行了计算，研究了六方 RMnO3（R = Lu、Y 和 Sc）化合物中不同反铁磁阶的电子能带结构。这些化合物是一类重要的多功能材料，具有各种有趣的应用特性。通过比较不同磁性构型的能带结构，可以观察到其中一些表现出能带分裂，这可归因于铁磁性面间耦合。ScMnO3 化合物的能带分裂明显更大（331 meV），这可能与较高的面间磁相互作用有关。此外，我们还发现，对于那些沿六边形 c 轴具有弱磁矩的磁性构型，自旋轨道耦合也会在布里渊区的某些区域引起能带分裂。这些发现对六方锰矿带状结构的拓扑特征提供了一个有趣的洞察，而这在现有文献中还没有被探索过。这一发现为该领域未来的研究开辟了道路。

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引用次数: 0

A low-cost electronic and optical system for magnetic hyperthermia experimental studies 用于磁热效应实验研究的低成本电子和光学系统

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-26 DOI: 10.1016/j.jmmm.2024.172552

Yavuz Öztürk , Ali Altan Yılmaz , Yiğit Seymen , Coşkun Harmanşah

Magnetic hyperthermia is an alternative to treatments such as chemotherapy and radiotherapy that employs the heat generated by magnetic nanoparticles under the influence of a magnetic field to kill cancer cells while ideally causing no harm to healthy tissues. A low-cost magnetic hyperthermia investigation platform with commercially available and easy-to-assemble parts was presented to provide and expand research in this area for a larger scientific community. The magnetic hyperthermia measurement system consists of three main parts: a designed thermally insulated sample holder, a commercial 88 kHz magnetic induction heater, and a custom-built fiber optic based refractometer as temperature sensor. The system was tested with commercial EFH-1 magnetic fluids. Time dependent temperature changes were measured for applied magnetic fields of 3.5 kA/m, 4.8 kA/m, and 6.0 kA/m. The corresponding specific loss power values were calculated as 0.28 W/g, 0.51 W/g, and 0.79 W/g, respectively. Intrinsic loss power of commercial ferrofluid was determined as 0.25 ± 0.01 nHm²/kg, found to be comparable to the results of specialized commercial magnetic hyperthermia systems. The results show that the system can easily be used for hyperthermia demonstrations for educational purposes as well as in convenient scientific research with proper calibration.

磁性热疗是化疗和放疗等治疗方法的替代疗法，它利用磁性纳米粒子在磁场影响下产生的热量杀死癌细胞，同时最好不会对健康组织造成伤害。为了向更多的科学界提供并扩大这一领域的研究，我们展示了一个低成本的磁热效应研究平台，其部件可在市场上买到，且易于组装。磁性热疗测量系统由三个主要部分组成：设计的隔热样品架、商用 88 kHz 磁感应加热器和定制的光纤折射仪作为温度传感器。该系统使用商用 EFH-1 磁性流体进行了测试。在 3.5 kA/m、4.8 kA/m 和 6.0 kA/m 的应用磁场下测量了随时间变化的温度。计算得出相应的比损耗功率值分别为 0.28 W/g、0.51 W/g 和 0.79 W/g。商用铁流体的本征损耗功率被测定为 0.25 ± 0.01 nHm2/kg，与专业商用磁热系统的结果相当。结果表明，该系统可轻松用于教育目的的热疗演示，也可在适当校准的情况下用于方便的科学研究。

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引用次数: 0

Single crystal growth and magnetic properties in triangular chain compound Ni2SiO4 三角链化合物 Ni2SiO4 的单晶生长和磁性能

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-26 DOI: 10.1016/j.jmmm.2024.172559

R. Chen , Z. Qu , T. Li , H.J. Hu , C.B. Liu , C. Dong , Y. Qiu

Sub-centimeter-scale Ni₂SiO₄ single crystals were grown by a flux method with K₂MoO₄ as the flux. The obtained crystals exhibit high quality and were characterized using X-ray diffraction, chemical analysis, and magnetic properties, including high magnetic field (H) magnetization (M) measurements. The results of magnetic susceptibility and specific heat of a single crystal reveal significant magnetic anisotropy and antiferromagnetic ordering below T_N = 30 K. High-field magnetization up to 43 T of polycrystalline shows six magnetic phase transitions at H₁ = 14 T, H₂ = 18.4 T, H₃ = 23 T, H₄ = 29 T, H₅ = 32.5 T, and H₆ = 37 T, forming a complex magnetic phase diagram with seven phases. Notably, the M exhibits a linear relationship with H during phases V (H₄ < H < H₅) and VII (H > H₆), showing intercepts at 0 and half of magnetization saturation respectively, implying the presence of a spin flop transition and a 1/2 magnetization plateau. These novel phenomena in such a triangular chain system highlight complex physical nature, making Ni₂SiO₄ a promising candidate for studying intricate magnetic interactions.

以 K2MoO4 作为助熔剂，通过助熔剂法生长出了亚厘米级的 Ni2SiO4 单晶体。所获得的晶体质量很高，并通过 X 射线衍射、化学分析和磁性能（包括高磁场（H）磁化（M）测量）进行了表征。单晶的磁感应强度和比热结果表明，在 TN = 30 K 以下具有显著的磁各向异性和反铁磁有序性。高磁场磁化高达 43 T 的多晶体在 H1 = 14 T、H2 = 18.4 T、H3 = 23 T、H4 = 29 T、H5 = 32.5 T 和 H6 = 37 T 处显示出六个磁相变，形成了一个具有七个相的复杂磁相图。值得注意的是，在相 V（H4 <；H <；H5）和相 VII（H >；H6）期间，M 与 H 呈线性关系，截距分别为磁化饱和的 0 和一半，这意味着存在自旋翻转转变和 1/2 磁化高原。这种三角链体系中的这些新现象凸显了其复杂的物理本质，使 Ni2SiO4 成为研究复杂磁相互作用的理想候选物质。

{"title":"Single crystal growth and magnetic properties in triangular chain compound Ni2SiO4","authors":"R. Chen , Z. Qu , T. Li , H.J. Hu , C.B. Liu , C. Dong , Y. Qiu","doi":"10.1016/j.jmmm.2024.172559","DOIUrl":"10.1016/j.jmmm.2024.172559","url":null,"abstract":"<div><div>Sub-centimeter-scale Ni<sub>2</sub>SiO<sub>4</sub> single crystals were grown by a flux method with K<sub>2</sub>MoO<sub>4</sub> as the flux. The obtained crystals exhibit high quality and were characterized using X-ray diffraction, chemical analysis, and magnetic properties, including high magnetic field (<em>H</em>) magnetization (<em>M</em>) measurements. The results of magnetic susceptibility and specific heat of a single crystal reveal significant magnetic anisotropy and antiferromagnetic ordering below <em>T<sub>N</sub></em> = 30 K. High-field magnetization up to 43 T of polycrystalline shows six magnetic phase transitions at <em>H<sub>1</sub></em> = 14 T, <em>H<sub>2</sub></em> = 18.4 T, <em>H<sub>3</sub></em> = 23 T, <em>H<sub>4</sub></em> = 29 T, <em>H<sub>5</sub></em> = 32.5 T, and <em>H<sub>6</sub></em> = 37 T, forming a complex magnetic phase diagram with seven phases. Notably, the <em>M</em> exhibits a linear relationship with <em>H</em> during phases V (<em>H<sub>4</sub></em> < <em>H</em> < <em>H<sub>5</sub></em>) and VII (<em>H</em> > <em>H<sub>6</sub></em>), showing intercepts at 0 and half of magnetization saturation respectively, implying the presence of a spin flop transition and a 1/2 magnetization plateau. These novel phenomena in such a triangular chain system highlight complex physical nature, making Ni<sub>2</sub>SiO<sub>4</sub> a promising candidate for studying intricate magnetic interactions.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172559"},"PeriodicalIF":2.5,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nonreciprocal damping of spin waves propagating in magnetic domain walls induced by Dzyaloshinskii-Moriya interaction 由 Dzyaloshinskii-Moriya 相互作用诱发的磁畴壁中传播的自旋波的非互惠阻尼

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-24 DOI: 10.1016/j.jmmm.2024.172556

Xiang Liu, Zhi-Xiong Li, Xi-Guang Wang, Guang-Hua Guo

The nonreciprocity of spin waves refers to the phenomenon that spin waves propagating in opposite directions display different features. This phenomen becomes a fundamental requirement for implementing magnon logic architectures. The nonreciprocal transportion of spin waves induced by Dzyaloshinskii-Moriya interaction (DMI) has been studied extensively. It is characterized by a shift of spin-wave dispersion. Here we report another feature of the DMI-induced nonreciprocity, i.e., the nonreciprocal spin wave damping. We find that the spin waves propagating with opposite wave vectors in magnetic domain wall have different damping, which is frequency dependent and especially evident in low frequancy range. For spin waves with sufficient low frequencies (around 1 GHz), the damping nonreciprocity is so extreme that spin waves can transport only in one direction, thus realizing the spin-wave diode function. The theoretical predictions are validated by micromagnetic simulations. The findings in this work points out a new feature of DMI-induced spin wave nonreciprocity and may be exploited for designing novel magnonic devices.

自旋波的非互易性是指传播方向相反的自旋波显示出不同特征的现象。这一现象成为实现磁子逻辑架构的基本要求。由 Dzyaloshinskii-Moriya 相互作用（DMI）诱发的自旋波非互易传输已被广泛研究。它的特点是自旋波色散的移动。在这里，我们报告了 DMI 诱导的非互易性的另一个特征，即非互易自旋波阻尼。我们发现，在磁畴壁中以相反波矢量传播的自旋波具有不同的阻尼，这种阻尼与频率有关，在低频范围内尤其明显。对于足够低频（约 1 GHz）的自旋波，阻尼非互惠性是如此极端，以至于自旋波只能沿一个方向传播，从而实现了自旋波二极管功能。微磁模拟验证了理论预测。这项研究成果指出了 DMI 诱导的自旋波非折回性的一个新特征，可用于设计新型磁性器件。

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引用次数: 0

Robust Multi-Band DNG metamaterial absorber for GPS (L1), ISM, and 5G application with Enhanced polarization and angle stability 用于 GPS (L1)、ISM 和 5G 应用的稳健型多频段 DNG 超材料吸收器，具有更强的极化和角度稳定性

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-23 DOI: 10.1016/j.jmmm.2024.172554

Mayank A. Ardeshana , Falgunkumar N. Thakkar , Sunayana G. Domadia

This research introduces a triple-band metamaterial absorber characterized by insensitivity to both polarization and incident angles. The structure includes square ring resonators on the upper side and a continuous metal ground on the lower side, separated by an FR4 substrate. At the lowest operating frequency, the unit cell’s thickness, and length measure 0.0128λ and 0.156λ, respectively. Under normal incidence, the proposed absorber demonstrates three clear absorption peaks at 1.56, 2.43, and 3.36 GHz, achieving absorption rates of 98 %, 99 %, and 97 %, respectively. The absorption response exhibits variation with incident angles up to 70° for both TM and TE polarizations due to its high-level symmetry. This configuration attains negative permittivity and permeability suitable for operational frequencies in the L-band and S-band. The study examines the electric field, impedance, and surface current to provide additional evidence for the absorption analysis. A validated RLC circuit equivalent to the proposed structure has been confirmed using Advanced Design System (ADS). The results indicate a slight deviation, especially at frequencies beyond the resonance frequencies. The structure underwent fabrication and testing in an anechoic chamber, revealing a strong correlation between the simulated and measured results. The suggested absorber holds promise for ISM applications, radar systems, sensing technologies, and energy harvesting systems.

这项研究介绍了一种三波段超材料吸收器，其特点是对偏振和入射角都不敏感。该结构包括上侧的方形环状谐振器和下侧的连续金属接地，并由 FR4 基板隔开。在最低工作频率下，单元尺寸的厚度和长度分别为 0.0128λ 和 0.156λ。在正常入射条件下，所提出的吸收器在 1.56、2.43 和 3.36 GHz 处显示出三个明显的吸收峰，吸收率分别达到 98%、99% 和 97%。由于其高度对称性，吸收响应随入射角度的变化而变化，在 TM 和 TE 极化下最高可达 70°。这种结构可获得适合 L 波段和 S 波段工作频率的负介电常数和负导磁率。研究对电场、阻抗和表面电流进行了检测，为吸收分析提供了更多证据。使用高级设计系统 (ADS) 确认了与拟议结构等效的 RLC 电路。结果表明存在轻微偏差，尤其是在超出共振频率的频率上。该结构在电波暗室中进行了制造和测试，结果显示模拟和测量结果之间具有很强的相关性。建议的吸收器有望用于 ISM 应用、雷达系统、传感技术和能量收集系统。

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引用次数: 0

Influence of Dy3+ doping on Mössbauer, magnetic and microwave absorption properties of M-type Ba0.5Ca0.5DyxFe12-xO19 hexaferrites 掺杂 Dy3+ 对 M 型 Ba0.5Ca0.5DyxFe12-xO19 六价铁氧体的莫斯鲍尔、磁性和微波吸收特性的影响

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-23 DOI: 10.1016/j.jmmm.2024.172555

Varsha C. Pujari , Pramod D. Mhase , Sunil M. Patange , P.S. More , Sher Singh Meena , Shoyebmohamad F. Shaikh , Abdullah M. Al-Enizi , Santosh S. Jadhav

The present research paper reports a systematic study of the magnetic, and structural properties of Ba_0.5Ca_0.5Dy_xFe_12-xO₁₉ M-type hexaferrite. The dysprosium was doped @ x = 0 − 0.2, keeping Δx = 0.05, in BCDF by the sol–gel self-ignition technique. The sintering of the synthesized samples was performed for 4 h at 1050°C. The crystallographic analysis of the samples was made from the X-ray diffractograms (XRD), while the morphological and elemental analysis was made from field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDAX) profiles. The structural results revealed the formation of the M-type hexaferrite having P6₃/mmc as a space group along with the co-existence of a secondary Fe₂O₃ phase. FESEM micrographs exhibit the hexagonal platelets randomly arranged with agglomerations at some places giving rise to the random variations in particle size with varying ’x’. Magnetic measurements (VSM) show that the saturation magnetization (M_S) and coercivity (H_C) increase with the increasing Dy³⁺ doping pointing towards the fact that the Dy doping in Ba-Ca ferrite can be used to fabricate the hard ferrites with good saturation magnetization. The Mössbauer spectrum recorded at room temperature reveals five superimposed sextets representing the five Fe³⁺ ion sites. Investigating the Microwave absorption (MWA) characteristics in the frequency range 8 − 12 GHz (X-band), reveals that the sample with x = 0.1 having 3 mm thickness possesses good MWA power. Its minimum RL value for matching frequency 10.06 GHz is approximately −26.96 dB, indicating that more than 90 % of microwaves are absorbed. The current work offers the Dysprosium-doped BCDF hexaferrites, as promising candidates for microwave absorption applications.

本研究报告系统研究了 Ba0.5Ca0.5DyxFe12-xO19 M 型六价铁氧体的磁性和结构特性。采用溶胶-凝胶自点火技术在 BCDF 中掺入镝 @ x = 0 - 0.2，保持 Δx = 0.05。合成样品在 1050°C 下烧结 4 小时。样品的晶体学分析是通过 X 射线衍射图（XRD）进行的，而形态和元素分析则是通过场发射扫描电子显微镜（FESEM）和能量色散 X 射线光谱（EDAX）图谱进行的。结构结果显示，形成了以 P63/mmc 为空间群的 M 型六价铁氧体，同时还存在次生的 Fe2O3 相。FESEM 显微照片显示，六角形小板块随机排列，某些地方有团聚现象，导致粒度随 "x "的变化而随机变化。磁性测量（VSM）显示，饱和磁化（MS）和矫顽力（HC）随着 Dy3+ 掺杂量的增加而增加，这表明在 Ba-Ca 铁氧体中掺杂 Dy 可用于制造具有良好饱和磁化的硬铁氧体。室温下记录的莫斯鲍尔光谱显示出五个叠加的六面体，代表五个 Fe3+ 离子位点。对频率范围为 8 - 12 GHz（X 波段）的微波吸收（MWA）特性的研究表明，厚度为 3 毫米的 x = 0.1 样品具有良好的 MWA 功率。其匹配频率 10.06 GHz 的最小 RL 值约为 -26.96 dB，表明 90% 以上的微波被吸收。目前的研究工作为微波吸收应用提供了掺镝 BCDF 六晶片。

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引用次数: 0

Corrigendum to “An induced magnetic field utilization for hybrid nanoliquid flow subject to entropy generation” [J. Magn. Magn. Mater. 576 (2023) 170742] 对 "受熵产生影响的混合纳米液体流动的诱导磁场利用 "的更正 [J. Magn. Magn. Mater. 576 (2023) 170742]

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-22 DOI: 10.1016/j.jmmm.2024.172541

T. Hayat , A. Razaq , Sohail A. Khan , A. Alsaedi

引用次数: 0

Magnetic injection of α-CP nanoribbons and investigation of spintronic device applications of magnetic α-CP nanoribbons based on first principles calculations 基于第一性原理计算的 α-CP 纳米带的磁注入和磁性 α-CP 纳米带的自旋电子器件应用研究

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2024-09-22 DOI: 10.1016/j.jmmm.2024.172538

Yuzhu Wu , Sheng Liu , Minyang Zhang , Ziru Wang , Sicong Zhu

Since the successful synthesis of α-phosphorus carbide (α-CP) using carbon doping technology, α-CP has exhibited excellent carrier mobility and anisotropy at room temperature, underscoring its potential for spintronic applications. The application of CP in spintronic devices is limited due to its lack of magnetism. Effective magnetic injection in non-magnetic semiconductors can typically be achieved by doping with magnetic atoms. In this study, we calculated the electromagnetic properties of transition metal (TM) atoms adsorbed at different positions on α-CP using first principles. Notably, we found that α-CP nanoribbons adsorbed with Fe and Mn atoms of a specific width exhibit stable half-metallicity. We discovered that α-CP nanoribbons adsorbed with Fe and Mn atoms of a specific width exhibit stable half-metal properties and design magnetic tunnel junctions with half-metallic Fe_H12 and Mn_H12 adsorption structures. The results show that Mn_H12 and Fe_H12 devices exhibit a highly efficient spin filtering effect, with a TMR as high as 5521%. These findings provide theoretical guidance for the application of CP-based spintronic devices.

自从利用碳掺杂技术成功合成α-碳化磷（α-CP）以来，α-CP在室温下表现出优异的载流子迁移率和各向异性，突显了其在自旋电子应用方面的潜力。由于缺乏磁性，CP 在自旋电子器件中的应用受到了限制。非磁性半导体中有效的磁注入通常可以通过掺杂磁性原子来实现。在本研究中，我们利用第一性原理计算了吸附在 α-CP 不同位置的过渡金属 (TM) 原子的电磁特性。值得注意的是，我们发现吸附了特定宽度的铁原子和锰原子的 α-CP 纳米带具有稳定的半金属性。我们发现吸附了特定宽度的铁原子和锰原子的 α-CP 纳米带具有稳定的半金属特性，并设计出了具有半金属 Fe_H12 和 Mn_H12 吸附结构的磁隧道结。结果表明，Mn_H12 和 Fe_H12 器件具有高效的自旋过滤效应，其 TMR 高达 5521%。这些发现为基于 CP 的自旋电子器件的应用提供了理论指导。

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引用次数: 0