Journal of Magnetism and Magnetic Materials最新文献_第4页

Bragg resonances in left-handed bigyrotropic media based on periodic ferromagnetic semiconductor 基于周期性铁磁半导体的左手大反转介质中的布拉格共振

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-07 DOI: 10.1016/j.jmmm.2024.172630

M.A. Morozova , O.V. Matveev , S.V. Grishin , A.V. Bogomolova , S.A. Nikitov

引用次数: 0

Chirality- and Rashba- related effects in the spin texture of a two-dimensional centrosymmetric ferromagnet: The case of the CrI3 bilayer 二维中心对称铁磁体自旋纹理中的手性和拉什巴效应：CrI3 双层的情况

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-06 DOI: 10.1016/j.jmmm.2024.172610

Sukanya Ghosh , Nataša Stojić , Nadia Binggeli

{"title":"Chirality- and Rashba- related effects in the spin texture of a two-dimensional centrosymmetric ferromagnet: The case of the CrI3 bilayer","authors":"Sukanya Ghosh , Nataša Stojić , Nadia Binggeli","doi":"10.1016/j.jmmm.2024.172610","DOIUrl":"10.1016/j.jmmm.2024.172610","url":null,"abstract":"<div><div>The newly discovered two-dimensional (2D) magnetic semiconductors such as CrI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> have triggered a surge of interest stemming from their exotic spin-dependent properties and potential applications in spintronics and magneto-optoelectronics. Using first-principle density-functional-theory calculations, we investigate the properties of the spin-polarization texture in momentum space in the prototype 2D centrosymmetric ferromagnetic (FM) bilayer of CrI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> with perpendicular magnetization, with a goal of identifying general features due to interlayer interaction and their microscopic origins in 2D centrosymmetric FM materials. The FM CrI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> bilayer displays a rich in-plane spin texture in its highest valence bands. We show the existence of two distinct spin canting effects induced by the coupling of the two FM layers in establishing the in-plane spin texture. The first effect is generated by the mirror-related chirality of the layer stacking and the spin–orbit-polarized nature of the valence states, and yields the same canting on both layers. The second effect is a Rashba-related effect, which in a centrosymmetric ferromagnet induces in a single electronic state two opposite spin-canted components on the two layers, resulting in a notable frustration effect on the energy of the bonding states. Finally, we show that the above effects can be effectively used to manipulate the spin texture via compressive vertical strain, which induces in the FM CrI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> bilayer valence-band-edge states with canted spins.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"612 ","pages":"Article 172610"},"PeriodicalIF":2.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660790","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

Droplet generation in a co-flowing microchannel under the non-uniform magnetic fields produced by an electric current loop 在电流环产生的非均匀磁场作用下，在共流微通道中产生液滴

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-06 DOI: 10.1016/j.jmmm.2024.172645

Mehdi Fadaei, Sahand Majidi, Hadi Shoeibi

{"title":"Droplet generation in a co-flowing microchannel under the non-uniform magnetic fields produced by an electric current loop","authors":"Mehdi Fadaei, Sahand Majidi, Hadi Shoeibi","doi":"10.1016/j.jmmm.2024.172645","DOIUrl":"10.1016/j.jmmm.2024.172645","url":null,"abstract":"<div><div>Micro-magnetofluidics, the study of fluid behavior under magnetic fields in microscale systems, is vital for applications like drug delivery, chemical synthesis, and lab-on-a-chip technologies. Controlling droplet size and formation frequency in these systems is challenging due to the complex interplay of magnetic forces and fluid dynamics. This study introduces a novel approach to control droplet generation in a co-flowing microchannel under a non-uniform magnetic field generated by an electric current loop. Critical parameters such as electric current intensity, continuous phase flow rate, and current loop position are systematically examined for their impact on droplet behavior. The results highlight the unique influence of the magnetic field configuration, specifically the electric current loop, in inducing a transition from dripping to jetting flow patterns with increasing current intensity, leading to larger droplets and reduced generation frequency. Additionally, a distinct behavior of droplet coalescence near the current loop, followed by re-separation, is observed when the loop is positioned downstream of the inlet. Moreover, increasing the continuous phase flow rate consistently reduced droplet size and increased generation frequency, regardless of the current loop’s position.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"612 ","pages":"Article 172645"},"PeriodicalIF":2.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660157","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

High-performance anisotropic Sm2Co17/Fe(Co) bulk nanocomposite magnets fabricated by two-step high-pressure thermal compression deformation 通过两步高压热压变形制造高性能各向异性 Sm2Co17/Fe(Co)块状纳米复合磁体

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-04 DOI: 10.1016/j.jmmm.2024.172640

Tiancong Li, Jieqiong Gao, Xiaohong Li, Jinyi wang, Li Lou, Yingxin Hua, Yiran Li, Wenyue Qin, Defeng Guo, Wei Li

{"title":"High-performance anisotropic Sm2Co17/Fe(Co) bulk nanocomposite magnets fabricated by two-step high-pressure thermal compression deformation","authors":"Tiancong Li, Jieqiong Gao, Xiaohong Li, Jinyi wang, Li Lou, Yingxin Hua, Yiran Li, Wenyue Qin, Defeng Guo, Wei Li","doi":"10.1016/j.jmmm.2024.172640","DOIUrl":"10.1016/j.jmmm.2024.172640","url":null,"abstract":"<div><div>In the realm of Sm<sub>2</sub>Co<sub>17</sub> nanocomposite magnetic materials, it remains a challenge to fabricate anisotropic magnets by forming nanocrystalline Sm<sub>2</sub>Co<sub>17</sub> phases with strong texture, alongside soft phases of small size and high soft phase content. In this paper, we present a novel approach for fabricating anisotropic Sm<sub>2</sub>Co<sub>17</sub>/Fe(Co) nanocomposite bulk magnets with a prominent (00<em>l</em>) texture of the Sm<sub>2</sub>Co<sub>17</sub> phase, the 25 wt% content of the Fe(Co) phase, and a refined grain size of 25 nm. This fabrication is achieved using a two-step high-pressure thermal compression (HPTC) deformation process. The fabricated magnets exhibit a maximum energy product [(<em>BH</em>)<sub>max</sub>] of 20.0 MGOe with a pronounced magnetic anisotropy (<em>B</em><sub>r</sub><sup>//</sup>/<em>B</em><sub>r</sub><sup>⊥</sup> = 1.23). This result is 53 % higher than the previously reported largest value [(<em>BH</em>)<sub>max</sub> = 13.1 MGOe] for Sm<sub>2</sub>Co<sub>17</sub>-based nanocomposites. The magnets also exhibit a low remanence temperature coefficient (<em>α</em> = −0.014 %/°C) and a low coercivity temperature coefficient (<em>β</em> = −0.23 %/°C), demonstrating exceptional thermal stability. Our findings may improve the fabrication of anisotropic bulk Sm<sub>2</sub>Co<sub>17</sub> nanostructure magnets for practical applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"612 ","pages":"Article 172640"},"PeriodicalIF":2.5,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660158","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

The influence of pre-sintering temperature on the structural, magnetic, and dielectric properties of Sr0.67La0.33Fe11.7Zn0.1Co0.2O19 ferrite 预烧结温度对 Sr0.67La0.33Fe11.7Zn0.1Co0.2O19 铁氧体结构、磁性和介电性质的影响

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-03 DOI: 10.1016/j.jmmm.2024.172641

Qingyang Meng , Wei Sun , Xucai Kan , Xiansong Liu , Sheng Gao , Hongjian Yang , Jian Yang , Zhixiang Wang , Yujie Liu

{"title":"The influence of pre-sintering temperature on the structural, magnetic, and dielectric properties of Sr0.67La0.33Fe11.7Zn0.1Co0.2O19 ferrite","authors":"Qingyang Meng , Wei Sun , Xucai Kan , Xiansong Liu , Sheng Gao , Hongjian Yang , Jian Yang , Zhixiang Wang , Yujie Liu","doi":"10.1016/j.jmmm.2024.172641","DOIUrl":"10.1016/j.jmmm.2024.172641","url":null,"abstract":"<div><div>The present study explores the impact of varying heat treatment temperatures on the magnetic properties, structural configuration and dielectric characteristics of Sr<sub>0.67</sub>La<sub>0.33</sub>Fe<sub>11.7</sub>Zn<sub>0.1</sub>Co<sub>0.2</sub>O<sub>19</sub> ferrite. M-type ferrite was synthesized using the traditional solid-state method, with thermal treatment temperatures incrementally increasing from 1230 °C to 1310 °C. Pure M-phase strontium ferrite was achieved at temperatures above 1250 °C. The ideal pre-sintering temperature was identified as 1270 °C, where several factors coalesced to enhance the magnetic properties, including the completion of the solid-state reaction and the diminution of the easily magnetized c-axis, which together fostered the intensification of the superexchange interaction. At this temperature, the magnetic properties reached their zenith, with a saturation magnetization (<em>M<sub>s</sub></em>) of 84.81 emu/g, a remanence (<em>B<sub>r</sub></em>) of 419 mT, and a coercivity (<em>H<sub>cj</sub></em>) of 3301 Oe. Additionally, the dielectric constant was significantly high at low frequencies but rapidly declined with increasing frequency, achieving its optimal performance at 1270 °C.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172641"},"PeriodicalIF":2.5,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652559","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

Revisiting the assessment of magnetic texture of Rare-Earth Magnets: The role of coercivity 重新审视稀土磁体的磁性质地评估：矫顽力的作用

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-03 DOI: 10.1016/j.jmmm.2024.172639

Luis T. Quispe , Leonardo F. Antunes , A.A. Baldárrago-Alcántara , Wagner C. Macedo , Marcelo A. Rosa , Querem H.F. Rebelo , Leonardo U. Lopes , Sérgio M. Souza , Paulo A.P. Wendhausen

{"title":"Revisiting the assessment of magnetic texture of Rare-Earth Magnets: The role of coercivity","authors":"Luis T. Quispe , Leonardo F. Antunes , A.A. Baldárrago-Alcántara , Wagner C. Macedo , Marcelo A. Rosa , Querem H.F. Rebelo , Leonardo U. Lopes , Sérgio M. Souza , Paulo A.P. Wendhausen","doi":"10.1016/j.jmmm.2024.172639","DOIUrl":"10.1016/j.jmmm.2024.172639","url":null,"abstract":"<div><div>A crucial figure of merit of rare-earth magnets is their magnetic texture, because it is closely related to the maximum remanence a magnet can achieve, hence assessing the magnetic texture is pivotal in terms of magnet’s performance. Fernengel <em>et al</em>. (1996) developed a methodology based on magnetometry, which allows for a quick determination of the texture by calculating the degree of alignment 〈cosθ〉 from the remanent magnetization in directions parallel and perpendicular to the texture axis of the magnet. Although this method provided reliable values, its application was limited to magnets with high degrees of alignment (〈cosθ〉 > 95 %), a restriction that was corrected by Quispe <em>et al</em>. (2020). Nevertheless, recent experiments have indicated that the magnetometry technique can introduce errors in texture assessment when the magnet presents high levels of coercivity. This work presents an approach that incorporates a correction factor into the magnetometry technique, accounting for the effect of the coercivity and circumventing this error source in texture assessment. The proposed methodology has been successfully applied to magnets with varying levels of coercivity.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"612 ","pages":"Article 172639"},"PeriodicalIF":2.5,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660802","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

First-principles study of structural, elastic, mechanical, electronic, magnetic, optical, and thermoelectric properties of CoFeTe half-heusler alloy CoFeTe 半休斯勒合金结构、弹性、机械、电子、磁性、光学和热电特性的第一性原理研究

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-03 DOI: 10.1016/j.jmmm.2024.172628

A. Samih , E. Salmani , Hussein. Sabbah , R. El Fdil , Z. Fadil , Fohad Mabood Husain , Seong Cheol Kim , Chaitany Jayprakash Raorane

引用次数: 0

A novel bulk magnetostrictive sensor for bending applications 用于弯曲应用的新型块状磁致伸缩传感器

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-02 DOI: 10.1016/j.jmmm.2024.172636

Mohammad Reza Karafi, Mina Poursadr

引用次数: 0

Anomalous switching pattern in the ferrimagnetic memory cell 铁磁记忆单元中的异常开关模式

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-02 DOI: 10.1016/j.jmmm.2024.172614

Zhuo Xu , Zhengping Yuan , Xue Zhang , Zhengde Xu , Yixiao Qiao , Yumeng Yang , Zhifeng Zhu

{"title":"Anomalous switching pattern in the ferrimagnetic memory cell","authors":"Zhuo Xu , Zhengping Yuan , Xue Zhang , Zhengde Xu , Yixiao Qiao , Yumeng Yang , Zhifeng Zhu","doi":"10.1016/j.jmmm.2024.172614","DOIUrl":"10.1016/j.jmmm.2024.172614","url":null,"abstract":"<div><div>Replacing the ferromagnet with ferrimagnet (FiM) in the magnetic tunnel junction (MTJ) allows faster magnetization switching in picoseconds. The operation of a memory cell that consists of the MTJ and a transistor requires reversable magnetization switching. When a constant voltage is applied, we find that the spin-transfer torque can only switch the FiM-MTJ from parallel to antiparallel state. This stems from the small switching window of FiM and the dynamic resistance variation during the magnetization switching. We find the resulting current variation can be suppressed by reducing the magnetoresistance ratio. Furthermore, we demonstrate that the switching window can be expanded by adjusting the amount of Gd in FiM. We predict that the polarity of both switching current (<em>J</em><sub>c,switch</sub>) and oscillation current (<em>J</em><sub>c,osc</sub>) reverses at the angular momentum compensation point but not the magnetization compensation point. This anomalous dynamic behavior is attributed to the different physical nature of magnetization switching and oscillation in FiM, which must be considered when designing FiM-based MRAM.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172614"},"PeriodicalIF":2.5,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652560","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

Magnetic field effects on the thermal performance of Fe3O4 nanofluids in a forced convection system 磁场对强制对流系统中 Fe3O4 纳米流体热性能的影响

IF 2.5 3区材料科学

Journal of Magnetism and Magnetic Materials Pub Date : 2024-11-02 DOI: 10.1016/j.jmmm.2024.172637

Mohammadmahdi Kamyabi, Seyed Mohammad Sadegh Hosseini

{"title":"Magnetic field effects on the thermal performance of Fe3O4 nanofluids in a forced convection system","authors":"Mohammadmahdi Kamyabi, Seyed Mohammad Sadegh Hosseini","doi":"10.1016/j.jmmm.2024.172637","DOIUrl":"10.1016/j.jmmm.2024.172637","url":null,"abstract":"<div><div>This study experimentally investigates the effects of magnetic field strength, Reynolds number, and nanoparticle concentration on the unsteady heat transfer characteristics of a Fe<sub>3</sub>O<sub>4</sub>-water nanofluid. The nanofluid was prepared by dispersing nanoparticles in water at concentrations of 0 %, 0.08% v/v and 0.16% v/v, using a stabilizer to maintain dispersion. A double-pipe system, encased in a copper coil (solenoid), was employed to facilitate heat exchange between tap water and the nanofluid under magnetic field. The solenoid exerts the desired magnetic field. The Taguchi method was utilized for experimental design and analysis. Results indicate that the Reynolds number, magnetic field strength, and nanofluid concentration all enhance the heat transfer rate; however, their effects differ due to distinct mechanisms of action. Analysis of variance reveals that the Reynolds number has the most significant impact although at low Reynolds only. This is while the effects of nanoparticle concentration and magnetic field strength are comparable. The findings suggest that even a magnetic field aligned with the fluid flow can serve as an auxiliary factor to enhance heat transfer in ferrofluids, particularly when increasing nanoparticle concentration is constrained by rising pressure drops and the risk of agglomeration.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172637"},"PeriodicalIF":2.5,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652558","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