Pub Date : 2024-09-21DOI: 10.1016/j.jmmm.2024.172553
Jing Xu, Wei Xu
This study presents a framework for simulation-experiment closed-loop analysis of nanocomposite magnets. Firstly, hysteresis loops of nanocomposite permanent magnets were calculated using micromagnetic simulations. Then, the experimental preparation was carried out by rapid quenching of the melt and spark plasma sintering (SPS). We analyzed the effect of different sintering temperatures on the physical phase composition and magnetic properties of the samples. Characterization results show that the samples sintered at 600 °C have the highest magnetic energy product. Using transmission electron microscopy data, the polycrystalline model was refined, and further micromagnetic simulations were performed. The close agreement between simulated and experimental data confirms the improved accuracy of our simulation model. This iterative process of experimental characterization and simulation improvement reduces the discrepancy between simulation predictions and actual sample performance. It could facilitate rapid iteration in magnet development and provide valuable insights for optimizing the preparation of nanocomposite permanent magnets.
本研究提出了纳米复合磁体的模拟-实验闭环分析框架。首先，利用微磁模拟计算了纳米复合永磁体的磁滞回线。然后，通过熔体快速淬火和火花等离子烧结（SPS）进行实验制备。我们分析了不同烧结温度对样品物理相组成和磁性能的影响。表征结果表明，在 600 °C 下烧结的样品具有最高的磁能积。利用透射电子显微镜数据完善了多晶模型，并进一步进行了微磁模拟。模拟数据与实验数据之间的密切吻合证实了模拟模型准确性的提高。这种实验表征和模拟改进的迭代过程减少了模拟预测与实际样品性能之间的差异。它可以促进磁体开发的快速迭代，并为优化纳米复合永磁体的制备提供有价值的见解。
{"title":"Closed-Loop Analysis of Nanocomposite Magnets: Integrating Micromagnetic Simulation and Experimental Testing","authors":"Jing Xu, Wei Xu","doi":"10.1016/j.jmmm.2024.172553","DOIUrl":"10.1016/j.jmmm.2024.172553","url":null,"abstract":"<div><div>This study presents a framework for simulation-experiment closed-loop analysis of nanocomposite magnets. Firstly, hysteresis loops of nanocomposite permanent magnets were calculated using micromagnetic simulations. Then, the experimental preparation was carried out by rapid quenching of the melt and spark plasma sintering (SPS). We analyzed the effect of different sintering temperatures on the physical phase composition and magnetic properties of the samples. Characterization results show that the samples sintered at 600 °C have the highest magnetic energy product. Using transmission electron microscopy data, the polycrystalline model was refined, and further micromagnetic simulations were performed. The close agreement between simulated and experimental data confirms the improved accuracy of our simulation model. This iterative process of experimental characterization and simulation improvement reduces the discrepancy between simulation predictions and actual sample performance. It could facilitate rapid iteration in magnet development and provide valuable insights for optimizing the preparation of nanocomposite permanent magnets.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172553"},"PeriodicalIF":2.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311757","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}
Pub Date : 2024-09-21DOI: 10.1016/j.jmmm.2024.172548
Lichao Yu , Qingmei Lu , Liying Cong , Xinyuan Yang , Weiqiang Liu , Gaihua Dong , Shulin Huang , Yuan Deng , Lijuan Meng , Youhao Liu , Xiaofei Yi , Yufeng Wu , Ming Yue
The grinding sludge of grain boundary diffusion Nd-Fe-B magnet is rich in heavy rare earth and has a typical core–shell microstructure. In this work, an ultra-short process was developed to realize green, in-situ regeneration of the sludge and efficient reuse of heavy rare earth elements. The regenerated magnets showed excellent magnetic performance and good temperature stability which were fabricated after the purification of sludge, composition regulation with rare earth-rich compounds, Nd42.1FebalB0.79, NdHx, (PrNd)Hx, and sintering. Especially, the magnet prepared by using Nd42.1FebalB0.79 alloy had significant property recovery, where remanence and coercivity were restored to 12.8 kG, and 20.6 kOe, respectively, reaching 97.7 % and 162.5 % of the original magnet. The magnetization reversal behavior and the coercivity mechanism were analyzed to keep the nucleation mechanism, and the high coercivity stemmed from the repair and optimization of the grain boundary by introducing rare earth-rich alloys, the full utilization of heavy rare earth elements, and the core–shell microstructure rooted in the sludge as well.
{"title":"Achieving high-performance regeneration of grain boundary diffusion Nd-Fe-B sludge via an ultra-short process","authors":"Lichao Yu , Qingmei Lu , Liying Cong , Xinyuan Yang , Weiqiang Liu , Gaihua Dong , Shulin Huang , Yuan Deng , Lijuan Meng , Youhao Liu , Xiaofei Yi , Yufeng Wu , Ming Yue","doi":"10.1016/j.jmmm.2024.172548","DOIUrl":"10.1016/j.jmmm.2024.172548","url":null,"abstract":"<div><div>The grinding sludge of grain boundary diffusion Nd-Fe-B magnet is rich in heavy rare earth and has a typical core–shell microstructure. In this work, an ultra-short process was developed to realize green, in-situ regeneration of the sludge and efficient reuse of heavy rare earth elements. The regenerated magnets showed excellent magnetic performance and good temperature stability which were fabricated after the purification of sludge, composition regulation with rare earth-rich compounds, Nd<sub>42.1</sub>Fe<sub>bal</sub>B<sub>0.79</sub>, NdH<sub>x</sub>, (PrNd)H<sub>x</sub>, and sintering. Especially, the magnet prepared by using Nd<sub>42.1</sub>Fe<sub>bal</sub>B<sub>0.79</sub> alloy had significant property recovery, where remanence and coercivity were restored to 12.8 kG, and 20.6 kOe, respectively, reaching 97.7 % and 162.5 % of the original magnet. The magnetization reversal behavior and the coercivity mechanism were analyzed to keep the nucleation mechanism, and the high coercivity stemmed from the repair and optimization of the grain boundary by introducing rare earth-rich alloys, the full utilization of heavy rare earth elements, and the core–shell microstructure rooted in the sludge as well.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172548"},"PeriodicalIF":2.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322151","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}
Pub Date : 2024-09-21DOI: 10.1016/j.jmmm.2024.172550
Jie Jiang , Yujing Zhang , Shiqi Zheng , Chuyang Liu , Yilin Zhang , Liang Yan , Rui Liu , Fan Wu , Dong-Hyun Kim , Feng Xu
Transition metal magnetic alloys have garnered extensive interests in electromagnetic wave absorption due to the remarkable magnetic loss capacity and unique magnetism-frequency characteristics. Herein, we report a novel magnetic absorbent of Ni1-xCox micro chains that synthesized through a magnetic field-assisted reduction method. The precipitated Ni1-xCox particles could be connected and aligned during the magnetic reduction process. Due to the modified electronic structure of the Co active site by Ni, the particle size in the Ni1-xCox micro chains noticeably increases with increased x. Meanwhile, the complex dielectric constants exhibit a decreasing trend, which contributes to the improved impedance matching and higher resonance frequencies. The connected Ni1-xCox micro/nano particles not only benefit to the conductive loss, but also strengthened the polarization loss on the contacted interfaces among the particles. As a result, significantly enhanced electromagnetic wave absorption performance was obtained with the minimum reflection loss of −21.0 dB and the effective absorption bandwidth of 3.92 GHz at a thickness of only 1.35 mm. Overall, this work has demonstrated the strategy of designing aligned bimetallic absorbent, possessing great potentials in improving their microwave absorption properties.
过渡金属磁性合金具有显著的磁损耗能力和独特的磁频特性，因此在电磁波吸收领域受到广泛关注。在此，我们报告了一种通过磁场辅助还原法合成的新型 Ni1-xCox 微链磁性吸波材料。在磁还原过程中，沉淀的 Ni1-xCox 颗粒可以连接和排列。由于镍改变了 Co 活性位点的电子结构，Ni1-xCox 微链中的颗粒尺寸随着 x 的增加而明显增大，同时，复合介电常数呈下降趋势，这有助于改善阻抗匹配和提高共振频率。连接在一起的 Ni1-xCox 微/纳米粒子不仅有利于降低导电损耗，还能增强粒子间接触界面上的极化损耗。因此，在厚度仅为 1.35 毫米的情况下，电磁波吸收性能得到了显著增强，最小反射损耗为 -21.0 dB，有效吸收带宽为 3.92 GHz。总之，这项工作展示了设计对齐双金属吸收体的策略，在改善微波吸收特性方面具有巨大潜力。
{"title":"Chain-arranged Ni1-xCox micro/nano particles prepared via a magnetic field-assisted reduction for enhanced electromagnetic wave absorption","authors":"Jie Jiang , Yujing Zhang , Shiqi Zheng , Chuyang Liu , Yilin Zhang , Liang Yan , Rui Liu , Fan Wu , Dong-Hyun Kim , Feng Xu","doi":"10.1016/j.jmmm.2024.172550","DOIUrl":"10.1016/j.jmmm.2024.172550","url":null,"abstract":"<div><div>Transition metal magnetic alloys have garnered extensive interests in electromagnetic wave absorption due to the remarkable magnetic loss capacity and unique magnetism-frequency characteristics. Herein, we report a novel magnetic absorbent of Ni<sub>1-x</sub>Co<sub>x</sub> micro chains that synthesized through a magnetic field-assisted reduction method. The precipitated Ni<sub>1-x</sub>Co<sub>x</sub> particles could be connected and aligned during the magnetic reduction process. Due to the modified electronic structure of the Co active site by Ni, the particle size in the Ni<sub>1-x</sub>Co<sub>x</sub> micro chains noticeably increases with increased x. Meanwhile, the complex dielectric constants exhibit a decreasing trend, which contributes to the improved impedance matching and higher resonance frequencies. The connected Ni<sub>1-x</sub>Co<sub>x</sub> micro/nano particles not only benefit to the conductive loss, but also strengthened the polarization loss on the contacted interfaces among the particles. As a result, significantly enhanced electromagnetic wave absorption performance was obtained with the minimum reflection loss of −21.0 dB and the effective absorption bandwidth of 3.92 GHz at a thickness of only 1.35 mm. Overall, this work has demonstrated the strategy of designing aligned bimetallic absorbent, possessing great potentials in improving their microwave absorption properties.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172550"},"PeriodicalIF":2.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311750","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}
Pub Date : 2024-09-21DOI: 10.1016/j.jmmm.2024.172545
Sanjay Kumar Upadhyay , Shivani Kulasari , Rosni Roy , Sagar Sen , Rajib Mondal
Sm2BaCoO5, a spin chain based polycrystalline compound which crystallize in orthorhombic structure (space group, Immm), is known to order antiferromagnetically close to 38 K. As motivated by 1) its Tb analogues [1] which show giant magneto-dielectric coupling and a new type-II multiferroic and 2) recently discovered multiferroicity in Sm2BaMO5 (M=Ni and Cu) compounds [2], [3], detailed dielectric, ferroelectric and magneto-electric measurements have been carried out for Sm2BaCoO5. Magnetic and heat capacity measurements confirm the antiferromagnetic ordering at around 38 K. Interestingly ferroelectric transition also occurs around 38 K as revealed by frequency independent dielectric data as well as pyro-current measurements in various protocols. Therefore, the presented experimental results show that spin chain oxide Sm2BaCoO5 is new type-II multiferroic and we have identified R2BaCoO5 (R=Tb, Sm)- spin chain based cobaltates, is the new multiferroic series, so far unexplored.
{"title":"Multiferrocity in spin chain based polycrystalline Sm2BaCoO5","authors":"Sanjay Kumar Upadhyay , Shivani Kulasari , Rosni Roy , Sagar Sen , Rajib Mondal","doi":"10.1016/j.jmmm.2024.172545","DOIUrl":"10.1016/j.jmmm.2024.172545","url":null,"abstract":"<div><div>Sm<sub>2</sub>BaCoO<sub>5</sub>, a spin chain based polycrystalline compound which crystallize in orthorhombic structure (space group, Immm), is known to order antiferromagnetically close to 38 K. As motivated by 1) its Tb analogues <span><span>[1]</span></span> which show giant magneto-dielectric coupling and a new type-II multiferroic and 2) recently discovered multiferroicity in Sm<sub>2</sub>BaMO<sub>5</sub> (M=Ni and Cu) compounds <span><span>[2]</span></span>, <span><span>[3]</span></span>, detailed dielectric, ferroelectric and magneto-electric measurements have been carried out for Sm<sub>2</sub>BaCoO<sub>5</sub>. Magnetic and heat capacity measurements confirm the antiferromagnetic ordering at around 38 K. Interestingly ferroelectric transition also occurs around 38 K as revealed by frequency independent dielectric data as well as pyro-current measurements in various protocols. Therefore, the presented experimental results show that spin chain oxide Sm<sub>2</sub>BaCoO<sub>5</sub> is new type-II multiferroic and we have identified R<sub>2</sub>BaCoO<sub>5</sub> (R=Tb, Sm)- spin chain based cobaltates, is the new multiferroic series, so far unexplored.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172545"},"PeriodicalIF":2.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311753","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}
In this work styrene-ethylene-butylene-styrene (SEBS) block copolymer based smart magnetorheological elastomeric (MREs) materials have been additively manufactured using solvent-cast 4D Printing (SC-4DP) technique. The effect of carbonyl iron powder (CIP) content on the particle distribution, particle–matrix adhesion, surface and layer morphology of the 4D Printed MRE sample was investigated. CIP particles were observed to be well embedded and dispersed up to 60 wt% content. However, at higher CIP content the tendency of the particles to agglomerate increased significantly. Furthermore, samples with CIP content ≥70 wt% showed poor particle–matrix adhesion and possessed inter-layer coalescence defects. Investigations were also performed to evaluate the magnetic properties of MREs at room temperature. Magnetorheological behaviour was studied to evaluate the effect of varying magnetic field on dynamic viscoelastic properties. Magnetorheological effect increased from ∼79 % to ∼211 % with an increase in CIP content. However, the particle–matrix adhesion also significantly affected the magnetorheological effect for higher CIP content samples. Magnetic actuation capability of flexible MRE samples was evaluated for gripper-based application. SC-4D Printed flexible grippers were able to successfully grip, lift, and drop both the soft deformable and rigid freeform profile objects in different media (air and sodium hydroxide solution) suggesting suitability for remotely actuated gripper-based applications.
{"title":"Magnetorheological and magnetic actuation behaviour of solvent cast 4D printed styrene-ethylene-butylene-styrene block copolymer based magnetorheological elastomeric materials","authors":"Arun Kumar , Pulak Mohan Pandey , Kuldeep , Sunil Jha , G.A. Basheed , Shib Shankar Banerjee","doi":"10.1016/j.jmmm.2024.172551","DOIUrl":"10.1016/j.jmmm.2024.172551","url":null,"abstract":"<div><div>In this work styrene-ethylene-butylene-styrene (SEBS) block copolymer based smart magnetorheological elastomeric (MREs) materials have been additively manufactured using solvent-cast 4D Printing (SC-4DP) technique. The effect of carbonyl iron powder (CIP) content on the particle distribution, particle–matrix adhesion, surface and layer morphology of the 4D Printed MRE sample was investigated. CIP particles were observed to be well embedded and dispersed up to 60 wt% content. However, at higher CIP content the tendency of the particles to agglomerate increased significantly. Furthermore, samples with CIP content ≥70 wt% showed poor particle–matrix adhesion and possessed inter-layer coalescence defects. Investigations were also performed to evaluate the magnetic properties of MREs at room temperature. Magnetorheological behaviour was studied to evaluate the effect of varying magnetic field on dynamic viscoelastic properties. Magnetorheological effect increased from ∼79 % to ∼211 % with an increase in CIP content. However, the particle–matrix adhesion also significantly affected the magnetorheological effect for higher CIP content samples. Magnetic actuation capability of flexible MRE samples was evaluated for gripper-based application. SC-4D Printed flexible grippers were able to successfully grip, lift, and drop both the soft deformable and rigid freeform profile objects in different media (air and sodium hydroxide solution) suggesting suitability for remotely actuated gripper-based applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172551"},"PeriodicalIF":2.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358022","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}
Rare-earth iron garnet epitaxial films famous for their unique magnetic, microwave and optical properties consistently attract high interest. Domain structure of both bulk and interfaces of garnet films is closely connected with their magnetic properties and magnetization dynamics. In this work, we investigate the magnetic behaviour and domain structure of an epitaxial bismuth-substituted lutetium iron garnet film with a regular array of planar submicron particles made of Co film or Co/Pt multilayer on its surface. Optical polarization microscopy and magnetic force microscopy techniques used for the characterization of these composite structures confirm the mutual influence of the garnet and metal nanostructured layers on each other. On the one hand, dense ordered metal particles provide the pinning of the surface magnetic domains of the garnet film, which further affects the organization of the bulk stripe domains. On the other hand, we observed that the domain structure in the metallic pattern is governed by the domain structure of the garnet placed beneath it.
稀土铁石榴石外延薄膜以其独特的磁性、微波和光学特性而闻名，一直以来都备受关注。石榴石薄膜块体和界面的畴结构与其磁性能和磁化动态密切相关。在这项工作中，我们研究了铋取代镥铁石榴石外延薄膜的磁行为和畴结构，该薄膜表面有由 Co 薄膜或 Co/Pt 多层制成的规则平面亚微米粒子阵列。用于表征这些复合结构的光学偏振显微镜和磁力显微镜技术证实了石榴石层和金属纳米结构层之间的相互影响。一方面，致密有序的金属颗粒为石榴石薄膜的表面磁畴提供了引脚，从而进一步影响了块状条纹磁畴的组织。另一方面，我们观察到金属图案中的磁畴结构受置于其下的石榴石磁畴结构的支配。
{"title":"Pinning of domain walls in epitaxial garnet film patterned by surface arrays of ferromagnetic metal particles","authors":"M.P. Temiryazeva , I.A. Kolmychek , A.G. Temiryazev , V.B. Novikov , A.I. Maydykovskiy , N.S. Gusev , E.V. Skorokhodov , S.A. Gusev , S.A. Nikitov , K.S. Napolskii , T.V. Murzina","doi":"10.1016/j.jmmm.2024.172534","DOIUrl":"10.1016/j.jmmm.2024.172534","url":null,"abstract":"<div><div>Rare-earth iron garnet epitaxial films famous for their unique magnetic, microwave and optical properties consistently attract high interest. Domain structure of both bulk and interfaces of garnet films is closely connected with their magnetic properties and magnetization dynamics. In this work, we investigate the magnetic behaviour and domain structure of an epitaxial bismuth-substituted lutetium iron garnet film with a regular array of planar submicron particles made of Co film or Co/Pt multilayer on its surface. Optical polarization microscopy and magnetic force microscopy techniques used for the characterization of these composite structures confirm the mutual influence of the garnet and metal nanostructured layers on each other. On the one hand, dense ordered metal particles provide the pinning of the surface magnetic domains of the garnet film, which further affects the organization of the bulk stripe domains. On the other hand, we observed that the domain structure in the metallic pattern is governed by the domain structure of the garnet placed beneath it.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172534"},"PeriodicalIF":2.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322152","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}
Pub Date : 2024-09-21DOI: 10.1016/j.jmmm.2024.172549
Shalini Badola, Aprajita Joshi, Surajit Saha
A spin-liquid state can be induced by uncompensated interactions in the spin lattice due to disorder or randomness in exchange pathways. Sr2CuTeO6 and Sr2CuWO6 are square-lattice antiferromagnetic double perovskites (A2BB′O6) with dominant nearest-neighbor (Néel-type) and next-nearest neighbor (Columnar-type) magnetic interactions, respectively. Random distribution of these interactions in a system has been theoretically predicted to be a way to induce the spin-liquid state. Here, we have synthesized a spin-liquid candidate Sr2CuTe0.5W0.5O6 with B′-site mixing of its parent systems (Sr2CuTeO6 and Sr2CuWO6) to explore the phonon properties and their correlations with the liquid-like magnetic interactions. Our measurements reveal the presence of a broad continuum in the Raman spectrum of Sr2CuTe0.5W0.5O6, instead of the well-defined spin-wave excitations (magnon) observed in the parent systems. Observation of continuum feature in the Raman spectrum in conjunction with the lack of long-range magnetic order provide the signatures of liquid-like correlations. On the other hand, phonon anomalies are observed below the short-ranged magnetic ordering temperature indicating the onset of spin-phonon coupling.
{"title":"Signatures of spin-liquid-like state and spin-phonon coupling in square lattice Sr2CuTe0.5W0.5O6","authors":"Shalini Badola, Aprajita Joshi, Surajit Saha","doi":"10.1016/j.jmmm.2024.172549","DOIUrl":"10.1016/j.jmmm.2024.172549","url":null,"abstract":"<div><div>A spin-liquid state can be induced by uncompensated interactions in the spin lattice due to disorder or randomness in exchange pathways. Sr<sub>2</sub>CuTeO<sub>6</sub> and Sr<sub>2</sub>CuWO<sub>6</sub> are square-lattice antiferromagnetic double perovskites (A<sub>2</sub>BB′O<sub>6</sub>) with dominant nearest-neighbor (Néel-type) and next-nearest neighbor (Columnar-type) magnetic interactions, respectively. Random distribution of these interactions in a system has been theoretically predicted to be a way to induce the spin-liquid state. Here, we have synthesized a spin-liquid candidate Sr<sub>2</sub>CuTe<sub>0.5</sub>W<sub>0.5</sub>O<sub>6</sub> with B′-site mixing of its parent systems (Sr<sub>2</sub>CuTeO<sub>6</sub> and Sr<sub>2</sub>CuWO<sub>6</sub>) to explore the phonon properties and their correlations with the liquid-like magnetic interactions. Our measurements reveal the presence of a broad continuum in the Raman spectrum of Sr<sub>2</sub>CuTe<sub>0.5</sub>W<sub>0.5</sub>O<sub>6</sub>, instead of the well-defined spin-wave excitations (magnon) observed in the parent systems. Observation of continuum feature in the Raman spectrum in conjunction with the lack of long-range magnetic order provide the signatures of liquid-like correlations. On the other hand, phonon anomalies are observed below the short-ranged magnetic ordering temperature indicating the onset of spin-phonon coupling.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172549"},"PeriodicalIF":2.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314282","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}
In order to improve biomimicry, a four-bar linkage prosthetic knee with magnetorheological (MR) damper was developed in this paper. The principle and structure of four-bar linkage MR prosthetic knee was introduced and its kinetic model was established. A MR damper matching the proposed prosthetic knee was designed, fabricated and tested, and the forward and inverse mechanical model were conducted. In addition, to solve the problems of complex model, poor bionics and low trajectory tracking accuracy in the MR prosthetic knee, a PD-type iterative learning control (ILC) controller was developed. The simulated and experimental test results show that the positive maximum error of the knee joint swing trajectory based on PD-type ILC controller are 2.2°(speed of 0.5 m/s), 4.1°(speed of 1.0 m/s), and 1.9°(speed of 1.5 m/s), respectively, and the negative maximum error of that are −1.4°(speed of 0.5 m/s), −6.7°(speed of 1.0 m/s), and −5.5°(speed of 1.5 m/s), respectively, which effectively tracks the reference swing trajectory.
{"title":"Trajectory tracking control of a four-bar linkage prosthetic knee with magnetorheological damper","authors":"Jiawei Zhang , Guoliang Hu , Jinpeng Zhao , Wencai Zhu","doi":"10.1016/j.jmmm.2024.172537","DOIUrl":"10.1016/j.jmmm.2024.172537","url":null,"abstract":"<div><div>In order to improve biomimicry, a four-bar linkage prosthetic knee with magnetorheological (MR) damper was developed in this paper. The principle and structure of four-bar linkage MR prosthetic knee was introduced and its kinetic model was established. A MR damper matching the proposed prosthetic knee was designed, fabricated and tested, and the forward and inverse mechanical model were conducted. In addition, to solve the problems of complex model, poor bionics and low trajectory tracking accuracy in the MR prosthetic knee, a PD-type iterative learning control (ILC) controller was developed. The simulated and experimental test results show that the positive maximum error of the knee joint swing trajectory based on PD-type ILC controller are 2.2°(speed of 0.5 m/s), 4.1°(speed of 1.0 m/s), and 1.9°(speed of 1.5 m/s), respectively, and the negative maximum error of that are −1.4°(speed of 0.5 m/s), −6.7°(speed of 1.0 m/s), and −5.5°(speed of 1.5 m/s), respectively, which effectively tracks the reference swing trajectory.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172537"},"PeriodicalIF":2.5,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314281","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}
The nanocrystalline Zn-doped Nickel ferrite nanoparticles, ZnxNi1-xFe2O4 (x = 0.2, 0.4, 0.6 and 0.8) have been developed using the sol–gel method. The average crystallite size was calculated using the Debye- Scherrer formula through X-ray diffractometry and found to be in the range of ∼ 4 nm to 7 nm. Rietveld refinement of the prepared samples suggested the cubic spinel phase of the nanoparticles. For the surface morphology analysis of the nanoparticles, the Field Emission Scanning Electron Microscope (FESEM) technique was utilized, which showed the spherical shape of the particles. Elemental Dispersive X-ray spectroscopy (EDAX) ascertained the experimentally obtained elemental composition with the calculated elemental composition and identified the elements present within the sample. Fourier Transform Infrared Spectroscopy (FTIR) revealed the two prominent absorbing bands, i.e., tetrahedral complex, υ1 and octahedral complex, υ2 in the range of 4000–300 cm−1. Photoluminescence spectroscopy and UV Visible diffuse reflectance spectroscopy determined the optical properties of the samples and it was observed that with the increasing concentration of Zinc, the value of band gap decreased from 2.29 eV to 2.11 eV. The M−H curves of the Zn-doped nickel ferrites exhibit superparamagnetic behavior at room temperature, confirming the presence of a single domain in the sample.
利用溶胶-凝胶法研制出了掺锌镍铁氧体纳米粒子 ZnxNi1-xFe2O4（x = 0.2、0.4、0.6 和 0.8）。通过 X 射线衍射测量法，使用 Debye- Scherrer 公式计算出平均晶粒尺寸，发现其范围在 4 纳米至 7 纳米之间。对制备的样品进行的里特维尔德细化表明，纳米粒子为立方尖晶石相。利用场发射扫描电子显微镜（FESEM）技术对纳米颗粒进行了表面形貌分析，结果显示颗粒呈球形。元素色散 X 射线光谱（EDAX）确定了实验得出的元素组成与计算得出的元素组成，并确定了样品中存在的元素。傅立叶变换红外光谱（FTIR）显示了两个显著的吸收带，即在 4000-300 cm-1 范围内的四面体络合物 υ1 和八面体络合物 υ2。光致发光光谱和紫外可见光漫反射光谱测定了样品的光学性质，观察到随着锌浓度的增加，带隙值从 2.29 eV 下降到 2.11 eV。掺锌镍铁氧体的 M-H 曲线在室温下呈现超顺磁性，证实了样品中存在单畴。
{"title":"Development and characterization of superparamagnetic Zn-Doped Nickel ferrite nanoparticles","authors":"Sarita , Anchal , Priya , R.K. Beniwal , M.S. Rulaniya , P.M. Saini , Pooja Yadav , Upendra Kumar , Aakansha , P.A. Alvi , B.L. Choudhary","doi":"10.1016/j.jmmm.2024.172547","DOIUrl":"10.1016/j.jmmm.2024.172547","url":null,"abstract":"<div><div>The nanocrystalline Zn-doped Nickel ferrite nanoparticles, Zn<sub>x</sub>Ni<sub>1-x</sub>Fe<sub>2</sub>O<sub>4</sub> (x = 0.2, 0.4, 0.6 and 0.8) have been developed using the sol–gel method. The average crystallite size was calculated using the Debye- Scherrer formula through X-ray diffractometry and found to be in the range of ∼ 4 nm to 7 nm. Rietveld refinement of the prepared samples suggested the cubic spinel phase of the nanoparticles. For the surface morphology analysis of the nanoparticles, the Field Emission Scanning Electron Microscope (FESEM) technique was utilized, which showed the spherical shape of the particles. Elemental Dispersive X-ray spectroscopy (EDAX) ascertained the experimentally obtained elemental composition with the calculated elemental composition and identified the elements present within the sample. Fourier Transform Infrared Spectroscopy (FTIR) revealed the two prominent absorbing bands, i.e., tetrahedral complex, υ<sup>1</sup> and octahedral complex, υ<sup>2</sup> in the range of 4000–300 cm<sup>−1</sup>. Photoluminescence spectroscopy and UV Visible diffuse reflectance spectroscopy determined the optical properties of the samples and it was observed that with the increasing concentration of Zinc, the value of band gap decreased from 2.29 eV to 2.11 eV. The M−H curves of the Zn-doped nickel ferrites exhibit superparamagnetic behavior at room temperature, confirming the presence of a single domain in the sample.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172547"},"PeriodicalIF":2.5,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311751","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}
Pub Date : 2024-09-20DOI: 10.1016/j.jmmm.2024.172539
Ishita Tikader, Muktish Acharyya
The equilibrium and nonequilibrium properties of an Ising ferromagnetic cubic shell have been extensively studied by Monte Carlo simulation using Metropolis single spin flip algorithm. Although, geometrically the Euclidean dimension of the cubical shell is three, interestingly, the Ising ferromagnetic cubic shell undergoes ferromagnetic phase transition at a temperature which is very close to that for two-dimensional Ising ferromagnet. Surprisingly, the Ising ferromagnetic cubic shell shows a strange (neither exponential nor stretched exponential) kind of relaxation behaviour, instead of exponential relaxation as usually observed in the two dimensional Ising ferromagnet. The metastable lifetime of a ferromagnetic Ising cubical shell is studied as a function of the applied magnetic field. Here also, the cubic shell behaves more likely a two-dimensional object as found from statistical analysis and comparison with Becker–Döring prediction of classical nucleation theory.
{"title":"What will be the Euclidean dimension of an Ising ferromagnetic cubic shell?","authors":"Ishita Tikader, Muktish Acharyya","doi":"10.1016/j.jmmm.2024.172539","DOIUrl":"10.1016/j.jmmm.2024.172539","url":null,"abstract":"<div><div>The equilibrium and nonequilibrium properties of an Ising ferromagnetic cubic shell have been extensively studied by Monte Carlo simulation using Metropolis single spin flip algorithm. Although, geometrically the Euclidean dimension of the cubical shell is three, interestingly, the Ising ferromagnetic cubic shell undergoes ferromagnetic phase transition at a temperature which is very close to that for two-dimensional Ising ferromagnet. Surprisingly, the Ising ferromagnetic cubic shell shows a strange (neither exponential nor stretched exponential) kind of relaxation behaviour, instead of exponential relaxation as usually observed in the two dimensional Ising ferromagnet. The metastable lifetime of a ferromagnetic Ising cubical shell is studied as a function of the applied magnetic field. Here also, the cubic shell behaves more likely a two-dimensional object as found from statistical analysis and comparison with Becker–Döring prediction of classical nucleation theory.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"610 ","pages":"Article 172539"},"PeriodicalIF":2.5,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311756","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}
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