Journal of Magnetism and Magnetic Materials最新文献

{"title":"Understanding the role of multi-component elements on the magnetic and magnetocaloric properties of (Mg0.2Mn0.2Co0.2Ni0.2Cu0.2)Fe2O4 high entropy spinel oxide","authors":"Deepak Verma,&nbsp;Tulika Maitra,&nbsp;V.K. Malik,&nbsp;G.D. Varma","doi":"10.1016/j.jmmm.2025.173033","DOIUrl":"10.1016/j.jmmm.2025.173033","url":null,"abstract":"<div><div>We have investigated the magnetic and magnetocaloric properties of (Mg_0.2Mn_0.2Co_0.2Ni_0.2Cu_0.2)Fe₂O₄ high entropy spinel oxide (0.2 HEO) synthesized by solid-state reaction method. The structural and morphological features have been investigated using X-ray diffraction, field-emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, high-resolution X-ray photoelectron spectroscopy, and transmission electron microscopy. The obtained Tauc plot confirms the semiconducting nature of the sample. The real part of ac susceptibility measurement indicates the absence of the spin-glass state, which suggests the presence of local magnetic ordering due to typical ferromagnetic or AFM behaviour. The dc magnetization data is obtained under zero-field and field-cooled conditions indicating some inflection points/magnetic anomalies pointing towards the onset of local magnetic ordering in some regions of the sample that become more discernible at higher fields. A second-order magnetic phase transition has been deduced from Arrott’s plot measured at and below room temperature. The magnetocaloric effect (MCE), determined from the magnetic entropy change (ΔS_m), indicates both inverse and direct MCE. The measured values of ΔS_m show an abrupt change above 250 K whose value changes from positive to a large negative and found to attain a maximum of 1.96 J Kg⁻¹ K⁻¹ at 290 K under 5 T of the applied magnetic field, which agrees with the magnetic anomaly observed in the heat capacity measurement. We have fitted the zero-field low-temperature heat capacity data from the Debye-Einstein model and the phonon-magnon contribution to heat capacity. Also, we have observed an improved ΔS_m value at around room temperature using multi-component elements.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 173033"},"PeriodicalIF":2.5,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777660","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}

{"title":"The high entropy multi-component diffusion of Tb60Dy10Cu10Al10Zn10 effectively enhances the diffusion depth of heavy rare earths and coercivity in NdFeB magnets","authors":"Chengzhi Sun ,&nbsp;Xin Ming ,&nbsp;Pengbo Fu ,&nbsp;Jianqiang Lin ,&nbsp;Fang Wang ,&nbsp;Fanbin Meng ,&nbsp;Jian Zhang ,&nbsp;Baogen Shen","doi":"10.1016/j.jmmm.2025.173027","DOIUrl":"10.1016/j.jmmm.2025.173027","url":null,"abstract":"<div><div>Grain boundary diffusion (GBD) magnets are essential for high-power density motors in applications like new energy vehicles and wind power. However, current GBD magnets face challenges such as limited diffusion depth and low heavy rare earth (HRE) utilization, hindering their development. In this study, magnetron sputtering was used to deposit 10 μm thick quinary Tb₆₀Dy₁₀Cu₁₀Al₁₀Zn₁₀, binary Tb₇₀Cu₃₀, and Tb diffusion layers on commercial 52H magnets. After diffusion heat treatment, GBD magnets were produced. Magnetic tests showed that coercivity increased from 16.72 kOe to 23.53kOe, 22.02 kOe, and 22.03 kOe for the quinary, binary, and Tb diffusion magnets, respectively. The quinary diffusion magnet achieved 22.23 kOe/wt% HRE, significantly higher than 16.85 kOe/wt% HRE and 14.67 kOe/wt% HRE for Tb₇₀Cu₃₀ and Tb diffusion magnets. Microstructural analysis revealed that, compared to binary TbCu and Tb diffusion magnets, the HRE-rich shell and thin grain boundary phase in the quinary diffusion magnet extended further along the diffusion direction, leading to high coercivity. Quantitative Tb analysis confirmed that quinary alloy diffusion enhances HRE diffusion depth. We propose that higher entropy in multi-component diffusion sources lowers Gibbs free energy, preventing HRE from entering main phase grains, thus improving diffusion depth and HRE utilization. Multi-component diffusion is a promising approach for high-performance GBD NdFeB magnets. Our study offers valuable insights for advancing GBD magnets.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 173027"},"PeriodicalIF":2.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783100","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}

{"title":"Neutron scattering studies on NdCrTiO5 and RCrGeO5 (R = Nd, Ho, Er) possessing spin-32 antiferromagnetic alternating chains of Cr3＋ spins","authors":"Masashi Hase ,&nbsp;Shinichiro Asai ,&nbsp;Minoru Soda ,&nbsp;Daichi Kawana ,&nbsp;Takatsugu Masuda ,&nbsp;Shinichi Itoh ,&nbsp;Tetsuya Yokoo ,&nbsp;Masanori Kohno ,&nbsp;Vladimir Yu. Pomjakushin ,&nbsp;Andreas Dönni ,&nbsp;Martin Rotter","doi":"10.1016/j.jmmm.2025.172970","DOIUrl":"10.1016/j.jmmm.2025.172970","url":null,"abstract":"&lt;div&gt;&lt;div&gt;We performed inelastic neutron scattering experiments on NdCrTiO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and &lt;em&gt;R&lt;/em&gt;CrGeO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; (&lt;em&gt;R&lt;/em&gt; = Nd, Ho, Er) powders and neutron diffraction experiments on NdCrGeO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; powder. The spin system of Cr&lt;sup&gt;3＋&lt;/sup&gt; spins is a spin-&lt;span&gt;&lt;math&gt;&lt;mfrac&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/mfrac&gt;&lt;/math&gt;&lt;/span&gt; antiferromagnetic (AFM) alternating (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;J&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;J&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) chain whose ground state (GS) is a nonmagnetic spin–singlet state with a spin gap. We observed magnetic excitations of Cr&lt;sup&gt;3＋&lt;/sup&gt; spins and evaluated the spin gap and two exchange interactions. The value of the spin gap is smaller in NdCrTiO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; (6.9 meV) than in NdCrGeO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; (18 meV). We observed magnetic reflections in NdCrGeO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and evaluated Cr and Nd ordered moments at 1.9 K (AFM transition temperature &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; K). The Cr moment for NdCrGeO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; is very small (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;22&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), whereas that for NdCrTiO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; has been reported to be 1.6 – 2.4 &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; at 6 K (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;21&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; K). In NdCrTiO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, the first-excited triplet state of the AFM alternating chain can be hybridized with the spin–singlet GS by other interactions because of the small spin gap. &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; is high because Cr spins and Nd moments can be ordered cooperatively. In NdCrGeO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, Cr spins are almost disordered even below &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; because of the large spin gap. &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; is low because the magnetic order is substantially generated by only Nd moments. &lt;em&gt;R&lt;/em&gt;CrGeO&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mr","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 172970"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769274","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}

{"title":"Testing of magnetic properties of amorphous and nanocrystalline alloys applied out-of-plane stress at wide frequency range","authors":"Changgeng Zhang,&nbsp;Guochen Niu,&nbsp;Wenbin Meng,&nbsp;Yongjian Li","doi":"10.1016/j.jmmm.2025.173013","DOIUrl":"10.1016/j.jmmm.2025.173013","url":null,"abstract":"<div><div>Nanocrystalline and amorphous alloys are extensively utilized as core materials in devices such as motors and transformers. Their magnetic properties can be altered by stress, significantly impacting the operational efficiency and reliability of electrical equipment. In this study, a wide-frequency-range magnetic property testing system capable of applying out-of-plane stress is designed. The design of the stress application components and the uniformity of stress distribution in the samples are thoroughly analyzed through simulations. This system is used to measure the changes in the magnetic properties of nanocrystalline and amorphous alloy sheets under out-of-plane stress over a wide frequency range. The test results indicate that the out-of-plane stress applied to nanocrystalline alloys leads to an increase in the core loss. The core loss in amorphous alloys initially decreases and subsequently increases at frequencies exceeding the kilohertz range.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 173013"},"PeriodicalIF":2.5,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769171","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}

{"title":"Electronic structure and magnetic properties of La(Co1−xXx)Si; X=Fe and Ni","authors":"Himanshu,&nbsp;J.J. Pulikkotil","doi":"10.1016/j.jmmm.2025.172996","DOIUrl":"10.1016/j.jmmm.2025.172996","url":null,"abstract":"<div><div>LaCoSi, a 4 K superconductor, exhibits paramagnetic behavior experimentally, contradicting the ferromagnetic ground state predicted by first-principles electronic structure methods. This discrepancy usually underscores the role of dynamical spin fluctuations which are neglected in the local density approximation. Our calculations based on the Korringa–Kohn–Rostoker method with disorder taken into account using coherent potential approximation calculations further corroborate this notion. Fe substitution at the Co sites suppresses magnetism, coinciding with the experimentally observed enhancement of the superconducting transition temperature. Conversely, Ni substitution preserves the local magnetic moment, aligning with its suppressive effect on superconductivity. These contrasting effects of Fe and Ni substitutions in LaCoSi suggest a close interplay of superconductivity and magnetism, suggesting its proximity to a ferromagnetic quantum critical point.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 172996"},"PeriodicalIF":2.5,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747201","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}

{"title":"Magnetic properties of La2M4Sb2O12, M = Ni, Co with CaFe2O4-type superstructure","authors":"Anna V. Egorysheva ,&nbsp;Olga G. Ellert ,&nbsp;Svetlana V. Golodukhina ,&nbsp;Lada S. Razvorotneva ,&nbsp;Stanislav I. Bezzubov ,&nbsp;Denis I. Kirdyankin","doi":"10.1016/j.jmmm.2025.173020","DOIUrl":"10.1016/j.jmmm.2025.173020","url":null,"abstract":"<div><div>Crystal structure of the novel compounds La₂M₄Sb₂O₁₂, M = Ni, Co, has been determined for the first time. La₂M₄Sb₂O₁₂ crystalize as superstructure of CaFe₂O₄-type, sp. gr. <em>Pnma</em> (# 62). Their crystal lattices are ordered by both B and A sites, namely M / Sb atoms and La vacancies along the <em>b</em> axis. The structure is formed by zigzag chains [MO₄]_∞ of edge-shared octahedra. Exchange interactions of magnetic ions in/between the chains determine the magnetic properties. An antiferromagnetic transition and magnetization reversal at T_N = 25 K occur in La₂Ni₄Sb₂O₁₂. Magnetic transitions at T_N = 9.3 K and T_tr = 16 K are detected in La₂Co₄Sb₂O₁₂ in low magnetic field. For both compounds in low magnetic fields and temperatures T &lt; T_N a magnetic behavior characteristic of canted antiferromagnets is observed. A stepwise hysteresis and transition at H = 15 kOe in La₂Co₄Sb₂O₁₂, can be considered as characteristic features of metamagnets.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 173020"},"PeriodicalIF":2.5,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759569","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}

{"title":"Reducing the annealing heating rate sensitivity of Fe83.5Si3B10P2Cu1.5 soft magnetic nanocrystalline alloy by adjusting the B/P ratio","authors":"T.X. Huang ,&nbsp;Q. Yan ,&nbsp;F.G. Chen ,&nbsp;Aditya Jain ,&nbsp;H.Z. Zhou ,&nbsp;Y.G. Wang","doi":"10.1016/j.jmmm.2025.173005","DOIUrl":"10.1016/j.jmmm.2025.173005","url":null,"abstract":"<div><div>The effects of B/P ratio on microstructure, crystallization behavior and soft magnetic characteristics of Fe_83.5Si₃B_10-<em>_x</em>P₂₊<em>_x</em>Cu_1.5 (<em>x</em> = 0, 3, 6 &amp; 8 at.%) amorphous alloys were studied. The results of Mössbauer spectra indicate that B/P ratio significantly impact the microstructure of amorphous alloy. A decrease in the B/P ratio facilitates the formation of an amorphous precursor containing more α-Fe-like structure and Cu(P)-clusters. As the B/P ratio reduces, the saturation magnetic induction (<em>B</em>_s) and the coercivity (<em>H</em>_c) of the as-quenched Fe_83.5Si₃B_10-<em>_x</em>P₂₊<em>_x</em>Cu_1.5 amorphous alloy decreases. After annealing with a low heating rate (1 °C/s), the Fe_83.5Si₃B₄P₈Cu_1.5 alloy shows a low <em>H</em>_c (≤ 10 A/m) in a broad temperature range. With the decrease of the B/P ratio, the sensitivity of the soft magnetic properties of the nanocrystalline alloys to the annealing heating rate decreases.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 173005"},"PeriodicalIF":2.5,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739163","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}

{"title":"Multivariate magnetorheological fluid modeling based on Mason number","authors":"Guo Peilin ,&nbsp;L.v. Jingcheng ,&nbsp;Wu Mingyu ,&nbsp;Kuang Senyun ,&nbsp;WEI Yintao ,&nbsp;Wang Xin","doi":"10.1016/j.jmmm.2025.172957","DOIUrl":"10.1016/j.jmmm.2025.172957","url":null,"abstract":"<div><div>This paper analyses the nonlinear rheological behavior of magnetorheological fluids over a wide range of shear rates, finding that the ELMA model describes this well, and explains the mechanism by using the long and short-range forces and Stribeck effects. A modified Mason number is proposed to solve the problem that the off-state nonlinear behavior of magnetorheological fluids cannot be handled by the existing dimensionless analysis based on the Mason number. Then, the ELMA multivariate model is designed based on the modified Mason number. The proposed ELMA multivariate model has certain physical meanings and can accurately describe the magnetorheological behavior of magnetorheological fluids in a wide range of shear rates. Specifically, contrasting with the polynomial model, the proposed model demonstrates an improvement by at least an order of magnitude in fitting accuracy.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 172957"},"PeriodicalIF":2.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759464","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}

{"title":"Magnetic properties of (Mo2/3Dy1/3)2AlC arc melted polycrystalline samples","authors":"Binod K. Rai ,&nbsp;Christopher A. Mizzi ,&nbsp;Alex Bretaña ,&nbsp;Logan Breton ,&nbsp;Catherine Housley ,&nbsp;Destiny Ivy ,&nbsp;Joshua Abbott ,&nbsp;Boris Maiorov ,&nbsp;Bhoj R. Gautam ,&nbsp;Matthias Frontzek ,&nbsp;Ram C. Rai ,&nbsp;Stuart Calder","doi":"10.1016/j.jmmm.2025.172992","DOIUrl":"10.1016/j.jmmm.2025.172992","url":null,"abstract":"<div><div>This study investigates the structural and magnetic properties of arc-melted (Mo<span><math><msub><mrow></mrow><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msub></math></span>Dy<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>/</mo><mn>3</mn></mrow></msub></math></span>)<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>AlC polycrystalline samples, a member of the <span><math><mi>i</mi></math></span>-MAX phase family. Temperature-dependent magnetization and specific heat measurements confirm the low-temperature antiferromagnetic transitions around 14 K and 17 K. Neutron diffraction data collected at 4 K reveal the emergence of magnetic Bragg peaks that are not allowed in the paramagnetic space group <span><math><mrow><mi>C</mi><mn>2</mn><mo>/</mo><mi>c</mi></mrow></math></span>, further confirming the presence of antiferromagnetic ordering. The detection of a secondary phase, DyAl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, is complicated by overlapping Bragg peaks with the monoclinic phase of (Mo<span><math><msub><mrow></mrow><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msub></math></span>Dy<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>/</mo><mn>3</mn></mrow></msub></math></span>)<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>AlC in powder XRD patterns. However, magnetization and neutron diffraction data suggest the presence of DyAl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, evidenced by a ferromagnetic phase transition around 62 K.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"624 ","pages":"Article 172992"},"PeriodicalIF":2.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143786109","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}

{"title":"Efficient design of non-contact magnetic induction-based energy harvesters from electromagnetic fields","authors":"Bahram Rashidi","doi":"10.1016/j.jmmm.2025.172988","DOIUrl":"10.1016/j.jmmm.2025.172988","url":null,"abstract":"<div><div>This paper presents the design and implementation of efficient non-contact magnetic induction-based energy harvesters utilizing various cores. Several cores are developed by adding a pair of ferrite magnetic flux collector parts to both ends of the rod core. This configuration enables the cores to guide more magnetic flux effectively. Exposing these cores to the magnetic flux enhances the energy harvesting rate. The proposed energy harvesters are based on non-contact coils with ferrite cores, so they do not need to be clamped around the conductor-an approach that often limits practical applications. Parameters such as the ability to charge a capacitor, the open-circuit voltage across the harvesters, and the output power are evaluated to assess the performance of the proposed structures. The results show that the structures meet acceptable specifications for practical requirements. Experimental results demonstrate the electrical output performance of the best proposed energy harvester (the <span><math><mo>○</mo></math></span>-shaped core) achieved a maximum open-circuit output voltage of 23.702 V and an output power of 1.994 mW under a magnetic field of 20 <span><math><mi>μ</mi></math></span>T. Since the presented non-contact energy harvesting structures are very simple and low-cost, the proposed method can be widely applied in power transmission, distribution, and smart grid systems.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"623 ","pages":"Article 172988"},"PeriodicalIF":2.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716324","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}