Pub Date : 2026-03-01Epub Date: 2026-01-17DOI: 10.1016/j.jmmm.2026.173849
M. Anisimov , V. Krasnorussky , A. Bogach , S. Demishev , A. Semeno , D. Salamatin , V. Sidorov , A. Bokov , A. Tsvyashchenko
Antiferromagnet (AFM) YbCoC with the highest for Yb-based compounds Neel temperature 25.8 K is studied by detailed measurements of galvanomagnetic properties [electrical resistivity, transverse magnetoresistance (TMR)] at temperatures 2–300 K and magnetic fields up to 82 kOe. Negative quadratic TMR detected in paramagnetic (PM) state is explained in terms of Yosida’s model, which takes into account the scattering of the conduction electrons on localized magnetic moments (LMMs) of rare-earth (RE) ions. The analysis of both local and bulk magnetic susceptibilities allows proposing the existence of short-range correlations in wide PM vicinity of . The polaronic scenario is suggested. The data obtained allow us to detect the appearance of field-induced TMR hysteresis inside the magnetically ordered state. Magnetic - diagram is also reconstructed and a few additional phase boundaries are assumed. One of them is interpreted as -phase. It stabilizes in the range 71–77 kOe on the boundary between commensurate and incommensurate magnetic structures at 8–9 K.
{"title":"Magnetotransport and rich H-T phase diagram in moderately heavy fermionic antiferromagnet YbCoC2","authors":"M. Anisimov , V. Krasnorussky , A. Bogach , S. Demishev , A. Semeno , D. Salamatin , V. Sidorov , A. Bokov , A. Tsvyashchenko","doi":"10.1016/j.jmmm.2026.173849","DOIUrl":"10.1016/j.jmmm.2026.173849","url":null,"abstract":"<div><div>Antiferromagnet (AFM) YbCoC<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> with the highest for Yb-based compounds Neel temperature <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> <span><math><mo>≈</mo></math></span> 25.8 K is studied by detailed measurements of galvanomagnetic properties [electrical resistivity, transverse magnetoresistance (TMR)] at temperatures 2–300 K and magnetic fields up to 82 kOe. Negative quadratic TMR detected in paramagnetic (PM) state is explained in terms of Yosida’s model, which takes into account the scattering of the conduction electrons on localized magnetic moments (LMMs) of rare-earth (RE) ions. The analysis of both local and bulk magnetic susceptibilities allows proposing the existence of short-range correlations in wide PM vicinity of <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span>. The polaronic scenario is suggested. The data obtained allow us to detect the appearance of field-induced TMR hysteresis inside the magnetically ordered state. Magnetic <span><math><mi>H</mi></math></span>-<span><math><mi>T</mi></math></span> diagram is also reconstructed and a few additional phase boundaries are assumed. One of them is interpreted as <span><math><mi>A</mi></math></span>-phase. It stabilizes in the range 71–77 kOe on the boundary between commensurate and incommensurate magnetic structures at <span><math><mi>T</mi></math></span> <span><math><mo>≤</mo></math></span>8–9 K.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173849"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035297","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 : 2026-03-01Epub Date: 2026-01-14DOI: 10.1016/j.jmmm.2026.173840
Jie Xing , Feng Ye , Daniel Duong , Sai Mu , Max T. Pan , Rongying Jin
Complex magnetic materials are extremely attractive for revealing unconventional spin states and novel magnetic excitations. Here, we report the structural, thermodynamic, and magnetic properties of a novel magnetic material Li2Co3Se4O12 based on x-ray and neutron diffraction, specific heat, magnetization, and x-ray photoelectron spectroscopy measurements. X-ray and neutron diffraction refinements reveal two Co sites Co (1) and Co (2) even though both are in the octahedral environment. While they are not connected along the b and c directions, these octahedra are edge-shared forming the Co (2) – Co (1) – Co (2) trimer chain along the a direction. The magnetic susceptibility exhibits the Curie-Weiss (CW) temperature dependence at high temperatures (above ∼50 K) with the negative CW temperature, a dip centered at T⁎ ∼ 8.0 K, and an antiferromagnetic transition at TN = 3.3 K. The specific heat confirms that there is a phase transition at TN and a hump at T⁎. The long-range magnetic transition at TN implies that, in addition to the intra-chain interaction, there is strong inter-chain interaction, which is likely due to polarized SeO3 bridging between chains. Single crystal neutron diffraction refinement reveals a complex magnetic structure with the angle between Co (1) and Co (2) moments ∼105°. Within the Co (2) – Co (1) – Co (2) trimer, two Co (2) moments are parallelly aligned. Surprisingly, the Co (1) moment (1.92μB) is only half of the Co (2) moment (3.96μB). There is likely the spin-state change for Co (1) from the high-spin state at T > T⁎ to the low-spin state at T < T⁎, causing a dip in the magnetic susceptibility and a hump in the specific heat. When the magnetic field is applied, multiple metamagnetic transitions are found in all directions, implying field-driven magnetic excitations. Our results demonstrate rich magnetic properties of Li2Co3Se4O12 that are sensitive to the external stimuli such as the magnetic field.
{"title":"Complex spin structure in co-trimer-chain Li2Co3Se4O12","authors":"Jie Xing , Feng Ye , Daniel Duong , Sai Mu , Max T. Pan , Rongying Jin","doi":"10.1016/j.jmmm.2026.173840","DOIUrl":"10.1016/j.jmmm.2026.173840","url":null,"abstract":"<div><div>Complex magnetic materials are extremely attractive for revealing unconventional spin states and novel magnetic excitations. Here, we report the structural, thermodynamic, and magnetic properties of a novel magnetic material Li<sub>2</sub>Co<sub>3</sub>Se<sub>4</sub>O<sub>12</sub> based on x-ray and neutron diffraction, specific heat, magnetization, and x-ray photoelectron spectroscopy measurements. X-ray and neutron diffraction refinements reveal two Co sites Co (1) and Co (2) even though both are in the octahedral environment. While they are not connected along the <em>b</em> and <em>c</em> directions, these octahedra are edge-shared forming the Co (2) – Co (1) – Co (2) trimer chain along the <em>a</em> direction. The magnetic susceptibility exhibits the Curie-Weiss (CW) temperature dependence at high temperatures (above ∼50 K) with the negative CW temperature, a dip centered at T<sup>⁎</sup> ∼ 8.0 K, and an antiferromagnetic transition at T<sub>N</sub> = 3.3 K. The specific heat confirms that there is a phase transition at T<sub>N</sub> and a hump at T<sup>⁎</sup>. The long-range magnetic transition at T<sub>N</sub> implies that, in addition to the intra-chain interaction, there is strong inter-chain interaction, which is likely due to polarized SeO<sub>3</sub> bridging between chains. Single crystal neutron diffraction refinement reveals a complex magnetic structure with the angle between Co (1) and Co (2) moments ∼105°. Within the Co (2) – Co (1) – Co (2) trimer, two Co (2) moments are parallelly aligned. Surprisingly, the Co (1) moment (1.92μ<sub>B</sub>) is only half of the Co (2) moment (3.96μ<sub>B</sub>). There is likely the spin-state change for Co (1) from the high-spin state at T > T<sup>⁎</sup> to the low-spin state at T < T<sup>⁎</sup>, causing a dip in the magnetic susceptibility and a hump in the specific heat. When the magnetic field is applied, multiple metamagnetic transitions are found in all directions, implying field-driven magnetic excitations. Our results demonstrate rich magnetic properties of Li<sub>2</sub>Co<sub>3</sub>Se<sub>4</sub>O<sub>12</sub> that are sensitive to the external stimuli such as the magnetic field.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173840"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035353","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 : 2026-03-01Epub Date: 2026-01-02DOI: 10.1016/j.jmmm.2025.173809
Yong Gong , Zhubing Yan , Francesco Cugini , Fengjiao Qian , Jiawei Lai , Xuefei Miao , Jun Liu , Zhixiang Qi , Yuanyuan Gong , Feng Xu , Luana Caron
The 〈001〉 − oriented (Mn,Fe)2(P,Si)/epoxy composites were fabricated via magnetic field-assisted dynamic self-assembly. These textured composites demonstrate remarkable adaptability for diverse applications that require either substantial coefficients (αl) of negative thermal expansion (NTE) or broad NTE temperature windows (ΔTNTE). A two-dimensional NTE with a colossal αl of −144.37 × 10−6 K−1 is realized between 280 and 360 K in the composite displaying a first-order phase transition (FOPT). The ΔTNTE can be significantly extended to 190 K (120−310K) in the composite exhibiting a second-order phase transition (SOPT), while preserving a large αl of −23.89 × 10−6 K−1. Besides that, anisotropic MCE is observed in the textured composites. The FOPT composite exhibits a maximum entropy change of 7.18 Jkg−1 K−1 under a magnetic field of 1 T applied perpendicular to the texture direction, which is 34 % higher than the parallel field configuration. Consequently, our study demonstrates that grain-orientation engineering can be effectively employed to explore NTE and achieve anisotropic magnetocaloric properties.
{"title":"Grain-orientation engineering enables dual-functionality in (Mn,Fe)2(P,Si)/epoxy composites: Colossal negative thermal expansion and anisotropic magnetocaloric effect","authors":"Yong Gong , Zhubing Yan , Francesco Cugini , Fengjiao Qian , Jiawei Lai , Xuefei Miao , Jun Liu , Zhixiang Qi , Yuanyuan Gong , Feng Xu , Luana Caron","doi":"10.1016/j.jmmm.2025.173809","DOIUrl":"10.1016/j.jmmm.2025.173809","url":null,"abstract":"<div><div>The 〈001〉 − oriented (Mn,Fe)<sub>2</sub>(P,Si)/epoxy composites were fabricated via magnetic field-assisted dynamic self-assembly. These textured composites demonstrate remarkable adaptability for diverse applications that require either substantial coefficients (<em>α</em><sub><em>l</em></sub>) of negative thermal expansion (NTE) or broad NTE temperature windows (Δ<em>T</em><sub>NTE</sub>). A two-dimensional NTE with a colossal <em>α</em><sub><em>l</em></sub> of −144.37 × 10<sup>−6</sup> K<sup>−1</sup> is realized between 280 and 360 K in the composite displaying a first-order phase transition (FOPT). The Δ<em>T</em><sub>NTE</sub> can be significantly extended to 190 K (120−310<em>K</em>) in the composite exhibiting a second-order phase transition (SOPT), while preserving a large <em>α</em><sub><em>l</em></sub> of −23.89 × 10<sup>−6</sup> K<sup>−1</sup>. Besides that, anisotropic MCE is observed in the textured composites. The FOPT composite exhibits a maximum entropy change of 7.18 Jkg<sup>−1</sup> K<sup>−1</sup> under a magnetic field of 1 T applied perpendicular to the texture direction, which is 34 % higher than the parallel field configuration. Consequently, our study demonstrates that grain-orientation engineering can be effectively employed to explore NTE and achieve anisotropic magnetocaloric properties.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173809"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941257","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}
Two-dimensional (2D) magnetic tunnel junctions (MTJs) based on van der Waals heterostructures, as core spintronics devices, offer high storage density and fast information processing capabilities. However, the influences of intrinsic point defects on their Tunneling Magneto-resistance (TMR) effects as well as physical mechanisms remain underexplored. Here, we design a Cu(111)|CrBr3|WS2|CrBr3|Cu(111) MTJ utilizing first-principles calculations combined with the nonequilibrium Green's function method. The perfect MTJ exhibits near 100% spin polarization and an ultrahigh TMR of 4312.77%; it maintains TMR above 1000% and high spin filtering efficiency within a bias voltage range from −0.5 to 0.5 V. To investigate the factors contributing to the low TMR in experimentally fabricated MTJs, we systematically investigated the impact of point defects (intrinsic vacancies/substitutions) on CrBr3|WS2|CrBr3 MTJ performance. Spin-polarized electron transport channels are modified by point defects. S and Br vacancies show negligible effects on TMR. While W and Cr vacancies enhance spin-down electron transmission in parallel magnetization configurations, thereby reducing TMR. Substituting S atoms with Br atoms significantly improves TMR to 6916.36%. The work highlights defect engineering as a viable approach to optimize 2D MTJ performance, offering theoretical insights for designing high-efficiency spintronic devices with enhanced stability and tunability.
{"title":"Modulation of spin transport in CrBr3|WS2|CrBr3 magnetic tunnel junctions via point defects","authors":"Yongsheng Zhao , Yuxin Zhang , Haishan Zhang, Juan Lyu, Jian Gong, Shaoqiang Guo","doi":"10.1016/j.jmmm.2026.173837","DOIUrl":"10.1016/j.jmmm.2026.173837","url":null,"abstract":"<div><div>Two-dimensional (2D) magnetic tunnel junctions (MTJs) based on van der Waals heterostructures, as core spintronics devices, offer high storage density and fast information processing capabilities. However, the influences of intrinsic point defects on their Tunneling Magneto-resistance (TMR) effects as well as physical mechanisms remain underexplored. Here, we design a Cu(111)|CrBr<sub>3</sub>|WS<sub>2</sub>|CrBr<sub>3</sub>|Cu(111) MTJ utilizing first-principles calculations combined with the nonequilibrium Green's function method. The perfect MTJ exhibits near 100% spin polarization and an ultrahigh TMR of 4312.77%; it maintains TMR above 1000% and high spin filtering efficiency within a bias voltage range from −0.5 to 0.5 V. To investigate the factors contributing to the low TMR in experimentally fabricated MTJs, we systematically investigated the impact of point defects (intrinsic vacancies/substitutions) on CrBr<sub>3</sub>|WS<sub>2</sub>|CrBr<sub>3</sub> MTJ performance. Spin-polarized electron transport channels are modified by point defects. S and Br vacancies show negligible effects on TMR. While W and Cr vacancies enhance spin-down electron transmission in parallel magnetization configurations, thereby reducing TMR. Substituting S atoms with Br atoms significantly improves TMR to 6916.36%. The work highlights defect engineering as a viable approach to optimize 2D MTJ performance, offering theoretical insights for designing high-efficiency spintronic devices with enhanced stability and tunability.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173837"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035295","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 : 2026-03-01Epub Date: 2026-01-12DOI: 10.1016/j.jmmm.2026.173834
Hanji Zhu , Baoming Gong , Yunfeng Zhao , Caiyan Deng , Yong Liu
In this study, full-scale hydrostatic experiments were performed on a pipeline to investigate the behavior of the magnetic flux under varying internal pressures and sensor lift-off distances. Full-field strain distribution with finite element modeling was used to characterize the stress–strain condition at the girth weld. A comprehensive investigation was conducted into the behavior of triaxial magnetic flux signals and their mechanical responses. A novel magnetic parameter, Beff, was proposed based on correlation analysis of multiple signal types and was experimentally validated. The influence of lift-off distance on Beff was discussed, and the underlying mechanism behind environmental magnetic interference was uncovered. Building upon these findings, a robust empirical model was proposed for the quantitative assessment of stress states in buried pipelines. The results are instructive for the application of metal magnetic memory (MMM) technology in non-contact pipeline health monitoring.
{"title":"Quantitative stress modeling in full-scale pipelines via dual-probe differential magneto-mechanical coupling technique","authors":"Hanji Zhu , Baoming Gong , Yunfeng Zhao , Caiyan Deng , Yong Liu","doi":"10.1016/j.jmmm.2026.173834","DOIUrl":"10.1016/j.jmmm.2026.173834","url":null,"abstract":"<div><div>In this study, full-scale hydrostatic experiments were performed on a pipeline to investigate the behavior of the magnetic flux under varying internal pressures and sensor lift-off distances. Full-field strain distribution with finite element modeling was used to characterize the stress–strain condition at the girth weld. A comprehensive investigation was conducted into the behavior of triaxial magnetic flux signals and their mechanical responses. A novel magnetic parameter, <em>B</em><sub>eff</sub>, was proposed based on correlation analysis of multiple signal types and was experimentally validated. The influence of lift-off distance on <em>B</em><sub>eff</sub> was discussed, and the underlying mechanism behind environmental magnetic interference was uncovered. Building upon these findings, a robust empirical model was proposed for the quantitative assessment of stress states in buried pipelines. The results are instructive for the application of metal magnetic memory (MMM) technology in non-contact pipeline health monitoring.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173834"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975168","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}
We systematically investigated the structural, electronic, and magnetic properties of zigzag silicene–germanene nanoribbons (zSiGeNRs) with various edge modifications using first-principles density functional theory. The results reveal that the ground-state properties of zSiGeNRs are highly sensitive to both the chemical composition and the symmetry of edge terminations. Homogeneous symmetric modifications (e.g., 2Cl–zSiGeNR–2Cl, 2F–zSiGeNR–2F, 2H–zSiGeNR–2H) exhibit antiferromagnetic metallic behavior, whereas homogeneous asymmetric ones (e.g., 2F–zSiGeNR–1F, 2Cl–zSiGeNR–1Cl) induce robust half-metallicity. Heterogeneous edge functionalizations further enhance tunability: symmetric configurations display narrow-gap semiconducting characteristics, while asymmetric ones yield half-metallic states, with the direction of edge asymmetry determining the metallic spin channel. The application of a transverse electric field enables reversible transitions between metallic, semiconducting, and half-metallic phases, demonstrating strong electric-field control. Certain asymmetric systems preserve half-metallicity under high fields, indicating excellent stability for spintronic applications. Additionally, width-dependent analysis demonstrates that quantum confinement and edge interactions govern electronic evolution, with asymmetric systems such as 2F–zSiGeNR–1F retaining half-metallicity across a broad width range (). The Si–Ge hybridization provides enhanced tunability compared to single-element nanoribbons, enabling band gap and spin polarization control via simple edge chemistry. These findings highlight that combining edge modification, external electric fields, and width engineering offers an effective route for tailoring the properties of zSiGeNRs. The observed field-tunable half-metallicity and Si-based compatibility make these nanoribbons promising candidates for next-generation spintronic and nanoelectronic devices.
{"title":"Tailoring electronic and magnetic properties of edge-functionalized silicene–germanene nanoribbons through first-principles simulations","authors":"Koussai Lazaar , Mohamed Barhoumi , Wissem Dimassi , Moncef Said","doi":"10.1016/j.jmmm.2026.173854","DOIUrl":"10.1016/j.jmmm.2026.173854","url":null,"abstract":"<div><div>We systematically investigated the structural, electronic, and magnetic properties of zigzag silicene–germanene nanoribbons (zSiGeNRs) with various edge modifications using first-principles density functional theory. The results reveal that the ground-state properties of zSiGeNRs are highly sensitive to both the chemical composition and the symmetry of edge terminations. Homogeneous symmetric modifications (e.g., 2Cl–zSiGeNR–2Cl, 2F–zSiGeNR–2F, 2H–zSiGeNR–2H) exhibit antiferromagnetic metallic behavior, whereas homogeneous asymmetric ones (e.g., 2F–zSiGeNR–1F, 2Cl–zSiGeNR–1Cl) induce robust half-metallicity. Heterogeneous edge functionalizations further enhance tunability: symmetric configurations display narrow-gap semiconducting characteristics, while asymmetric ones yield half-metallic states, with the direction of edge asymmetry determining the metallic spin channel. The application of a transverse electric field enables reversible transitions between metallic, semiconducting, and half-metallic phases, demonstrating strong electric-field control. Certain asymmetric systems preserve half-metallicity under high fields, indicating excellent stability for spintronic applications. Additionally, width-dependent analysis demonstrates that quantum confinement and edge interactions govern electronic evolution, with asymmetric systems such as 2F–zSiGeNR–1F retaining half-metallicity across a broad width range (<span><math><mrow><msub><mrow><mi>N</mi></mrow><mrow><mi>z</mi></mrow></msub><mo>=</mo><mn>6</mn><mo>−</mo><mn>14</mn></mrow></math></span>). The Si–Ge hybridization provides enhanced tunability compared to single-element nanoribbons, enabling band gap and spin polarization control via simple edge chemistry. These findings highlight that combining edge modification, external electric fields, and width engineering offers an effective route for tailoring the properties of zSiGeNRs. The observed field-tunable half-metallicity and Si-based compatibility make these nanoribbons promising candidates for next-generation spintronic and nanoelectronic devices.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173854"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975172","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 : 2026-03-01Epub Date: 2026-01-14DOI: 10.1016/j.jmmm.2026.173838
Lichun Zhan , Wenyu Pan , Ruihua Du , Weiqiang Liu , Zan Long , Shengli Jia , Qifeng Wei , Xiongfei Wu , Ming Yue
Laser cutting, recognized for its narrow kerf, high efficiency, and adaptability to complex geometries, is increasingly employed in the machining of thin sintered Nd–Fe–B magnets. This work systematically evaluates the influence of laser cutting versus conventional multi-wire cutting combined with grinding on the microstructure, mechanical strength, and magnetic properties of magnets under black, chamfered, and pickled conditions. Laser cutting induces stepped demagnetization curves, lowers intrinsic coercivity and mechanical properties compared to conventional multi-wire cutting combined with grinding method. Results indicate that chamfering improves the three-point bending force of laser-cut samples by approximately 31.4% on average. After pickling, the specific magnetic moment of laser-cut samples is only 0.13% lower, and the irreversible flux loss is merely 0.08% higher than that of ground specimens. Microstructural analysis reveals that laser-cut surfaces contain a resolidified layer, micropores, and networked microcracks, which contribute to the degradation in mechanical and magnetic properties. Magnetic domain observations further demonstrate that laser-cut black samples exhibit blurred domain boundaries and maze domains, whereas chamfered specimens show a marked reduction in maze domains and improved domain alignment. Under identical reverse magnetic fields, domain reversal occurs more readily in black samples than in chamfered ones. In summary, through appropriate parameter selection and post-processing, such as chamfering and pickling, the mechanical and magnetic performance of laser-cut thin Nd-Fe-B magnets can closely match that of ground magnets, offering valuable guidance for process optimization in thin magnet manufacturing.
{"title":"Effects of laser cutting and post-processing on the microstructure and properties of thin sintered Nd-Fe-B magnets","authors":"Lichun Zhan , Wenyu Pan , Ruihua Du , Weiqiang Liu , Zan Long , Shengli Jia , Qifeng Wei , Xiongfei Wu , Ming Yue","doi":"10.1016/j.jmmm.2026.173838","DOIUrl":"10.1016/j.jmmm.2026.173838","url":null,"abstract":"<div><div>Laser cutting, recognized for its narrow kerf, high efficiency, and adaptability to complex geometries, is increasingly employed in the machining of thin sintered Nd–Fe–B magnets. This work systematically evaluates the influence of laser cutting versus conventional multi-wire cutting combined with grinding on the microstructure, mechanical strength, and magnetic properties of magnets under black, chamfered, and pickled conditions. Laser cutting induces stepped demagnetization curves, lowers intrinsic coercivity and mechanical properties compared to conventional multi-wire cutting combined with grinding method. Results indicate that chamfering improves the three-point bending force of laser-cut samples by approximately 31.4% on average. After pickling, the specific magnetic moment of laser-cut samples is only 0.13% lower, and the irreversible flux loss is merely 0.08% higher than that of ground specimens. Microstructural analysis reveals that laser-cut surfaces contain a resolidified layer, micropores, and networked microcracks, which contribute to the degradation in mechanical and magnetic properties. Magnetic domain observations further demonstrate that laser-cut black samples exhibit blurred domain boundaries and maze domains, whereas chamfered specimens show a marked reduction in maze domains and improved domain alignment. Under identical reverse magnetic fields, domain reversal occurs more readily in black samples than in chamfered ones. In summary, through appropriate parameter selection and post-processing, such as chamfering and pickling, the mechanical and magnetic performance of laser-cut thin Nd-Fe-B magnets can closely match that of ground magnets, offering valuable guidance for process optimization in thin magnet manufacturing.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173838"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974635","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 : 2026-03-01Epub Date: 2026-01-22DOI: 10.1016/j.jmmm.2026.173863
O.A. Kosmachev, E.O. Fadeeva, Yu.A. Fridman
Using the mean field approximation, the influence of the magnetic field on the phase states and excitation spectra of a spin nematic with anisotropic bilinear exchange interaction was studied. It is established that in the case of easy-plane exchange anisotropy, depending on the ratio of exchange integrals and the external field perpendicular to the easy plane, three phase states are realized in the system: nematic collinear phase with a nonzero value of the average magnetic moment, angular ferromagnetic phase, and collinear ferromagnetic phase. It is established that in the case under consideration, the angular nematic phase is energetically unfavorable. The case of easy-axis interionic anisotropy and Ising-like bilinear exchange interaction is also considered. The spectra of elementary excitations in all phases are determined, phase diagrams are constructed.
{"title":"Spin nematic with anisotropic exchange interaction in an external magnetic","authors":"O.A. Kosmachev, E.O. Fadeeva, Yu.A. Fridman","doi":"10.1016/j.jmmm.2026.173863","DOIUrl":"10.1016/j.jmmm.2026.173863","url":null,"abstract":"<div><div>Using the mean field approximation, the influence of the magnetic field on the phase states and excitation spectra of a spin nematic with anisotropic bilinear exchange interaction was studied. It is established that in the case of easy-plane exchange anisotropy, depending on the ratio of exchange integrals and the external field perpendicular to the easy plane, three phase states are realized in the system: nematic collinear phase with a nonzero value of the average magnetic moment, angular ferromagnetic phase, and collinear ferromagnetic phase. It is established that in the case under consideration, the angular nematic phase is energetically unfavorable. The case of easy-axis interionic anisotropy and Ising-like bilinear exchange interaction is also considered. The spectra of elementary excitations in all phases are determined, phase diagrams are constructed.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173863"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074398","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 : 2026-03-01Epub Date: 2025-12-29DOI: 10.1016/j.jmmm.2025.173793
Yulin Pan, Yong Li
In this paper, the structural characteristics, magnetic properties and magnetocaloric performance of a series of high-entropy alloys (HEAs) Mn20Co20Ni20Fe26+xCu14-x (x = 0, 2, 4) have been experimentally determined and theoretically analyzed. The results showed that these alloys have a disordered FCC crystal structure. The Fe concentration determines the temperature range within which the ferromagnetic behavior and Curie temperatures can be adjusted. In particular, it decreases from 274 K for Fe26Cu14 to 242 K for Fe30Cu10. In addition, the maximum magnetic entropy change values are obtained in the magnetic field change of 7 T for 1.37, 1.28 and 1.33 J/kgK were obtained for x = 0, 2 and 4, respectively. Compared to other transition metal-based high-entropy alloys reported in the literatures, the present material shows comparable or superior performance. The experimental characterization results are in good agreement with the theoretical predictions and affords an extensive series of rare-earth-free HEAs exhibiting pronounced magnetocaloric properties.
{"title":"Magnetic phase transition and magnetocaloric effect in rare-earth-free high entropy alloys MnCoNiFeCu","authors":"Yulin Pan, Yong Li","doi":"10.1016/j.jmmm.2025.173793","DOIUrl":"10.1016/j.jmmm.2025.173793","url":null,"abstract":"<div><div>In this paper, the structural characteristics, magnetic properties and magnetocaloric performance of a series of high-entropy alloys (HEAs) Mn<sub>20</sub>Co<sub>20</sub>Ni<sub>20</sub>Fe<sub>26+x</sub>Cu<sub>14-x</sub> (x = 0, 2, 4) have been experimentally determined and theoretically analyzed. The results showed that these alloys have a disordered FCC crystal structure. The Fe concentration determines the temperature range within which the ferromagnetic behavior and Curie temperatures can be adjusted. In particular, it decreases from 274 K for Fe<sub>26</sub>Cu<sub>14</sub> to 242 K for Fe<sub>30</sub>Cu<sub>10</sub>. In addition, the maximum magnetic entropy change values are obtained in the magnetic field change of 7 T for 1.37, 1.28 and 1.33 J/kgK were obtained for x <em>=</em> 0, 2 and 4, respectively. Compared to other transition metal-based high-entropy alloys reported in the literatures, the present material shows comparable or superior performance. The experimental characterization results are in good agreement with the theoretical predictions and affords an extensive series of rare-earth-free HEAs exhibiting pronounced magnetocaloric properties.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173793"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941220","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 : 2026-03-01Epub Date: 2026-01-06DOI: 10.1016/j.jmmm.2026.173814
Manikandan Dhamodaran , Rahul Kumar Yadav , N. Raja , Ramesh Karuppannan , Rajeev Gupta
We examine the impact of iron and manganese co-doping on the local atomic environment in hydrothermally synthesized In2O3 using synchrotron X-ray absorption spectroscopy analysis, correlating the findings with the observed magnetic properties. The results revealed that manganese is mainly present in the +3-valence state with a dilute contribution from the +4 state. These oxidation states indicate the formation of oxygen vacancies resulting from charge imbalance. The effective co-substitution of iron and manganese atoms in the In2O3 was established, accompanied by specific changes in bond lengths. Additionally, the bond length of MnO slightly increased for In1.94Fe0.02Mn0.04O3, and subsequently, decreased for the higher Mn-doped samples. Density functional theory calculations revealed that the FeO bond length decreases from 2.194 to 2.141 Å upon the introduction of oxygen vacancies, indicating enhanced FeO interactions. Conversely, the MnO bond increased from 2.140 to 2.210 Å, reflecting the weakened local bonding environment and reduced lattice integration of Mn atoms. Magnetic investigations revealed a room-temperature ferromagnetism in In1.94Fe0.02Mn0.04O3, characterized by an enhanced coercivity and saturation magnetization. Density functional theory calculations show that oxygen vacancy formation stabilizes the high magnetic moments 3.85 μB for Fe and 4.23 μB for Mn, driven by FeO and MnO hybridization and increased d-electron localization around the transition metal centers. These findings offer new insights into the local micro-environment and magnetic characteristics of iron and manganese-codoped indium oxide.
{"title":"Probing the local atomic structure and magnetism in Iron and manganese co-doped indium oxide Nanocubes using XAS and DFT","authors":"Manikandan Dhamodaran , Rahul Kumar Yadav , N. Raja , Ramesh Karuppannan , Rajeev Gupta","doi":"10.1016/j.jmmm.2026.173814","DOIUrl":"10.1016/j.jmmm.2026.173814","url":null,"abstract":"<div><div>We examine the impact of iron and manganese co-doping on the local atomic environment in hydrothermally synthesized In<sub>2</sub>O<sub>3</sub> using synchrotron X-ray absorption spectroscopy analysis, correlating the findings with the observed magnetic properties. The results revealed that manganese is mainly present in the +3-valence state with a dilute contribution from the +4 state. These oxidation states indicate the formation of oxygen vacancies resulting from charge imbalance. The effective co-substitution of iron and manganese atoms in the In<sub>2</sub>O<sub>3</sub> was established, accompanied by specific changes in bond lengths. Additionally, the bond length of Mn<img>O slightly increased for In<sub>1.94</sub>Fe<sub>0.02</sub>Mn<sub>0.04</sub>O<sub>3</sub>, and subsequently, decreased for the higher Mn-doped samples. Density functional theory calculations revealed that the Fe<img>O bond length decreases from 2.194 to 2.141 Å upon the introduction of oxygen vacancies, indicating enhanced Fe<img>O interactions. Conversely, the Mn<img>O bond increased from 2.140 to 2.210 Å, reflecting the weakened local bonding environment and reduced lattice integration of Mn atoms. Magnetic investigations revealed a room-temperature ferromagnetism in In<sub>1.94</sub>Fe<sub>0.02</sub>Mn<sub>0.04</sub>O<sub>3</sub>, characterized by an enhanced coercivity and saturation magnetization. Density functional theory calculations show that oxygen vacancy formation stabilizes the high magnetic moments 3.85 μ<sub>B</sub> for Fe and 4.23 μ<sub>B</sub> for Mn, driven by Fe<img>O and Mn<img>O hybridization and increased d-electron localization around the transition metal centers. These findings offer new insights into the local micro-environment and magnetic characteristics of iron and manganese-codoped indium oxide.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173814"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941222","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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