Pub Date : 2026-03-01Epub Date: 2026-01-14DOI: 10.1016/j.jmmm.2026.173827
J.M. Martínez , J.M. Nieto-Jalil , A. Lobo Guerrero , J.H. García Gallegos
We present a fast magnetometry route to quantify dipolar mean-field coupling and recover the intrinsic switching-field distribution (iSFD) using only a major hysteresis loop plus the initial magnetization curve acquired from an AC-demagnetized state. Within a Stoner–Wohlfarth/Preisach mean-field picture, interaction-induced shearing broadens susceptibilities; α is obtained from area identities at high remanence and, for low-remanence systems, from an offset-free derivative estimator. Validation on Sr-hexaferrite nanoparticles embedded in PVA nanofibers yields and − 840 Oe for 1.5%, 2.0% and 2.5% loadings, respectively, and deshearing collapses loops and susceptibilities onto their intrinsic references. The workflow includes two internal consistency checks, post-deshearing antisymmetry of branches and initial-curve/upper-branch overlap for , making the estimate auditable. Compared to /Henkel and FORC, the method requires a single loop plus one initial curve and remains robust in the presence of reversible contributions.
{"title":"Quantifying dipolar mean-field interactions from hysteresis and initial curves: A fast Magnetometry route to iSFD Deshearing","authors":"J.M. Martínez , J.M. Nieto-Jalil , A. Lobo Guerrero , J.H. García Gallegos","doi":"10.1016/j.jmmm.2026.173827","DOIUrl":"10.1016/j.jmmm.2026.173827","url":null,"abstract":"<div><div>We present a fast magnetometry route to quantify dipolar mean-field coupling <span><math><mfenced><mi>α</mi></mfenced></math></span> and recover the intrinsic switching-field distribution (iSFD) using only a major hysteresis loop plus the initial magnetization curve acquired from an AC-demagnetized state. Within a Stoner–Wohlfarth/Preisach mean-field picture, interaction-induced shearing broadens susceptibilities; α is obtained from area identities at high remanence and, for low-remanence systems, from an offset-free derivative estimator. Validation on Sr-hexaferrite nanoparticles embedded in PVA nanofibers yields <span><math><mi>α</mi><mo>≈</mo><mo>−</mo><mn>535</mn><mo>,</mo><mo>−</mo><mn>740</mn></math></span> and − 840 Oe for 1.5%, 2.0% and 2.5% loadings, respectively, and deshearing collapses loops and susceptibilities onto their intrinsic references. The workflow includes two internal consistency checks, post-deshearing antisymmetry of branches and initial-curve/upper-branch overlap for <span><math><mi>H</mi><mo>≥</mo><mn>0</mn></math></span>, making the estimate auditable. Compared to <span><math><mi>Δ</mi><mi>M</mi></math></span>/Henkel and FORC, the method requires a single loop plus one initial curve and remains robust in the presence of reversible contributions.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173827"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073680","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: 2026-01-24DOI: 10.1016/j.jmmm.2026.173860
N. Bouzakraoui , A. Samih , R. El Fdil , Z. Fadil , E. Salmani , Chaitany Jayprakash Raorane , Seong-Cheol Kim , S. Saadaoui
This work examines the structural, mechanical, electronic, magnetic, optical, and thermodynamic properties of CoCrTe and NiVTe half-Heusler alloys. Stability analysis identifies the β-configuration (X at 4c, Y at 4a, and Z at 4b) as the most favorable structure. Both compounds are thermodynamically stable, as confirmed by negative formation energies and convex hull analysis. Their mechanical and dynamical stability is further verified through elastic constants and phonon spectra. Electronic structure and magnetic properties are investigated using the GGA-PBE and meta-GGA-SCAN functionals to better describe the strongly correlated 3d states. The results reveal that both CoCrTe and NiVTe are ferromagnetic half-metals with a total magnetic moment of 3 μB, consistent with the Slater–Pauling rule, highlighting their potential for spintronic applications. Optical calculations indicate promising performance in infrared and ultraviolet optoelectronic devices. Finally, thermodynamic analysis demonstrates that both alloys possess excellent thermal stability.
{"title":"Comprehensive DFT study of CoCrTe and NiVTe half-Heuslers: Structure, magnetism, and optical response","authors":"N. Bouzakraoui , A. Samih , R. El Fdil , Z. Fadil , E. Salmani , Chaitany Jayprakash Raorane , Seong-Cheol Kim , S. Saadaoui","doi":"10.1016/j.jmmm.2026.173860","DOIUrl":"10.1016/j.jmmm.2026.173860","url":null,"abstract":"<div><div>This work examines the structural, mechanical, electronic, magnetic, optical, and thermodynamic properties of CoCrTe and NiVTe half-Heusler alloys. Stability analysis identifies the β-configuration (X at 4c, Y at 4a, and Z at 4b) as the most favorable structure. Both compounds are thermodynamically stable, as confirmed by negative formation energies and convex hull analysis. Their mechanical and dynamical stability is further verified through elastic constants and phonon spectra. Electronic structure and magnetic properties are investigated using the GGA-PBE and meta-GGA-SCAN functionals to better describe the strongly correlated 3d states. The results reveal that both CoCrTe and NiVTe are ferromagnetic half-metals with a total magnetic moment of 3 μ<sub>B</sub>, consistent with the Slater–Pauling rule, highlighting their potential for spintronic applications. Optical calculations indicate promising performance in infrared and ultraviolet optoelectronic devices. Finally, thermodynamic analysis demonstrates that both alloys possess excellent thermal stability.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173860"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073682","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: 2026-01-16DOI: 10.1016/j.jmmm.2026.173848
A. El Boubekri , M. Sajieddine , M. Lassri , M. Sahlaoui , A. Razouk , H. Lassri , A. Essoumhi
Amorphous alloys with the composition Fe78−xCr2+xSi8B12 (x = 0–10 at. %) were produced by rapid quenching melt-spinning. X-ray diffraction confirmed their fully amorphous nature, while thermal analysis revealed glass transition and crystallization events, with the onset of crystallization shifting to higher temperatures as chromium content increased. Scanning electron microscopy showed uniform and defect-free surfaces, confirming compositional homogeneity across all samples. At the atomic scale, 57Fe Mössbauer spectroscopy provided insights into the local magnetic environment. The spectra exhibited broad and bimodal hyperfine field distributions, reflecting two of atomic surroundings: Fe-rich clusters and regions diluted by Cr, Si, and B. Increasing Cr content progressively reduced both the average hyperfine field and the Fe magnetic moment. These microscopic trends were echoed in bulk magnetic behavior. Hysteresis loops revealed soft ferromagnetic characteristics with low coercivity, and the saturation magnetization closely followed the Mössbauer-derived Fe moments. The correlations between local atomic order and magnetism highlight the dual role of chromium: it stabilizes the amorphous structure while tuning magnetic softness.
{"title":"Mössbauer study and magnetic properties of Fe78-xCr2+xSi8B12 amorphous ribbons","authors":"A. El Boubekri , M. Sajieddine , M. Lassri , M. Sahlaoui , A. Razouk , H. Lassri , A. Essoumhi","doi":"10.1016/j.jmmm.2026.173848","DOIUrl":"10.1016/j.jmmm.2026.173848","url":null,"abstract":"<div><div>Amorphous alloys with the composition Fe<sub>78−x</sub>Cr<sub>2+x</sub>Si<sub>8</sub>B<sub>12</sub> (<em>x</em> = 0–10 at. %) were produced by rapid quenching melt-spinning. X-ray diffraction confirmed their fully amorphous nature, while thermal analysis revealed glass transition and crystallization events, with the onset of crystallization shifting to higher temperatures as chromium content increased. Scanning electron microscopy showed uniform and defect-free surfaces, confirming compositional homogeneity across all samples. At the atomic scale, <sup>57</sup>Fe Mössbauer spectroscopy provided insights into the local magnetic environment. The spectra exhibited broad and bimodal hyperfine field distributions, reflecting two of atomic surroundings: Fe-rich clusters and regions diluted by Cr, Si, and B. Increasing Cr content progressively reduced both the average hyperfine field and the Fe magnetic moment. These microscopic trends were echoed in bulk magnetic behavior. Hysteresis loops revealed soft ferromagnetic characteristics with low coercivity, and the saturation magnetization closely followed the Mössbauer-derived Fe moments. The correlations between local atomic order and magnetism highlight the dual role of chromium: it stabilizes the amorphous structure while tuning magnetic softness.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173848"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035347","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.2026.173839
Zhixin Shu , Jiaying Jin , Liang Zhou , Boyu Li , Jifei Hong , Dong Ma , Wang Chen , Mi Yan
High-Ce-substituted Nd-Ce-Fe-B permanent magnets offer a cost-effective solution but are limited by magnetic dilution and microstructural degradation. This study specifically investigates the Ce-75 sintered magnets (Ce/total rare earth = 75 wt%) using a dual-modification approach that combines the intergranular addition of (Nd, Pr)Hx and (Nd, Pr)90Dy10Hx with optimized two-step annealing. The 4 wt% (Nd, Pr)Hx-modified magnet achieves a 54% coercivity improvement from 5.48 to 8.45 kOe via the formation of Nd/Pr-rich shell. More remarkably, the 4 wt% (Nd, Pr)90Dy10Hx-modified counterpart demonstrates a 90% enhancement from 5.48 to 10.36 kOe with minimal remanence sacrifice, attributed to synergistic effects of Dy-rich grain shells coupled with Nd/Pr-rich grain boundaries. These findings demonstrate the significance of controlled elemental spatial distribution for achieving simultaneous coercivity enhancement and efficient rare earth utilization.
{"title":"Enhanced coercivity in high-Ce-substituted Nd-Ce-Fe-B magnets via intergranular addition and optimized annealing","authors":"Zhixin Shu , Jiaying Jin , Liang Zhou , Boyu Li , Jifei Hong , Dong Ma , Wang Chen , Mi Yan","doi":"10.1016/j.jmmm.2026.173839","DOIUrl":"10.1016/j.jmmm.2026.173839","url":null,"abstract":"<div><div>High-Ce-substituted Nd-Ce-Fe-B permanent magnets offer a cost-effective solution but are limited by magnetic dilution and microstructural degradation. This study specifically investigates the Ce-75 sintered magnets (Ce/total rare earth = 75 wt%) using a dual-modification approach that combines the intergranular addition of (Nd, Pr)H<sub>x</sub> and (Nd, Pr)<sub>90</sub>Dy<sub>10</sub>H<sub>x</sub> with optimized two-step annealing. The 4 wt% (Nd, Pr)H<sub>x</sub>-modified magnet achieves a 54% coercivity improvement from 5.48 to 8.45 kOe via the formation of Nd/Pr-rich shell. More remarkably, the 4 wt% (Nd, Pr)<sub>90</sub>Dy<sub>10</sub>H<sub>x</sub>-modified counterpart demonstrates a 90% enhancement from 5.48 to 10.36 kOe with minimal remanence sacrifice, attributed to synergistic effects of Dy-rich grain shells coupled with Nd/Pr-rich grain boundaries. These findings demonstrate the significance of controlled elemental spatial distribution for achieving simultaneous coercivity enhancement and efficient rare earth utilization.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173839"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035354","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.2026.173815
Zhengang Zhao , Kuisong Yang , Junjiang Shi , Yinjie Hou , Chuan Luo
In this paper, we propose and design a novel fluxgate current sensor with low inter-coil coupling. The design has an openable structure that allows rapid installation and removal without interrupting the circuit. The design achieves a closed rectangular magnetic core by optimizing a parallel dual-core configuration. The physical separation between the excitation flux and the induction path enables the formation of a closed magnetic circuit and the implementation of low-coupling coil arrangements, effectively suppressing electromagnetic interference while maintaining strong flux modulation capability. The operational principle of the sensor probe is first derived analytically, followed by the development of a finite element simulation model of the fluxgate probe. The magnetic coupling characteristics of sensors employing two distinct winding configurations are compared and analyzed, and two prototypes are fabricated and tested for performance evaluation. Experimental results indicate that the sensor with the proposed low inter-coil coupling structure has a linearity error of 0.169 %, a repeatability of 0.154 %, a sensitivity of 0.260 V/A. The overall absolute error is less than 8.5 mV, while the offset drift is 3.24 mV. Furthermore, the sensor exhibits a measurement uncertainty of 0.307 % within a DC current range of ±10 A. This study provides novel insights into the design of high-performance, high-stability fluxgate current sensors, highlighting their potential for a wide range of engineering applications.
{"title":"Design of an openable structure fluxgate current sensor with low inter-coil coupling","authors":"Zhengang Zhao , Kuisong Yang , Junjiang Shi , Yinjie Hou , Chuan Luo","doi":"10.1016/j.jmmm.2026.173815","DOIUrl":"10.1016/j.jmmm.2026.173815","url":null,"abstract":"<div><div>In this paper, we propose and design a novel fluxgate current sensor with low inter-coil coupling. The design has an openable structure that allows rapid installation and removal without interrupting the circuit. The design achieves a closed rectangular magnetic core by optimizing a parallel dual-core configuration. The physical separation between the excitation flux and the induction path enables the formation of a closed magnetic circuit and the implementation of low-coupling coil arrangements, effectively suppressing electromagnetic interference while maintaining strong flux modulation capability. The operational principle of the sensor probe is first derived analytically, followed by the development of a finite element simulation model of the fluxgate probe. The magnetic coupling characteristics of sensors employing two distinct winding configurations are compared and analyzed, and two prototypes are fabricated and tested for performance evaluation. Experimental results indicate that the sensor with the proposed low inter-coil coupling structure has a linearity error of 0.169 %, a repeatability of 0.154 %, a sensitivity of 0.260 V/A. The overall absolute error is less than 8.5 mV, while the offset drift is 3.24 mV. Furthermore, the sensor exhibits a measurement uncertainty of 0.307 % within a DC current range of ±10 A. This study provides novel insights into the design of high-performance, high-stability fluxgate current sensors, highlighting their potential for a wide range of engineering applications<strong>.</strong></div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173815"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145908883","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: 2026-01-09DOI: 10.1016/j.jmmm.2026.173825
Connor J. Wood, Robert E. Camley
We analyze the nonlinear behavior of two ferromagnetic films which are antiferromagnetically coupled. The resulting equations are solved numerically to determine what would be measured in magnetic resonance or pulse inductive microwave magnetometry experiments. We find a strong, power-dependent, hysteresis in the resonant absorption that is dependent on whether one scans upwards or downwards in frequency, which can extend over 14 GHz in some cases. We show that the hysteretic behavior is due to a dynamically modified canting angle that deviates from the equilibrium value found for the linear solutions. In addition, we look at the spectral decomposition to analyze how energy is transformed. For nonlinear modes, we find major differences between the driving frequency and the frequencies of the resonance modes which are ultimately created. This includes a down-conversion from a 13.5 GHz driving signal to a 1.5 GHz resonance frequency, as well as half frequency responses. Our synchronization studies dramatically illustrate the limits of the linear and nonlinear regions in terms of initial amplitudes and time evolution of the correlation between the two films moments.
{"title":"Nonlinear resonance in antiferromagnetically coupled magnetic bilayers: Hysteresis, spectral response, and synchronization","authors":"Connor J. Wood, Robert E. Camley","doi":"10.1016/j.jmmm.2026.173825","DOIUrl":"10.1016/j.jmmm.2026.173825","url":null,"abstract":"<div><div>We analyze the nonlinear behavior of two ferromagnetic films which are antiferromagnetically coupled. The resulting equations are solved numerically to determine what would be measured in magnetic resonance or pulse inductive microwave magnetometry experiments. We find a strong, power-dependent, hysteresis in the resonant absorption that is dependent on whether one scans upwards or downwards in frequency, which can extend over 14 GHz in some cases. We show that the hysteretic behavior is due to a dynamically modified canting angle that deviates from the equilibrium value found for the linear solutions. In addition, we look at the spectral decomposition to analyze how energy is transformed. For nonlinear modes, we find major differences between the driving frequency and the frequencies of the resonance modes which are ultimately created. This includes a down-conversion from a 13.5 GHz driving signal to a 1.5 GHz resonance frequency, as well as half frequency responses. Our synchronization studies dramatically illustrate the limits of the linear and nonlinear regions in terms of initial amplitudes and time evolution of the correlation between the two films moments.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173825"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975214","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: 2026-01-08DOI: 10.1016/j.jmmm.2026.173826
Xijia Chen, Junmiao Lin, Xiaoli Gong, Liyao Zhu, Lingwei Li
A number of Gd-incorporated magnetic solids have been recently determined with respect to their magnetocaloric performances, which are attempted to identify candidate magnetocaloric materials for cryogenic magnetic refrigeration (MR) application and unveil their intrinsic magneto-thermal properties. We herein synthesized the single-phased Gd2NbLaO7 compound by a solid-state reaction method and experimentally unveiled its structural, chemical states, magnetic, and magnetocaloric properties. The Gd2NbLaO7 compound is crystallized in an orthorhombic structure with C2221 space group. The consistent elementals in Gd2NbLaO7 compound all distribute uniformly and with the valence states as Gd3+, Nb5+, La3+, and O2−, respectively. Large reversible cryogenic magnetocaloric effects with notable performances in Gd2NbLaO7 compound were realized. The maximum magnetic entropy change and refrigerant capacity/relative cooling power (magnetic field variation of 0–7 T) of Gd2NbLaO7 compound are identified to be 35.18 J kg−1 K−1 and 248.42/330.51 J kg−1, respectively, which surpass most of recently updated Gd-incorporated magnetic solids with notable magnetocaloric performances, making present Gd2NbLaO7 compound also considerable for cryogenic MR applications.
最近，研究人员测定了一些含有gd的磁性固体的磁热性能，试图确定用于低温磁制冷（MR）应用的候选磁热材料，并揭示其固有的磁热性能。本文采用固相反应法合成了单相Gd2NbLaO7化合物，并通过实验揭示了其结构、化学状态、磁性和磁热学性质。Gd2NbLaO7化合物结晶为具有C2221空间基的正交晶型结构。Gd2NbLaO7化合物中一致元素分布均匀，价态分别为Gd3+、Nb5+、La3+和O2−。在Gd2NbLaO7化合物中实现了具有显著性能的大可逆低温磁热效应。Gd2NbLaO7化合物的最大磁熵变化和制冷剂容量/相对冷却功率（0-7 T的磁场变化）分别为35.18 J kg - 1 K - 1和248.42/330.51 J kg - 1，超过了最近更新的大多数具有显着磁热性能的gd掺杂磁性固体，使该化合物在低温MR应用中也相当可观。
{"title":"Magnetic properties and cryogenic magnetocaloric performances in Gd2NbLaO7 compound","authors":"Xijia Chen, Junmiao Lin, Xiaoli Gong, Liyao Zhu, Lingwei Li","doi":"10.1016/j.jmmm.2026.173826","DOIUrl":"10.1016/j.jmmm.2026.173826","url":null,"abstract":"<div><div>A number of Gd-incorporated magnetic solids have been recently determined with respect to their magnetocaloric performances, which are attempted to identify candidate magnetocaloric materials for cryogenic magnetic refrigeration (MR) application and unveil their intrinsic magneto-thermal properties. We herein synthesized the single-phased Gd<sub>2</sub>NbLaO<sub>7</sub> compound by a solid-state reaction method and experimentally unveiled its structural, chemical states, magnetic, and magnetocaloric properties. The Gd<sub>2</sub>NbLaO<sub>7</sub> compound is crystallized in an orthorhombic structure with <em>C</em>222<sub>1</sub> space group. The consistent elementals in Gd<sub>2</sub>NbLaO<sub>7</sub> compound all distribute uniformly and with the valence states as Gd<sup>3+</sup>, Nb<sup>5+</sup>, La<sup>3+</sup>, and O<sup>2−</sup>, respectively. Large reversible cryogenic magnetocaloric effects with notable performances in Gd<sub>2</sub>NbLaO<sub>7</sub> compound were realized. The maximum magnetic entropy change and refrigerant capacity/relative cooling power (magnetic field variation of 0–7 T) of Gd<sub>2</sub>NbLaO<sub>7</sub> compound are identified to be 35.18 J kg<sup>−1</sup> K<sup>−1</sup> and 248.42/330.51 J kg<sup>−1</sup>, respectively, which surpass most of recently updated Gd-incorporated magnetic solids with notable magnetocaloric performances, making present Gd<sub>2</sub>NbLaO<sub>7</sub> compound also considerable for cryogenic MR applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173826"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035302","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.2026.173832
Gorachand Biswal , Babita Ojha , Varsa Purohit , Rakesh Ranjan Sahoo , Dhrubananda Behera , Deba Nirmalya Das
The ferrite samples Mg0.5Mn0.5Fe2-xErxO4 (x = 0, 0.02, 0.04, 0.06, 0.1) prepared using the solid-state route were evaluated for microwave absorption applications. X-ray diffraction with Rietveld refinement revealed multiphase characteristics and the coexistence of a spinel phase with an orthorhombic phase attributed to the larger Er3+ ionic radius. The SEM analysis of rare earth-doped spinel ferrites reveals that grain size and porosity are significantly influenced by doping concentration, which in turn strongly affect the dielectric and magnetic properties. AFM indicated high surface roughness. The favourable figures of dielectric constant and loss factor recorded at frequency variation makes the material suitable in high frequency performances. The Er modified ferrites possessing a broad range of relaxation period can interact and effectively absorb an extended range of spectrum from the microwave frequency range. UV–Vis spectroscopy demonstrated an increase in the optical forbidden band gap from 1.06 eV to 2.30 eV after doping of erbium, enhancing light absorption. The combined improvements in optical, dielectric, and thermal properties confirm that Er-modified ferrites are promising candidates for high-frequency, high-temperature microwave absorbing applications. The increase of coercivity with respect to doping concentration may be attributed to the anisotropy due to the strong spin orbit coupling of Er3+.
{"title":"Improvement in magnetic, optical and dielectric behavior on erbium addition to Mg0.5Mn0.5Fe2O4 for device applications","authors":"Gorachand Biswal , Babita Ojha , Varsa Purohit , Rakesh Ranjan Sahoo , Dhrubananda Behera , Deba Nirmalya Das","doi":"10.1016/j.jmmm.2026.173832","DOIUrl":"10.1016/j.jmmm.2026.173832","url":null,"abstract":"<div><div>The ferrite samples Mg<sub>0.5</sub>Mn<sub>0.5</sub>Fe<sub>2-x</sub>Er<sub>x</sub>O<sub>4</sub> (x = 0, 0.02, 0.04, 0.06, 0.1) prepared using the solid-state route were evaluated for microwave absorption applications. X-ray diffraction with Rietveld refinement revealed multiphase characteristics and the coexistence of a spinel phase with an orthorhombic phase attributed to the larger Er<sup>3+</sup> ionic radius. The SEM analysis of rare earth-doped spinel ferrites reveals that grain size and porosity are significantly influenced by doping concentration, which in turn strongly affect the dielectric and magnetic properties. AFM indicated high surface roughness. The favourable figures of dielectric constant and loss factor recorded at frequency variation makes the material suitable in high frequency performances. The Er modified ferrites possessing a broad range of relaxation period can interact and effectively absorb an extended range of spectrum from the microwave frequency range. UV–Vis spectroscopy demonstrated an increase in the optical forbidden band gap from 1.06 eV to 2.30 eV after doping of erbium, enhancing light absorption. The combined improvements in optical, dielectric, and thermal properties confirm that Er-modified ferrites are promising candidates for high-frequency, high-temperature microwave absorbing applications. The increase of coercivity with respect to doping concentration may be attributed to the anisotropy due to the strong spin orbit coupling of Er<sup>3+</sup>.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173832"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035303","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: 2026-01-16DOI: 10.1016/j.jmmm.2026.173853
Omar H. El-Talkhawy , Samy H. Aly , Sherif Yehia , Fatema Z. Mohammad
In this work, we present a mean-field study using the two-sublattice model to investigate the magnetothermal and magnetocaloric properties of Tb (Fe1-x Mnx)2 compounds with x = 0 and 0.12. Specifically, we have calculated the magnetization, heat capacity, entropy, isothermal entrop change ΔSm and adiabatic temperature change ∆Tad. This study investigates the aforementioned properties at temperatures up to 900 K and magnetic fields up to 5 T. Additionally, we report the relative cooling powers (RCP) in a 5 T field. We have used the Wien2k code to calculate the electron density of states (DOS) for TbFe2. The maximum values obtained, for TbFe2, for ΔSm, ∆Tad, RCP(S) and RCP(T) for a field change of 5 T are 2.37 J/mol. K, 3.05 K, 410 J/mol. and 1070 K2, respectively. The Curie temperatures of the compounds with x = 0 and x = 0.12 are 694 and 626 K respectively. The maximum magnetic entropy, in zero fields, for these two compounds is about 40 J/mol. K. The electronic γe = 0.018 J/mol. K2 for the x = 0 compound. The nature of the phase transition was analyzed, as well, using the universal curve and Belov-Arrott plots. The scaling exponent n is found to be fairly close to n = 2/3 for second order phase transitions described by the mean-field model. It has been confirmed that the transition is a second-order phase transition in both compounds.
{"title":"Magnetic Properties and Magnetocaloric Effect in Tb (Fe1-x Mnx)2 Compounds for x = 0, 0.12","authors":"Omar H. El-Talkhawy , Samy H. Aly , Sherif Yehia , Fatema Z. Mohammad","doi":"10.1016/j.jmmm.2026.173853","DOIUrl":"10.1016/j.jmmm.2026.173853","url":null,"abstract":"<div><div>In this work, we present a mean-field study using the two-sublattice model to investigate the magnetothermal and magnetocaloric properties of Tb (Fe<sub>1-x</sub> Mn<sub>x</sub>)<sub>2</sub> compounds with x = 0 and 0.12. Specifically, we have calculated the magnetization, heat capacity, entropy, isothermal entrop change ΔS<sub>m</sub> and adiabatic temperature change ∆T<sub>ad</sub>. This study investigates the aforementioned properties at temperatures up to 900 K and magnetic fields up to 5 T. Additionally, we report the relative cooling powers (RCP) in a 5 T field. We have used the Wien2k code to calculate the electron density of states (DOS) for TbFe<sub>2</sub>. The maximum values obtained, for TbFe<sub>2</sub>, for ΔS<sub>m</sub>, ∆T<sub>ad</sub>, RCP(S) and RCP(T) for a field change of 5 T are 2.37 J/mol. K, 3.05 K, 410 J/mol. and 1070 K<sup>2</sup>, respectively. The Curie temperatures of the compounds with x = 0 and x = 0.12 are 694 and 626 K respectively. The maximum magnetic entropy, in zero fields, for these two compounds is about 40 J/mol. K. The electronic γ<sub>e</sub> = 0.018 J/mol. K<sup>2</sup> for the x = 0 compound. The nature of the phase transition was analyzed, as well, using the universal curve and Belov-Arrott plots. The scaling exponent n is found to be fairly close to <em>n</em> = 2/3 for second order phase transitions described by the mean-field model. It has been confirmed that the transition is a second-order phase transition in both compounds.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173853"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035304","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}
This paper focuses on the determination of the influence of V on the stability, magnetic properties, and features of phase transitions in Mn55-xA42+xV3 alloys (x = 0, 2, and 4), both in the cast and rapidly quenched states. It has been shown that vanadium decreases the stability of the ferromagnetic τ-phase. The feasibility of directly producing the τ-phase through rapid quenching has been confirmed by achieving a high proportion of the τ-phase, approximately 90 vol%, in the Mn53Al44V3 as-quenched alloy. Additionally, the Curie temperature of this alloy has been determined to exhibit hysteresis during heating and subsequent cooling. Based on these findings, it was suggested that Mn53Al44V3 undergoes a first-order magnetic phase transformation. Based on the experimental data, a Mn-Al-V phase diagram for alloys with a vanadium concentration of 3% and a manganese concentration of 51–55% has been proposed, and a diagram of the dependence of the phase composition in rapidly quenched ribbons on the composition of Mn55-xA42+xV3 has been constructed.
{"title":"Influence of vanadium doping and rapid quenching on phase stability and magnetic properties of τ-MnAl alloys","authors":"A.S. Fortuna , K.S. Nechaev , N.M. Vazhinskii , M.V. Gorshenkov , D.Yu. Karpenkov","doi":"10.1016/j.jmmm.2026.173851","DOIUrl":"10.1016/j.jmmm.2026.173851","url":null,"abstract":"<div><div>This paper focuses on the determination of the influence of V on the stability, magnetic properties, and features of phase transitions in Mn<sub>55-x</sub>A<sub>42+x</sub>V<sub>3</sub> alloys (x = 0, 2, and 4), both in the cast and rapidly quenched states. It has been shown that vanadium decreases the stability of the ferromagnetic τ-phase. The feasibility of directly producing the τ-phase through rapid quenching has been confirmed by achieving a high proportion of the τ-phase, approximately 90 vol%, in the Mn<sub>53</sub>Al<sub>44</sub>V<sub>3</sub> as-quenched alloy. Additionally, the Curie temperature of this alloy has been determined to exhibit hysteresis during heating and subsequent cooling. Based on these findings, it was suggested that Mn<sub>53</sub>Al<sub>44</sub>V<sub>3</sub> undergoes a first-order magnetic phase transformation. Based on the experimental data, a Mn-Al-V phase diagram for alloys with a vanadium concentration of 3% and a manganese concentration of 51–55% has been proposed, and a diagram of the dependence of the phase composition in rapidly quenched ribbons on the composition of Mn<sub>55-x</sub>A<sub>42+x</sub>V<sub>3</sub> has been constructed.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173851"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035294","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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