Journal of Magnetism and Magnetic Materials最新文献

{"title":"Magneto-dielectric composites synthesized using industrial waste","authors":"Sunil Kumar ,&nbsp;Shiffali Middha ,&nbsp;Sajan Masih ,&nbsp;Arshdeep Kaur ,&nbsp;Jaswinder Pal ,&nbsp;Norah Alhokbany ,&nbsp;Jahangeer Ahmed ,&nbsp;Gurpreet Singh ,&nbsp;López-García ,&nbsp;Satvir Singh ,&nbsp;Nitin Tandon ,&nbsp;Indu Sharma ,&nbsp;Arvind Kumar Sharma ,&nbsp;Anupinder Singh","doi":"10.1016/j.jmmm.2025.173306","DOIUrl":"10.1016/j.jmmm.2025.173306","url":null,"abstract":"<div><div>Coal Ash (CA) is an industrial waste procured from brick klin as waste obtained during the firing of raw bricks using rock coal, whereas BaTiO₃ (BT) &amp; KNaNbO₃ (KNN) well well-known ferroelectric perovskites synthesized in the laboratory using conventional solid solution approach. Multiferroic composites of _0.5Coal Ash-_0.5BaTiO₃ &amp; _0.5Coal Ash-_0.5KNaNbO₃ have been synthesized by mechanical mixing approach of Coal Ash collected from brick clan and as-synthesized BaTiO₃ &amp; KNaNbO₃. Structural phases present in Coal Ash have been analyzed according to metal ions confirmed from energy dispersive X-ray spectroscopy whereas diffraction peaks correspond to the tetragonal phase of BaTiO₃ and monoclinic phase of KNaNbO₃ in prepared composites of CA &amp; BT, KNN confirmed the successful synthesis of ceramic composites mentioned above. Morphological analysis has been carried out by scanning the surface of sintered pellets using an electron microscope, whereas energy dispersive spectroscopy (EDS) gives details of different elements present in studied samples. S-shaped magnetic hysteresis (Magnetization vs. Magnetic field hysteresis) manifests magnetic ordering in composites of Coal Ash &amp; non-magnetic ferroelectric BT &amp; KNN. The magnetic behavior of ceramic composites mainly due to different magnetic particles were present during coal combustion confirmed from x-ray diffraction analysis as well as presence of Fe metal ion confirmed from EDS spectroscopy. ε’ &amp; ε“ and σ_ac vs frequency evident for enhanced dielectric and conducting properties of multiferroic composites by processing Coal Ash with BT &amp; KNN and ‘α’ (Obtained from Fitting of Dielectric data) determined the deviation in dielectric behavior of ceramic composites from normal Debye behavior. The change in the value of dielectric permittivity in the presence and absence of a magnetic field stamped for the presence of magneto-dielectric response in _0.5Coal Ash-_0.5BaTiO₃ &amp; _0.5Coal Ash-_0.5KNaNbO₃ multiferroic composites.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173306"},"PeriodicalIF":2.5,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144490467","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":"Impact of charge stripes on magnetization processes in rare-earth tetraborides","authors":"Pavol Farkašovský","doi":"10.1016/j.jmmm.2025.173284","DOIUrl":"10.1016/j.jmmm.2025.173284","url":null,"abstract":"<div><div>We examine the impact of charge stripes on magnetization processes in rare-earth tetraborides within a complex model which takes into account the electron and spin subsystem as well as the coupling (of the Ising type) between both subsystems. The charge stripes in this model are induced by adding the phenomenological, spatially varying local potential <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>. Our assumption is based on a comparison of structural and electronic similarities between the rare-earth tetraborides and rare-earth hexaborides/dodecaborides, where such charge stripes (as a consequence of the Jahn–Teller effect) were experimentally observed. It is shown that the form and intensity of local potential <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> (the type of charge stripes) have dramatic impact on the stability of individual plateaus on magnetization curves. The largest effects have been observed for the periodic potential forming the full charge stripes alternating with chessboard charge stripes. This type of charge ordering leads to magnetization curves with extremely simple structure consisting of only two main magnetization plateaus with fractional magnetization m=1/2 and m=1/3, the stability regions of which depend strongly on the model parameters. It is shown that with increasing intensity of local potential <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> the 1/2 plateau (1/3 plateau) is generally stabilized (suppressed) and this effect is further enhanced by increasing spin-electron coupling leading to total disappearance of the 1/3 plateau, exactly as is observed in TmB<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> and ErB<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>. It should be noted that although charge stripes are introduced here ad hoc, the fact that our picture of magnetization processes is fully consistent with experimental measurements in TmB<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> and ErB<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> indicates that this assumption is reasonable and could serve as motivation for experimental physicists to find such a type of charge ordering in these materials.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173284"},"PeriodicalIF":2.5,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144490466","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":"Electron spin resonance study of the van der Waals ferromagnet Fe5GeTe2","authors":"Yang Yang ,&nbsp;Fanying Meng ,&nbsp;Wei Liu ,&nbsp;Jingxin Li ,&nbsp;Jing Zhang ,&nbsp;Jiyu Fan ,&nbsp;Chunlan Ma ,&nbsp;Min Ge ,&nbsp;Li Pi ,&nbsp;Zhe Qu ,&nbsp;Lei Zhang","doi":"10.1016/j.jmmm.2025.173251","DOIUrl":"10.1016/j.jmmm.2025.173251","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The van der Waals (vdW) material Fe&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;GeTe&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&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; is a promising candidate for spintronic applications due to its high Curie temperature (&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;C&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) and easily controllable properties. In this study, we thoroughly investigate the magnetic anisotropy of Fe&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;GeTe&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&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; single crystals using magnetization and electron spin resonance (ESR) techniques. We find that the magnetization for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; is stronger than that for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; below &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∗&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;100 K, exhibiting a weak easy-plane anisotropy (EPA). This EPA is significantly enhanced in the temperature range of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∗&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, indicating an enhanced EPA effect. Meanwhile, the ESR spectra show weak intensity below &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∗&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; while significantly anisotropic signals are observed in the enhanced EPA region, with stronger ESR intensity for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; compared to that for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. The resonance fields (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; display opposite trends. The resonance field &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; shifts toward lower fields, while &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; moves toward higher fields upon cooling. This contrary trends of &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; are attributed to the effects of ","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173251"},"PeriodicalIF":2.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471055","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":"Study of magnetic, thermodynamic, and transport properties in orthorhombic GdNiAl3","authors":"S. Nallamuthu ,&nbsp;K. Arun ,&nbsp;A.R. Vimaljith ,&nbsp;Sergej Ilkovic ,&nbsp;Ivan Curlik ,&nbsp;Marian Reiffers ,&nbsp;R. Nagalakshmi","doi":"10.1016/j.jmmm.2025.173319","DOIUrl":"10.1016/j.jmmm.2025.173319","url":null,"abstract":"<div><div>The compound GdNiAl₃ crystallizes in an orthorhombic structure with the space group Pnma. Magnetization and heat capacity measurements reveal the presence of multiple magnetic transitions below the ordering temperature T_ord = 72.5 K, suggesting the existence of competing magnetic interactions within the system. This behavior is likely associated with the structural complexity of GdNiAl₃, which features randomly oriented Ni-centered tricapped trigonal prisms, further coordinated by additional aluminum atoms. Additionally, a ferromagnetic transition observed at 165.5 K is attributed to the presence of a GdAl₂ impurity phase.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173319"},"PeriodicalIF":2.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471056","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":"Enhancing the Tb utilization efficiency and coercivity in high Ce content Nd-Fe-B magnets by Pr-Tb-Zn grain boundary diffusion","authors":"Zhibin Li ,&nbsp;Wenbing Fan ,&nbsp;Rongshun Lai,&nbsp;Haibo Xu,&nbsp;Xiaoxuan Zheng,&nbsp;Xin Wang,&nbsp;Qianji Wang,&nbsp;Bo Jiang,&nbsp;Xianglong Zhou,&nbsp;Qiang Ma","doi":"10.1016/j.jmmm.2025.173316","DOIUrl":"10.1016/j.jmmm.2025.173316","url":null,"abstract":"<div><div>Grain boundary diffusion is an effective method for improving the coercivity of Nd-Fe-B sintered magnets. However, the coercivity is not significantly enhanced after grain boundary diffusion in magnets with high Ce content due to the presence of the REFe₂ phase. In this study, we have designed a novel low-melting-point ternary diffusion source of Pr₅₃Tb₄₂Zn₅ that can effectively improve the diffusion efficiency and utilization of Tb, thereby significantly enhancing the coercivity of the magnets. After diffusion of Tb and Pr₅₃Tb₄₂Zn₅ in sintered magnets with 25.8 wt% Ce substituted, the coercivity of the magnets was enhanced from 1019.7 kA/m to 1412.9 and 1500.5 kA/m, respectively. Observations of the microstructure and element distribution showed that after diffusion of Tb and Pr₅₃Tb₄₂Zn₅, Tb penetrated the surface of the RE₂Fe₁₄B main phase grains and formed a Tb-rich shell, which significantly increased its anisotropy field. Compared to the Tb diffused magnets, the Pr₅₃Tb₄₂Zn₅ diffused magnets exhibited a more uniform distribution of the Tb-rich shell and a deeper diffusion depth. Additionally, transmission electron microscopy analysis indicated that in the Tb diffused magnets, some Tb elements were consumed by the REFe₂ phase, whereas in the Pr₅₃Tb₄₂Zn₅ diffused magnets, there was almost no Tb in the REFe₂ phase, which improved the utilization of Tb and resulted in a higher increment in coercivity.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173316"},"PeriodicalIF":2.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479947","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":"Effect of Mn substitution on first order antiferromagnetic–ferromagnetic phase transition and magnetocaloric effect in FeRh","authors":"Rajeev Joshi ,&nbsp;Pramod R. Nadig ,&nbsp;Satish Yadav ,&nbsp;Suman Karmakar ,&nbsp;R. Rawat","doi":"10.1016/j.jmmm.2025.173217","DOIUrl":"10.1016/j.jmmm.2025.173217","url":null,"abstract":"<div><div>Influence of Mn substitution on the first order antiferromagnetic (AF) to ferromagnetic (FM) transition and magnetocaloric effect (MCE) in FeRh has been investigated. It shows that 1.2% Mn substitution for Fe in Fe₄₉Rh₅₁ decreases transition temperature to around 285 K. Though a majority of sample volume transforms with a hysteresis of <span><math><mo>≈</mo></math></span>10 K, a narrow hysteresis remains over a wide temperature (<span><math><mo>&gt;</mo></math></span> <span><math><mrow><mn>150</mn></mrow></math></span> K) and field (<span><math><mo>&gt;</mo></math></span> <span><math><mrow><mn>90</mn></mrow></math></span> kOe) range. The values of isothermal change in entropy (<span><math><mi>Δ</mi></math></span>S<span><math><msub><mrow></mrow><mrow><mi>t</mi><mi>h</mi></mrow></msub></math></span>) and adiabatic change in temperature (<span><math><mi>Δ</mi></math></span>T<span><math><msub><mrow></mrow><mrow><mi>a</mi><mi>d</mi></mrow></msub></math></span>) were found to be 14 J/kg-K and -7 K, respectively for 50 kOe magnetic field change which are comparable to the maximum values observed in FeRh system.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173217"},"PeriodicalIF":2.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144490464","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":"Investigation of magnetocaloric properties and critical phenomenon of the intermetallic compound DyCoAl across magnetic transition","authors":"Mily Kundu,&nbsp;Sourav Sarkar,&nbsp;Kalyan Mandal","doi":"10.1016/j.jmmm.2025.173290","DOIUrl":"10.1016/j.jmmm.2025.173290","url":null,"abstract":"<div><div>Herein we report the magnetocaloric properties, critical analysis across magnetic phase transition and investigated their correlation for the ternary intermetallic compound DyCoAl that belongs to MgZn<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-type structure with space group <em>P6</em><span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span><em>/mmc</em>. The nature of magnetic phase transition is investigated by conducting critical analysis in the vicinity of ferromagnetic-paramagnetic transition temperature (<span><math><mrow><mo>∼</mo><mn>37</mn></mrow></math></span> K) by means of modified Arrot plot, Kouvel-Fisher plot, critical isotherm, heat capacity data analysis as well as magnetocaloric study. We acquire the critical exponents <span><math><mrow><mi>α</mi><mo>∼</mo><mn>0</mn><mo>.</mo><mn>81</mn></mrow></math></span>, <span><math><mrow><mi>β</mi><mo>∼</mo><mn>0</mn><mo>.</mo><mn>20</mn></mrow></math></span>, <span><math><mrow><mi>γ</mi><mo>∼</mo><mn>0</mn><mo>.</mo><mn>77</mn></mrow></math></span>, <span><math><mrow><mi>δ</mi><mo>∼</mo><mn>4</mn><mo>.</mo><mn>8</mn></mrow></math></span>, <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>∼</mo><mn>39</mn></mrow></math></span> K, validating their self-consistency and reliability through the Widom scaling law and scaling equations. The compound exhibits a very high relative cooling power (RCP) of <span><math><mrow><mo>∼</mo><mn>1319</mn></mrow></math></span> J/kg and a moderate adiabatic temperature change of <span><math><mrow><mo>∼</mo><mn>6</mn><mo>.</mo><mn>7</mn></mrow></math></span> K for a field change of 90 kOe. The mechanical efficiency of this compound is significantly larger compared to other refrigerants operating in cryogenic temperature range, positioning it as a promising candidate for various technological applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173290"},"PeriodicalIF":2.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144490465","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":"Investigating the influence of magnetization intensity on magnetoelectric coupling in MnxZn1-xFe2O4-PbZr0.5Ti0.5O3 multiferroic liquids","authors":"Haowen Mu ,&nbsp;Shubao Yang ,&nbsp;Weihao Wu ,&nbsp;Hong Ao ,&nbsp;Gang Meng ,&nbsp;Rongli Gao ,&nbsp;Xiaoling Deng ,&nbsp;Wei Cai","doi":"10.1016/j.jmmm.2025.173309","DOIUrl":"10.1016/j.jmmm.2025.173309","url":null,"abstract":"<div><div>The optoelectronic detectors made of multiferroic materials provide more possibilities for clinical diagnosis. In this study, Mn<em>_x</em>Zn₁<em>_-x</em>Fe₂O₄ (<em>x</em> = 0, 0.25, 0.5, 0.75, 1) magnetic nanoparticles were prepared using a solid-phase method, to investigate how the magnetization effect the magnetoelectric coupling effect, Mn<em>_x</em>Zn₁<em>_-x</em>Fe₂O₄-PbZr_0.5Ti_0.5O₃ multiferroic fluids were obtained by ball milling. Results show that as the concentration of Mn²⁺ ions (<em>x</em>) increases, the magnetization strength gradually increases, reaching a maximum saturation magnetization of 81.83 emu/g when <em>x</em> = 1. Additionally, the dielectric constant of the Mn_0.5Zn_0.5Fe₂O₄-PZT (<em>x</em> = 0.5) multiferroic fluids reaches a maximum value of 4.67. Under the application of an external magnetic field, the dielectric constant variation rate reaches a maximum of 78.43 % when <em>x</em> = 0.75. Ferroelectric performance studies show that when <em>x</em> = 0.75, the remnant polarization strength is 8.11 nC/cm², and the saturation polarization strength is 15.84 nC/cm². After applying a magnetic field, the remnant polarization strength variation rate reaches a maximum of 56.12 % at <em>x</em> = 0.5, yielding a coupling coefficient of 11.49 V/(cm∙Oe), demonstrating excellent magnetoelectric coupling performance. This study reveals the significant impact of magnetization strength on the performance of magnetoelectric composite multiferroic fluids, providing insights for further optimization of the magnetoelectric coupling coefficient.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173309"},"PeriodicalIF":2.5,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338345","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":"Comparison of pinning potentials, depinning currents and scalability for domain wall-based synapses with various pinning structures","authors":"Guntas Kaur,&nbsp;Tanmoy Pramanik","doi":"10.1016/j.jmmm.2025.173280","DOIUrl":"10.1016/j.jmmm.2025.173280","url":null,"abstract":"<div><div>Domain wall (DW) based magnetic tunnel junctions (MTJ) are one of the promising candidates for memristive artificial synapses. Various domain wall tracks have recently been studied, and different geometric configurations for pinning domain walls have been proposed. Geometric pinning helps to control the domain wall (DW) motion along the track and quantizes the conductance of the DW-MTJ to specific values. This work compares various geometric pinning options in terms of thermal stability, depinning currents, and programming reliability under random thermal fluctuations for scaled device dimensions. Results show that all pinning configurations can meet the thermal stability limits required for non-volatile operation if the device is designed appropriately. However, depending on the pinning geometry, depinning current requirements can vary considerably. Reliable programming with good linearity can be achieved for all of the studied configurations. Additionally, one-dimensional pinning potentials suitable for a compact model of DW motion are obtained for each pinning geometry. The results could provide valuable guidelines for designing DW tracks with scaled dimensions, thermally stable quantized conductance states, and highly reliable programming behavior.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173280"},"PeriodicalIF":2.5,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471054","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":"A closed-form formula-based method for magnetic dipole localization in a constant magnetic field by measurement of its magnetic field vectors and magnetic gradient tensors","authors":"Massimo Stefanoni ,&nbsp;Ákos Odry ,&nbsp;Peter Sarcevic","doi":"10.1016/j.jmmm.2025.173313","DOIUrl":"10.1016/j.jmmm.2025.173313","url":null,"abstract":"<div><div>The problem of dipole localization and its parameter estimation has been widely investigated. In the literature, various approaches have been proposed, including iterative methods and resolution schemes based on inverse formulas. This paper introduces the Closed-form Formula-based Method (CFM), which addresses the dipole localization problem when the source is placed in the Earth’s magnetic field, assumed to be constant within the region of interest. The CFM is based on a modified version of the Yin formula that is a closed-form expression originally developed to estimate the position of a dipole in the absence of a constant magnetic field. The proposed method utilizes this modified Yin formula in combination with a specific magnetometer array configuration designed to measure both gradients and magnetic field values, along with a selection algorithm. The concept was tested by simulations in which different dipole parameters and different positions are tested to verify all possible configurations. Both the Yin formula and the CFM were simulated in MATLAB by developing scenarios in which infinitesimal gradient schemes were considered. Additionally, the CFM was tested by taking into account a finite gradient scheme, the effect of white noise, different trajectories in space, and different strengths of the dipole. Results show that the CFM can be used in all configurations in which the Yin formula does not work, and that it localizes a 100 Am² dipole at a distance of 3 m, with a white noise of 0.01 nT as a standard deviation, providing a mean and maximum absolute error of 0.01 m and 0.03 m, respectively.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173313"},"PeriodicalIF":2.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366231","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}