Journal of Magnetism and Magnetic Materials最新文献

英文中文

Governing the magnetic hyperthermia performance through assembly effect in superparamagnetic biocomposites: Dispersed chains and clustered assemblies immobilized on the bacterial nanocellulose fibers

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-19 DOI: 10.1016/j.jmmm.2025.173076

Aszad Alam , Gongotree Phukan , Chandrasekhar Murapaka , J.P. Borah , Aimin Yu , Mudrika Khandelwal

Superparamagnetic scaffolds with tailored magnetic response and hyperthermia efficiency are highly researched for biomedical applications, including nanomedicines and cancer therapy. However, the hyperthermia efficiency of such composites/scaffolds has always been investigated with respect to the amount of magnetic nanoparticles (MNPs), undermining the importance of MNP’s assembly and arrangement, particularly when the MNPs are immobilized within the matrices/scaffolds. This study achieves two drastically different arrangements of iron oxide-based MNPs in the bacterial nano-cellulose matrix, keeping the final MNP content the same: (i) Dispersed chains and (ii) Highly aggregated clusters, by varying the iron-ion concentrations with simultaneous oleic acid (OA) capping. Consequently, two significantly different hyperthermia performances were obtained at the same fraction of MNPs: (i) a rapid rise to 76 ℃ in MNP chains and (ii) a gradual rise to 40 ℃ in MNP clusters in the 900 s. This is attributed to substantial enhancement in the effective magnetic anisotropy constant owing to the in-situ governed chain assembly of MNPs in the nanofibrous reactor. The highly stable performance (>180 days), along with room-temperature superparamagnetism and excellent biocompatibility of both the m-BC assemblies, pave the way for tunable hyperthermia and drug delivery applications. Nevertheless, assembly-driven tailored hyperthermia observed in this study underscores the need to evaluate the magnetic scaffolds (or MNPs) under practical biological conditions for accurate quantifications.

具有定制磁响应和热疗效率的超顺磁性支架在生物医学（包括纳米药物和癌症治疗）方面的应用受到了高度关注。然而，此类复合材料/支架的热疗效率一直都是根据磁性纳米粒子（MNPs）的数量来研究的，这削弱了 MNP 的组装和排列的重要性，尤其是当 MNPs 被固定在基质/支架中时。本研究在保持最终 MNP 含量不变的情况下，通过改变铁离子浓度并同时使用油酸 (OA) 封盖，在细菌纳米纤维素基质中实现了两种截然不同的氧化铁基 MNP 排列：(i) 分散链和 (ii) 高度聚集簇。因此，在 MNP 含量相同的情况下，获得了两种明显不同的高热性能：(i) MNP 链迅速升至 76 ℃，(ii) MNP 簇在 900 秒内逐渐升至 40 ℃。这两种 m-BC 组合物的性能高度稳定（180 天），具有室温超顺磁性和良好的生物相容性，为可调热疗和药物输送应用铺平了道路。尽管如此，本研究中观察到的组装驱动的定制热疗强调了在实际生物条件下评估磁性支架（或 MNPs）以进行精确量化的必要性。

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引用次数: 0

Effects of disorder in a single-site anisotropic XY ferromagnet: A Monte Carlo study

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-19 DOI: 10.1016/j.jmmm.2025.173045

Olivia Mallick

We perform Monte Carlo simulation to study the effects of random disorder on equilibrium phase transition of three-dimensional single-site anisotropic XY ferromagnet. The disorder is incorporated in two ways; having a randomly distributed anisotropy and presence of a quenched random field. The ferro-para transition temperature has been found to increase with the increase of the strength of constant (over the space) anisotropy. In contrast, the system gets ordered at lower temperatures if the anisotropy has random distribution. The effects of quenched random fields are also studied in single-site anisotropic XY ferromagnet. The transition temperature reduces due to the presence of quenched random field. The compensating field (the required amount of field which preserves the critical temperature for isotropic XY ferromagnet) linearly depends on the strength of constant single-site anisotropy. We compute the magnetic and susceptibility exponent ratios for constant single-site anisotropic XY system only via detailed finite-size scaling analysis.

引用次数: 0

Gelatin grafted magnetic hydroxyapatite nanocomposite for chemo-hyperthermia therapy

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-19 DOI: 10.1016/j.jmmm.2025.173086

Gunjan Verma , Pankaj Gautam , Sandeep B. Shelar , K.C. Barick , P.A. Hassan

The combinatorial therapy comprising chemotherapy and magnetic hyperthermia could provide a promising treatment modality for cancer by making the treatment safer and more effective. In the present study, we have developed magnetic-hydroxyapatite nanocomposite with an aim to be used for chemo-hyperthermia therapy. A soft-chemical approach was employed for the synthesis of nanocomposite, where phosphate coated Fe₃O₄ nanoparticles were used as a core and hydroxyapatite was anchored on their surface through chemical precipitation. The nanocomposite was in-situ functionalized with gelatin moieties for providing aqueous colloidal stability as well as active sites for the binding of drugs. The nanocomposite showed high payload of anticancer drug, doxorubicin hydrochloride (DOX) with a drug content of ∼ 8.2 %. A pH-responsive sustained release of drug was observed with pronounced release under acidic pH conditions, which is favourable for cancer therapy. The cytotoxicity assay in human cancer cells (MCF-7 and A549) suggested non-toxic behaviour of nanocomposite, while DOX loaded nanocomposite showed enhanced toxicity with higher cellular uptake in cancer cells as compared to free DOX. The nanocomposite exhibited superparamagnetic behaviour with magnetic field strength and particle concentration dependent heating efficacy under AC magnetic field (AMF). The specific absorption rate values of nanocomposite were in the appropriate range (100 – 300 W/g under AMF of 0.422 kOe) required for magnetic hyperthermia treatment. Overall, the study demonstrates that the developed nanocomposite could simultaneously serve as a drug carrier and heating source for hyperthermia therapy.

由化疗和磁热疗组成的组合疗法可以使治疗更安全、更有效，从而为癌症治疗提供一种前景广阔的治疗模式。在本研究中，我们开发了磁性羟基磷灰石纳米复合材料，旨在用于化疗-热疗。纳米复合材料的合成采用了软化学方法，以磷酸盐包覆的 Fe3O4 纳米粒子为核心，通过化学沉淀将羟基磷灰石锚定在其表面。该纳米复合材料原位功能化了明胶分子，以提供水性胶体稳定性和药物结合的活性位点。该纳米复合材料具有较高的抗癌药物盐酸多柔比星（DOX）有效载荷，药物含量为 8.2%。在酸性 pH 条件下，药物释放明显，有利于癌症治疗。在人类癌细胞（MCF-7 和 A549）中进行的细胞毒性试验表明，纳米复合材料无毒性，而与游离 DOX 相比，负载 DOX 的纳米复合材料在癌细胞中的细胞吸收率更高，毒性更强。纳米复合材料在交流磁场（AMF）下表现出超顺磁性，其加热效果与磁场强度和颗粒浓度有关。纳米复合材料的比吸收率值处于磁热疗所需的适当范围（在 0.422 kOe 的 AMF 下为 100 - 300 W/g）。总之，该研究表明，所开发的纳米复合材料可同时作为药物载体和热疗的加热源。

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引用次数: 0

Demagnetization factors and field of hemispherical objects

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-19 DOI: 10.1016/j.jmmm.2025.173047

Frederik L. Durhuus , Ellen Fogh , Thomas Jauho , Marco Beleggia

Demagnetization factors play an important role in micromagnetics modeling but exact solutions only exist for a limited number of particle shapes. Here we use a Fourier space based approach coupled to the concept of magnetic charges to derive analytically the demagnetization factors for shapes that are subsets of a sphere: spherical sectors and spherical caps. For the uniformly magnetized hemisphere, which is a special case of both geometries, the exact demagnetization factors are shown to be

N_{x} = N_{y} = 7 / (9 π)

parallel to the bottom plane and

N_{z} = 1 - 14 / (9 π)

in the direction of the dome. Additionally, we provide expressions for shape amplitudes and demagnetization fields of these objects in terms of rapidly converging series. Our work demonstrates the potential of evaluating shape amplitudes to determine demagnetization factors in certain geometries and our results may facilitate numerical simulations of, for example, ferromagnetic droplets.

{"title":"Demagnetization factors and field of hemispherical objects","authors":"Frederik L. Durhuus , Ellen Fogh , Thomas Jauho , Marco Beleggia","doi":"10.1016/j.jmmm.2025.173047","DOIUrl":"10.1016/j.jmmm.2025.173047","url":null,"abstract":"<div><div>Demagnetization factors play an important role in micromagnetics modeling but exact solutions only exist for a limited number of particle shapes. Here we use a Fourier space based approach coupled to the concept of magnetic charges to derive analytically the demagnetization factors for shapes that are subsets of a sphere: spherical sectors and spherical caps. For the uniformly magnetized hemisphere, which is a special case of both geometries, the exact demagnetization factors are shown to be <span><math><mrow><msub><mrow><mi>N</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>=</mo><msub><mrow><mi>N</mi></mrow><mrow><mi>y</mi></mrow></msub><mo>=</mo><mn>7</mn><mo>/</mo><mrow><mo>(</mo><mn>9</mn><mi>π</mi><mo>)</mo></mrow></mrow></math></span> parallel to the bottom plane and <span><math><mrow><msub><mrow><mi>N</mi></mrow><mrow><mi>z</mi></mrow></msub><mo>=</mo><mn>1</mn><mo>−</mo><mn>14</mn><mo>/</mo><mrow><mo>(</mo><mn>9</mn><mi>π</mi><mo>)</mo></mrow></mrow></math></span> in the direction of the dome. Additionally, we provide expressions for shape amplitudes and demagnetization fields of these objects in terms of rapidly converging series. Our work demonstrates the potential of evaluating shape amplitudes to determine demagnetization factors in certain geometries and our results may facilitate numerical simulations of, for example, ferromagnetic droplets.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173047"},"PeriodicalIF":2.5,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868194","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}

引用次数: 0

On the modeling of magneto-mechanical effects in solids

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-18 DOI: 10.1016/j.jmmm.2025.173038

C. Giorgi , A. Morro

The paper develops a thermodynamically-consistent approach to magnetostriction. This is performed by following two different approaches depending on whether a three-dimensional or a one-dimensional setting is considered. In the three-dimensional case the symmetry condition required by the balance of angular momentum results in the need of appropriate variables in the constitutive equations. These variables prove to be Euclidean invariant and comprise the so-called Lagrangian fields usually adopted in the literature. The consequences of the second law of thermodynamics are then determined for a solid described by the temperature, the deformation gradient, and the magnetic field. With this background the magnetostriction is modeled for linear or nonlinear magnetic laws. Next a one-dimensional setting is addressed mainly in connection with available experimental data. The symmetry condition becomes ineffective and hence the classical Eulerian fields are used. Based on the relations established through the thermodynamic consistency a detailed set of constitutive equations, for magnetization and strain, is established. These equations are set up so as to fit the experimental data from a one-dimensional sample under tensile stresses and magnetic fields.

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引用次数: 0

Measurements of stray magnetic fields of Co-rich amorphous microwires using a scanning GMI magnetometer

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-17 DOI: 10.1016/j.jmmm.2025.173078

Yuriy Grebenshchikov , Georgy Danilov , Anastasiya Popova , Sergey Gudoshnikov

A magnetoimpedance sensor-based scanning magnetometer was used to measure the distribution of the stray magnetic induction vertical component for segments of amorphous ferromagnetic Co-rich microwires in longitudinal magnetic field of Helmholtz coils in the range of ± 350 A/m. The distribution of the longitudinal magnetization of the tested samples was determined within a variation model. In magnetic fields below the effective anisotropy field, the Co-rich microwires were found to have the longitudinal magnetization proportional to the magnitude of the external magnetic field, and the width of the distributed closing magnetic charges is stable and equal to ∼ 1.8 mm.

引用次数: 0

Wide magnetic refrigeration window in ferromagnetic shape memory alloys with intermartensitic transformation 具有敏化转变的铁磁形状记忆合金的宽磁制冷窗口

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-17 DOI: 10.1016/j.jmmm.2025.173083

Qinyu Zhang, Mingfang Qian, Xuexi Zhang, Lin Geng

Narrow refrigeration temperature window is a significant drawback for the magnetic refrigeration application of ferromagnetic shape memory alloys (FMSMAs). In this work, the effect of intermartensitic transformation (IMT) on the widening refrigeration temperature window was demonstrated in a Ni-Co-Mn-Sn-Ga alloy. The presence of the thermoelastic IMT behavior was corroborated by DSC, XRD, magnetization (M−T) and isothermal magnetization (M−H) measurements. The IMT appeared during both cooling and heating processes (a two-way IMT) and was essentially different from the one-way IMT (occurs only during cooling or heating process) in other FMSMAs. XRD revealed that the thermoelastic IMT process at heating stage was presumably related to the sequential structural transformations from 6 M → 4O → A. Consequently, the studied Ni-Co-Mn-Sn-Ga alloy exhibited significant inverse magnetocaloric effect (IMCE) due to the large magnetization difference between weak magnetic martensite and strong ferromagnetic austenite. The obtained magnetic entropy change (ΔS_m) showed two successive peaks, amounting to 22.9 and 23.6 J kg⁻¹ K⁻¹ at temperatures of 285.5 and 295.7 K respectively under a magnetic field change of 5 T. The refrigeration capacity (RC, 353.6 J kg⁻¹) and effective RC (RC_eff, 253.8 J kg⁻¹) with a wide magnetic refrigeration window of 17.5 K were achieved in the Ni-Co-Mn-Sn-Ga alloy, which may act as promising working materials for solid-state cooling.

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引用次数: 0

Study on the hydrogen damage of sintered NdFeB and the fabrication of protective Al coating

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-17 DOI: 10.1016/j.jmmm.2025.173067

Falang Lin , Zexin Lu , Yingjie Ding , Jianjun Jiang , Bizhang Zheng , Lijing Yang , Anli Lin , Shengzhi Dong , Guangjian Peng , Zhenlun Song

This study focuses on the hydrogen damage process of sintered NdFeB magnets. A reactor was utilized to evaluate the hydrogen barrier performance of the coatings. The results indicate that bare magnets and normal Al coated magnets have almost no hydrogen resistance at 100°C. Al coating by a DC magnetron sputtering with IBAD (Ion Beam Assisted Deposition) was employed to enhance the resistance of the magnets in hydrogen environments. The IBAD (0.8A) Al coating has excellent hydrogen barrier performance, reaching 180 h at 200°C and 10 bar hydrogen.

引用次数: 0

Heterogeneous microstructure evolution of melt-spun NdFeB powder during the hot deformation process 热变形过程中熔融纺丝钕铁硼粉末的异质微观结构演变

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-16 DOI: 10.1016/j.jmmm.2025.173082

Van Dao Nguyen , Taek-Soo Kim , Sun-woo Nam , Myung-suk Song , Dong-Hwan Kim , Hyo-young Park , YeeUn Lee , Soon-Jik Hong

The heterogeneous structure is unfavorable in hot deformed magnets due to poor magnetic properties. In our previous results, the initial melt-spun powder of type MQU-F also exhibited a heterogeneous microstructure, which could be a contributing factor. In this work, anisotropic nanocrystalline NdFeB magnets of a large size were prepared from commercial MQU-F powder by using spark plasma sintering (SPS) followed by hot deformation (HD). The microstructure evolution from the heterogeneous structure from the powder to the final HD magnet is thoroughly investigated. This study minimized coarse grain regions and provided superior grain alignment by optimizing the HD process. As a result, a Ф30mm NdFeB magnet with a remanence of 13.84 kGs, a coercivity of 15.79 kOe, and a maximum energy product of 47 MGOe was successfully obtained.

引用次数: 0

HYbO2: A Jeff = 12 anisotropic triangular lattice

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials

Pub Date : 2025-04-15 DOI: 10.1016/j.jmmm.2025.173034

V.K. Sahu , P. Dutta , M.P. Saravanan , R.C. Moharana , A. Thamizhavel , S. Bhowal , B. Koteswararao

Highly frustrated magnets exhibit unusually ordered and disordered quantum ground states. The two-dimensional (2D) antiferromagnetic triangular lattice is one of the simplest models to explore unconventional excitations. A family of compounds AYbX₂ (A = Na, K, and X = O, S, Se) hold the 2D isotropic triangular lattices and exhibit the ground state of quantum spin liquid with gapless excitations originating from the Spinon-Fermi surface. The compound HYbO₂ has a chemical formula similar to the AYbX₂ family, but the crystal structure has an anisotropic 2D triangular lattice. We successfully synthesized HYbO₂ polycrystalline samples using the hydrothermal synthesis method and confirmed the single phase using powder X-ray diffraction measurements. Magnetic susceptibility and specific heat measurements confirm that Yb

^{3 +}

hosts the

J_{eff}

\frac{1}{2}

state at low temperatures. The magnetic moments interact antiferromagnetically with

θ_{CW}

= −3.8 K at low temperatures. The system exhibits magnetic long-range order at 1.18 K, possibly due to the non-negligible inter-layer interactions between the anisotropic triangular lattice layers. The electronic structure calculations further evidence anisotropy in the effective spin space due to the involvement of strong spin–orbit coupling. Overall, the system HYbO₂ is anisotropic in both spatial and spin space.

{"title":"HYbO2: A Jeff = 12 anisotropic triangular lattice","authors":"V.K. Sahu , P. Dutta , M.P. Saravanan , R.C. Moharana , A. Thamizhavel , S. Bhowal , B. Koteswararao","doi":"10.1016/j.jmmm.2025.173034","DOIUrl":"10.1016/j.jmmm.2025.173034","url":null,"abstract":"<div><div>Highly frustrated magnets exhibit unusually ordered and disordered quantum ground states. The two-dimensional (2D) antiferromagnetic triangular lattice is one of the simplest models to explore unconventional excitations. A family of compounds AYbX<sub>2</sub> (A = Na, K, and X = O, S, Se) hold the 2D isotropic triangular lattices and exhibit the ground state of quantum spin liquid with gapless excitations originating from the Spinon-Fermi surface. The compound HYbO<sub>2</sub> has a chemical formula similar to the AYbX<sub>2</sub> family, but the crystal structure has an anisotropic 2D triangular lattice. We successfully synthesized HYbO<sub>2</sub> polycrystalline samples using the hydrothermal synthesis method and confirmed the single phase using powder X-ray diffraction measurements. Magnetic susceptibility and specific heat measurements confirm that Yb<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> hosts the <span><math><msub><mrow><mi>J</mi></mrow><mrow><mi>eff</mi></mrow></msub></math></span> = <span><math><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></math></span> state at low temperatures. The magnetic moments interact antiferromagnetically with <span><math><msub><mrow><mi>θ</mi></mrow><mrow><mi>CW</mi></mrow></msub></math></span> = −3.8 K at low temperatures. The system exhibits magnetic long-range order at 1.18 K, possibly due to the non-negligible inter-layer interactions between the anisotropic triangular lattice layers. The electronic structure calculations further evidence anisotropy in the effective spin space due to the involvement of strong spin–orbit coupling. Overall, the system HYbO<sub>2</sub> is anisotropic in both spatial and spin space.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"626 ","pages":"Article 173034"},"PeriodicalIF":2.5,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868193","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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