Journal of Superconductivity and Novel Magnetism最新文献

{"title":"Effect of Sintering Time on Microstructural Evolution and Superconducting Properties of MgB2 Bulk Fabricated via Mold-assisted Gas-solid Method","authors":"Hongli Suo,&nbsp;Chenfei Yu,&nbsp;Zili Zhang,&nbsp;Benzhe Zhou,&nbsp;Lei Wang,&nbsp;Jianhua Liu,&nbsp;Qiuliang Wang","doi":"10.1007/s10948-026-07205-9","DOIUrl":"10.1007/s10948-026-07205-9","url":null,"abstract":"<div><p>Magnesium diboride (MgB₂) bulks, as a superconducting material with a relatively high superconducting transition temperature, low raw material cost, absence of weak-link effects, and flexible fabrication routes, have shown great potential for applications in various fields. Among the available fabrication methods, the gas-solid method has attracted considerable attention due to its ability to significantly reduce the MgO impurity content in the samples. However, cracking is prone to occur during the gas-solid reaction process, which adversely affects the structural integrity of the bulks. The introduction of molds can effectively suppress crack formation and improve the shaping quality of MgB₂ bulks. Nevertheless, the use of molds also reduces the diffusion rate of Mg vapor, resulting in a slower reaction process and consequently lower production efficiency. In this work, the optimal sintering time for MgB₂ bulk fabrication via the mold-assisted gas-solid method is optimized, thereby reducing experimental cost. A series of MgB₂ bulk samples with sintering times ranging from 12 h to 72 h were fabricated using the mold-assisted gas-solid method. The results show that all samples are dominated by the MgB₂ phase with a small amount of MgO impurity. With increasing sintering time, the grain size gradually increases, mechanical properties such as microhardness are significantly enhanced, and electrical resistivity decreases. Meanwhile, the <i>A</i>_f, <i>J</i>_c, <i>F</i>_p, and <i>H</i>_irr are all improved. Nano-CT results reveal that Mg vapor diffuses from the exterior to the interior of the boron compact and reacts progressively. The internal defects evolve from dispersed pores at the early stage of sintering to planar cracks at later stages. Among all samples, the one sintered for 60 h exhibits the optimal comprehensive performance, indicating that 60 h is the optimal sintering time for the mold-assisted gas-solid fabrication of MgB₂ bulks. This work provides important experimental evidence and theoretical guidance for further optimization of the fabrication process, microstructural control, and performance enhancement of MgB₂ bulk materials.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148236719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Green Engineered ZnFe2O4@ZnO Heterostructures with Tunable Charge Transport and Magnetic Response","authors":"Muhammad Faizan,&nbsp;Yasir Zaman,&nbsp;Muhammad Zahid Ishaque,&nbsp;Wenjing Wang,&nbsp;Muhammad Usman,&nbsp;Hira Zaman","doi":"10.1007/s10948-026-07203-x","DOIUrl":"10.1007/s10948-026-07203-x","url":null,"abstract":"<div><p>This study synthesized ZnFe₂O₄@ZnO nanocomposites with different ZnFe₂O₄ concentrations <b>(1:3</b>,<b> 1:1</b>,<b> 3:1)</b> by a green process utilizing Chrysanthemum plant extract and the structural, electrical, dielectric and magnetic characteristics were studied. XRD verified the presence of hexagonal ZnO and cubic spinel ZnFe₂O₄ phases. W-H analysis revealed composition-dependent crystallite refinement and lattice distortion, with crystallite size varying from 8.4 to 7.5 nm and microstrain changing from <span>(:14.71times:{10}^{-3})</span> to <span>(:15.75times:{10}^{-3})</span> as the ZnFe₂O₄/ZnO molar ratio increased. Dielectric measurements showed that at low frequencies, there was a high degree of Maxwell Wagner interfacial polarization, and that the dielectric constant and conductivity of the ACs increased with increased ZnFe₂O₄ contents because of accumulation and hopping charge interfaces. The tunable soft ferrimagnetic behaviour was confirmed magnetically, with the highest saturation magnetization of 11.7 emu/g observed for the intermediate composition and the lowest value of 8.7 emu/g observed at higher ferrite loading, which can be attributed to surface spin disorder and strain-induced magnetic decoupling. The findings suggest a close connection between microstructure, charge transport, and magnetic ordering.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148172919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electronic Structure and Antiferromagnetism in Tetragonal CuMnSn","authors":"Thatshinashree P,&nbsp;Uma Mahendra Kumar Koppolu","doi":"10.1007/s10948-026-07201-z","DOIUrl":"10.1007/s10948-026-07201-z","url":null,"abstract":"<div><p>Using density functional theory combined with an effective Heisenberg model and classical Monte Carlo simulations, we investigate the structural, electronic, and magnetic properties of the tetragonal intermetallic compound CuMnSn. The compound is predicted to stabilize in an antiferromagnetic ground state analogous to that observed in CuMnAs, a prototypical antiferromagnetic spintronic material. The calculated electronic structure exhibits metallic behavior with multiple band crossings and nearly linear dispersions in the vicinity of the Fermi level, indicating a complex low-energy electronic structure. Inclusion of spin–orbit coupling introduces only small band splittings, preserving the overall character of the electronic states near the Fermi level. Classical Monte Carlo simulations yield a Néel temperature of approximately 329 K, suggesting robust antiferromagnetic ordering close to room temperature. The coexistence of stable antiferromagnetism and distinctive electronic features makes CuMnSn a promising candidate for antiferromagnetic spintronic applications.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148172604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling Magnetic Induction Coercivity of Strontium Hexaferrite Based Compounds for Media and Sensors Applications Using Single Hidden Layer Computational Intelligent Method","authors":"Fawaz Saad Alharbi","doi":"10.1007/s10948-026-07202-y","DOIUrl":"10.1007/s10948-026-07202-y","url":null,"abstract":"<div><p>Strontium hexaferrite (SrFe₁₂O₁₉) is a magnetic material with distinct features such as low production cost, excellent chemical stability, non-toxicity, resistance to corrosion and tunable coercivity. Magnetic induction coercivity of this compound contributes significantly to its wider applications in magnetic sensors, magnetic recording media, microwave devices, magnetic wave shielding and other biomedical applications. Experimental synthesis of strontium hexaferrite as well as introductions of different cations in the crystal structure at different concentrations through doping for magnetic induction coercivity enhancement, are laborious and costly. This necessitates the need for computational methods of coercivity prediction and enhancement. This work develops extreme learning machine (ELM) based model using ionic (Ionic) radii of the doping cations descriptors and crystal lattice (Latt) descriptors with sine (SN) and sigmoid (SG) activation functions. The predictive models were developed and validated using experimental data extracted from one hundred and twenty-two strontium hexaferrite compounds. Results of Ionic-ELM-SN, Latt-ELM-SG and Ionic-ELM-SG intelligent predictive models were compared with stepwise regression (STR) based model using root mean square error (RMSE), correlation coefficient (CC) and mean absolute error (MAE) metrics. Ionic-ELM-SN performs better than Latt-ELM-SG, Ionic-ELM-SG and Latt-STR predictive models with improvement of 27.06%, 35.61% and 60.49% respectively, using MAE metric on testing strontium hexaferrites. The developed predictive model was further validated using new experimental data and the obtained magnetic induction coercivity agreed excellently with the measured values. The developed predictive intelligent models would facilitate magnetic induction coercivity enhancement in strontium hexaferrite based compounds for several industrial and technological magnetic applications.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diameter and Temperature Dependent Structure and Magnetic Properties of Electrodeposited CoNiCu Alloy Nanowires","authors":"Shreesh Kumar Shrivastava,&nbsp;Shivani Agarwal,&nbsp;Mohammad Abushuhel,&nbsp;Koushik V. Prasad,&nbsp;Sikata Samantaray,&nbsp;Amrita Pal,&nbsp;Ripendeep Singh","doi":"10.1007/s10948-026-07199-4","DOIUrl":"10.1007/s10948-026-07199-4","url":null,"abstract":"<div><p>CoNiCu alloy nanowires were fabricated by electrodeposition into the pores of anodised aluminium oxide (AAO) templates. Here, we have investigated four samples of CoNiCu nanowires with different alumina oxide template pore diameters 40 nm, 100 nm, 160 nm and 200 nm. Transmission electron microscopy and scanning electron microscopy images confirms that the wires are uniform, continuous, and densely packed wires. The presence of (111) (200) and (220) XRD reflections observed at 2<i>θ</i> ~ 44.9°, 52° and 76°, indicate that these nanowires have purely face-centred cubic structure. A significant increase in coercivity is observed as the diameter and temperature changes. The coercivity of CoNiCu nanowires are found 2000 Oe for 40 nm and 488 Oe for 200 nm diameter when the applied field is parallel to the wire axis. The coercivity is 363 Oe for 40 nm and 192 Oe for 200 nm diameter when the applied field is perpendicular to the wire axis. A high value of coercivity parallel to the wire axis attributed to dipolar interactions and substantial shape anisotropy. A temperature dependence of the coercivity has also been observed for all the diameter. For 40 nm nanowires the value of coercivity is 2000 Oe at 300 K and 2892 Oe at 50 K, while for 200 nm it is 488 Oe at 300 K and 863 Oe at 50 K when the field is applied parallel to the wire axis. The increase in coercivity at low temperature is due to the freezing of thermal fluctuations blocks where each domain in a fixed magnetisation state.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tunable and Synergistic Enhancement of Electromagnetic Shielding Efficiency through Zn Doping in NiFe₂O₄/MWCNT Hybrid Architectures","authors":"Suraj Kumar,&nbsp;Sumit Kumar,&nbsp;Neelam Singh,&nbsp;Vivek Verma,&nbsp; Meenakshi,&nbsp;Prashant Kumar,&nbsp;Vijay Arora","doi":"10.1007/s10948-026-07200-0","DOIUrl":"10.1007/s10948-026-07200-0","url":null,"abstract":"<div><p>In this study, hybrid composites with improved EMI shielding in the Ku-band (12.4–18 GHz) were created using Zn-doped nickel ferrite nanoparticles (<i>x</i> = 0, 0.1, 0.2, 0.3, 0.4) and multi-walled carbon nanotubes (MWCNTs). X-ray diffraction showed that all compositions formed a pure cubic spinel phase with regular changes in lattice parameter and crystallite size as a function of Zn concentration, affecting cation distribution and magnetic behavior. VSM tests at room temperature showed soft-magnetic properties with moderate coercivity and a non-monotonic saturation magnetization trend, peaking at 41.1 emu/g for x = 0.2 before dropping at higher doping levels. EMI shielding efficacy was assessed using a vector network analyzer and 12.4–18 GHz transmission/reflection (S-parameter) tests. The Ni₀.₈Zn₀.₂Fe₂O₄/MWCNT composite had the maximum shielding efficacy of 61 dB due to synergistic dielectric and magnetic loss processes, enhanced impedance matching, and significant interfacial polarization from the conductive MWCNT network and magnetic ferrite phase. These findings show that controlled Zn substitution and MWCNT hybridization can be used to create lightweight, broadband, high-performance EMI shielding materials for aerospace, military, and next-generation telecommunications applications.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Dy-Al Grain Boundary Diffusion on the Properties and Microstructure of Sintered Nd-Fe-B Magnets","authors":"Jiandong Yang,&nbsp;Zhiqiang Li,&nbsp;Zhihao Dai,&nbsp;Yusong Du,&nbsp;Guangrui Zhang,&nbsp;Jinxu Li","doi":"10.1007/s10948-026-07193-w","DOIUrl":"10.1007/s10948-026-07193-w","url":null,"abstract":"<div><p>To enhance the high-temperature coercivity and thermal stability of sintered Nd-Fe-B magnets, this study employs low-melting-point Dy-Al eutectic alloys (Dy₉₅Al₅, Dy₉₀Al₁₀, Dy₈₅Al₁₅) as diffusion sources via magnetron sputtering and heat treatment. Systematic investigation reveals that the synergistic effect of Dy and Al is crucial for performance improvement, operating through dual mechanisms: “main-phase hardening” and “grain boundary optimisation.” Dy penetrates along optimised grain boundaries to form (Nd, Dy)₂Fe₁₄B core-shell structures on main-phase grains, hindering reverse domain nucleation. Simultaneously, Al improves the wettability and continuity of the grain boundary phase, enhancing intergranular decoupling and providing efficient channels for Dy diffusion. Among the investigated compositions, Dy₉₀Al₁₀ shows the best overall performance, which yields the highest coercivity increase from 13.39 kOe to 22.40 kOe (a 67.3% enhancement) and the best temperature stability within 300–390 K (remanence temperature coefficient <i>α</i> = − 0.093%/K, coercivity temperature coefficient <i>β</i> = − 0.592%/K). Microstructural analysis confirms the formation of a uniform core-shell structure and continuous grain boundary phases at this composition. This work clarifies the appropriate Al content and the dual strengthening mechanism, providing a theoretical and practical foundation for developing high-performance, thermally stable Nd-Fe-B magnets with reduced heavy rare-earth consumption.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Singlet-bond Superconductivity Theory for the Simultaneous Enhancements of (T^{(n)}_{c}) and (sigma ^{(n)}(0) propto 1/lambda ^{(n)}(0)^{2}) in Multiple n-CuO(_{2})-layer Cuprate High-(T_{c}) Superconductors","authors":"Hiroyuki Kaga","doi":"10.1007/s10948-026-07197-6","DOIUrl":"10.1007/s10948-026-07197-6","url":null,"abstract":"<div><p>The study of multiple <i>n</i>-CuO<span>(_{2})</span>-layer (multilayer) cuprate high-temperature superconductors in the singlet-bond (SB) superconductivity theory reveals that the large enhancements of superconducting transition temperatures <span>(T^{(n)}_{c})</span> are the result of increased condensation energy which is added to the layer by the motion of interlayer-tunneled condensed SB-pairs from the adjacent layers. This mechanism is endorsed by the experimental observations of the large enhancements of muon-spin-relaxation rate <span>(sigma ^{(n)}(0))</span> proportional to inverse squared London penetration depth at <span>(T = 0)</span>, <span>(sigma ^{(n)}(0) propto 1/lambda ^{(n)}(0)^{2})</span>, where <span>(2 |Psi ^{(n)}|^{2})</span> in <span>(1/lambda ^{(n)}(0)^{2} = 4 pi 2 |Psi ^{(n)}|^{2} e^{2}/mc^{2})</span> (<span>(Psi ^{(n)})</span> the order-parameter of Ginzburg-Landau free energy) is enhanced by the same factor as the condensation energy increase due to the kinetic energy increase. These enhancements are a very unique effect particular to multilayer superconductors where while SB-pairs in the normal-state pseudogap insulator phase are strictly two-dimensional and confined to one CuO<span>(_{2})</span>-layer, SB-pairs in the superconductng phase can tunnel to adjacent layers where they increase both condensation and kinetic energies through the coherent motion. The calculations of <span>(T^{(n)}_{c})</span> and <span>(1/lambda ^{(n)}(0)^{2})</span> give the results; (1) <span>(T^{(n)}_{c})</span> and <span>(1/lambda ^{(n)}(0)^{2})</span> increase from <span>(n = 1)</span> to <span>(n = 3)</span>, decrease from <span>(n = 3)</span> to <span>(n = 5)</span> and then level off for <span>(n ge 6)</span>, having the maxima <span>(T^{(3)}_{c})</span> and <span>(1/lambda ^{(3)}(0)^{2})</span> always at <span>(n = 3)</span>, (2) the maximum superconducting transition temperature <span>(T^{max}_{c})</span> that can be achieved at the ambient pressure by <span>(T^{(3)}_{c})</span> in any multilayer cuprates is bounded by the maximum condensation onset-temperature <span>(T_{0}^{max} sim 156 K)</span> at the optimal doping <span>(delta _{m} sim 0.15)</span>, (3) the multilayer enhancements <span>(T^{(n)}_{c} / T^{(1)}_{c})</span> as a function of <i>n</i> of all the multilayer cuprate superconductors examined are the same and can be expressed by a singe curve (except with one correction to the low <span>(T^{(1)}_{c})</span> values as explained in the text). This <span>(T^{(n)}_{c} / T^{(1)}_{c})</span> - <i>n</i> curve is well reproduced by the multilayer SB superconductivity with the restricted entropy (RE) imposed on the pseudogap insulator phase.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aegle Marmelos Mediated Green Synthesis of Chromium-doped Nickel Ferrite Nanoparticles for Antibacterial Activity","authors":"Kajal A. Gurav,&nbsp;Sudarshan Gawali,&nbsp;Subhash M Wani,&nbsp;A. P. Keche,&nbsp;K. M. Jadhav","doi":"10.1007/s10948-026-07198-5","DOIUrl":"10.1007/s10948-026-07198-5","url":null,"abstract":"<div><p>Here, we present the preparation of (NiFe_2−xCr_xO₄), with x = 0.0, 0.1, 0.2, 0.3 and 0.4 nanoparticles using a green synthesis method, employing the extract of Aegle marmelos (Bel leaves<i>)</i> as biogenic green fuel. The single-phase production having an FCC-type simple cubic spinel structure was verified by XRD analysis. The prepared nanoparticles exhibit crystallite sizes of 14 to 8 nm. The lattice constant (a) calculated from XRD data decreased from 8.346 Å to 8.307 Å. The formation of spherical grains with some agglomeration was observed through FE-SEM analysis. The surface area determined by BET analysis increases with Cr³⁺ content and ranges from 33.62 m²/g to 59.32 m²/g. The band gap energy calculated using the Tauc plot was in the range 1.57 eV-1.74 eV. Saturation magnetization decreases with Cr³⁺ content. The low coercivity values suggest the superparamagnetic nature of the prepared nanoparticles. No systematic dependence of antibacterial properties of the synthesized nanoparticles was found against Gram-positive (S. Aureus and B. Subtilis) and Gram-negative (E. coli, K. Pneumonia) bacteria for varying Cr³⁺ content. However, the sample with x = 0.2 exhibits enhanced antibacterial activity compared to the other compositions.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Cu Addition on Magnetic Properties and Microstructure of Melt-spun NdFeB Alloys","authors":"Fang Li,&nbsp;Xiaohua Tan,&nbsp;Hui Xu","doi":"10.1007/s10948-026-07195-8","DOIUrl":"10.1007/s10948-026-07195-8","url":null,"abstract":"<div><p>The (Nd_10.23Pr_2.56Fe_69.77Co_11.63B_5.81)_{100−<i>x</i>}Cu_<i>x</i> (<i>x</i> = 0–2.0) alloy ribbons were fabricated by melt-spinning technique at 15 m/s, and their hard magnetic performance and microstructure were systematically examined. The experimental results indicate that the intrinsic coercivity (<i>H</i>_<i>ci</i>) initially increases significantly with minor Cu addition, followed by a gradual decrease at higher Cu contents, while both the remanence (<i>B</i>_<i>r</i>) and maximum magnetic energy product ((<i>BH</i>)_max) exhibit a declining trend. Notably, the <i>x</i> = 0.5 alloy achieves the highest intrinsic coercivity of 1260 kA/m, representing a 40.6% improvement compared to the Cu-free alloy. Cu addition results in a marked increase in the grain size. Transmission electron microscopy (TEM) analysis shows that a minor Cu addition has a dramatic effect on the average grain size, enlarging it from 19 ± 1 nm (<i>x</i> = 0) to 60 ± 1 nm (<i>x</i> = 0.5). The mechanism of coercivity improvement induced by Cu addition is discussed by the observed intergranular phase. A distinct ferromagnetic intergranular phase enriched in Nd, Pr, and Cu is observed in the <i>x</i> = 0.5 alloy. The ~ 8 nm-thick intergranular phase exceeds the ferromagnetic exchange interaction length (over 4.18 nm) between 2:14:1 grains, thereby weakening ferromagnetic exchange coupling interaction and enhancing coercivity.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"39 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}