Journal of Magnetism and Magnetic Materials最新文献

{"title":"Stability of inertial magnetization driven by spin Hall effect","authors":"Yan-Ting Wang ,&nbsp;Si-Jia Chen ,&nbsp;Zai-Dong Li","doi":"10.1016/j.jmmm.2025.173595","DOIUrl":"10.1016/j.jmmm.2025.173595","url":null,"abstract":"<div><div>Based on the inertial Landau–Lifshitz–Gilbert equation, this study systematically reveals the regulatory mechanisms of the coupling effect between inertial effects and spin Hall effects on magnetization stability by employing a combined approach of fourth-order Runge–Kutta numerical simulation and linear stability analysis. Numerical simulations demonstrate that the system exhibits self-stabilizing characteristics. Theoretical analysis reveals that in the absence of an external magnetic field, the construction of a spin Hall angle-current density phase diagram shows that inertial effects significantly influence the distribution of stable regions. This research uncovers the regulatory mechanisms of inertial time scales on magnetization stability, providing a theoretical foundation for the design of magnetic memory devices based on inertial effects.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"635 ","pages":"Article 173595"},"PeriodicalIF":3.0,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145334681","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":"Graph neural networks to predict coercivity and maximum energy product of hard magnetic microstructures","authors":"H. Moustafa ,&nbsp;A. Kovacs ,&nbsp;J. Fischbacher ,&nbsp;M. Gusenbauer ,&nbsp;Q. Ali ,&nbsp;L. Breth ,&nbsp;T. Schrefl ,&nbsp;H. Oezelt","doi":"10.1016/j.jmmm.2025.173594","DOIUrl":"10.1016/j.jmmm.2025.173594","url":null,"abstract":"<div><div>Graph neural networks (GNN) are a promising tool to predict magnetic properties of large multi-grain structures, which can speed up the search for rare-earth free permanent magnets. In this paper, we use our magnetic simulation data to train a GNN to predict coercivity of hard magnetic microstructures. We evaluate the performance of the trained GNN and quantify its uncertainty. Subsequently, we reuse the GNN architecture for predicting the maximum energy product. Out-of-distribution predictions of coercivity are also performed, following feature engineering based on the observed dependence of coercivity on system size.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173594"},"PeriodicalIF":3.0,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326356","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":"Micromagnetic dynamics of a skyrmionium diode in a nanotrack","authors":"Rishma Thilakaraj,&nbsp;Kanimozhi Natarajan,&nbsp;Amuda Rajamani,&nbsp;Brinda Arumugam","doi":"10.1016/j.jmmm.2025.173588","DOIUrl":"10.1016/j.jmmm.2025.173588","url":null,"abstract":"<div><div>Magnetic Skyrmionium or Donut skyrmion are unique magnetic spin textures that show promise for future memory and logic technologies. Unlike regular skyrmions, they do not experience Skyrmion Hall Effect (SkHE), making them more stable and easier to glide in nanotrack. In this study, we use micromagnetic simulation to investigate the motion of skyrmionium, when a spin-polarized current is applied along the x-direction using the Spin-Transfer Torque (STT). We report the dependence of skyrmionium dynamics on the geometry of the track. In symmetric track, skyrmionium moves in both directions, whereas in asymmetric track, it moves in one direction while getting blocked in the other, similar to semiconductor diode effect. This shows the possibility of building a skyrmionium diode with a velocity of 75–100 m/s. We validate the dynamics using a modified Thiele equation to support the simulation results. In addition to current-driven dynamics, we have also examined the response of skyrmionium motion to spin wave excitations. By applying an oscillating magnetic field with different frequencies, we have observed a strong frequency dependence in the motion, including enhancements in velocity at specific frequencies. This suggests that resonant conditions can enhance controlled skyrmionium motion, opening up new ways to tune their behaviour. We have studied the dependence and effective control of skyrmionium motion on different parameters.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173588"},"PeriodicalIF":3.0,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326355","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":"Annealing-induced sign reversal of magnetic entropy change, giant magnetocaloric effect with strong perpendicular magnetic anisotropy in Ta/GdFeCo/Ta thin films","authors":"Jagadish Kumar Galivarapu,&nbsp;Lisha Gu,&nbsp;Zhiwen Wang,&nbsp;Ke Wang","doi":"10.1016/j.jmmm.2025.173557","DOIUrl":"10.1016/j.jmmm.2025.173557","url":null,"abstract":"<div><div>We demonstrate the magnetic, magnetocaloric and perpendicular magnetic anisotropy (PMA) properties of sputtered Ta/GdFeCo/Ta thin films subjected to thermal annealing. Change in compensation temperature (T_comp), Curie temperature (T_c), sign reversal of magnetic entropy change, and giant magnetocaloric effect is noticed after annealing at 150 °C. As-deposited thin films exhibit a strong inverse magnetocaloric effect (ΔS_M^max of −1.1 J/kgK @ μ₀H = 1.5 T) flips to a normal giant magnetocaloric effect (ΔS_M^max of 5.1 J/kgK @ μ₀H = 1.5 T) after annealing at 150 °C due to atomic diffusion and in turn improves short-range ordering of Gd and Fe/Co atoms. Strong exchange interaction within the sublattices and across the Gd-FeCo interface results in a large entropy change. Annealing results in a substantial enhancement of perpendicular magnetic anisotropy, evidenced by a one-order increase in the effective anisotropy constant. We assert that annealing Ta/GdFeCo/Ta thin films up to 150 °C could reduce structural defects and enhance atomic ordering, thus improving magnetocrystalline anisotropy. These results provide an important insight into the physics of magnetocaloric effect and perpendicular magnetic anisotropy in materials with antiferromagnetically couple sublattices.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173557"},"PeriodicalIF":3.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326197","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":"Simulation analysis and performance evaluation of a novel magnetorheological damper with composite flow channel and curved magnetic circuit","authors":"Xiaoshu Deng,&nbsp;Xiaolong Yang,&nbsp;Dan Lan,&nbsp;Weishuai Meng,&nbsp;Minmin Qiu","doi":"10.1016/j.jmmm.2025.173592","DOIUrl":"10.1016/j.jmmm.2025.173592","url":null,"abstract":"<div><div>To improve the magnetic field utilization in the fluid flow channel of traditional magnetorheological dampers(MRDs), as well as their adaptability and performance stability in complex vibration environments, this study proposes a novel magnetorheological damper with composite flow channel and curved magnetic circuit(CFCCMC-MRD). The magnetic circuit and flow channel of the CFCCMC-MRD were designed, and its magnetic circuit model and damping force model were constructed. Electromagnetic field simulation was used to examine the impact of various structural parameters on magnetic field distribution. A prototype of the CFCCMC-MRD was fabricated, and its performance was verified through experimental tests. The results show that under an excitation current of 2.5 A, the activation rate of the flow channel in the CFCCMC-MRD reaches 72.9 %, which is 29.6 % higher than that of the traditional dual-coil MRD. In addition, under specific conditions, a maximum output damping force(ODF) of 6299.56 N can be achieved by the CFCCMC-MRD, and a maximum dynamic adjustable range(DAR) of 7.399 is reached by it. This study provides a theoretical basis and experimental support for the design of high standard MRDs.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173592"},"PeriodicalIF":3.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326143","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":"Design of tool-electromagnet for finishing of aluminum using ball end MR processing technique","authors":"Dilshad Ahmad Khan ,&nbsp;Zafar Alam ,&nbsp;Faiz Iqbal ,&nbsp;Sunil Jha","doi":"10.1016/j.jmmm.2025.173591","DOIUrl":"10.1016/j.jmmm.2025.173591","url":null,"abstract":"<div><div>Aluminum, widely used in various industries, requires fine surface finishes for aesthetic precision, especially in the machine and equipment sector. Since aluminum is soft, finishing forces must be carefully controlled, making the manual finishing approach more expensive as compared to harder materials. Ball end magnetorheological (MR) finishing is a way to subjugate the limitations of manual finishing as it allows for precise control of the finishing forces. However, given the non-magnetic nature of aluminum, finishing cannot be done at a lower magnetizing current and takes longer time to finish. Therefore, the design of a ball end MR finishing tool that can withstand higher magnetizing current and operate for extended period of time without overheating is necessary. This study addresses the gap in electromagnet design for ball end MR finishing of aluminum (Al-6063 alloy), commonly used in molds and metallic mirrors. A novel electromagnet tool was designed and fabricated taking into account the design specifications for the electromagnet coil, thermal analysis and coolant flow rate. A total of 1984 design combinations were assessed using MATLAB in order to determine the optimal magnetic field. The electromagnet dimensions was determined to be of 140 mm length, 50 mm of outer diameter and 2400 turns of copper wire. Based on the selected dimension, the electromagnet was fabricated with 24 layers of copper wire, and a cooling oil flow rate of 3 liters/minute was established using the thermal analysis to maintain prolonged, uninterrupted operation, even at higher magnetizing currents.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173591"},"PeriodicalIF":3.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326145","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":"Dynamics of magnetization reversal and enhanced magnetic properties in FeTaC/SiO2 multilayer thin films","authors":"Camelia Das ,&nbsp;Perumal Alagarsamy ,&nbsp;Subhankar Bedanta","doi":"10.1016/j.jmmm.2025.173590","DOIUrl":"10.1016/j.jmmm.2025.173590","url":null,"abstract":"<div><div>We systematically explore the impact of the number and thickness of the spacer layer on the magnetic properties in multilayer FeTaC/SiO₂ films fabricated on thermally oxidized Si substrate using the DC and RF magnetron sputtering system. At room temperature, 100 nm Fe₈₀Ta₈C₁₂ film shows a transcritical hysteresis loop characterized by large coercivity (<em>H</em>_<em>C</em>) and saturation field (<em>H</em>_<em>S</em>) due to the formation of stripe domain. This study builds upon our earlier findings on single-layer Fe₈₀Ta₈C₁₂ films and focuses on the magnetization reversal dynamics and enhanced magnetic properties of multilayer films as influenced by the number (<em>n</em>), thickness (<em>z</em>) of the spacer layer and temperature (<em>T</em>). The introduction of the spacer layers transform the transcritical loop observed in thick FeTaC (&gt; 50 nm) film into rectangular loop, enabling single or multi-step magnetization reversal. Also it results in significant reductions in <em>H</em>_<em>C</em> from 1.96 kA/m for 100 nm single-layer film to 0.43 kA/m and <em>H</em>_<em>S</em> from 66.4 kA/m to 2.42 kA/m for multilayer film with <em>n</em> = 2, while improving the remanent-to-saturation magnetization ratio. Analysis of domain configuration exhibits Kerr loops at different angles, revealing the role of transverse components that vary with the coupling strength between the adjacent layers. Additionally, the temperature-dependent hysteresis behavior of multilayer films varies significantly with <em>n</em>, <em>z</em>, and the nature of interlayer coupling. These factors lead to significant changes in magnetic domain structure and switching dynamics. Overall, this work highlights the role of multilayer structure and interlayer coupling in tuning the magnetic properties of FeTaC/SiO₂ films, allowing significant control over domain dynamics.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173590"},"PeriodicalIF":3.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326144","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":"First-principles-computational quantum insights into the interplay between magnetism and superconductivity in heavy fermions PrGaxAs1-x","authors":"Azmat Iqbal Bashir ,&nbsp;Muhmmad Siddique ,&nbsp;M.H. Sahafi ,&nbsp;Qaisar Rafiq","doi":"10.1016/j.jmmm.2025.173574","DOIUrl":"10.1016/j.jmmm.2025.173574","url":null,"abstract":"<div><div>The competitive interplay between the quantum phenomenon of magnetism and superconductivity is of immense research interest, both for the basic scientific interest and technological implications. The two phenomena are at the forefront of understanding the nature of conventional and nonconventional superconductivity in light of quantum correlation between the spin and conduction. In this context, the energy bands topology around the Fermi surface (FS) plays a crucial role, since the FS is the hallmark of novel materials such as semimetals, topological insulators, Weyl metals, heavy fermions, and superconductors. For instance, the non-dispersive flat bands near the FS shows strong magnetism and heavy fermionic nature, while the conical dispersive bands show strong conductivity. The competitive interplay between the superconducting, heavy fermionic, and magnetic attributes of quantum materials can be manipulated by tuning the topological morphology of the FS. The same can be accomplished by modifying the intensity of density of states and shapes of energy bands near the FS by chemical doping and substitution, etc. Hereby, we report on the interplay and coexistence of the phenomena of unconventional superconductivity and magnetism in the heavy fermions PrAs by Ga substitution by tuning the FS of PrAs via PrGa_xAs_1-x (x = 0 %, 25 %, 50 %, 75 % &amp;100 %) alloys. For a better understanding on the interplay and quantum insights into the intriguing phenomena, this study implements density functional computational procedure within the full-potential linearized augmented plane wave with the localized Kohn Sham orbitals. To account for the exchange-correlation effects, GGA + PBE corrected density approximation is employed. The major part in the density of states around the Fermi energy level stems from the Pr-5d4f and the (Ga + As)-4p orbital states. As compared with spin magnetic moments of PrAs alloys, an enhancement in spin magnetic moments is predicted by increasing the Ga/As ratio in light of PrGaAs alloys. The computed results predict a considerable modification in the intensity, flatness, curvature, and width of energy bands and hence the morphology of the FS of PrAs compounds on varying the Ga/As doping ratio. This in turn leads to the simultaneous existence and enhancement of the unconventional superconductivity and magnetism in the proposed heavy fermions PrGa_xAs_1-x.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173574"},"PeriodicalIF":3.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264576","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":"Structural, magnetotransport, and thermoelectric properties of bismuth-doped Sm₀.₅₅Sr₀.₄₅MnO₃ manganites","authors":"Masroor Ahmad Bhat ,&nbsp;Nageena Parveen ,&nbsp;Syed Sarim Imam ,&nbsp;Khalid bin Masood ,&nbsp;Saleem Yousuf ,&nbsp;S.A. Sheikh ,&nbsp;Arshid Mir","doi":"10.1016/j.jmmm.2025.173577","DOIUrl":"10.1016/j.jmmm.2025.173577","url":null,"abstract":"<div><div>Bi-doped Sm₀.₄₅Sr₀.₄₅MnO₃ manganites were synthesized via the solid-state reaction method and examined for structural, magnetic, and magneto-transport characteristics. X-ray diffraction confirmed a single-phase orthorhombic structure with slight lattice distortions from Bi³⁺ substitution. The Bi-doped sample (x = 0.10) exhibited peak MR values exceeding the undoped compound by factors of ≈12.1 (1 T), ≈12.0 (5 T), and ≈12.0 (8 T), while the TCR increased from ∼11 % to ∼24 %, highlighting a sharper resistive transition. Magnetic hysteresis at 5 K revealed reduced saturation magnetization and coercivity with Bi doping, indicating suppression of long-range ferromagnetic order and enhanced competition between ferromagnetic and antiferromagnetic phases. Thermoelectric power (S) measurements from 10 to 300 K showed a sign reversal from negative at high temperatures (n-type conduction) to positive at low temperatures (p-type conduction), consistent with band transitions from t₂g to e₉ states and spin-polarization effects. Low-temperature resistivity followed Mott's VRH model (localization length ≈ 2.22 nm⁻¹), while high-temperature conduction was dominated by non-adiabatic small polaron hopping. These results demonstrate that Bi incorporation enhances carrier localization and spin-dependent scattering, leading to superior magnetoresistive efficiency and thermal sensitivity for potential sensing applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173577"},"PeriodicalIF":3.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326357","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":"Nonlinear transport and magnetoelectric effect in ferroic and antiferroic magnetic toroidal dipole orderings","authors":"Megumi Yatsushiro,&nbsp;Satoru Hayami","doi":"10.1016/j.jmmm.2025.173580","DOIUrl":"10.1016/j.jmmm.2025.173580","url":null,"abstract":"<div><div>We theoretically investigate physical phenomena induced by magnetic toroidal dipole orderings in a distorted kagome lattice structure, inspired by recent experiments on the rare-earth compound HoAgGe. By considering both ferroic and antiferroic magnetic toroidal dipole orderings within a tight-binding model that includes antisymmetric spin–orbit interaction, we analyze the emergence of the nonlinear transport and the linear magnetoelectric effect. Our results show that even antiferroic magnetic toroidal dipole ordering, where the magnetic toroidal dipole moment is canceled out in the magnetic unit cell, can exhibit similar behaviors to those in ferroic magnetic toroidal dipole phase, depending on the inter-plaquette hopping strength. We examine the essential model parameters for the asymmetric band deformation, nonlinear conductivity, and linear magnetoelectric effect, elucidating how the microscopic degrees of freedom are related to emergent responses under both ferroic and antiferroic magnetic toroidal dipole orderings. This study highlights the potential of antiferroic magnetic toroidal multipole orderings to host functional transport and cross-correlation phenomena, extending the scope of multipolar physics in antiferromagnetic materials.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"634 ","pages":"Article 173580"},"PeriodicalIF":3.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326201","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}