Magnetochemistry

34 pages, 2311 KB

Open AccessReview

Iron Oxide Nanoparticles Enabled Ultrasound-Guided Theranostic Systems

by Thiago Tiburcio Vicente, Prabu Periyathambi, Ariane Franson Sanches, Marina Yuki Azevedo Nakakubo, Nicholas Zufelato, Karina Bezerra Salomão, María Sol Brassesco, Theo Zeferino Pavan, Koiti Araki and Antônio A. O. Carneiro

Magnetochemistry 2026, 12(2), 21; https://doi.org/10.3390/magnetochemistry12020021 - 3 Feb 2026

Abstract

The tumor microenvironment, characterized by higher acidity, hypoxia, and dense cellular structures, plays a pivotal role in cancer progression, therapeutic resistance, and treatment response. Nanoparticle-based contrast agents enable the precise delineation of solid regions within heterogeneous tumors through advanced molecular imaging techniques. Since [...] Read more.

The tumor microenvironment, characterized by higher acidity, hypoxia, and dense cellular structures, plays a pivotal role in cancer progression, therapeutic resistance, and treatment response. Nanoparticle-based contrast agents enable the precise delineation of solid regions within heterogeneous tumors through advanced molecular imaging techniques. Since 1956, ultrasound (US) medical imaging has provided essential anatomical and functional insights about internal organs. More recently, magnetomotive ultrasound (MMUS) has emerged as a promising imaging modality, using a modulated magnetic field to exert force on superparamagnetic iron oxide nanoparticles (SPIONs), inducing motion in the surrounding tissues through mechanical coupling. In parallel, magnetic hyperthermia (MH), which employs localized heating by alternating magnetic fields, has demonstrated significant potential in selectively destroying cancer cells while sparing healthy tissues. This review summarizes the current state of IONP-based contrast agents, with particular emphasis on their use in MH for cancer treatment, as well as their potential in multimodal imaging, including MMUS, and photoacoustic (PA) imaging. The advantages and limitations of IONPs in tumor detection and characterization are discussed, examining the development of surface-functionalized MNPs, and analyzing how material properties and environmental factors affect their diagnostic and therapeutical performance. Finally, strategies for combining MMUS and PA modalities for pre-clinical cancer imaging are proposed. Full article

(This article belongs to the Special Issue Magnetic Nano- and Microparticles in Biotechnology)

► Show Figures

Figure 1

22 pages, 5511 KB

Open AccessArticle

Study on Some Factors That Influence the Yield Stress in Kerosene-Based Magnetic Fluids Using an Orthogonal Experimental Design

by Miaotian Zhang, Licong Jin and Yu Feng

Magnetochemistry 2026, 12(2), 20; https://doi.org/10.3390/magnetochemistry12020020 - 2 Feb 2026

Abstract

Magnetic fluid sealing is a novel sealing technology wherein magnetic fluids play a pivotal role in the sealing process. The yield stress of the magnetic fluid directly affectsits sealing performance and is governed by multiple interdependent factors. Conventional approaches that evaluate the effect [...] Read more.

Magnetic fluid sealing is a novel sealing technology wherein magnetic fluids play a pivotal role in the sealing process. The yield stress of the magnetic fluid directly affectsits sealing performance and is governed by multiple interdependent factors. Conventional approaches that evaluate the effect of a single parameter while keeping other parameters constant are insufficient to fully characterize the relative contributions of each parameter to the yield stress. In this study, we investigate the preparation factors affecting the yield stress of kerosene-based magnetic fluids and propose a parameter sensitivity analysis method based on orthogonal experimental design to determine the optimal combination of factor levels within the studied range. The sensitivity of key preparation factors affecting the yield stress of kerosene-based magnetic fluids was determined via range and variance analyses of the orthogonal experimental data. The factors, ranked in descending order of sensitivity, were surfactant (C₁₈H₃₄O₂) dosage, precipitant (NH₃·H₂O) dosage, and deionized water (H₂O) volume. Moreover, the effects of different levels of the same factor were analyzed using multiple approaches. These findings provide a theoretical foundation for optimizing the preparation of magnetic fluids and enhancing their sealing performance. Full article

(This article belongs to the Special Issue Ferrofluids: Electromagnetic Properties and Applications)

► Show Figures

Figure 1

24 pages, 2544 KB

Open AccessArticle

Perspectives of Machine Learning for Ligand-Field Analyses in Lanthanide-Based Single Molecule Magnets

by Zayan Ahsan Ali, Preeti Tewatia and Oliver Waldmann

Magnetochemistry 2026, 12(2), 19; https://doi.org/10.3390/magnetochemistry12020019 - 2 Feb 2026

Abstract

Lanthanide-based single-molecule magnets are promising candidates for potential applications. Their magnetism is governed by ligand-field splittings, which may require up to 27 ligand-field parameters for accurate modeling. Determining these parameters reliably from measured data is a major challenge, for which machine learning approaches [...] Read more.

Lanthanide-based single-molecule magnets are promising candidates for potential applications. Their magnetism is governed by ligand-field splittings, which may require up to 27 ligand-field parameters for accurate modeling. Determining these parameters reliably from measured data is a major challenge, for which machine learning approaches offer promising solutions. We provide an overview of these approaches and present our perspective on addressing the inverse problem relating experimental data to ligand-field parameters. Previously, a machine learning architecture combining a variational autoencoder (VAE) and an invertible neural network (INN) showed promise for analyzing temperature-dependent magnetic susceptibility data. In this work, the VAE-INN model is extended through data augmentation to enhance its tolerance to common experimental inaccuracies. Focusing on second-order ligand-field parameters, diamagnetic and molar-mass errors are incorporated by augmenting the training dataset with experimentally motivated error distributions. Tests on simulated experimental susceptibility curves demonstrate substantially improved prediction accuracy and robustness when the distributions correspond to realistic error ranges. When applied to the experimental susceptibility curve of the complex

{Al}_{2}^{III}

{Er}_{2}^{III}

, the augmented VAE–INN recovers ligand-field solutions consistent with least-squares benchmarks. The proposed data augmentation thus overcomes a key limitation, bringing the ML approach closer to practical use for higher-order ligand-field parameters. Full article

(This article belongs to the Special Issue Magnetic Nanoscale Materials and Exotic Spin Structures: A 65th Birthday Gift to Annie K. Powell)

► Show Figures

Graphical abstract

11 pages, 2474 KB

Open AccessArticle

Properties Comparison of Fe₃O₄ Particles with Different Morphologies as Mimetic Enzyme

by Xiaoying Li, Li Wei, Lianqi Li, Junying Suo, Shuai Li and Honggang Jiang

Magnetochemistry 2026, 12(2), 18; https://doi.org/10.3390/magnetochemistry12020018 - 2 Feb 2026

Abstract

In this work, four different magnetic Fe₃O₄ nanoparticles are prepared via solvothermal method. According to the morphology, the products can be divided into flower-like Fe₃O₄ (F-Fe₃O₄), solid spherical Fe₃O₄ (S-Fe [...] Read more.

In this work, four different magnetic Fe₃O₄ nanoparticles are prepared via solvothermal method. According to the morphology, the products can be divided into flower-like Fe₃O₄ (F-Fe₃O₄), solid spherical Fe₃O₄ (S-Fe₃O₄), hollow spherical Fe₃O₄ (HO-Fe₃O₄), and hexahedral Fe₃O₄ (HE-Fe₃O₄). A set of measurements is performed to confirm the structure, composition, and pore properties of the obtained materials. The catalytic activities of the prepared materials are examined and compared. The results prove that the four materials have an intrinsic catalytic property. HO-Fe₃O₄ ranks first in the catalytic activity mainly due to its large surface area and reasonable element composition. The maximum specific saturation magnetization and specific surface area of HO-Fe₃O₄ are 72.94 emu/g and 42.60 m²/g. Fe²⁺/Fe³⁺ in HO-Fe₃O₄ is 51.5%. It is found that HO-Fe₃O₄ possesses fantastic stability and perfect reproducibility as it is used as a catalyst several times without significant loss in its activity. Full article

(This article belongs to the Special Issue Magnetic Materials and Composites: Synthesis, Properties, and Applications)

► Show Figures

Figure 1

18 pages, 5858 KB

Open AccessArticle

Improved Wide-Temperature-Range Magnetocaloric Properties of (Mn,Fe)₂(P,Si) Alloys by Mg-Co Co-Doping

by Jimei Niu, Zhigang Zheng and Hongyu Wang

Magnetochemistry 2026, 12(2), 17; https://doi.org/10.3390/magnetochemistry12020017 - 2 Feb 2026

Abstract

To enhance the wide-temperature-range magnetocaloric performance of (Mn,Fe)₂(P,Si) alloys, the effects of Mg-Co co-doping on their structural and magnetocaloric properties were systematically investigated. Mn_1.05−yCo_yFe_0.9P_0.5Si_0.48Mg_0.02 alloys were prepared by the [...] Read more.

To enhance the wide-temperature-range magnetocaloric performance of (Mn,Fe)₂(P,Si) alloys, the effects of Mg-Co co-doping on their structural and magnetocaloric properties were systematically investigated. Mn_1.05−yCo_yFe_0.9P_0.5Si_0.48Mg_0.02 alloys were prepared by the arc melting method. The results show that Mg-Co co-doping can tune the lattice parameters and ferromagnetic coupling between Mn and Fe atoms. The Mn_1.03Co_0.02Fe_0.9P_0.5Si_0.48Mg_0.02 alloy exhibited an effective refrigeration capacity of 425.4 J·kg⁻¹ and an effective working temperature span of 52 K. During the temperature-induced ferromagnetic transition, coupling between the magnetic moment of Fe-Si layers and the crystal lattice drives a magnetoelastic transition, leading to a giant magnetocaloric effect. The Mg-Co co-doping strategy effectively tunes the crystal structure and local electron density distribution of the Fe-Si layer, thereby influencing the total magnetic moment and magnetothermal properties of the alloys. Full article

(This article belongs to the Special Issue Advance of Magnetocaloric Effect and Materials)

► Show Figures

Figure 1

19 pages, 2848 KB

Open AccessArticle

Development of a Cost-Effective Magnetic Microparticle Protocol for DNA Purification in Molecular Diagnosis of Gynecological Infections

by Carolina Otonelo, Carla Layana, Elisa de Sousa, Luciana Juncal, Melina D. Ibarra, Constanza Toledo, Alejo Melamed, Karen L. Salcedo Rodríguez, Patricia L. Schilardi, Lucia Poleri, Carlos Golijow, Sheila Ons, Pedro Mendoza Zélis and Claudia Rodríguez Torres

Magnetochemistry 2026, 12(2), 16; https://doi.org/10.3390/magnetochemistry12020016 - 27 Jan 2026

Abstract

In this work, we evaluate the efficiency of a DNA purification protocol from gynecological samples using locally synthesized Fe₃O₄@SiO₂ magnetic microparticles and a low-cost, guanidinium thiocyanate (GITC)-free lysis buffer. The microparticles were characterized by SEM, EDS, FTIR, and [...] Read more.

In this work, we evaluate the efficiency of a DNA purification protocol from gynecological samples using locally synthesized Fe₃O₄@SiO₂ magnetic microparticles and a low-cost, guanidinium thiocyanate (GITC)-free lysis buffer. The microparticles were characterized by SEM, EDS, FTIR, and magnetic measurements, confirming the formation of compact silica-coated aggregates with suitable magnetic responsiveness for rapid and complete capture. Using this material in combination with a simple, GITC-free lysis buffer, we achieved DNA extraction yields comparable to those obtained with standard methods based on chaotropic salts. The purified DNA showed high compatibility with molecular assays for the detection of Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, and human papilloma virus. Clinical validation demonstrated excellent diagnostic performance, with only a few discrepancies observed in samples near the detection threshold of qPCR, a limitation shared with commercial kits. Overall, the method represents a low-cost, safe, and sustainable alternative for routine clinical and epidemiological applications, compared to methods based on chaotropic salt buffers. Furthermore, it reduces reliance on imported commercial consumables and minimizes the handling of hazardous reagents. Full article

(This article belongs to the Special Issue Magnetic Nano- and Microparticles in Biotechnology)

► Show Figures

Figure 1

12 pages, 3100 KB

Open AccessArticle

A Comparative Assessment of Several Deconvolution Methods Used for Fourier Transform Nuclear Magnetic Resonance Spectroscopy

by Shu-Ping Chen, Sandra M. Taylor, Sai Huang and Baoling Zheng

Magnetochemistry 2026, 12(1), 15; https://doi.org/10.3390/magnetochemistry12010015 - 22 Jan 2026

Abstract

Based on our deconvolution result of the Tetraphenyl porphyrin nuclear magnetic resonance (NMR) spectrum, we initiated a goodness-of-fitting evaluation by overlaying the third-order derivatives of the native NMR spectrum and the entire reconstructed spectrum to appraise the accuracy of the reverse curve fitting [...] Read more.

Based on our deconvolution result of the Tetraphenyl porphyrin nuclear magnetic resonance (NMR) spectrum, we initiated a goodness-of-fitting evaluation by overlaying the third-order derivatives of the native NMR spectrum and the entire reconstructed spectrum to appraise the accuracy of the reverse curve fitting method. Then, the same NMR overlapping band was deconvoluted by even-order derivatives and Fourier self-deconvolution, respectively. The reverse curve fitting demonstrated its superior achievements to the other two methods in the comparative assessment. Meanwhile, three traditional window functions (Bessel, Hamming, and 3-term Blackman–Harris) were examined for their apodization effects which will benefit reverse curve fitting performance. Full article

(This article belongs to the Section Magnetic Resonances)

► Show Figures

Figure 1

18 pages, 10969 KB

Open AccessArticle

Simulation Data-Based Dual Domain Network (Sim-DDNet) for Motion Artifact Reduction in MR Images

by Seong-Hyeon Kang, Jun-Young Chung, Youngjin Lee and for The Alzheimer’s Disease Neuroimaging Initiative

Magnetochemistry 2026, 12(1), 14; https://doi.org/10.3390/magnetochemistry12010014 - 20 Jan 2026

Abstract

Brain magnetic resonance imaging (MRI) is highly susceptible to motion artifacts that degrade fine structural details and undermine quantitative analysis. Conventional U-Net-based deep learning approaches for motion artifact reduction typically operate only in the image domain and are often trained on data with [...] Read more.

Brain magnetic resonance imaging (MRI) is highly susceptible to motion artifacts that degrade fine structural details and undermine quantitative analysis. Conventional U-Net-based deep learning approaches for motion artifact reduction typically operate only in the image domain and are often trained on data with simplified motion patterns, thereby limiting physical plausibility and generalization. We propose Sim-DDNet, a simulation-data-based dual-domain network that combines k-space-based motion simulation with a joint image-k-space reconstruction architecture. Motion-corrupted data were generated from T2-weighted Alzheimer’s Disease Neuroimaging Initiative brain MR scans using a k-space replacement scheme with three to five random rotational and translational events per volume, yielding 69,283 paired samples (49,852/6969/12,462 for training/validation/testing). Sim-DDNet integrates a real-valued U-Net-like image branch and a complex-valued k-space branch using cross attention, FiLM-based feature modulation, soft data consistency, and composite loss comprising L1, structural similarity index measure (SSIM), perceptual, and k-space-weighted terms. On the independent test set, Sim-DDNet achieved a peak signal-to-noise ratio of 31.05 dB, SSIM of 0.85, and gradient magnitude similarity deviation of 0.077, consistently outperforming U-Net and U-Net++ across all three metrics while producing less blurring, fewer residual ghost/streak artifacts, and reduced hallucination of non-existent structures. These results indicate that dual-domain, data-consistency-aware learning, which explicitly exploits k-space information, is a promising approach for physically plausible motion artifact correction in brain MRI. Full article

(This article belongs to the Special Issue Magnetic Resonances: Current Applications and Future Perspectives)

► Show Figures

Figure 1

13 pages, 4669 KB

Open AccessArticle

Comparative Buffer and Spacer Layer Engineering in Co/Pt-Based Perpendicular Synthetic Antiferromagnets

by Mehmet Emre Aköz, Frowin Dörr, Ahmet Yavuz Oral and Yasser Shokr

Magnetochemistry 2026, 12(1), 13; https://doi.org/10.3390/magnetochemistry12010013 - 19 Jan 2026

Abstract

Perpendicular magnetic tunnel junctions (p-MTJs) rely on synthetic antiferromagnets (SAFs) as reference layers to achieve strong perpendicular magnetic anisotropy (PMA) together with stable interlayer exchange coupling. In this study, we present a comparative materials study of buffer and spacer layer engineering in Co/Pt-based [...] Read more.

Perpendicular magnetic tunnel junctions (p-MTJs) rely on synthetic antiferromagnets (SAFs) as reference layers to achieve strong perpendicular magnetic anisotropy (PMA) together with stable interlayer exchange coupling. In this study, we present a comparative materials study of buffer and spacer layer engineering in Co/Pt-based perpendicular synthetic antiferromagnets (p-SAFs). The influence of buffer layer selection, number of multilayer repeats, and annealing at 330 °C for 30 min on PMA and interlayer exchange coupling is systematically examined. Co/Pt multilayers with four and six repeats were grown on Ta/Ru and Ta/CuN buffer layers separately, followed by the fabrication of SAF structures incorporating Ru spacers with thickness between 0.60 and 0.80 nm. Magnetic measurements show that Ta/Ru-buffered structures exhibit squarer hysteresis loops, higher remanence, and greater tolerance to annealing at 330 °C for 30 min compared to Ta/CuN-buffered counterparts. The SAF structures display clear two-step magnetization reversal and robust antiferromagnetic coupling across the investigated Ru thickness range, with large exchange fields and bias fields in the deposited state. Although annealing reduces the absolute coupling strength, a Ru spacer thickness of 0.60 nm retains the strongest antiferromagnetic response within the studied thermal budget. These results underscore the importance of comparative buffer and spacer layer engineering and provide materials insights into the design of Co/Pt-based p-SAF reference stacks that may inform future p-MTJ structures. Full article

► Show Figures

Figure 1

14 pages, 488 KB

Open AccessReview

Improving Nuclear Magnetic Dipole Moments: Gas Phase NMR Spectroscopy Research

by Włodzimierz Makulski

Magnetochemistry 2026, 12(1), 12; https://doi.org/10.3390/magnetochemistry12010012 - 16 Jan 2026

Abstract

High-resolution NMR spectroscopy is the leading method for determining nuclear magnetic moments. It is designed to measure stable nuclei, which can be investigated in macroscopic samples. In this work, we discuss the progress in research into light nuclei from the first three periods [...] Read more.

High-resolution NMR spectroscopy is the leading method for determining nuclear magnetic moments. It is designed to measure stable nuclei, which can be investigated in macroscopic samples. In this work, we discuss the progress in research into light nuclei from the first three periods of the Periodic Table and several selected heavy nuclides. The ¹H and ³He nuclear magnetic moments, established using the new double Penning trap facility, are also considered. Both nuclei can be used as references in gaseous mixtures. Gas-phase NMR spectroscopy enables precise measurements of the frequencies and shielding constants of isolated single molecules. They can be used to determine new, accurate nuclear magnetic moments of nuclides in stable, gaseous substances. Particular attention is paid to the importance of diamagnetic corrections for obtaining accurate results. Finding precise diamagnetic corrections—shielding factors —even for light nuclei in molecules is a significant challenge. To date, nuclear moments have been obtained primarily from experimental data. The theoretical approach is mostly unable to predict these values accurately. Some remarks are also made on pure theoretical treatments of nuclear moments. Full article

(This article belongs to the Special Issue 10th Anniversary of Magnetochemistry: Past, Present and Future)

► Show Figures

Graphical abstract

13 pages, 2281 KB

Open AccessArticle

Microstructural Engineering of Magnetic Wood for Enhanced Magnetothermal Conversion

by Yuxi Lin, Chen Chen and Wei Xu

Magnetochemistry 2026, 12(1), 11; https://doi.org/10.3390/magnetochemistry12010011 - 13 Jan 2026

Abstract

The increasing energy crisis demands sustainable functional materials. Wood, with its natural three-dimensional porous structure, offers an ideal renewable template. This study demonstrates that microstructural engineering of wood is a decisive strategy for enhancing magnetothermal conversion. Using eucalyptus wood, we precisely tailored its [...] Read more.

The increasing energy crisis demands sustainable functional materials. Wood, with its natural three-dimensional porous structure, offers an ideal renewable template. This study demonstrates that microstructural engineering of wood is a decisive strategy for enhancing magnetothermal conversion. Using eucalyptus wood, we precisely tailored its pore architecture via delignification and synthesized Fe₃O₄ nanoparticles in situ through coprecipitation. We systematically investigated the effects of delignification and precursor immersion time (24, 48, 72 h) on the loading, distribution, and magnetothermal performance of the composites. Delignification drastically increased wood porosity, raising the Fe₃O₄ loading capacity from ~5–6% (in non-delignified wood) to over 14%. Immersion time critically influenced nanoparticle distribution: 48 h achieved optimal deep penetration and uniformity, whereas extended time (72 h) induced minor local agglomeration. The optimized composite (MDW-48) achieved an equilibrium temperature of 51.2 °C under a low alternating magnetic field (0.06 mT, 35 kHz), corresponding to a temperature rise (ΔT) > 24 °C and a Specific Loss Power (SLP) of 1.31W·g⁻¹. This performance surpasses that of the 24 h sample (47 °C, SLP = 1.16 W·g⁻¹) and rivals other bio-based magnetic systems. This work establishes a clear microstructure–property relationship: delignification enables high loading, while controlled impregnation tunes distribution uniformity, both directly governing magnetothermal efficiency. Our findings highlight delignified magnetic wood as a robust, sustainable platform for efficient low-field magnetothermal conversion, with promising potential in low-carbon thermal management. Full article

► Show Figures

Figure 1

18 pages, 10340 KB

Open AccessArticle

Numerical Study on Thermal–Flow Characteristics of Liquid Metal Blankets in a Magnetic Field

by Shuaibing Chang, Feng Li and Jiewen Deng

Magnetochemistry 2026, 12(1), 10; https://doi.org/10.3390/magnetochemistry12010010 - 13 Jan 2026

Abstract

The tokamak is a toroidal device that utilizes magnetic confinement to achieve controlled nuclear fusion. One of the major technical challenges hindering the development of this technology lies in effectively dissipating the generated heat. In this study, the inner blanket structure of a [...] Read more.

The tokamak is a toroidal device that utilizes magnetic confinement to achieve controlled nuclear fusion. One of the major technical challenges hindering the development of this technology lies in effectively dissipating the generated heat. In this study, the inner blanket structure of a tokamak is selected as the research object, and a multi–physics numerical model coupling magnetic field, temperature field, and flow field is established. The effects of background magnetic field strength, blanket channel width, and inlet velocity of the liquid metal coolant on the thermal–flow characteristics of the blanket were systematically investigated. The results indicate that compared with the L-shaped channel, the U-shaped channel reduces flow resistance in the turning region by 6%, exhibits a more uniform temperature distribution, and decreases the outlet–inlet temperature difference by 4%, thereby significantly enhancing the heat transfer efficiency. An increase in background magnetic field strength suppresses coolant flow but has only a limited impact on the temperature field. When the background magnetic field reaches a certain strength, the magnetic field has a certain hindering effect on the flow of the working fluid. Increasing the thickness of the blankets appropriately can alleviate the hindering effect of the magnetic field on the flow and improve the velocity distribution in the outlet area. Full article

► Show Figures

Figure 1

3 pages, 163 KB

Open AccessEditorial

NMR Spectroscopy and Imaging in Biological Chemistry and Medicine

by Serge L. Smirnov

Magnetochemistry 2026, 12(1), 9; https://doi.org/10.3390/magnetochemistry12010009 - 13 Jan 2026

Abstract

In recent years, research in the areas of Biological Chemistry and Medicine has been advancing along many directions including those centered around NMR spectroscopy and imaging [...] Full article

(This article belongs to the Special Issue NMR Spectroscopy and Imaging in Biological Chemistry and Medicine)

16 pages, 78279 KB

Open AccessArticle

Characterization of Magnetic Structure and Large Barkhausen Jump Mechanism in Wiegand Wires Using Multiple Experimental Techniques

by Guorong Sha, Liang Jiang, Chao Yang, Zenglu Song and Yasushi Takemura

Magnetochemistry 2026, 12(1), 8; https://doi.org/10.3390/magnetochemistry12010008 - 10 Jan 2026

Abstract

The Wiegand effect is a nonlinear magnetic phenomenon observed in specially processed Wiegand wires, representing a macroscopic manifestation of the Barkhausen effect. It is characterized by a large, sharp Barkhausen jump in the wire’s magnetization curve under an external alternating magnetic field. However, [...] Read more.

The Wiegand effect is a nonlinear magnetic phenomenon observed in specially processed Wiegand wires, representing a macroscopic manifestation of the Barkhausen effect. It is characterized by a large, sharp Barkhausen jump in the wire’s magnetization curve under an external alternating magnetic field. However, the underlying magnetic structure of these wires and the precise mechanism responsible for the Wiegand effect remain inadequately understood. In this study, we propose a conceptual model for the magnetic structure of Wiegand wires. Experimental samples with varying diameters were prepared through FeCl₃ solution etching. The magnetic properties of individual layers within the wire were systematically investigated using the surface magneto-optic Kerr effect, Wiegand pulse measurements, and minor hysteresis loop analysis. By correlating these experimental results with JMAG simulations based on the proposed magnetic structure model, we elucidate the layer-by-layer magnetization reversal processes under alternating magnetic fields and clarify the fundamental mechanism that triggers the large Barkhausen jump. Full article

► Show Figures

Figure 1

28 pages, 6767 KB

Open AccessArticle

A Physics-Informed Neural Network with Hybrid Architecture for Magnetic Core Loss Prediction Under Complex Conditions

by Xiaoyan Shen, Hongkui Zhong and Ruiqing Han

Magnetochemistry 2026, 12(1), 7; https://doi.org/10.3390/magnetochemistry12010007 - 10 Jan 2026

Abstract

Magnetic core loss is an important indicator for describing the performance of magnetic elements. The traditional physical model has an insufficient performance for predicting the magnetic core loss of magnetic elements under complex conditions such as high temperature, non-sinusoidal waveform, and high frequency. [...] Read more.

Magnetic core loss is an important indicator for describing the performance of magnetic elements. The traditional physical model has an insufficient performance for predicting the magnetic core loss of magnetic elements under complex conditions such as high temperature, non-sinusoidal waveform, and high frequency. To address this issue, this study proposes a physics-informed neural network (PINN)-based model for magnetic core loss prediction. In particular, this PINN-based model is constructed with a hybrid network architecture as a baseline algorithm, which combines a convolutional long short-term memory network (Conv-LSTM), power spectral density (PSD), and an ensemble learning method (including extreme gradient boosting (XGB), gradient boosting regression (GBR), and random forest (RF)). This design aims to address the complexity of magnetic core loss prediction. Moreover, the Steinmetz equation (SE) is improved to enhance the adaptability under complex conditions, and this improved Steinmetz equation (ISE) is integrated as physical constraints embedded in the neural network for magnetic core loss prediction. Based on the traditional data-driven loss term, the physical residual term is introduced as a regularization constraint to enable the prediction to satisfy both the observed data distribution and physical law. The experimental results show that the PINN-based model has a good prediction performance of magnetic core loss under complex conditions. Full article

(This article belongs to the Section Magnetic Materials)

► Show Figures

Figure 1

22 pages, 5386 KB

Open AccessArticle

A Temperature-Corrected High-Frequency Non-Sinusoidal Excitation Core Loss Prediction Model

by Jingwen Zhang, Cunhao Lu, Jian Chen and Yaoji Deng

Magnetochemistry 2026, 12(1), 6; https://doi.org/10.3390/magnetochemistry12010006 - 6 Jan 2026

Abstract

Predicting core loss under high-frequency non-sinusoidal excitation is crucial for power electronics equipment design. Temperature significantly affects core loss, and traditional core loss prediction models typically incorporate temperature corrections to enable accurate loss estimation across varying temperatures. Based on the Modified Steinmetz Equation [...] Read more.

Predicting core loss under high-frequency non-sinusoidal excitation is crucial for power electronics equipment design. Temperature significantly affects core loss, and traditional core loss prediction models typically incorporate temperature corrections to enable accurate loss estimation across varying temperatures. Based on the Modified Steinmetz Equation (nonT-MSE) model, this study considers the temperature effect by employing a combination of the Tanh function and a linear term to modify the three empirical parameters, with the Tanh function capturing the nonlinear saturation of the loss coefficient k with increasing temperature. This leads to the establishment of the temperature-corrected non-TMSE (T-MSE) model for predicting magnetic core loss under high-frequency non-sinusoidal excitation. During model derivation, training data undergo logarithmic transformation processing. Subsequently, with T-MSE empirical parameters as variables and the minimum mean squared error between T-MSE predicted values and experimental values as the objective function, a single-objective optimization model is established. Finally, the empirical parameters of T-MSE are calculated using the training data and the single-objective optimization model. Comparing the core loss experimental results of the four materials, the average MSE values for the T-MSE model, the nonT-MSE model, and the square-root temperature-corrected non-TMSE model proposed by Zeng et al. (Zeng) are 0.0082, 0.0459, and 0.0110, respectively; with average MAPE of 1.57%, 1.87%, and 2.17%, respectively; and average R² of 0.9862, 0.9807, and 0.9731. Compared to the nonT-MSE model and the Zeng model, the T-MSE model demonstrated higher prediction accuracy. Full article

► Show Figures

Figure 1

22 pages, 3229 KB

Open AccessArticle

Influence of the Polarizing Magnetic Field and Volume Fraction of Nanoparticles in a Ferrofluid on the Specific Absorption Rate (SAR) in the Microwave Range

by Iosif Malaescu, Paul C. Fannin, Catalin N. Marin and Madalin O. Bunoiu

Magnetochemistry 2026, 12(1), 5; https://doi.org/10.3390/magnetochemistry12010005 - 30 Dec 2025

Abstract

For the study, we used four kerosene-based ferrofluid samples containing magnetite nanoparticles stabilized with oleic acid. Starting from the initial sample (A0), the other three samples were obtained by dilution with kerosene. The complex magnetic permeability measurements were performed in the microwave region [...] Read more.

For the study, we used four kerosene-based ferrofluid samples containing magnetite nanoparticles stabilized with oleic acid. Starting from the initial sample (A0), the other three samples were obtained by dilution with kerosene. The complex magnetic permeability measurements were performed in the microwave region (0.5–6) GHz, for different H values of the polarizing magnetic field, between (0–115) kA/m. These measurements revealed the ferromagnetic resonance phenomenon for each sample, allowing the determination of the anisotropy field (H_A) and the effective anisotropy constant (K_eff) of nanoparticles, depending on the volume fraction of particles (φ). At the same time, the measurements allowed the determination of the specific magnetic loss power (p_m), effective heating rate (HR_eff), intrinsic loss power (ILP), and specific absorption rate (SAR) as functions of the frequency (f) and magnetic field (H), of all investigated samples, using newly proposed equations for their calculation. For the first time, this study evaluates the maximum limit of the applied polarizing magnetic field (H_max ≈ 80 kA/m) and the minimum limit volume fraction of nanoparticles (φ_min ≈ 3.5%) at which microwave heating of the ferrofluid remains efficient. At the same time, the results obtained show that the temperature increase of the ferrofluid samples, upon interaction with a microwave field, can be controlled by varying both H and φ, pointing to possible applications in magnetic hyperthermia. Full article

(This article belongs to the Special Issue 10th Anniversary of Magnetochemistry: Past, Present and Future)

► Show Figures

Figure 1

15 pages, 2654 KB

Open AccessArticle

Hydroxypropyl-β-Cyclodextrin Improves Removal of Polycyclic Aromatic Hydrocarbons by Fe₃O₄ Nanocomposites

by Wenhui Ping, Juan Yang, Xiaohong Cheng, Weibing Zhang, Yilan Shi and Qinghua Yang

Magnetochemistry 2026, 12(1), 4; https://doi.org/10.3390/magnetochemistry12010004 - 26 Dec 2025

Abstract

The contamination of water bodies by polycyclic aromatic hydrocarbons (PAHs) poses a significant concern for the ecological systems, along with public health. Magnetic adsorption stands out as a green and practical solution for treating polluted water. To make the process more efficient and [...] Read more.

The contamination of water bodies by polycyclic aromatic hydrocarbons (PAHs) poses a significant concern for the ecological systems, along with public health. Magnetic adsorption stands out as a green and practical solution for treating polluted water. To make the process more efficient and economical, it is important to create materials that not only absorb contaminants effectively but also allow for easy recovery and reuse. This study proposes a simple yet effective method for coating Fe₃O₄ nanoparticles with hydroxypropyl-β-cyclodextrin polymer (HP-β-CDCP). The physicochemical properties of the synthesized sorbent were characterized using a transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Vibrating Sample Magnetometer (VSM) analysis. The adsorption performance of HP-β-CDCP/Fe₃O₄ nanoparticles was well-described by the pseudo-second-order kinetic model, thermodynamic analysis, and the Freundlich isotherm model, indicating multiple interaction mechanisms with PAHs, such as π–π interactions, hydrogen bonding, and van der Waals forces. Using HP-β-CDCP/Fe₃O₄ nanoparticles as the adsorbent, the purification rates for the fifteen representative PAHs were achieved within the range of 33.9–93.1%, compared to 15.3–64.8% of the unmodified Fe₃O₄ nanoparticles. The adsorption of all studied PAHs onto HP-β-CDCP/Fe₃O₄ nanocomposites was governed by pH, time, and temperature. Equilibrium in the uptake mechanism was obtained within 15 min, with the largest adsorption capacities for PAHs in competitive adsorption mode being 6.46–19.0 mg·g⁻¹ at 20 °C, pH 7.0. This study points to the practical value of incorporating cyclodextrins into tailored polymer frameworks for improving the removal of PAHs from polluted water. Full article

(This article belongs to the Special Issue Applications of Magnetic Materials in Water Treatment—2nd Edition)

► Show Figures

Figure 1

10 pages, 4824 KB

Open AccessArticle

Controlled Synthesis, Microstructure Evolution, and Soft Magnetic Properties of Flaky Iron Nitride

by Sicheng Zhai, Xiaoqiang Li, Changkuan Zheng and Qun Wang

Magnetochemistry 2026, 12(1), 3; https://doi.org/10.3390/magnetochemistry12010003 - 23 Dec 2025

Abstract

Ball milling treatment facilitates the transformation of carbonyl iron powders from a spherical to a flaky morphology, while simultaneously introducing numerous defects that approach the nanometer scale in one dimension. Flaky iron nitride was synthesized via the gas nitridation in an NH₃ [...] Read more.

Ball milling treatment facilitates the transformation of carbonyl iron powders from a spherical to a flaky morphology, while simultaneously introducing numerous defects that approach the nanometer scale in one dimension. Flaky iron nitride was synthesized via the gas nitridation in an NH₃/N₂ atmosphere. The microstructure, morphology, and magnetic properties of the samples nitrided at different temperatures were characterized using XRD, SEM, TEM, and VSM. The formation of γ′-Fe₄N and ε-Fe₃N phases impedes domain wall movement, resulting in a slight increase in the H_c of the samples. Notably, γ′-Fe₄N positively influences the magnetic properties of iron nitride. As the nitriding temperature rises, the content of the γ′-Fe₄N phase initially increases before subsequently declining. Consequently, the flaky iron nitride synthesized at 610 °C exhibits excellent soft magnetic properties with a high M_s value reaching up to 177.1 emu/g and a low H_c value, indicating its potential applications in the field of magnetic materials. Full article

► Show Figures

Figure 1

Journal Description

Magnetochemistry

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Further Information

Guidelines

MDPI Initiatives

Follow MDPI