Journal Description
Magnetochemistry
Magnetochemistry
is an international, peer-reviewed, open access journal on all areas of magnetism and magnetic materials published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Chemistry, Inorganic and Nuclear) / CiteScore - Q2 (Chemistry (miscellaneous))
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 18.7 days after submission; acceptance to publication is undertaken in 2.8 days (median values for papers published in this journal in the first half of 2024).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
2.6 (2023);
5-Year Impact Factor:
2.7 (2023)
Latest Articles
Two New 2p–3d Metal Complexes with a Nitronyl-Nitroxide Ligand Derived from o-Vanillin: Synthesis, Crystals Structures and Magnetic Properties
Magnetochemistry 2024, 10(11), 86; https://doi.org/10.3390/magnetochemistry10110086 - 1 Nov 2024
Abstract
Two new 2p–3d complexes, (Et3NH)[ML(hfac)2], have been obtained using the nitronyl-nitroxide radical (HL) derived from 2-hydroxy-3-methoxy-5-nitrobenzaldehyde (M = Mn 1; Co 2). The two compounds are isomorphous and their structures consist of anionic mononuclear species, [M(hfac)2
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Two new 2p–3d complexes, (Et3NH)[ML(hfac)2], have been obtained using the nitronyl-nitroxide radical (HL) derived from 2-hydroxy-3-methoxy-5-nitrobenzaldehyde (M = Mn 1; Co 2). The two compounds are isomorphous and their structures consist of anionic mononuclear species, [M(hfac)2L]−, M = Mn 1; Co 2, and triethylammonium cations, Et3NH+. The metal ions adopt an octahedral geometry, being coordinated by phenoxido and aminoxyl oxygen atoms from the ligand and four oxygen atoms from the hexafluoroacetylacetonato (hfac−) ligand. The cryomagnetic behaviors of the two compounds reveal relatively strong antiferromagnetic M(II)-Rad interactions (JMnRad = −191 cm−1, JCoRad = −166 cm−1 with H = −JSMSRad). The EPR spectra (X- and Q-band) of compound 1 below 70 K show the characteristical features of a S = 2 spin system with zero field splitting terms of D = 0.26 cm−1 and E = 0.031 cm−1.
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(This article belongs to the Special Issue Magnetic Coordination Compounds and More... a Long and Successful Story: A Tribute to M. Julve and F. Lloret)
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Slow Magnetic Relaxation in a [Co4O4] Cubane Complex with Tridentate NNO-Schiff Base Ligands
by
Yuki Suemitsu, Yoshitaka Amakusa, Haruka Yoshino, Masaaki Ohba and Masayuki Koikawa
Magnetochemistry 2024, 10(11), 85; https://doi.org/10.3390/magnetochemistry10110085 - 30 Oct 2024
Abstract
Two tetranuclear Co(II) complexes, [Co4(pmab)4Cl4] (1) and [Co4(pmab)4(OBz)2]Cl2 (2) [Hpmab = 2-{(p-pyridinylmethylene)amino}benzenemethanol], have been synthesized and characterized through single-crystal X-ray diffraction, IR and UV-VIS
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Two tetranuclear Co(II) complexes, [Co4(pmab)4Cl4] (1) and [Co4(pmab)4(OBz)2]Cl2 (2) [Hpmab = 2-{(p-pyridinylmethylene)amino}benzenemethanol], have been synthesized and characterized through single-crystal X-ray diffraction, IR and UV-VIS spectroscopy, and magnetic measurements. Structural analysis revealed that both complexes possess a [Co4O4] cubane-like metal core connected by μ3-alkoxo bridges. Magnetic measurements of Complex 1 indicate weak ferromagnetic interactions (J ~ +0.75 cm−1) within the tetranuclear core, while Complex 2 exhibits antiferromagnetic behavior due to the presence of syn-syn bridging benzoate ligands. Alternating current (AC) magnetic measurements suggest that Complex 1 exhibits slow magnetic relaxation behavior.
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(This article belongs to the Section Molecular Magnetism)
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Radiation-Induced Paramagnetic Centers in Meso- and Macroporous Synthetic Opals from EPR and ENDOR Data
by
Alexander Rodionov, Larisa Latypova, Georgy Mamin and Marat Gafurov
Magnetochemistry 2024, 10(11), 84; https://doi.org/10.3390/magnetochemistry10110084 - 30 Oct 2024
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The paramagnetic defects and radiation-induced paramagnetic centers (PCs) in silica opals can play a crucial role in determining the magnetic and electronic behavior of materials and serve as local probes of their electronic structure. Systematic investigations of paramagnetic defects are essential for advancing
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The paramagnetic defects and radiation-induced paramagnetic centers (PCs) in silica opals can play a crucial role in determining the magnetic and electronic behavior of materials and serve as local probes of their electronic structure. Systematic investigations of paramagnetic defects are essential for advancing both theoretical and practical aspects of material science. A series of silica opal samples with different geometrical parameters were synthesized and radiation-induced PCs were investigated by means of the conventional and pulsed X- and W-band electron paramagnetic resonance, and 1H/2H Mims electron-nuclear double resonance. Two groups of PCs were distinguished based on their spectroscopic parameters, electron relaxation characteristics, temperature and time stability, localization relative to the surface of silica spheres, and their origin. The obtained data demonstrate that stable radiation-induced E’ PCs can be used as sensitive probes for the hydrogen-containing fillers of the opal pores, for the development of compact radiation monitoring equipment, and for quantum technologies.
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Open AccessReview
Influence of Magnetic Field on Calcium Carbonate Precipitation: A Critical Review
by
Fathi Alimi
Magnetochemistry 2024, 10(11), 83; https://doi.org/10.3390/magnetochemistry10110083 - 29 Oct 2024
Abstract
This review reports a critical study on the effect of magnetic fields on the precipitation process of calcium carbonate scale from hard water. Indeed, the harmful consequences of the water scaling phenomenon urged researchers to find effective solutions. One of the interesting antiscaling
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This review reports a critical study on the effect of magnetic fields on the precipitation process of calcium carbonate scale from hard water. Indeed, the harmful consequences of the water scaling phenomenon urged researchers to find effective solutions. One of the interesting antiscaling processes is the magnetic treatment of water, which triggers a reduction in the precipitation of calcium carbonate on the walls when in contact with hard water. In the present review, we discuss selected examples related to this process in a combined analysis of the latest advances and the mechanism of action of the magnetic field. Despite the diversity of studies investigating this phenomenon, the effectiveness of this treatment remains a controversial issue, and it is not possible to obtain a clear explanation of the phenomenon. This review proposes, finally, interesting hypotheses which can effectively explain the effect of magnetic treatment on the behavior of hard waters and the precipitation of calcium carbonate, which include magnetohydrodynamics and the hydration effect.
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(This article belongs to the Section Magnetic Field)
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Strong Antiferromagnetic Interactions in the Binuclear Cobalt(II) Complex with a Bridged Nitroxide Diradical
by
Vitaly A. Morozov, Eugenia V. Peresypkina, Wolfgang Wernsdorfer and Kira E. Vostrikova
Magnetochemistry 2024, 10(11), 82; https://doi.org/10.3390/magnetochemistry10110082 - 28 Oct 2024
Abstract
A binuclear cobalt–radical complex formed by the reaction of Co(hfac)2·2H2O (hfac = hexafluoroacetylacetonate) with the 2,2-bis(1-oxyl-3-oxide-4,4,5,5-tetramethylimidazolinyl) biradical (BR) has been synthesized. The complex {(hfac)CoII(BN)CoII(hfac)} crystallizes in the triclinic space group P : C
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A binuclear cobalt–radical complex formed by the reaction of Co(hfac)2·2H2O (hfac = hexafluoroacetylacetonate) with the 2,2-bis(1-oxyl-3-oxide-4,4,5,5-tetramethylimidazolinyl) biradical (BR) has been synthesized. The complex {(hfac)CoII(BN)CoII(hfac)} crystallizes in the triclinic space group P : C34H28Co2F24N4O12, a = 11.1513(5) Å, b = 12.8362(7) Å, c = 18.2903(8) Å, α = 103.061(1)°, β = 100.898(2)°, γ = 102.250(1)°, Z = 2. The compound consists of two non-equivalent pseudo-octahedral CoII ions, each bearing two hfac ancillary ligands bridged by the tetradentate bis-nitroxide (BN). The temperature dependence of the magnetic susceptibility indicates a strong antiferromagnetic exchange between each of the Co2+ ions and the nitroxyl biradical, as well as between the spins within the bridging ligand, forming a spin-frustrated system. Micro-squid investigations, performed on a single crystal of {(hfac)CoII(BN)CoII(hfac)}, reveal a peculiarity of the M(H) graph at temperatures below 0.4 K displaying a step that is a result of ground and first excited levels mixing by the applied magnetic field due to a small energy gap between them, as inferred from ab initio calculation. The latter was also carried out for two models of mononuclear Co2+ complexes in order to obtain a set of initial parameters for fitting the experimental magnetic curves using the Phi program. Moreover, direct CAS(12,10)/def2-TZVP calculations of the magnetic dependences χT(T) and M(H) were performed, which satisfactorily reproduced the experimental ones.
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(This article belongs to the Section Molecular Magnetism)
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Digital Magnetic Sorting for Fractionating Cell Populations with Variable Antigen Expression in Cell Therapy Process Development
by
Savannah Bshara-Corson, Andrew Burwell, Timothy Tiemann and Coleman Murray
Magnetochemistry 2024, 10(11), 81; https://doi.org/10.3390/magnetochemistry10110081 - 23 Oct 2024
Abstract
Cellular therapies exhibit immense potential in treating complex diseases with sustained responses. The manufacture of cell therapies involves the purification and engineering of specific cells from a donor or patient to achieve a therapeutic response upon injection. Magnetic cell sorting targeting the presence
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Cellular therapies exhibit immense potential in treating complex diseases with sustained responses. The manufacture of cell therapies involves the purification and engineering of specific cells from a donor or patient to achieve a therapeutic response upon injection. Magnetic cell sorting targeting the presence or absence of surface markers is commonly used for upfront purification. However, emerging research shows that optimal therapeutic phenotypes are characterized not only by the presence or absence of specific antigens but also by antigen density. Unfortunately, current cell purification tools like magnetic or fluorescence-activated cell sorting (FACS) lack the resolution to differentiate populations based on antigen density while maintaining scalability. Utilizing a technique known as digital magnetic sorting (DMS), we demonstrate proof of concept for a scalable, magnetic-based approach to fractionate cell populations based on antigen density level. Targeting CD4 on human leukocytes, DMS demonstrated fractionation into CD4Hi T cells and CD4Low monocytes and neutrophils as quantified by flow cytometry and single-cell RNA seq. DMS also demonstrated high throughput processing at throughputs 3–10× faster than FACS. We believe DMS can be leveraged and scaled to enable antigen density-based sorting in cell therapy manufacturing, leading to the production of more potent and sustainable cellular therapies.
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(This article belongs to the Section Applications of Magnetism and Magnetic Materials)
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Analysis of Magnetization Dynamics in NiFe Thin Films with Growth-Induced Magnetic Anisotropies
by
Leah Merryweather and Aidan T. Hindmarch
Magnetochemistry 2024, 10(10), 80; https://doi.org/10.3390/magnetochemistry10100080 - 21 Oct 2024
Abstract
We have used angled magnetron sputter deposition with and without sample rotation to control the magnetic anisotropy in 20 nm NiFe films. Ferromagnetic resonance spectroscopy, with data analysis using a Bayesian approach, is used to extract material parameters relating to the magnetic anisotropy.
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We have used angled magnetron sputter deposition with and without sample rotation to control the magnetic anisotropy in 20 nm NiFe films. Ferromagnetic resonance spectroscopy, with data analysis using a Bayesian approach, is used to extract material parameters relating to the magnetic anisotropy. When the sample is rotated during growth, only shape anisotropy is present, but when the sample is held fixed, a strong uniaxial anisotropy emerges with in-plane easy axis along the azimuthal direction of the incident atom flux. When the film is deposited in two steps, with an in-plane rotation of 90 degrees between steps, the two orthogonal induced in-plane easy-axes effectively cancel. The analysis approach enables precise and accurate determination of material parameters from ferromagnetic resonance measurements; this demonstrates the ability to precisely control both the direction and strength of uniaxial magnetic anisotropy, which is important in magnetic thin-film device applications.
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(This article belongs to the Special Issue Fabrication, Characterization and Application of Magnetic Thin Films)
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Comprehensive Characterization of Bi1.34Fe0.66Nb1.34O6.35 Ceramics: Structural, Morphological, Electrical, and Magnetic Properties
by
Susana Devesa, Carlos Oliveira Amorim, João Horta Belo, João P. Araújo, Sílvia Soreto Teixeira, Manuel P. F. Graça and Luís Cadillon Costa
Magnetochemistry 2024, 10(10), 79; https://doi.org/10.3390/magnetochemistry10100079 - 20 Oct 2024
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Recent research in solid-state physics and materials engineering focuses on the development of new dielectric materials, with bismuth-based pyrochlores being already extensively applied in communications technology for their excellent dielectric properties and relatively low sintering temperatures. Herein, the structural, morphological, electrical, and magnetic
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Recent research in solid-state physics and materials engineering focuses on the development of new dielectric materials, with bismuth-based pyrochlores being already extensively applied in communications technology for their excellent dielectric properties and relatively low sintering temperatures. Herein, the structural, morphological, electrical, and magnetic properties of Bi1.34Fe0.66Nb1.34O6.35 ceramic, prepared by the sol–gel method and sintered at 500 °C, are investigated. The Rietveld refinement of the XRD pattern showed a cubic phase belonging to the space group Fd-3m and a crystallite size of 42 nm. Transmission electron microscopy further confirmed the crystallite size and the homogeneous distribution of Bi, Fe, Nb, and O elements, as evidenced by high-angle annular dark field imaging and STEM-EDX mapping. The morphology of the sample, assessed by scanning electron microscopy, is characterized by submicron-sized spherical particles. Dielectric spectroscopic studies revealed that the dielectric properties, strongly influenced by frequency and temperature, indicate the material’s potential for energy storage due to lower dielectric loss compared to the dielectric constant. The observed relaxation phenomena, confirmed through variations in dielectric loss and loss tangent, highlight the influence of grain boundaries and temperature on electron hopping and charge carrier dynamics. Using SQUID magnetometry, we identified two distinct magnetic phases. The primary phase, corresponding to the Bi1.34Fe0.66Nb1.34O6.35 ceramic, exhibits an antiferromagnetic behavior below its Néel temperature at around 8.8 K. A secondary high-Curie temperature ferrimagnetic phase, likely vestigial maghemite and/or magnetite, was also detected, indicating an estimated fraction below 0.02 wt.%.
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Open AccessArticle
Short-Period Skyrmion Crystals in Itinerant Body-Centered Tetragonal Magnets
by
Satoru Hayami
Magnetochemistry 2024, 10(10), 78; https://doi.org/10.3390/magnetochemistry10100078 - 16 Oct 2024
Abstract
In this study, we investigate the stability of a magnetic skyrmion crystal with short-period magnetic modulations in a centrosymmetric body-centered tetragonal system. By performing the simulated annealing for the spin model, incorporating the effects of the biquadratic interaction and high-harmonic wave–vector interaction in
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In this study, we investigate the stability of a magnetic skyrmion crystal with short-period magnetic modulations in a centrosymmetric body-centered tetragonal system. By performing the simulated annealing for the spin model, incorporating the effects of the biquadratic interaction and high-harmonic wave–vector interaction in momentum space, we find that the double-Q square skyrmion crystal consisting of two spin density waves is stabilized in an external magnetic field. We also show that double-Q states appear in both low- and high-field regions; the low-field spin configuration is characterized by an anisotropic double-Q modulation consisting of a superposition of the spiral wave and sinusoidal wave, while the high-field spin configuration is characterized by an isotropic double-Q modulation consisting of a superposition of two sinusoidal waves. Furthermore, we show that the obtained multiple-Q instabilities can be realized for various ordering wave vectors. The results provide the possibility of realizing the short-period skyrmion crystals under the body-centered tetragonal lattice structure.
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(This article belongs to the Special Issue Spin and Charge Transport in Novel Quantum and Topological Materials)
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Incorporation of Superparamagnetic Magnetic–Fluorescent Iron Oxide Nanoparticles Increases Proliferation of Human Mesenchymal Stem Cells
by
Willian Pinheiro Becker, Juliana Barbosa Torreão Dáu, Wanderson de Souza, Rosalia Mendez-Otero, Rosana Bizon Vieira Carias and Jasmin
Magnetochemistry 2024, 10(10), 77; https://doi.org/10.3390/magnetochemistry10100077 - 12 Oct 2024
Abstract
Mesenchymal stem cells (MSCs) have significant therapeutic potential and their use requires in-depth studies to better understand their effects. Labeling cells with superparamagnetic iron oxide nanoparticles allows real-time monitoring of their location, migration, and fate post-transplantation. This study aimed to investigate the efficacy
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Mesenchymal stem cells (MSCs) have significant therapeutic potential and their use requires in-depth studies to better understand their effects. Labeling cells with superparamagnetic iron oxide nanoparticles allows real-time monitoring of their location, migration, and fate post-transplantation. This study aimed to investigate the efficacy and cytotoxicity of magnetic–fluorescent nanoparticles in human adipose tissue-derived mesenchymal stem cells (hADSCs). The efficacy of Molday ION rhodamine B (MIRB) labeling in hADSCs was evaluated and their biocompatibility was assessed using various techniques and differentiation assays. Prussian blue and fluorescence staining confirmed that 100% of the cells were labeled with MIRB and this labeling persisted for at least 3 days. Transmission electron microscopy revealed the internalization and clustering of the nanoparticles on the outer surface of the cell membrane. The viability assay showed increased cell viability 3 days after nanoparticle exposure. Cell counts were higher in the MIRB-treated group compared to the control group at 3 and 5 days and an increased cell proliferation rate was observed at 3 days post-exposure. Adipogenic, osteogenic, and chondrogenic differentiation was successfully achieved in all groups, with MIRB-treated cells showing an enhanced differentiation rate into adipocytes and osteocytes. MIRB was efficiently internalized by hADSCs but induced changes in cellular behavior due to the increased cell proliferation rate.
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(This article belongs to the Special Issue Advances in Magnetic Nanoparticles: Biocompatibility, Toxicity, and Biomedical Applications)
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[MnIII6MnIINaI2], [MnIII3MnIINaI], and [MnIII3] Clusters Derived from Schiff Bases: Syntheses, Structures, and Magnetic Properties
by
Johannes Löhr, Mercè Font-Bardia, Júlia Mayans and Albert Escuer
Magnetochemistry 2024, 10(10), 76; https://doi.org/10.3390/magnetochemistry10100076 - 10 Oct 2024
Abstract
The reaction of manganese halides with polydentate Schiff bases obtained by the condensation of 3-ethoxysalicylaldehyde and different amino alcohols, resulting in a NO3 set of donors, yielded a series of manganese clusters with {MnIII6MnIINa2}, {Mn
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The reaction of manganese halides with polydentate Schiff bases obtained by the condensation of 3-ethoxysalicylaldehyde and different amino alcohols, resulting in a NO3 set of donors, yielded a series of manganese clusters with {MnIII6MnIINa2}, {MnIII3MnIINa}, and {MnIII3} metallic cores. The influence of the ligand substituents and the halide on the final nuclearity has been studied. Analysis of their static magnetic behaviour confirms the ground states of 19/2 for the {MnIII6MnIINa2} complexes, 7/2 for the {MnIII3MnIINa} clusters, and 12/2 for the triangular {MnIII3} systems, and a weak field induced a slow relaxation of the magnetization for the trinuclear complexes.
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(This article belongs to the Special Issue Magnetic Coordination Compounds and More... a Long and Successful Story: A Tribute to M. Julve and F. Lloret)
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Optimizing Magnetic Separation and Cleaning Module in Fully Automated Chemiluminescence Immunoassay Analyzer Using a Special Arrangement of Spliced Magnets and a Three-Stage Magnetic Bead Collection Method
by
Chuan Lyu, Yu Jiang, Zhen Dai, Xu Xu, Yu Cai, Bo Liang, Congcong Zhou, Xuesong Ye and Jing Wang
Magnetochemistry 2024, 10(10), 75; https://doi.org/10.3390/magnetochemistry10100075 - 30 Sep 2024
Abstract
The magnetic separation and cleaning module, as a core component of the fully automated chemiluminescence immunoassay (CLIA) analyzer, encounters issues including high magnetic bead loss rate, long cleaning time, and poor cleaning effect. Based on a simulation analysis using COMSOL, we proposed a
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The magnetic separation and cleaning module, as a core component of the fully automated chemiluminescence immunoassay (CLIA) analyzer, encounters issues including high magnetic bead loss rate, long cleaning time, and poor cleaning effect. Based on a simulation analysis using COMSOL, we proposed a novel magnetic separation and cleaning module applied to a fully automated CLIA analyzer. The module adopted a method of arranging spliced rectangular magnets on opposite sides, where the same polarity faced each other, as well as a three-stage magnetic bead collection method. With the proposed method, the total cleaning process can be accomplished within 225 s; the total magnetic bead loss rate over three rounds of cleaning is 6.03%, whereas that of traditional instruments is 25.85%; the coefficient of variation (CV) of the magnetic bead loss rate is less than 0.5%; effective cleaning of free markers is achieved under various sample conditions. Compared with traditional CLIA instruments, this method comprehensively improves key performance indicators of the magnetic separation and cleaning module, providing a reference for similar modules in fully automated CLIA analyzers and positively impacting the accuracy of CLIA for the detection of disease biomarkers.
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(This article belongs to the Section Applications of Magnetism and Magnetic Materials)
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Facile Synthesis of Core-Shell Magnetic Iron Oxide@SiO2-NH2 Nanoparticles and Their Application in Rapid Boron Removal from Aqueous Solutions
by
Qinqin Hu, Manman Zhang, Jiaoyu Peng, Yaping Dong, Wu Li and Lingzong Meng
Magnetochemistry 2024, 10(10), 74; https://doi.org/10.3390/magnetochemistry10100074 - 30 Sep 2024
Abstract
In this study, amino-functionalized magnetic particles (iron oxide@SiO2-NH2) with core-shell structures were synthesized and evaluated for rapid boron removal from aqueous solutions. The results showed that the specific surface area of the iron oxide@SiO2-NH2 (131.24 m
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In this study, amino-functionalized magnetic particles (iron oxide@SiO2-NH2) with core-shell structures were synthesized and evaluated for rapid boron removal from aqueous solutions. The results showed that the specific surface area of the iron oxide@SiO2-NH2 (131.24 m2⋅g−1) increased greatly compared to pure iron oxide (30.98 m2⋅g−1). The adsorption equilibrium was less than 2 h, with an adsorption capacity of 29.76 mg⋅g−1 at pH = 6 at 15 °C. The quasi-second-order kinetic model described the boron adsorption process well, and both the Langmuir and Freundlich models were suitable for characterizing the adsorption isotherms. The zeta potential and XPS analysis before and after adsorption revealed that the main adsorption mechanism was the hydrogen bonding formation between the terminal -NH2 groups of the adsorbent and the boric acid. In addition, the adsorbent still maintained a high adsorption performance after five adsorption–desorption cycles, which illustrated that the iron oxide@SiO2-NH2 may be a potential adsorbent for environmental boron removal treatment.
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(This article belongs to the Special Issue Current Trends in Magnetic Metallic Materials and Nanocomposites)
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Theoretical Hints to Optimize Energy Dissipation and Cell–Cell Response in Quantum Cellular Automata Based on Tetrameric and Bidimeric Cells
by
Andrew Palii, Shmuel Zilberg and Boris Tsukerblat
Magnetochemistry 2024, 10(10), 73; https://doi.org/10.3390/magnetochemistry10100073 - 30 Sep 2024
Abstract
This article is largely oriented towards the theoretical foundations of the rational design of molecular cells for quantum cellular automata (QCA) devices with optimized properties. We apply the vibronic approach to the analysis of the two key properties of such molecular cells, namely
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This article is largely oriented towards the theoretical foundations of the rational design of molecular cells for quantum cellular automata (QCA) devices with optimized properties. We apply the vibronic approach to the analysis of the two key properties of such molecular cells, namely the cell–cell response and energy dissipation in the course of the non-adiabatic switching of the electric field acting on the cell. We consider two kinds of square planar cells, namely cells represented by a two-electron tetrameric mixed valence (MV) cluster and bidimeric cells composed of two one-electron MV dimeric half-cells. The model includes vibronic coupling of the excess electrons with the breathing modes of the redox sites, electron transfer, intracell interelectronic Coulomb repulsion, and also the interaction of the cell with the electric field of polarized neighboring cells. For both kinds of cells, the heat release is shown to be minimal in the case of strong delocalization of excess electrons (weak vibronic coupling and/or strong electron transfer) exposed to a weak electric field. On the other hand, such a parametric regime proves to be incompatible with a strong nonlinear cell–cell response. To reach a compromise between low energy dissipation and a strong cell–cell response, we suggest using weakly interacting MV molecules with weak electron delocalization as cells. From this point of view, bidimeric cells are advantageous over tetrameric ones due to their smaller number of electron transfer pathways, resulting in a lower extent of electron delocalization. The distinct features of bidimeric cells, such as their two possible mutual arrangements (“side-by-side” and “head-to-tail”), are discussed as well. Finally, we briefly discuss some relevant results from a recent ab initio study on electron transfer and vibronic coupling from the perspective of the possibility of controlling the key parameters of molecular QCA cells.
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(This article belongs to the Special Issue Magnetic Coordination Compounds and More... a Long and Successful Story: A Tribute to M. Julve and F. Lloret)
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Magnetohydrodynamic Analysis and Fast Calculation for Fractional Maxwell Fluid with Adjusted Dynamic Viscosity
by
Yi Liu and Mochen Jiang
Magnetochemistry 2024, 10(10), 72; https://doi.org/10.3390/magnetochemistry10100072 - 29 Sep 2024
Abstract
From the perspective of magnetohydrodynamics (MHD), the heat transfer properties of Maxwell fluids under MHD conditions with modified dynamic viscosity present complex challenges in numerical simulations. In this paper, we develop a time-fractional coupled model to characterize the heat transfer and MHD flow
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From the perspective of magnetohydrodynamics (MHD), the heat transfer properties of Maxwell fluids under MHD conditions with modified dynamic viscosity present complex challenges in numerical simulations. In this paper, we develop a time-fractional coupled model to characterize the heat transfer and MHD flow of Maxwell fluid with consideration of the Hall effect and Joule heating effect and incorporating a modified dynamic viscosity. The fractional coupled model is numerically solved based on the -algorithm and the spectral collocation method. We introduce a novel approach that integrates advanced algorithms with a fully discrete scheme, focusing particularly on the computational cost. Leveraging this approach, we aim to significantly enhance computational efficiency while ensuring accurate representation of the underlying physics. Through comprehensive numerical experiments, we explain the thermodynamic behavior in the MHD flow process and extensively examine the impact of various critical parameters on both MHD flow and heat transfer. We establish an analytical framework for the MHD flow and heat transfer processes, further investigate the influence of magnetic fields on heat transfer processes, and elucidate the mechanical behavior of fractional Maxwell fluids.
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(This article belongs to the Special Issue Advances in Multifunctional Magnetic Nanomaterial)
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Open AccessCommunication
The Creation of Remote Spin Entanglement with a Nanomechanical Cantilever
by
Vladimir I. Tsifrinovich
Magnetochemistry 2024, 10(10), 71; https://doi.org/10.3390/magnetochemistry10100071 - 29 Sep 2024
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We consider the creation of entanglement between remote electron spins using a magnetic nanoparticle attached to a cantilever tip (CT). We assume that the frequency of the CT vibrations matches the Larmor frequency of the spin (CT–spin resonance). Under the conditions of CT–spin
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We consider the creation of entanglement between remote electron spins using a magnetic nanoparticle attached to a cantilever tip (CT). We assume that the frequency of the CT vibrations matches the Larmor frequency of the spin (CT–spin resonance). Under the conditions of CT–spin resonance, the CT–spin system is described using the Jaynes–Cummings model. In this work, using the evolution operator of the Jaynes–Cummings model, we show that a movable CT can create an entangled state between remote spins. The most striking result is that the entanglement between the remote spins can be achieved without measuring the vibrational state of the CT.
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Open AccessArticle
Identifying Different Components of Oil and Gas Shale from Low-Field NMR Two-Dimensional Spectra Based on Deep Learning
by
Zijian Jia, Can Liang, Chunlin Zeng and Rui Chen
Magnetochemistry 2024, 10(10), 70; https://doi.org/10.3390/magnetochemistry10100070 - 27 Sep 2024
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The detection and quantitative analysis of shale components are of great significance for comprehensively understanding the properties of shale, assessing its resource potential and promoting efficient development and utilization of resources. The low-field NMR T1-T2 two-dimensional spectrum can detect
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The detection and quantitative analysis of shale components are of great significance for comprehensively understanding the properties of shale, assessing its resource potential and promoting efficient development and utilization of resources. The low-field NMR T1-T2 two-dimensional spectrum can detect shale components non-destructively and effectively. Unfortunately, due to its complexity, the two-dimensional spectral results of low-field NMR are mainly analyzed using manual qualitative analysis, and accurate results of the composition cannot be obtained. Since the information contained in its two-dimensional map is determined by the morphological texture and the position in the map, commonly used image analysis networks cannot adapt. In order to solve these problems, this paper improves a novel Faster Region-based Convolutional Neural Network (Faster-RCNN). Compared with previous models, the improved Faster-RCNN has better image classification and visual key point estimation capabilities. The results show that compared with traditional methods, the deep learning method using this model can directly obtain key information such as kerogen and movable oil and gas content in rocks. The information provided in this study can help complement and improve the development of analytical methods for low-field 2D NMR spectra.
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Open AccessArticle
Tetradentate NOO′O″ Schiff-Base Ligands as a Platform for the Synthesis of Heterometallic CdII-FeIII and CdII-CrIII Coordination Clusters
by
Konstantinos N. Pantelis, Sotiris G. Skiadas, Zoi G. Lada, Catherine P. Raptopoulou, Vassilis Psycharis, Yiannis Sanakis, Mark M. Turnbull and Spyros P. Perlepes
Magnetochemistry 2024, 10(10), 69; https://doi.org/10.3390/magnetochemistry10100069 - 27 Sep 2024
Abstract
The chemistry of heterometallic metal complexes continues to attract the interest of molecular inorganic chemists mainly because of the properties that different metal ions can bring to compounds. Contrary to the plethora of 3d–4f- and 3d–3d′-metal complexes, complexes containing both 3d- and 4d-metal
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The chemistry of heterometallic metal complexes continues to attract the interest of molecular inorganic chemists mainly because of the properties that different metal ions can bring to compounds. Contrary to the plethora of 3d–4f- and 3d–3d′-metal complexes, complexes containing both 3d- and 4d-metal ions are much less studied. The choice of the bridging organic ligand is of paramount importance for the synthesis of such species. In the present work, we describe the use of the potentially tetradentate NOO′O″ Schiff bases N-(2-carboxyphenyl)salicylideneimine (saphHCOOH) and N-(4-chloro-carboxyphenyl)salicylideneimine (4ClsaphHCOOH) in CdII-MIII (M = Fe, Cr) chemistry. The complexes [Cd2Fe2(saphCOO)4(NO3)2(H2O)2] (1), [Cd2Cr2(saphCOO)4(NO3)2(H2O)2] (2), [Cd2Fe2(4ClsaphCOO)4(NO3)2(H2O)2] (3) and [CdCr2(4ClsaphCOO)4(H2O)3(EtOH)] (4) have been structurally characterized, the quality of the structure of the latter being poor but, permitting the knowledge of the connectivity and the main structural features. Complexes 1–3 are isostructural, but not isomorphous, possessing a variety of lattice solvent molecules (EtOH, MeCN, CH2Cl2, H2O). The metal topology can be described as two isosceles triangles sharing a common CdII…CdII edge. The two CdII atoms are doubly bridged by two μ-aqua groups. The MIII…CdII sides of the triangles are each asymmetrically bridged by one carboxylate oxygen atom of a 2.2111 saphCOO2−/4ClsaphCOO2− ligand. The core of the molecules is {Cd2M2(μ-Oaqua)2(μ-OR)4}6+, where the OR oxygen atoms are the bridging carboxylate oxygens. The coordination spheres of the metal ions in the centrosymmetric molecules are [Cd(Oaqua)2(Ocarboxylato)4(Onitrato)2] and [M(Nimino)2(Ocarboxylato)2(Ophenolato)2]. The biaugmented trigonal prism is the most appropriate for the description of the coordination geometry of the CdII atoms in 1 and 3, while the geometry of these metal ions in 2 is best described as distorted triangular dodecahedral. A combination of H-bonding and π–π stacking interactions give interesting supramolecular patterns in the three tetranuclear compounds. The three metal ions in 4 define an isosceles triangle with two almost equal CdII…CrIII sides. The CdII center is linked to each CrIII atom through one carboxylato oxygen of a 2.2111 4ClsaphCOO2− ligand. The core of the molecule is {CdCr2(μ-OR)2}6+, where the OR oxygen atoms are the bridging carboxylato oxygens. A tridentate chelating 1.1101 4ClsaphCOO2− ligand is bonded to each CrIII. The coordination spheres are [Cd(Oaqua)3(Oethanol)(Obridging carboxylato)2(Oterminal carboxylate)2] and [Cr(Obridging carboxylato)(Oterminal carboxylato)(Ophenolato)2(Nimino)2]. Complexes 1–4 are the first heterometallic 3d–4d complexes based on saphHCOOH and 4ClsaphCOOH. The structures are critically compared with those of previous reported ZnII-MIII (M = Fe, Cr) complexes. The IR and Raman spectra of the complexes are discussed in terms of the coordination modes of the ligands involved. UV/VIS spectra in CH2Cl2 are also reported, and the bands are assigned to the corresponding transitions. The δ and ΔEQ57Fe-Mössbauer parameters of 1 and 3 at room temperature and 80 K suggest the presence of isolated high-spin FeIII centers. Variable-temperature (1.8–310 K) and variable-field (0–50 kOe) magnetic studies for 1 and 2 indicate the absence of MIII…MIII exchange interactions, in agreement with the long distances (~8 Å) between the paramagnetic metal ions. The combined work demonstrates the ability of saphCOO2− and 4ClsaphCOO2− to give 3d–4d metal complexes.
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(This article belongs to the Special Issue Latest Research on the Magnetic Properties of Coordination Compounds)
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Open AccessArticle
The Effect of the Calcination Time on the Microstructure and Properties of MnZn Ferrite Powders
by
Zhanyuan Xu, Wei Zhao, Lichun Bai and Jinglian Fan
Magnetochemistry 2024, 10(10), 68; https://doi.org/10.3390/magnetochemistry10100068 - 24 Sep 2024
Abstract
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MnZn ferrite powders were prepared based on the novel nano in situ composite method and through chemical sol-spray drying–calcination technology. The precursor powders were calcined at 1060 °C at different calcination times (1–9 h) to research the influences of the calcination time on
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MnZn ferrite powders were prepared based on the novel nano in situ composite method and through chemical sol-spray drying–calcination technology. The precursor powders were calcined at 1060 °C at different calcination times (1–9 h) to research the influences of the calcination time on MnZn ferrite powders. The research results revealed that all samples had similar morphologies composed of fine particles. The pure MnZn ferrite spinel phase can only be obtained when the calcination time does not exceed 3 h. Otherwise, some α-Fe2O3 or γ-Fe2O3 impurities will appear. The particle size descended with an increasing calcination time and then ascended. After 3 h of preservation, the smallest particle size was obtained, and it exhibited a unimodal distribution. The saturation magnetization (Ms) increased at first and decreased later with an increasing calcination time, and the optimal value (53.4 emu/g) was reached after holding for 3 h. In view of this work, the optimal calcination time is 3 h.
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Open AccessArticle
Energy Conversion Associated with Intermittent Currents in the Magnetosheath Downstream of the Quasi-Parallel Shock
by
Xinmin Li, Rongsheng Wang, San Lu, Ao Guo and Zhijian Zhang
Magnetochemistry 2024, 10(9), 67; https://doi.org/10.3390/magnetochemistry10090067 - 21 Sep 2024
Abstract
Using the data from the Magnetospheric Multiscale (MMS) mission, we studied the energy conversion between electromagnetic fields and particles (ions and electrons) in a spacecraft rest frame inside a turbulent magnetosheath downstream of the quasi-parallel shock. The results show that the energy conversion
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Using the data from the Magnetospheric Multiscale (MMS) mission, we studied the energy conversion between electromagnetic fields and particles (ions and electrons) in a spacecraft rest frame inside a turbulent magnetosheath downstream of the quasi-parallel shock. The results show that the energy conversion was highly intermittent in the turbulent magnetosheath, and the perpendicular electric fields dominated the energy conversion process. The energy conversion among the electromagnetic fields, ions, and electrons was related to the current intensity. In the region with weak current, the ions gained energy from electromagnetic fields, while the electron energy was released and transferred into electromagnetic fields. In contrast, in the intense current region, the energy of ions was transferred into the electromagnetic fields, but the electrons gained energy from electromagnetic fields. The results quantitatively established the relationship between energy conversion rate and current density and revealed that the energy conversion among the electromagnetic fields, ions, and electrons was related to the local current intensity inside the shocked turbulence.
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(This article belongs to the Special Issue New Insight into the Magnetosheath)
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