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Magnetochemistry
Volume 10
Issue 8
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Magnetochemistry, Volume 10, Issue 8 (August 2024) – 11 articles

Cover Story (view full-size image): Six new manganese(III) compounds have been presented with various H2‐R‐salox ligands and 9‐anthracenecarboxylate anions, each featuring the triangular unit {Mn3O(R‐salox)3}‐. When working with H2‐salox and H2‐3‐Me‐salox ligands, it was observed that the topology of the resulting compound changes is dependent on the presence of Na+ or Cs+ ions. This structural dependency was not observed when using H2‐Me‐salox and H2‐Et‐salox ligands. Magnetic studies reveal that all compounds exhibit a magneto-structural correlation, linking the intramolecular Mn‐N‐O‐Mn torsion with the magnetic exchange within these units. Molecular magnet behaviour was observed in the compounds derived from H2‐Me‐salox and H2‐Et‐salox ligands. Luminescent properties have been observed in all these compounds. View this paper
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13 pages, 3047 KiB  
Article
The Asymmetrical Distribution of a Dominant Motional Electric Field within the Martian Magnetosheath
by Shibang Li, Haoyu Lu, Jinbin Cao, Xiaoshu Wu, Xiaoxin Zhang, Nihan Chen, Yihui Song, Jianxuan Wang, Yuchen Cao and Jianing Zhao
Magnetochemistry 2024, 10(8), 62; https://doi.org/10.3390/magnetochemistry10080062 - 21 Aug 2024
Viewed by 453
Abstract
Attributed to the lack of an Earth-like global intrinsic dipole magnetic field on Mars, the induced electromagnetic field environment plays a crucial role in the evolution of its atmosphere. The dominant motional electric field (EM) induced by the bulk motion [...] Read more.
Attributed to the lack of an Earth-like global intrinsic dipole magnetic field on Mars, the induced electromagnetic field environment plays a crucial role in the evolution of its atmosphere. The dominant motional electric field (EM) induced by the bulk motion of the magnetic field within the Martian magnetosheath serves to accelerate ions toward escape velocity, thereby forming a plume escape channel. However, the distribution morphology of EM itself has received limited attention in previous research. In this study, by taking advantage of the multi-fluid Hall-MHD model cooperating with the Martian crustal field model, we focus on elucidating the physical mechanisms underlying the asymmetrical distribution of EM and examining the influence of the crustal field on this asymmetry. The results obtained from the simulation conducted in the absence of the crustal field indicate that the EM is more intense within the −ZMSE magnetosheath, where EM is directed toward Mars, primarily due to its corresponding higher velocity and a stronger magnetic field at lower solar zenith angles. The Martian crustal field has the ability to enhance the local EM around the inner boundary of the magnetosheath by amplifying both the magnetic field and its associated velocity. Accordingly, these findings provide valuable insights into the asymmetric nature of EM within the Martian magnetosheath under typical quiet-time solar wind conditions. Full article
(This article belongs to the Special Issue New Insight into the Magnetosheath)
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19 pages, 4679 KiB  
Article
Reentrant Spin Glass and Magnetic Skyrmions in the Co7Zn7Mn6−xFex β-Mn-Type Alloys
by José F. Malta, Marta S. C. Henriques, José A. Paixão and António P. Gonçalves
Magnetochemistry 2024, 10(8), 61; https://doi.org/10.3390/magnetochemistry10080061 - 16 Aug 2024
Viewed by 451
Abstract
Co7Zn7Mn6 is a β-Mn-type alloy belonging to the CoxZnyMnz (x+y+z=20) family that notoriously features a skyrmionic magnetic phase below the ferromagnetic ordering temperature and, [...] Read more.
Co7Zn7Mn6 is a β-Mn-type alloy belonging to the CoxZnyMnz (x+y+z=20) family that notoriously features a skyrmionic magnetic phase below the ferromagnetic ordering temperature and, in addition, a reentrant spin glass transition at low temperatures. In this work, we have studied the effect of partial substitution of Mn by Fe in the magnetic properties of this alloy. Samples of Co7Zn7Mn6−xFex, 0≤x≤1, were synthesised using the Bridgman–Stockbarger method, and their structure and composition were fully characterised by XRD and EDS. VSM and AC susceptibility measurements show that the partial substitution of Mn by Fe increases TC and the skyrmionic region of the magnetic phase diagram is suppressed for x>0.5. The AC susceptibility behaviour at low temperatures can be ascribed to the presence of a reentrant spin glass state observed for all compositions, with a spin glass freezing temperature, Tg, that shifts to lower temperatures as the Fe content increases. Full article
(This article belongs to the Section Spin Crossover and Spintronics)
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9 pages, 2044 KiB  
Article
Preparation and Characterization of BXFO High-Entropy Oxides
by Saba Aziz, Anna Grazia Monteduro, Ritu Rawat, Silvia Rizzato, Angelo Leo, Shahid Khalid and Giuseppe Maruccio
Magnetochemistry 2024, 10(8), 60; https://doi.org/10.3390/magnetochemistry10080060 - 15 Aug 2024
Viewed by 464
Abstract
Increasing demand for functional materials crucial for advancing new technologies has motivated significant scientific and industrial research efforts. High-entropy materials (HEMs), with tunable properties, are gaining attention for their use in high-frequency transformers, microwave devices, multiferroics, and high-density magnetic memory components. The initial [...] Read more.
Increasing demand for functional materials crucial for advancing new technologies has motivated significant scientific and industrial research efforts. High-entropy materials (HEMs), with tunable properties, are gaining attention for their use in high-frequency transformers, microwave devices, multiferroics, and high-density magnetic memory components. The initial exploration of HEMs started with high-entropy alloys (HASs), such as CrMnFeCoNi, CuCoNiCrAlxFe, and AlCoCrTiZn and paved the way for a multitude of HEM variations, including oxides, oxyfluorides, borides, carbides, nitrides, sulfides, and phosphides. In this study, we fabricated the high-entropy oxide (HEO) compound Bi0.5La0.1In0.1Y0.1Nd0.1Gd0.1FeO3 through the solid-state synthesis method. Magnetic measurements at 300 K show ferromagnetic behavior with significant coercivity. At the same time, this novel composition exhibits excellent dielectric properties and shows potential for electronic applications demonstrating that a high-entropy approach can expand the compositional range of rare earth multiferroics and improve the multifunctional properties in multiferroic applications. Full article
(This article belongs to the Section Applications of Magnetism and Magnetic Materials)
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16 pages, 6066 KiB  
Article
Ni50Mn37.5Sn12.5 Heusler Alloy: Influence of Co Addition on the Structure, Martensitic Transition, and Magnetic Properties
by Ahlem Bekhouche, Safia Alleg, Karima Dadda, Benilde F. O. Costa, Asma Wederni and Joan-Josep Suñol
Magnetochemistry 2024, 10(8), 59; https://doi.org/10.3390/magnetochemistry10080059 - 15 Aug 2024
Viewed by 409
Abstract
The impact of Co-addition (x = 0, 2, 4, and 6 at. %) in the as-cast and annealed Ni50Mn37.5Sn12.5 Heusler alloy at 900 °C for 24 h on the microstructure, magnetic properties, and the martensitic transition was studied [...] Read more.
The impact of Co-addition (x = 0, 2, 4, and 6 at. %) in the as-cast and annealed Ni50Mn37.5Sn12.5 Heusler alloy at 900 °C for 24 h on the microstructure, magnetic properties, and the martensitic transition was studied using X-ray diffraction (XRD), scanning electron microscopy, vibrating sample magnetometry, and differential scanning calorimetry. The crystal structure of as-cast samples consists of a 14M modulated martensite structure, a face-centered (FCC) γ phase, and a face-centered tetragonal (FCT) MnNi-type phase L10. The as-cast samples show a dendritic microstructure with different contrasts and non-uniform distribution. The annealed samples exhibit dual 14M and γ phases for the Co0 and Co2, but 14M + γ + MnNi for the Co4 and Co6. The appearance of the martensitic transformation in the annealed Co0 and Co2 samples can be due to the disappearance of the dendritic microstructure. The characteristic temperatures (martensite start, Ms; martensite finish, Mf; austenite start, As; and austenite finish, Af) decrease with Co addition. A ferromagnetic-like order exists at a lower temperature of 1.8 K for the as-cast and annealed samples and decreases at 300 K. The annealing increases the fraction of the AFM contributions at 300 K. The exchange bias values of the Co0, An-Co2, and An-Co6 are 146.7 Oe, 24 O2, and 32.6 Oe, respectively, at 300 K. Full article
(This article belongs to the Special Issue Advance of Magnetocaloric Effect and Materials)
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13 pages, 1262 KiB  
Article
Paramagnetic Solid-State NMR Study of Solid Solutions of Cobaltocene with Ferrocene and Nickelocene
by Gabrielle E. Harmon-Welch, Vladimir I. Bakhmutov and Janet Blümel
Magnetochemistry 2024, 10(8), 58; https://doi.org/10.3390/magnetochemistry10080058 - 15 Aug 2024
Viewed by 491
Abstract
The metallocenes ferrocene (Cp2Fe, 1), nickelocene (Cp2Ni, 2), and cobaltocene (Cp2Co, 3) crystallize in the same space group (P21/a) and they have the same shape and similar size. Therefore, they form solid [...] Read more.
The metallocenes ferrocene (Cp2Fe, 1), nickelocene (Cp2Ni, 2), and cobaltocene (Cp2Co, 3) crystallize in the same space group (P21/a) and they have the same shape and similar size. Therefore, they form solid solutions with random distribution of the different molecules when crystallized from solution. Alternatively, the solid metallocenes can be ground together manually, and the solid solutions form at any molar ratio within minutes. The metallocenes 2 and 3 are paramagnetic. Solid solutions of 1/3 and 2/3 have been studied by paramagnetic solution and solid-state NMR spectroscopy. The effect of the paramagnetic species on the other components in the solid solutions has been investigated. The impact on the chemical shifts is limited. However, the halfwidths and the signal shapes, as defined by the rotational sideband intensities, change with increasing amounts of paramagnetic components. The 1H T1 relaxation times are shortened for diamagnetic protons in the presence of paramagnetic metallocenes in the solid solutions. It has been demonstrated that all metallocenes mix at the molecular level within the polycrystalline samples. The EPR spectra of the solid solutions are dominated by the most intensive signal of any paramagnetic metallocene in the solid samples. Full article
(This article belongs to the Special Issue Nuclear Magnetic Resonance Applied to Paramagnetic Molecules)
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25 pages, 14872 KiB  
Review
Exploring the Utilization of Magnetic Composite Materials for High-Risk Contaminant Removal from Wastewater by Adsorption and Catalytic Processes—A Review
by Oana-Georgiana Dragos-Pinzaru, Nicoleta Lupu, Horia Chiriac and Gabriela Buema
Magnetochemistry 2024, 10(8), 57; https://doi.org/10.3390/magnetochemistry10080057 - 14 Aug 2024
Viewed by 610
Abstract
In the context of waters polluted with different high-risk contaminants, the development of efficient materials able to efficiently clean them is necessary. In the first part, the present review focuses on the ability of various types of magnetic layered double hydroxide materials to [...] Read more.
In the context of waters polluted with different high-risk contaminants, the development of efficient materials able to efficiently clean them is necessary. In the first part, the present review focuses on the ability of various types of magnetic layered double hydroxide materials to act as adsorbents for water contaminated mainly with heavy metals and dyes. Also, this paper reviews the ability of different magnetic layered double hydroxide materials to act as potential adsorbents for the treatment of wastewater contaminated with other types of pollutants, such as pharmaceutical products, phenolic compounds, phytohormones, and fungicides. In the second part, the applicability of the catalytic method for water depollution is explored. Thus, the use of simple or composite materials based on Fe3O4 is reviewed for the purpose of the catalytic degradation of organic compounds (dyes/phenols/pharmaceuticals). At the end, a review of multifunctional materials able to simultaneously neutralize different types of pollutants from wastewater is provided. Full article
(This article belongs to the Special Issue Applications of Magnetic Materials in Water Treatment)
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15 pages, 1097 KiB  
Review
Research Progress of Magnetic Flocculation in Water Treatment
by Zhihao Hu, Kun Wu, Zihan Wang, Kinjal J. Shah and Yongjun Sun
Magnetochemistry 2024, 10(8), 56; https://doi.org/10.3390/magnetochemistry10080056 - 7 Aug 2024
Viewed by 551
Abstract
As people’s material quality of life continues to improve, water resources become subjected to varying degrees of contamination. As one of the most commonly utilised agents in water treatment, a flocculant exhibits a diverse range of forms and a vast scope of applications. [...] Read more.
As people’s material quality of life continues to improve, water resources become subjected to varying degrees of contamination. As one of the most commonly utilised agents in water treatment, a flocculant exhibits a diverse range of forms and a vast scope of applications. However, the application of flocculants gives rise to a series of issues, including the use of large doses, the formation of sludge, the difficulty of recycling flocculants, and other concerns. The development of new flocculation technology has become a crucial step in enhancing the purification of wastewater and reducing environmental pollution. Magnetic flocculation can be classified into two main categories: magnetic seeds flocculation and magnetic flocculation. This paper presents an overview of the factors influencing magnetic flocculation, including the type of magnetic seeds, magnetic seeds particle size, and other pertinent considerations. Furthermore, the classification of magnetic flocculants in the process of magnetic flocculation is discussed. This includes the types of magnetic flocculant, namely, inorganic composite magnetic flocculants, organic composite magnetic flocculants, and biological composite magnetic flocculants. Inorganic composite magnetic flocculants are inexpensive and simple to produce; however, their dosage is considerable, and the resulting floc is not tightly formed, which impairs the efficacy of flocculation. The use of organic composite magnetic flocculants requires a smaller dosage and exhibits a strong flocculating ability; however, it may possess toxic properties and potentially cause harm to the water body. The biological composite magnetic flocculant exhibits high efficiency and no pollution, yet it is subject to stringent environmental conditions, displays poor stability, and is applicable to a relatively limited range of treatment scenarios. Furthermore, the integration of magnetic flocculation technology with other techniques is classified and summarised in diverse contexts, and the prospective research focus and direction of magnetic flocculants are proposed. Full article
(This article belongs to the Special Issue Applications of Magnetic Materials in Water Treatment)
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21 pages, 4971 KiB  
Article
Manganese (III) Compounds Derived from R-Salicylaldoxime and 9-Anthracenecarboxylate Ligands: A Study of Their Synthesis and Structural, Magnetic, and Luminescent Properties
by Berta Casanovas, Ramon Vicente, Mercè Font-Bardía and Mohamed Salah El Fallah
Magnetochemistry 2024, 10(8), 55; https://doi.org/10.3390/magnetochemistry10080055 - 5 Aug 2024
Viewed by 606
Abstract
The reaction of Mn(II) salts in the air with different R-salicylaldehyde oximes and the sodium or cesium salts of 9-anthracenecarboxylato (9-AC) allows for the isolation of new six polynuclear compounds: [Mn3NaO(salox)3(9-AC)2(EtOH)3H2O]n·2EtOH [...] Read more.
The reaction of Mn(II) salts in the air with different R-salicylaldehyde oximes and the sodium or cesium salts of 9-anthracenecarboxylato (9-AC) allows for the isolation of new six polynuclear compounds: [Mn3NaO(salox)3(9-AC)2(EtOH)3H2O]n·2EtOH (1), [Mn3NaO(3-Me-salox)3(9-AC)2(EtOH)3H2O]n·EtOH (2), [Mn6O2(salox)6(9-AC)2(EtOH)2(H2O)2]·3EtOH (3), [Mn3O(3-Me-salox)3(9-AC)(EtOH)3(H2O)]·1.8EtOH·3H2O (4), [Mn6O2(Me-salox)6(9-AC)2(EtOH)4(H2O)2]·0.5H2O (5), and [Mn6O2(Et-salox)6(9-AC)2(EtOH)4(H2O)2]·3EtOH (6). H2salox is a salicylaldehyde oxime, H2(3-Me-salox) is a 3-methyl-salicylaldehyde oxime, H2Me-salox is a 1-(2-hydroxyphenyl)ethan-1-one oxime and a H2-Et-salox is 1-(2-hydroxyphenyl)propan-1-one oxime. Structurally, compounds 1 and 2 consist of chains of trinuclear {MnIII3(μ3-O)(salox)3}+ units connected by Na+ ions. Compounds 3, 5, and 6 are hexanuclear units formed by two parallel trinuclear units {MnIII3(μ3-O)(salox)3}+ or {MnIII3(μ3-O)(Me-salox)3}+ planes related through an inversion center. Compound 4 consists of two isolated [Mn3O(3-Me-salox)3(9-AC)(EtOH)3(H2O)] trinuclear molecules in the unit cell showing crystallographic differences. Magnetic studies reveal a set of antiferromagnetic interactions in compounds 1 and 2 and a combination of antiferromagnetic and ferromagnetic interactions in compounds 3, 5, and 6. In all cases, the magneto-structural correlation between the intramolecular MnIII-N-O-MnIII torsion angle and the magnetic exchange within these units have been confirmed. For compounds 5 and 6, ac magnetic measurements reveal the slow relaxation of magnetization with moderate energy barriers of 19.9 cm−1 and 31.1 cm−1, respectively. Absorbance and fluorescence measurements in solution show the transitions of the 9-anthracenecarboxylate chromophore for all the compounds. Full article
(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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10 pages, 5330 KiB  
Article
Direct Observation of Short Large-Amplitude Magnetic Field Structures from Formation to Destruction
by Shi-Chen Bai, Quanqi Shi, Ruilong Guo, Alexander W. Degeling, Hui Zhang, Anmin Tian and Yude Bu
Magnetochemistry 2024, 10(8), 54; https://doi.org/10.3390/magnetochemistry10080054 - 29 Jul 2024
Viewed by 654
Abstract
Short large-amplitude magnetic field structures (SLAMSs) are often seen upstream of quasi-parallel shocks. They play vital roles near the quasi-parallel shock, such as decelerating solar wind ions and contributing to the dissipation and reformation of the shock. The formation process of these structures [...] Read more.
Short large-amplitude magnetic field structures (SLAMSs) are often seen upstream of quasi-parallel shocks. They play vital roles near the quasi-parallel shock, such as decelerating solar wind ions and contributing to the dissipation and reformation of the shock. The formation process of these structures has attracted great attention and has long been realized in simulation. However, their formation mechanism is still full of mysteries. Here, using magnetospheric multiscale mission (MMS) observation, we provide direct observations of the SLAMS formation and destruction processes. SLAMS growth is powered by solar wind ions and shock-reflected ions through the ion-ion non-resonant mode. Reconnection occurs between and inside SLAMSs during their growth; however, these cumulative changes in magnetic field topology and the dissipation of the magnetic field energy contribute to the destruction of the SLAMS. These observations shed new light on the dissipation and reformation of the shock both in space physics and astrophysics. Full article
(This article belongs to the Special Issue New Insight into the Magnetosheath)
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21 pages, 5494 KiB  
Article
Band Structure Calculations, Magnetic Properties and Magnetocaloric Effect of GdCo1.8M0.2 Compounds with M = Fe, Mn, Cu, Al
by Gabriela Souca, Roxana Dudric, Karsten Küpper, Coriolan Tiusan and Romulus Tetean
Magnetochemistry 2024, 10(8), 53; https://doi.org/10.3390/magnetochemistry10080053 - 24 Jul 2024
Viewed by 694
Abstract
The magnetic properties, band structure results, and magnetocaloric effect of GdCo1.8M0.2 with M = Fe, Mn, Cu, and Al are reported. The band structure calculations demonstrate that all the samples have a ferrimagnetically ordered ground state, in perfect agreement with [...] Read more.
The magnetic properties, band structure results, and magnetocaloric effect of GdCo1.8M0.2 with M = Fe, Mn, Cu, and Al are reported. The band structure calculations demonstrate that all the samples have a ferrimagnetically ordered ground state, in perfect agreement with the magnetic measurements. Calculated magnetic moments and variation with the alloy composition are strongly influenced by hybridisation mechanisms as sustained by an analysis of the orbital projected local density of states. The XPS measurements reveal no significant shift in the binding energy of the investigated Co core levels with a change in the dopant element. The Co 3s core-level spectra gave us direct evidence of the local magnetic moments on Co sites and an average magnetic moment of 1.3 µB/atom was found, being in good agreement with the theoretical estimation and magnetic measurements. From the Mn 3s core-level spectra, a value of 2.1 µB/Mn was obtained. The symmetric shapes of magnetic entropy changes, the Arrott plots, and the temperature dependence of Landau coefficients clearly indicate a second-order phase transition. The relative cooling power, RCP(S), normalized relative cooling power, RCP(∆S)/∆B, and temperature-averaged entropy change values indicate that these compounds could be promising candidates for applications in magnetic refrigeration devices. Full article
(This article belongs to the Special Issue Advance of Magnetocaloric Effect and Materials)
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21 pages, 3796 KiB  
Review
Magnetic Substrates for Tissue Engineering—A Review
by Tomasz Blachowicz and Andrea Ehrmann
Magnetochemistry 2024, 10(8), 52; https://doi.org/10.3390/magnetochemistry10080052 - 24 Jul 2024
Viewed by 493
Abstract
Tissue engineering is based on combining cells with suitable scaffolds and growth factors. Recently, bone tissue engineering has been especially investigated deeply due to a large number of bone-related diseases. One approach to improve scaffolds is based on using piezoelectric materials as a [...] Read more.
Tissue engineering is based on combining cells with suitable scaffolds and growth factors. Recently, bone tissue engineering has been especially investigated deeply due to a large number of bone-related diseases. One approach to improve scaffolds is based on using piezoelectric materials as a way to influence the growing bone tissue by mechanical stress. Another method to stimulate tissue growth is by applying an external magnetic field to composites of magnetostrictive and piezoelectric materials, as well as the possibility to prepare oriented surfaces by orienting embedded magnetic fibers or nanoparticles. In addition, magnetic scaffolds without other special properties have also been reported to show improved properties for bone tissue and other tissue engineering. Here, we provide an overview of recent research on magnetic scaffolds for tissue engineering, differentiating between bone and other tissue engineering. We show the advantages of magnetic scaffolds, especially related to cell guidance and differentiation, and report recent progress in the production and application of such magnetic substrates for different areas of tissue engineering. Full article
(This article belongs to the Special Issue Magnetic Materials, Thin Films and Nanostructures (Volume II))
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