Magnetochemistry

3 pages, 604 KiB

Open AccessCorrection

Correction: Grewal et al. Structural and Photocatalytic Studies on Oxygen Hyperstoichiometric Titanium-Substituted Strontium Ferrite Nanoparticles. Magnetochemistry 2022, 8, 120

by Jaspreet Kaur Grewal, Manpreet Kaur, Rajeev K. Sharma, Aderbal C. Oliveira, Vijayendra Kumar Garg and Virender K. Sharma

Magnetochemistry 2024, 10(9), 65; https://doi.org/10.3390/magnetochemistry10090065 - 5 Sep 2024

Abstract

The authors wish to make a change to the published paper [...] Full article

► Show Figures

Figure 1

14 pages, 4615 KiB

Open AccessArticle

Controllable Synthesis of Magnetic Composite Derived from MIL-88D and Study on Adsorption Properties of Cu²⁺

by Zhongyuan Zheng, Jinshan Yu, Ling Jiang, Jiacheng Zhang and Min Lu

Magnetochemistry 2024, 10(9), 64; https://doi.org/10.3390/magnetochemistry10090064 - 31 Aug 2024

Abstract

In this paper, MIL-88D (Fe) with spindle shape was prepared by the hydrothermal synthesis method, a metal oxide with a new structure was obtained by calcination at different temperatures as a precursor, and a magnetic iron oxide composite was prepared successfully. At the [...] Read more.

In this paper, MIL-88D (Fe) with spindle shape was prepared by the hydrothermal synthesis method, a metal oxide with a new structure was obtained by calcination at different temperatures as a precursor, and a magnetic iron oxide composite was prepared successfully. At the same time, it was used as an adsorption material for the adsorption of heavy metal ions Cu²⁺. The influence of the initial pH value and adsorption time on the adsorption effect was investigated, the adsorption kinetics and adsorption isotherm were further fitted, and the adsorption mechanism was preliminarily analyzed. The results show that the magnetic iron oxide composites have a good adsorption capacity for Cu²⁺. The pH value is an important parameter that affects the adsorption effect. The adsorption of Cu²⁺ by magnetic iron oxide composites reached adsorption equilibrium in 30 min. The adsorption of Cu²⁺ by magnetic iron oxide composites conforms to the second-order reaction kinetics and Langmuir adsorption isotherm equation, which indicates that the adsorption process mainly occurs through chemisorption and typical single-molecular-layer adsorption. Full article

► Show Figures

Figure 1

9 pages, 2613 KiB

Open AccessCommunication

Microwave-Assisted Combustion Synthesized Sm₂Co₁₇ Magnetic Particles for Permanent Magnetic Application

by Yatao Wang, Xiangyu Ma, Yani Lu, Hui Wen, Guozhe Guo, Yingying Li, Pengming Zhang, Yan Wang and Zhi Yang

Magnetochemistry 2024, 10(9), 63; https://doi.org/10.3390/magnetochemistry10090063 - 29 Aug 2024

Abstract

We reported the new synthesis of Sm₂Co₁₇ particles by a microwave-assisted combustion (MACS) method. This process enables the controlled decomposition of Sm(NO₃)₃ and Co(NO₃)₂ into SmCo-O particles, followed by calcium reduction-diffusion. This SmCo-O particle [...] Read more.

We reported the new synthesis of Sm₂Co₁₇ particles by a microwave-assisted combustion (MACS) method. This process enables the controlled decomposition of Sm(NO₃)₃ and Co(NO₃)₂ into SmCo-O particles, followed by calcium reduction-diffusion. This SmCo-O particle provides an approach for achieving high magnetic properties in Sm₂Co₁₇ magnetic materials. The rhombohedral Sm₂Co₁₇ particles can be incorporated into epoxy resin and oriented, displaying a square-like hysteresis loop. The particles display magnetic properties at room temperature, with a saturation magnetization of 112.3 emu/g, coercivity of 5.6 kOe, and a maximum energy product of 9.4 MGOe. This method improves the synthesis efficiency of rare earth cobalt-based nano-materials, expands the synthesis scope, and provides ideas for the synthesis and applications of other rare earth nano-materials. Full article

► Show Figures

Figure 1

13 pages, 3047 KiB

Open AccessArticle

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

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 (

E_{M}

) 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 (

E_{M}

) 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

E_{M}

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

E_{M}

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

E_{M}

is more intense within the

{- Z}_{M S E}

magnetosheath, where

E_{M}

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

E_{M}

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

E_{M}

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)

► Show Figures

Figure 1

19 pages, 4679 KiB

Open AccessArticle

Reentrant Spin Glass and Magnetic Skyrmions in the Co₇Zn₇Mn_{_6−x}Fe_x 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

Abstract

Co₇Zn₇Mn₆ is a

β

-Mn-type alloy belonging to the Co_xZn_yMn_z (

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 Co_xZn_yMn_z (

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 Co₇Zn₇Mn_6−xFe_x,

0 \leq x \leq 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

T_{C}

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,

T_{g}

, that shifts to lower temperatures as the Fe content increases. Full article

(This article belongs to the Section Spin Crossover and Spintronics)

► Show Figures

Figure 1

9 pages, 2044 KiB

Open AccessArticle

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

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

{B i}_{0.5} {L a}_{0.1} {I n}_{0.1} Y_{0.1} {N d}_{0.1} {G d}_{0.1} F e O_{3}

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)

► Show Figures

Figure 1

16 pages, 6066 KiB

Open AccessArticle

Ni₅₀Mn_37.5Sn_12.5 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

Abstract

The impact of Co-addition (x = 0, 2, 4, and 6 at. %) in the as-cast and annealed Ni₅₀Mn_37.5Sn_12.5 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 Ni₅₀Mn_37.5Sn_12.5 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)

► Show Figures

Figure 1

13 pages, 1262 KiB

Open AccessArticle

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

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)

► Show Figures

Figure 1

25 pages, 14872 KiB

Open AccessReview

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

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)

► Show Figures

Figure 1

15 pages, 1097 KiB

Open AccessReview

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

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)

► Show Figures

Figure 1

21 pages, 4971 KiB

Open AccessArticle

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

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 {Mn^III₃(μ₃-O)(salox)₃}⁺ units connected by Na⁺ ions. Compounds 3, 5, and 6 are hexanuclear units formed by two parallel trinuclear units {Mn^III₃(μ₃-O)(salox)₃}⁺ or {Mn^III₃(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 Mn^III-N-O-Mn^III 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)

► Show Figures

Figure 1

10 pages, 5330 KiB

Open AccessArticle

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

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)

► Show Figures

Figure 1

21 pages, 5494 KiB

Open AccessArticle

Band Structure Calculations, Magnetic Properties and Magnetocaloric Effect of GdCo_1.8M_0.2 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

Abstract

The magnetic properties, band structure results, and magnetocaloric effect of GdCo_1.8M_0.2 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 GdCo_1.8M_0.2 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 µ_B/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 µ_B/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)

► Show Figures

Figure 1

21 pages, 3796 KiB

Open AccessReview

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

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))

► Show Figures

Figure 1

34 pages, 12724 KiB

Open AccessArticle

Impact of the Different Molecular Weights of Polyethylene Glycol (PEG) Coating Agents on the Magnetic Targeting Characteristics of Functionalized Magnetoresponsive Nanoclusters

by Sandor I. Bernad, Alexander Bunge, Maria C. Ioncica, Rodica Turcu, Monica Dan, Vlad Socoliuc, Daniela Susan-Resiga and Elena S. Bernad

Magnetochemistry 2024, 10(7), 51; https://doi.org/10.3390/magnetochemistry10070051 - 19 Jul 2024

Abstract

In this article, we investigated the influence of molecular weight (Mw) on particle deposition efficiency after PEG-functionalized (polyethylene glycol-PEG) magnetoresponsive magnetic cluster targeting. In this work, the clusters were obtained by the solvothermal polyol method using polyethylene glycol (PEG) as a coating agent. [...] Read more.

In this article, we investigated the influence of molecular weight (Mw) on particle deposition efficiency after PEG-functionalized (polyethylene glycol-PEG) magnetoresponsive magnetic cluster targeting. In this work, the clusters were obtained by the solvothermal polyol method using polyethylene glycol (PEG) as a coating agent. So, we investigated three kinds of magnetoresponsive clusters: MNC-2000, MNC-6000, and MNC-10,000. These clusters were coated with PEG, and had molecular weights (Mw) of 2000 Da, 6000 Da, and 10,000 Da, respectively. The authors propose that the key to achieving maximum efficiency in targeted drug delivery is to deposit a thin, uniform layer of medication that covers the vascular wall in the area of interest. We defined a set of efficiency criteria to focus on the most essential characteristics of the targeting results. These are the obstruction degree, which measures the level of vessel obstruction; the magnet coverage degree, which evaluates the quality of particle deposition along the vessel wall; and the proximal deposition degree, which assesses the effect of pulsatile flow on deposition length. We performed several tests to determine how molecular weight affected these efficiency parameters. These tests examined (a) the effect of the injected cluster quantities, (b) the effect of the magnet distance, and (c) the effect of the injection period. Our findings indicate that an increase in PEG’s molar weight significantly impacts magnetic particle targeting efficiency. Full article

(This article belongs to the Special Issue Functional Magnetic Materials: Synthesis, Structure and Application)

► Show Figures

Figure 1

25 pages, 6926 KiB

Open AccessReview

Magnon Excitation Modes in Ferromagnetic and Antiferromagnetic Systems

by Xing Chen, Cuixiu Zheng and Yaowen Liu

Magnetochemistry 2024, 10(7), 50; https://doi.org/10.3390/magnetochemistry10070050 - 14 Jul 2024

Abstract

Magnons, recognized as the quanta of spin waves, offer a pathway for transmitting information without the need for electron motion, thus emerging as a leading candidate for the next generation of low-power electronics. Firstly, this study gives an overview by examining magnon modes [...] Read more.

Magnons, recognized as the quanta of spin waves, offer a pathway for transmitting information without the need for electron motion, thus emerging as a leading candidate for the next generation of low-power electronics. Firstly, this study gives an overview by examining magnon modes possessing infinite wavelengths or zero wave numbers (known as ferromagnetic resonance) in classical ferromagnetic, antiferromagnetic, and synthetic antiferromagnetic systems. It delves into the dynamics of magnetization, particularly focusing on magnetic moments precession and the corresponding dispersion relationships under two distinct acoustic and optic eigenmodes. Furthermore, it elaborates on a novel hybrid quantum system termed magnon-magnon coupling. The study elucidates the mechanism behind the robust coupling between acoustic and optic magnon modes. Finally, we briefly discuss the current challenges and future research directions in this field. Full article

(This article belongs to the Special Issue Spin Waves in Magnonic Crystals and Hybrid Ferromagnetic Structures)

► Show Figures

Figure 1

19 pages, 7513 KiB

Open AccessArticle

Synergistic Effect of Magnetic Iron Oxide Nanoparticles with Medicinal Plant Extracts against Resistant Bacterial Strains

by Sereen M.B. Bataineh, Isam M. Arafa, Samya M. Abu-Zreg, Mohammad M. Al-Gharaibeh, Hanan M. Hammouri, Yaser H. Tarazi and Homa Darmani

Magnetochemistry 2024, 10(7), 49; https://doi.org/10.3390/magnetochemistry10070049 - 12 Jul 2024

Abstract

Nanoparticles are emerging as a fascinating alternative to antibiotics. When stabilized by chemical compounds, magnetite nanoparticles (MagNPs) consistently exhibit bactericidal effects across different types of bacteria. This study describes the synthesis, characterization, and antibacterial properties of magnetite MagNPs prepared by the coprecipitation method [...] Read more.

Nanoparticles are emerging as a fascinating alternative to antibiotics. When stabilized by chemical compounds, magnetite nanoparticles (MagNPs) consistently exhibit bactericidal effects across different types of bacteria. This study describes the synthesis, characterization, and antibacterial properties of magnetite MagNPs prepared by the coprecipitation method under continuous sonication. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Dynamic Light Scattering (DLS) techniques revealed Fe₃O₄-NPs as spherical, uniform particles with an average size of approximately 16 nm. The antibacterial efficacy of MagNPs was investigated by combining them with methanolic extracts of three medicinal plants known for their antibacterial properties: Aloysia triphylla, Sarcopoterium spinosum, and Urtica pilulifera. The combined effect was assessed against both wild type and resistant strains of Staphylococcus aureus and Escherichia coli. The antibacterial synergistic effect of MagNPs and plant extracts was evaluated by the MIC test, which showed significant inhibitory properties against the growth of the four bacterial strains as compared to control samples of plant extracts alone. Furthermore, the synergistic effect of MagNPs combined with extracts from Rosmarinus officinalis, Anchusa azurea, Quercus infectoria, and Urtica pilulifera significantly prevented biofilm development in both sensitive and resistant strains of Staphylococcus aureus. Full article

► Show Figures

Figure 1

15 pages, 3571 KiB

Open AccessArticle

Structural, Morphological and Ferroelectric Properties of Sr-Cd Co-Doped Nickel Ferrite for Energy Storage Devices

by Huda A. Alburaih, Muhammad Ahsan ul Haq, Abdul Jabbar, Atiq ur Rehman, Amel Laref, Mohamed Musa Saad Hasb Elkhalig and Naveed Ahmad Noor

Magnetochemistry 2024, 10(7), 48; https://doi.org/10.3390/magnetochemistry10070048 - 2 Jul 2024

Abstract

Ferroelectric materials, renowned for their capacity to demonstrate spontaneous electric polarization reversible through an external electric field, are essential in numerous technological applications owing to their distinctive characteristics. For this, a series of spinel Sr-Cd co-doped nickel ferrite nanomaterials Cd_0.5−xSr_x [...] Read more.

Ferroelectric materials, renowned for their capacity to demonstrate spontaneous electric polarization reversible through an external electric field, are essential in numerous technological applications owing to their distinctive characteristics. For this, a series of spinel Sr-Cd co-doped nickel ferrite nanomaterials Cd_0.5−xSr_xNi_0.5Fe₂O₄ (x = 0.0, 0.1, 0.2 and 0.3) were prepared through the standard sol-gel auto combustion method The XRD patterns showed that the prepared samples have a cubic spinel structure. The crystallite sizes of the samples vary from 29 to 40 nm. The morphology of prepared samples showed uniformly distributed spheres. Magnetic properties showed the soft magnetic nature of the prepared ferrites. The ferroelectric study revealed that Sr-Cd substituted ferrites exhibited the elliptical nature of ferroelectric loops at normal room temperature. The maximum polarization has been achieved at x = 0.3. The understanding of current and voltage (I–V) showed a slowly decreasing tendency of leakage current on both sides symmetrically against the increasing Sr content. The conductivity of the prepared spinel increases as a function of higher Sr doping. The real part of dielectric constant increases with increasing frequency. The materials show large elliptical loops indicating high asymmetric ferroelectric energy storage capability. Full article

► Show Figures

Figure 1

12 pages, 2436 KiB

Open AccessArticle

Effect of the Core–Shell Exchange Coupling on the Approach to Magnetic Saturation in a Ferrimagnetic Nanoparticle

by Sergey V. Komogortsev, Sergey V. Stolyar, Alexey A. Mokhov, Vladimir A. Fel’k, Dmitriy A. Velikanov and Rauf S. Iskhakov

Magnetochemistry 2024, 10(7), 47; https://doi.org/10.3390/magnetochemistry10070047 - 1 Jul 2024

Abstract

The generally accepted model of the magnetic structure of an iron oxide core–shell nanoparticle includes a single-domain magnetically ordered core surrounded by a layer with a frozen spin disorder. Due to the exchange coupling between the shell and core, the spin disorder should [...] Read more.

The generally accepted model of the magnetic structure of an iron oxide core–shell nanoparticle includes a single-domain magnetically ordered core surrounded by a layer with a frozen spin disorder. Due to the exchange coupling between the shell and core, the spin disorder should lead to nonuniform magnetization in the core. Suppression of this inhomogeneity by an external magnetic field causes the nonlinear behavior of the magnetization as a function of the field in the region of the approach to magnetic saturation. The equation proposed to describe this effect is tested using a micromagnetic simulation. Analysis of the approach to magnetic saturation of iron oxide nanoparticles at different temperatures using this equation can be used to estimate the temperature evolution of the core–shell coupling energy and the size of the uniformly magnetized nanoparticle core and the temperature behavior of this size. Full article

(This article belongs to the Special Issue Ferrimagnetic Materials: State of the Art and Future Perspective)

► 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