Magnetochemistry

24 pages, 6887 KiB

Open AccessArticle

Investigation of the Prospects for the Use of Iron-Containing Nanocomposites Doped with Rare Earth Elements as Catalysts for the Purification of Aqueous Media

by Kayrat K. Kadyrzhanov, Artem L. Kozlovskiy, Kamila B. Egizbek, Sholpan N. Kubekova, Inesh E. Kenzhina and Maxim V. Zdorovets

Magnetochemistry 2023, 9(3), 87; https://doi.org/10.3390/magnetochemistry9030087 - 22 Mar 2023

Viewed by 1140

Abstract

The great interest in nanostructured magnetic composites is due to their great prospects for use as a basis for the development of catalysts for the adsorption of manganese in wastewater. Interest in magnetic nanocomposites in this direction is primarily due to the possibility [...] Read more.

The great interest in nanostructured magnetic composites is due to their great prospects for use as a basis for the development of catalysts for the adsorption of manganese in wastewater. Interest in magnetic nanocomposites in this direction is primarily due to the possibility of extracting them from water media using ordinary magnets, which allows them to be used again. Additionally, it is worthwhile to note interest in research related to increasing the efficiency of adsorption, as well as an increase in the number of repeated cycles of operation. In this regard, the main goal of this study is to study the prospects for applying the method of mechanochemical synthesis for the creation of iron-containing nanocomposites doped by rare-earth elements Gd, Ce, Y, and Nd in order to obtain optimal catalysts for cleaning water media. During the studies, structural properties and phase composition of synthesized nanocomposites were established, as well as ultra-thin parameters of the magnetic field. It has been established that the kinetic curves of the adsorption process can be described by a pseudo-first-order model, and the process of manganese adsorption itself is associated with the cationic interaction of manganese ions with the surface of nanocomposites. The kinetic curves of degradation were determined, as well as the influence of the number of cyclic tests on the adsorption of manganese for synthesized nanocomposites, depending on the type of dopant and phase composition, respectively. Iron-containing nanocomposites doped with gadolinium and neodymium have been found to have the highest adsorption efficiency and corrosion resistance. Particular attention is paid to the study of the stability of storage of nanocomposites for a long time, as well as the preservation of their adsorbent properties in the purification of aqueous media. It has been determined that the modification of nanostructures with the help of rare earth compounds leads to an increase in resistance to degradation, as well as to the preservation of the efficiency of adsorption for 5–7 cycles in comparison with Fe₂O₃ nanoparticles, for which low resistance to degradation was observed. Full article

(This article belongs to the Special Issue Synthetic, Natural and Natural-Synthetic Hybrid Magnetic Structures: Technology and Application)

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20 pages, 9863 KiB

Open AccessArticle

Research on Identification and Detection of Aluminum Plate Thickness Step Change Based on Electromagnetic Acoustic Resonance

by Zhichao Cai, Yihu Sun, Zhengshi Lu and Qixiang Zhao

Magnetochemistry 2023, 9(3), 86; https://doi.org/10.3390/magnetochemistry9030086 - 22 Mar 2023

Viewed by 1095

Abstract

The conventional ultrasonic thickness measurement method is ineffective in detecting the measured specimen with a step change in thickness as it is easy to cause multimode acoustic mixing in the ultrasonic detection process. To solve this problem, this paper presented an electromagnetic acoustic [...] Read more.

The conventional ultrasonic thickness measurement method is ineffective in detecting the measured specimen with a step change in thickness as it is easy to cause multimode acoustic mixing in the ultrasonic detection process. To solve this problem, this paper presented an electromagnetic acoustic resonance (EMAR) moving scan identification method based on a frequency–frequency energy density precipitation (FFEDP) algorithm, which uses a standing wave resonance mode to accurately extract step thickness information and employs the algorithm to separate step thickness information. According to the simulation results, the ratio of the highest energy density of the spectrum signal on both sides of the step area to the total energy density had an opposite linear change rule with the equidistant movement of the transducer coil. The thickness step area can be identified by analyzing the crossover point of the contrast value change. The experimental results showed that the proposed method can accurately extract the thickness information under millimeter-level stepping distance for sector-notched specimens with step surfaces of different thicknesses, and at the same time realize the effective identification of the step surface. Full article

(This article belongs to the Special Issue Applications of Electromagnetic Acoustic Testing (EMAT))

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13 pages, 3734 KiB

Open AccessArticle

Magnetic and Transport Anomalies and Large Magnetocaloric Effect in Cubic R₄PtAl (R = Ho and Er)

by Kartik K. Iyer, Sudhindra Rayaprol, Ram Kumar, Shidaling Matteppanavar, Suneel Dodamani, Kalobaran Maiti and Echur V. Sampathkumaran

Magnetochemistry 2023, 9(3), 85; https://doi.org/10.3390/magnetochemistry9030085 - 20 Mar 2023

Cited by 1 | Viewed by 1235

Abstract

We report the electronic properties of R₄PtAl (R = Ho, and Er), which contains three sites for R, by the measurements of magnetization (ac and dc), heat-capacity, transport, and magnetoresistance (MR). Dc magnetization data reveal antiferromagnetic order below 19 K [...] Read more.

We report the electronic properties of R₄PtAl (R = Ho, and Er), which contains three sites for R, by the measurements of magnetization (ac and dc), heat-capacity, transport, and magnetoresistance (MR). Dc magnetization data reveal antiferromagnetic order below 19 K and 12 K in Ho and Er compounds, respectively. Additional features observed at lower temperatures (12 K for Ho₄PtAl and 5 K for Er₄PtAl) are akin to the cluster spin-glass phase. Resistivity data exhibit a weak minimum at a temperature marginally higher than their respective Néel temperature (T_N), which is unusual for such rare-earths with well-localized 4f states. Isothermal magnetization and magnetoresistance data well below T_N exhibit signatures of a subtle field-induced magnetic transition for a small magnetic field (<10 kOe). Notably, the isothermal entropy change at T_N has the largest peak value within this rare-earth family; for a field change from zero to 50 kOe, the entropy change is ~14.5 J/kg K (Ho4PtAl) and ~21.5 J/kg K (Er₄PtAl) suggesting a role of anisotropy of 4f orbital in determining this large value. The results provide some clues for the advancement of the field of magnetocaloric effect. The magnetocaloric property of Er₄PtAl is nonhysteretic, meeting a challenge to find materials with reversible magnetocaloric effect. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Magnetic and Magnetoelectric Materials)

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13 pages, 3605 KiB

Open AccessArticle

Dissolution of Lysozyme Amyloid Fibrils Using Magnetic Nanoparticles in an Alternating Magnetic Field: Design of an Effective Treatment for Cutaneous Amyloidosis

by Natália Andrýsková, Hana Vrbovská, Melánia Babincová, Peter Babinec and Mária Šimaljaková

Magnetochemistry 2023, 9(3), 84; https://doi.org/10.3390/magnetochemistry9030084 - 17 Mar 2023

Cited by 2 | Viewed by 1349

Abstract

The purpose of this study was to apply functionalized magnetic nanoparticles for the treatment of amyloidosis, a disease characterized by the accumulation of aberrant protein forms with an insoluble amyloid structure. The dissolution and clearance of these extremely stable fibrils from lesions is [...] Read more.

The purpose of this study was to apply functionalized magnetic nanoparticles for the treatment of amyloidosis, a disease characterized by the accumulation of aberrant protein forms with an insoluble amyloid structure. The dissolution and clearance of these extremely stable fibrils from lesions is very complicated. For this purpose, we examined the possibility of using magnetic nanoparticles that generate heat in an external alternating magnetic field with a frequency of 3.5 MHz. As a convenient model system, we used lysozyme fibrils. For the quantification of fibrillar status, we used Thioflavin T and Congo red, specific dyes which change their spectroscopic properties upon binding with the cross-beta structure of fibrils. We found that by using fluorescence, and polarization microscopy, as well as absorption spectrophotometry, the amyloid-like fibrils can be almost completely dissolved. The obtained results suggest that the application of magnetic nanoparticles could be a possible therapeutic intervention in cutaneous amyloidosis. Full article

(This article belongs to the Special Issue Soft and Hard Magnetic Materials: Latest Advances and Prospects)

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14 pages, 3429 KiB

Open AccessFeature PaperArticle

Four-Component Relativistic Calculations of NMR Shielding Constants of the Transition Metal Complexes—Part 3: Fe, Co, Ni, Pd, and Pt Glycinates

by Dmitry O. Samultsev, Valentin A. Semenov and Leonid B. Krivdin

Magnetochemistry 2023, 9(3), 83; https://doi.org/10.3390/magnetochemistry9030083 - 16 Mar 2023

Cited by 1 | Viewed by 918

Abstract

The relativistic effects of the values of the shielding constants of ¹H, ¹³C, ¹⁵N, ⁵⁷Fe, ⁵⁹Co, ⁶¹Ni, ¹⁰⁵Pd, and ¹⁹⁵Pt nuclei were studied at the four-component relativistic level and were compared to the results of [...] Read more.

The relativistic effects of the values of the shielding constants of ¹H, ¹³C, ¹⁵N, ⁵⁷Fe, ⁵⁹Co, ⁶¹Ni, ¹⁰⁵Pd, and ¹⁹⁵Pt nuclei were studied at the four-component relativistic level and were compared to the results of non-relativistic calculations perfomed on a series of biologically important Fe(II), Co(III), Ni, Pd, and Pt glycinates. The accuracy factors affecting the calculation of the chemical shifts of the title heavy nuclei were analyzed. First of all, the advantages and limitations of the different levels of theory used to take into account the electron correlation effects (namely HF, DFT, MP2, and CCSD) at the geometry optimization stage were thoroughly scrutinized. Among the employed DFT functionals, the behavior of 11 dedicated functionals of different types and hierarchies were analyzed. The contribution of the exact-exchange admixture was established both in the geometrical search and during the calculation of the shielding constants, which was exemplified with the PBE family of functionals. The main result of the performed study was that relativistic effects were of major importance to the theoretical calculations of the shielding constants and chemical shifts of the chelate complexes of the transition metals of the 8–10 groups. Thus, the relativistic effects of the values of the shielding constants of those metals, as well as those of the light nuclei located in the α-position to the latter, were found to reach as much as 35 ppm for nitrogen and up to an enormous 4300 ppm for platinum. Full article

(This article belongs to the Special Issue NMR Spectroscopy in Transition Metal Complexes)

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17 pages, 135217 KiB

Open AccessArticle

Magnetic Inversion and Regional Tectonics of the Dabie Orogen

by Liang Zhang, Guangyin Lu, Ziqiang Zhu, Shujin Cao, Yajing Mao, Xinyue Chen and Lichang Wang

Magnetochemistry 2023, 9(3), 82; https://doi.org/10.3390/magnetochemistry9030082 - 15 Mar 2023

Cited by 1 | Viewed by 915

Abstract

Physical property inversion techniques are the methods to reveal the internal structures of Earth’s lithosphere. In this study, we introduce an Occam-type inversion algorithm into a spherical coordinate system, and invert the magnetization based on the three-component magnetic anomalies. The synthetic model tests [...] Read more.

Physical property inversion techniques are the methods to reveal the internal structures of Earth’s lithosphere. In this study, we introduce an Occam-type inversion algorithm into a spherical coordinate system, and invert the magnetization based on the three-component magnetic anomalies. The synthetic model tests show that the inversion effects of the vertical components are relatively stable, while the anti-noise ability is strong. We apply the algorithm to a set of vertical component anomalies derived from the satellite magnetic field model and obtain Dabie orogen 3D magnetization distribution. Multiple magnetic sources are identified within the orogen and adjacent areas, and the related tectonic evolution processes are analyzed. The significant magnetization characteristics of the orogen can be associated with mantle upwelling caused by the Early Cretaceous lithospheric delamination, along with the partial melting of the mafic–ultramafic lower crust that had not participated in the delamination. The magnetic sources near the Mozitan–Xiaotian fault, and those located in the western Dabie area, are also restricted by Mesozoic and Jurassic–Cretaceous deep melt activities, respectively. The study provides evidence for the suture line position of the plate subduction in the deep lithosphere. Furthermore, the results display certain indications of mineralization activities in the middle–lower Yangtze Valley metallogenic belt. Full article

(This article belongs to the Special Issue Advances in Magnetotelluric Analysis)

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13 pages, 2951 KiB

Open AccessArticle

Preparation of Magnetic Iron Oxide Incorporated Mesoporous Silica Hybrid Composites for pH and Temperature-Sensitive Drug Delivery

by Madhappan Santhamoorthy, Kokila Thirupathi, Selvakumar Krishnan, Loganathan Guganathan, Sushma Dave, Thi Tuong Vy Phan and Seong-Cheol Kim

Magnetochemistry 2023, 9(3), 81; https://doi.org/10.3390/magnetochemistry9030081 - 12 Mar 2023

Cited by 4 | Viewed by 1640

Abstract

In clinical applications for cancer treatment, chemotherapy coupled with thermotherapy is highly considered. The development of multifunctional nanocomposite materials is an appealing strategy for use in various applications including biomedical applications. We present the preparation of dopamine-modified mesoporous silica material, in which magnetic [...] Read more.

In clinical applications for cancer treatment, chemotherapy coupled with thermotherapy is highly considered. The development of multifunctional nanocomposite materials is an appealing strategy for use in various applications including biomedical applications. We present the preparation of dopamine-modified mesoporous silica material, in which magnetic iron oxide nanoparticles (FeNP) were grown onto the outer surface via the complexation of iron (Fe(III) and Fe(II)) ions with the dopamine groups modified on the silica hybrid and subsequent chemical reduction approaches. The prepared magnetic iron oxide incorporated with mesoporous silica hybrid composite nanoparticles (FeNP@MSHC NPs) had a large surface area (346 m²/g), pore size (3.2 nm), and pore volume (0.048 cm³/g). The formation of FeNP on the outer surface of the FeNP@MSHC NPs results in superparamagnetic characteristics. Furthermore, the prepared FeNP@MSHC NPs have a high drug (Dox) loading capacity (~62%) as well as pH- and temperature-responsive drug release efficiency. In addition, the MTT assay result shows the biocompatibility of the prepared FeNP@MSHC NPs. As a result, the FeNP@MSHC NPs could be utilized in cancer treatment for pH and temperature-sensitive delivery of chemotherapeutic agents to the target sites. Full article

(This article belongs to the Special Issue Magnetic Nanoparticles: State of the Art and Future Perspectives)

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21 pages, 4757 KiB

Open AccessFeature PaperReview

Magnetic Switchability via Thermal-Induced Structural Phase Transitions in Molecular Solids

by Shan-Nan Du, Chan-Ying Yao, Jun-Liang Liu and Ming-Liang Tong

Magnetochemistry 2023, 9(3), 80; https://doi.org/10.3390/magnetochemistry9030080 - 09 Mar 2023

Viewed by 1502

Abstract

Magnetically switchable molecular solids with stimuli-responsive ON/OFF characteristics are promising candidates for smart switches and magnetic storage. In addition to conventional spin-crossover/charge-transfer materials whose magnetic responses arise from changes in the electronic structure of the metal centers, peripheral chemical entities that exhibit tunability [...] Read more.

Magnetically switchable molecular solids with stimuli-responsive ON/OFF characteristics are promising candidates for smart switches and magnetic storage. In addition to conventional spin-crossover/charge-transfer materials whose magnetic responses arise from changes in the electronic structure of the metal centers, peripheral chemical entities that exhibit tunability provide an alternative and promising tactic for the construction of magnetic multi-stable materials. Temperature changes can trigger a reversible structural phase transition that can affect the coordination environment of a transition-metal center because of the thermal-induced motion of ligands, counterions, neutral guests, and/or changes in coordination number, thus potentially realizing magnetic bistability which can arise from a concomitant spin state change or the modulation of orbital angular momentum. Perspectives and challenges are also highlighted to provide insights into its development. Full article

(This article belongs to the Special Issue Reviews on Molecular Magnetism)

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13 pages, 1461 KiB

Open AccessArticle

Artifacts’ Detection for MRI Non-Metallic Needles: Comparative Analysis for Artifact Evaluation Using K-Means and Manual Quantification

by Marwah AL-Maatoq, Melanie Fachet, Rajatha Rao and Christoph Hoeschen

Magnetochemistry 2023, 9(3), 79; https://doi.org/10.3390/magnetochemistry9030079 - 07 Mar 2023

Cited by 2 | Viewed by 1439

Abstract

Interventional biopsy needles need to be accurately localized to the target tissue during magnetic resonance imaging (MRI) interventions. In this context, severe susceptibility artifacts affect the visibility of structures in the MR images depending on the needle’s material composition. In particular, standard needles [...] Read more.

Interventional biopsy needles need to be accurately localized to the target tissue during magnetic resonance imaging (MRI) interventions. In this context, severe susceptibility artifacts affect the visibility of structures in the MR images depending on the needle’s material composition. In particular, standard needles for the spinal cord made of nickel-titanium alloys (NiTi) generate massive susceptibility artifacts during MRI. Consequently, this does not allow the precise placement of the needle to the target. The aim was to prove that using a non-metallic material for the needle can significantly reduce the appearance of artifacts. Hence, this work used a new combination of non-metallic materials based on an enforced fiber bundle as an inner core with different outer hollow sheets to fabricate seven prototypes of interventional spinal needles to optimize their visualization in MRI scans. Susceptibility artifacts for the non-metallic needles were evaluated in MRI images by an automatic quantification based on a K-means algorithm and compared with manual quantification. The width and length of the artifacts were measured for each needle. The non-metallic needles showed significantly lower artifacts in comparison to the standard needle. K-means provided the capability for detecting needle artifacts in MRI images, facilitating qualitative and quantitative assessment of MRI artifacts. Full article

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

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12 pages, 2385 KiB

Open AccessArticle

Antiferromagnetism and Structure of Sr_1−xBa_xFeO₂F Oxyfluoride Perovskites

by Crisanto A. Garcia-Ramos, Kiril Krezhov, María T. Fernández-Díaz and José A. Alonso

Magnetochemistry 2023, 9(3), 78; https://doi.org/10.3390/magnetochemistry9030078 - 07 Mar 2023

Cited by 1 | Viewed by 1171

Abstract

Recently, a series of oxyfluorides, Sr_1−xBa_xFeO₂F with x = 0, 0.25, 0.50, and 0.75 obtained through a novel synthesis route, were characterized by X-ray and neutron powder diffraction (NPD), magnetization measurements, and ⁵⁷Fe Mössbauer spectroscopy (MS). [...] Read more.

Recently, a series of oxyfluorides, Sr_1−xBa_xFeO₂F with x = 0, 0.25, 0.50, and 0.75 obtained through a novel synthesis route, were characterized by X-ray and neutron powder diffraction (NPD), magnetization measurements, and ⁵⁷Fe Mössbauer spectroscopy (MS). The diffraction data revealed random occupancy of Sr and Ba atoms at the A-cation site, and a statistical distribution of O and F at the anionic sublattice of the perovskite-like structure specified in space group Pm-3m. MS spectra analysis consistently indicated the presence of Fe³⁺ ions at B-site, confirming the Sr_1−xBa_xFeO₂F stoichiometry. Magnetic structure determination from the NPD data at room temperature established G-type antiferromagnetic arrangement in all compositions with Fe³⁺ moments of about 3.5 μB oriented along the c axis. In this study, we present and analyze additional NPD data concerning the low-temperature chemical and magnetic structure of Sr_0.5Ba_0.5FeO₂F (x = 0.5) and SrFeO₂F (x = 0). Basically, the three-dimensional G-type magnetic structure is maintained down to 2 K, where it is fully developed with an ordered magnetic moment of 4.25(5) μ_B/Fe at this temperature for x = 0.5 and 4.14(3) μ_B/Fe for x = 0. The data processing is complemented with a new approach to analyze the temperature dependence of the magnetic order T_N on the lattice parameters, based on the magnetic hyperfine fields extracted from the temperature-dependent MS data. Full article

(This article belongs to the Special Issue Sustainable Development Based on Magnetochemistry)

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11 pages, 3423 KiB

Open AccessCommunication

A New Organic Conductor of Tetramethyltetraselenafulvalene (TMTSF) with a Magnetic Dy(III) Complex

by Qingyun Wan, Masanori Wakizaka, Haitao Zhang, Yongbing Shen, Nobuto Funakoshi, Chi-Ming Che, Shinya Takaishi and Masahiro Yamashita

Magnetochemistry 2023, 9(3), 77; https://doi.org/10.3390/magnetochemistry9030077 - 06 Mar 2023

Cited by 1 | Viewed by 1574

Abstract

A new molecular conductor of (TMTSF)₅[Dy(NCS)₄(NO₃)₂]CHCl₃ was prepared using the electrochemical oxidation method. The complex crystallizes in the Cmc2₁ (36) space group, where the partially-oxidized TMTSF molecules form a 1D (one-dimensional) column structure. [...] Read more.

A new molecular conductor of (TMTSF)₅[Dy(NCS)₄(NO₃)₂]CHCl₃ was prepared using the electrochemical oxidation method. The complex crystallizes in the Cmc2₁ (36) space group, where the partially-oxidized TMTSF molecules form a 1D (one-dimensional) column structure. The crystal shows a semiconducting behavior with a room temperature conductivity of 0.2 S·cm⁻¹ and an activation energy of 34 meV at ambient pressure. Full article

(This article belongs to the Special Issue Functional Molecular Materials Insights—a Themed Issue in Honour of Professor Manuel Almeida on the Occasion of His 70th Birthday)

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10 pages, 366 KiB

Open AccessArticle

Magnetization, Band Gap and Specific Heat of Pure and Ion Doped MnFe₂O₄ Nanoparticles

by I. N. Apostolova, A. T. Apostolov and J. M. Wesselinowa

Magnetochemistry 2023, 9(3), 76; https://doi.org/10.3390/magnetochemistry9030076 - 04 Mar 2023

Cited by 1 | Viewed by 1153

Abstract

We have studied the magnetic properties of ion doped MnFe

_{2}

O

_{4}

nanoparticles with the help of a modified Heisenberg model and Green’s function theory taking into account all correlation functions. The magnetization

M_{s}

and the Curie temperature

T_{C}

increase [...] Read more.

We have studied the magnetic properties of ion doped MnFe

_{2}

O

_{4}

nanoparticles with the help of a modified Heisenberg model and Green’s function theory taking into account all correlation functions. The magnetization

M_{s}

and the Curie temperature

T_{C}

increase with decreasing particle size. This is the opposite behavior than that observed in CoFe

_{2}

O

_{4}

and CoCr

_{2}

O

_{4}

nanoparticles. By Co, Mg or Ni doping,

M_{s}

and

T_{C}

increase with enhancing the dopant concentration, whereas, by La or Gd doping, the opposite effect is obtained due to the different doping and host ionic radii which change the exchange interaction constants. The band gap energy

E_{g}

is calculated from the s–d model. It can decrease or increase by different ion doping. The peak observed in the temperature dependence of the specific heat at

T_{C}

is field dependent. Full article

(This article belongs to the Special Issue Advances in Magnetic Microspheres)

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23 pages, 7168 KiB

Open AccessStudy Protocol

Study on the Interference Law of AC Transmission Lines on the Cathodic Protection Potential of Long-Distance Transmission Pipelines

by Boyang Zhang, Lin Li, Yansong Zhang and Jielin Wang

Magnetochemistry 2023, 9(3), 75; https://doi.org/10.3390/magnetochemistry9030075 - 03 Mar 2023

Cited by 3 | Viewed by 1598

Abstract

Through inductive coupling, AC transmission lines can generate large amounts of voltage to buried oil and gas pipelines in areas with common corridors, posing a threat to the cathodic protection effect of pipelines. Therefore, this paper investigates the effect of AC transmission lines [...] Read more.

Through inductive coupling, AC transmission lines can generate large amounts of voltage to buried oil and gas pipelines in areas with common corridors, posing a threat to the cathodic protection effect of pipelines. Therefore, this paper investigates the effect of AC transmission lines on the cathodic protection of long-distance pipelines through inductive coupling. COMSOL Multiphysics finite element simulation software is used to calculate the distribution of cathodic protection potential of long-distance pipelines under different voltage levels, parallel spacing, conductor-to-ground height, conductor arrangement and pipeline burial depth for normal operation of AC transmission lines. Comparison and analysis of the AC transmission line on the pipeline cathodic protection potential interference law is conducted. The results show that: 1. AC transmission lines cause serious electromagnetic interference with the pipeline cathodic protection system, which will cause the pipeline cathodic protection potential to shift out of the effective protection area. 2. The maximum value of the induced voltage of the pipeline will appear at the two ends of the pipeline, and the induced voltage of the pipeline in the middle position is 0. 3. The shift of the pipeline cathodic protection potential increases with the increase of voltage level and decreases with the increase of parallel spacing, conductor height and burial depth. The pipeline cathodic protection potential shift is highest when the wires are arranged horizontally and lowest when they are arranged in an umbrella shape. Full article

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13 pages, 3498 KiB

Open AccessArticle

Investigation on Polishing the Concave Surface of Zirconia Ceramics with Magnetic Compound Fluid Enhanced by Hydration Reaction

by Xiaoxing Li, Jian Huang, Qipeng Cao, Yuhui Liao and Ming Feng

Magnetochemistry 2023, 9(3), 74; https://doi.org/10.3390/magnetochemistry9030074 - 03 Mar 2023

Viewed by 1228

Abstract

Zirconia ceramics are prominent engineering materials and are widely used in computers, consumer electronics, and the fifth-generation communication industry. However, zirconia ceramics are a typical hard-to-cut material, and the product structures are more complex as the demanding on the industry increases. In this [...] Read more.

Zirconia ceramics are prominent engineering materials and are widely used in computers, consumer electronics, and the fifth-generation communication industry. However, zirconia ceramics are a typical hard-to-cut material, and the product structures are more complex as the demanding on the industry increases. In this case, the polishing efficiency should be improved for meeting these requirements. To overcome the problem of polishing concave surfaces of zirconia ceramics, a small polishing tool with a magnetic compound fluid (MCF) was invented. The effect of the polishing parameters on the surface roughness and material removal rate was analyzed by an L9(3³) orthogonal experiment. The weight ratio of the parameters was also studied based on the experimental results. With the combination of chemical and mechanical functions, the polishing characteristics were further examined. Based on the soaking experiments, the material removal mechanism is discussed. The results are as follows: (1) the optimal polishing parameters were the revolution speed of the MCF carrier n_c of 400 rpm, the working gap h of 0.1 mm, the CIP size D of 5 μm for better surface roughness, the revolution speed of the MCF carrier n_c of 400 rpm, the working gap h of 0.1 mm, and the CIP size D of 7 μm for a higher material removal rate. The impact degrees on surface roughness and material removal rate were a revolution speed of the MCF carrier of 54% > working gap of 31%> CIP size of 15% and working gap of 40% > revolution speed of the MCF carrier of 32% > and CIP size of 18%, respectively. (2) Surface roughness was rapidly reduced in the first 20 min and tended to be stable in the last 10 min of polishing. A circular polished area was observed on the flat workpiece for studying the typical material removal curve, and the deepest point was found at the fringe of the material removal curve. The concave workpiece was polished successfully, and the best surface roughness R_a reached 1 nm and 1.2 nm. (3) A pH = 10 with a sodium hydroxide (NaOH) solution has a greater performance in hardness reduction. The chemical and mechanical functions were combined to remove material to enhance the polishing efficiency. All in all, the proposed polishing method with a combination of a small MCF polishing tool and hydration reaction was effective for polishing zirconia ceramics. Full article

(This article belongs to the Special Issue Advanced Applications of Magnetic Field-Responsive Fluid)

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28 pages, 3347 KiB

Open AccessReview

Interacting with Futuristic Topological Quantum Materials: A Potential Candidate for Spintronics Devices

by Prashant Kumar, Ravi Kumar, Sanjeev Kumar, Manoj Kumar Khanna, Ravinder Kumar, Vinod Kumar and Akanksha Gupta

Magnetochemistry 2023, 9(3), 73; https://doi.org/10.3390/magnetochemistry9030073 - 02 Mar 2023

Viewed by 2647

Abstract

Spintronics, also known as magneto-electronics or spin transport electronics, uses the magnetic moment of the electron due to intrinsic spin along with its electric charge. In the present review, the topological insulators (2D, 3D, and hydride) were discussed including the conducting edge of [...] Read more.

Spintronics, also known as magneto-electronics or spin transport electronics, uses the magnetic moment of the electron due to intrinsic spin along with its electric charge. In the present review, the topological insulators (2D, 3D, and hydride) were discussed including the conducting edge of 2D topological insulators (TIs). Preparation methods of TIs along with fundamental properties, such as low power dissipation and spin polarized electrons, have been explored. Magnetic TIs have been extensively discussed and explained. Weyl phases, topological superconductors, and TIs are covered in this review. We have focused on creating novel spintronic gadgets based on TIs which have metallic topological exterior facades that are topologically defended and have an insulating bulk. In this review, topological phases are discussed as a potential candidate for novel quantum phenomena and new technological advances for fault-tolerant quantum computation in spintronics, low-power electronics, and as a host for Majorana fermions are elucidated. Room temperature stable magnetic skyrmions and anti-skyrmions in spintronics for next-generation memory/storage devices have been reported. Full article

(This article belongs to the Special Issue Spin and Charge Transport in Novel Quantum and Topological Materials)

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10 pages, 2154 KiB

Open AccessArticle

Effect of Magnetic Coupling on the Optical Properties of Oxide Co Nanowires on Vicinal Pt Surfaces

by Kseniya M. Tsysar, Dmitry I. Bazhanov and Ekaterina M. Smelova

Magnetochemistry 2023, 9(3), 72; https://doi.org/10.3390/magnetochemistry9030072 - 02 Mar 2023

Viewed by 982

Abstract

Nowadays, modern scientific research has sparked a renewed interest to study the interaction of electromagnetic field (EM) with magnetic nanostructures and in particular in nanophotonics and spintronics. The current work is devoted to an ab initio study of the magneto-optical properties of step-decorated [...] Read more.

Nowadays, modern scientific research has sparked a renewed interest to study the interaction of electromagnetic field (EM) with magnetic nanostructures and in particular in nanophotonics and spintronics. The current work is devoted to an ab initio study of the magneto-optical properties of step-decorated oxide Co nanowires (1D oxides) on vicinal Pt surfaces. Theoretical calculations of the magnetic moments are based on ab initio spin-polarized density-functional theory (DFT) including a self-consistent treatment of spin-orbit coupling. The first-principles calculations revealed the effect of magnetic coupling between cobalt spins on refractivity and extinction spectra of these 1D oxides governed by atomic structure and cobalt-oxygen interaction within a nanowire at the step edge. The emergence of a sharp pronounced peak in the spectral difference of the refractive indexes has been observed between ferromagnetic and antiferromagnetic configurations of the nanowire. Anisotropy of an extinction coefficient in the terahertz (THz) range of the spectra was established for oxide Co nanowires in an antiferromagnetic state in contrast with a ferromagnetic one. Full article

(This article belongs to the Special Issue Recent Research on Ferromagnetic Materials)

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13 pages, 2975 KiB

Open AccessArticle

Delivery of dCas9 Activator System Using Magnetic Nanoparticles Technology as a Vector Delivery Method for Human Skin Fibroblast

by Mahdi Mohammadi Ghanbarlou, Shahriyar Abdoli, Hamed Omid, Leila Qazizadeh, Hadi Bamehr, Mozhgan Raigani, Hosein Shahsavarani, Morteza Karimipour and Mohammad Ali Shokrgozar

Magnetochemistry 2023, 9(3), 71; https://doi.org/10.3390/magnetochemistry9030071 - 28 Feb 2023

Cited by 3 | Viewed by 1493

Abstract

The overexpression of stem cell-related genes such as octamer-binding transcription factor 4 (OCT4) and (sex determining region Y)-box 2 (SOX2) has been indicated to play several critical roles in stem cell self-renewal; moreover, the elevation of the self-renewal of cancer cells with stem [...] Read more.

The overexpression of stem cell-related genes such as octamer-binding transcription factor 4 (OCT4) and (sex determining region Y)-box 2 (SOX2) has been indicated to play several critical roles in stem cell self-renewal; moreover, the elevation of the self-renewal of cancer cells with stem cell-like properties has been suggested. The clustered and regularly interspaced short palindromic repeats-associated protein 9 (CRISPR/Cas9) protein fused to transactivation domains can be used to activate gene expression in human cells. CRISPR-mediated activation (CRISPRa) systems represent an effective genome editing tool for highly specific gene activation in which a nuclease-deficient Cas9 (dCas9) is utilized to target a transcriptional activator to the gene’s regulatory element, such as a promoter and enhancer. The main drawback of typical delivery methods for CRISPR/Cas9 components is their low transfection efficiency or toxic effects on cells; thus, we generated superparamagnetic iron oxide nanoparticles (SPIONs) coated with polyethylenimine (PEI) to improve the delivery of CRISPR/Cas9 constructs into human foreskin fibroblast cells. The delivery system with magnetic PEI-coated nanoparticles complex was applied to constitute plasmid DNA lipoplexes. CRISPRa systems were used to overexpress the endogenous OCT4 and SOX2 in fibroblast cells. The quantitative polymerase chain reaction (QPCR) assessment exhibited a three-times higher expression of OCT4 and SOX2 transfected by CRISPRa using MNPs. Moreover, no additional cytotoxicity was observed with the application of magnetic nanoparticles (MNPs) compared to lipofectamine. Our results demonstrate that MNPs enable the effective delivery of the CRISPR/Cas9 construct into human foreskin fibroblasts with low cell toxicity and a consequential overexpression of endogenous OCT4 and SOX2. Full article

(This article belongs to the Special Issue Advances in Magnetic Nanocarrier for Biomedical Applications)

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13 pages, 2401 KiB

Open AccessArticle

μSR Study of Unconventional Pairing Symmetry in the Quasi-1D Na₂Cr₃As₃ Superconductor

by Amitava Bhattacharyya, Devashibhai Adroja, Yu Feng, Debarchan Das, Pabitra Kumar Biswas, Tanmoy Das and Jun Zhao

Magnetochemistry 2023, 9(3), 70; https://doi.org/10.3390/magnetochemistry9030070 - 28 Feb 2023

Cited by 1 | Viewed by 1189

Abstract

We report the finding of a novel pairing state in a newly discovered superconductor Na

_{2}

Cr

_{3}

As

_{3}

. This material has a non-centrosymmetric quasi-one-dimensional crystal structure and is superconducting at

T_{C} \sim

8.0 K. We find that the magnetic [...] Read more.

We report the finding of a novel pairing state in a newly discovered superconductor Na

_{2}

Cr

_{3}

As

_{3}

. This material has a non-centrosymmetric quasi-one-dimensional crystal structure and is superconducting at

T_{C} \sim

8.0 K. We find that the magnetic penetration depth data suggests the presence of a nodal line

p_{z}

-wave pairing state with zero magnetic moment using transverse-field muon-spin rotation (TF-

μ

SR) measurements. The nodal gap observed in Na

_{2}

Cr

_{3}

As

_{3}

compound is consistent with that observed in isostructural (K,Cs)

_{2}

Cr

_{3}

As

_{3}

compounds using TF-

μ

SR measurements. The observed pairing state is consistent with a three-band model spin-fluctuation calculation, which reveals the

S_{z} = 0

spin-triplet pairing state with the

sin k_{z}

pairing symmetry. The long-sought search for chiral superconductivity with topological applications could be aided by such a novel triplet

S_{z} = 0

p-wave pairing state. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Magnetic and Magnetoelectric Materials)

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11 pages, 2283 KiB

Open AccessArticle

Diverse Magnetic Properties of Two New Binuclear Complexes Affected by [FeN₆] Octahedral Distortion: Two-Step Spin Crossover versus Antiferromagnetic Interactions

by Yue Gao, Yu-Qin Li, Yao Li, Jing-Wei Dai, Jin-Hua Wang, Ying-Ying Wu, Masahiro Yamashita and Zhao-Yang Li

Magnetochemistry 2023, 9(3), 69; https://doi.org/10.3390/magnetochemistry9030069 - 28 Feb 2023

Viewed by 1205

Abstract

Polymetallic complexes with covalently bridged metal centers that interact magnetically are important in the molecular magnetism field, with binuclear compounds receiving special attention because they represent the simplest type of multinuclear species with covalently bridged metal centers. Herein, we report the synthesis and [...] Read more.

Polymetallic complexes with covalently bridged metal centers that interact magnetically are important in the molecular magnetism field, with binuclear compounds receiving special attention because they represent the simplest type of multinuclear species with covalently bridged metal centers. Herein, we report the synthesis and properties of two new binuclear Fe^II complexes, namely, {[Fe(abpt-TPE)(NCS)₂]₂(bpym)}·2MeOH·2MeCN (1) and {[Fe(abpt-TPE)(NCS)₂]₂(bpym)}·2CH₂Cl₂ (2) (bpym = 2,2′-bipyrimidine). The crystal structure is analyzed at different temperatures, and its properties are analyzed by variable-temperature magnetic susceptibility and variable-temperature fluorescence emission spectroscopy tests. Variable-temperature magnetic susceptibility measurements of two binuclear compounds show different types of magnetic behavior. Complex 1 exhibits two-step spin transition behavior with an intermediate state near 150 K (T_c1 = 191 K, T_c2 = 111 K); 1 undergoes an [LS–LS] ↔ [LS–HS] ↔ [HS–HS] spin transition during thermal induction. On the other hand, complex 2 exhibits intramolecular antiferromagnetic coupling, with J = −0.47 cm⁻¹. The analysis of correlations between the structural characteristics and different types of magnetic behaviors for two binuclear complexes, revealed that the different magnetic behaviors shown by the two complexes are attributable to different degrees of [FeN₆] octahedral distortion caused by different lattice solvents, ligand strain and crystal stacking. Full article

(This article belongs to the Special Issue Advances in Molecular Magnetism)

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17 pages, 4633 KiB

Open AccessArticle

Magnetic Hyperthermia and Antibacterial Response of CuCo₂O₄ Nanoparticles Synthesized through Laser Ablation of Bulk Alloy

by Imran Ali, Yasir Jamil, Saeed Ahmed Khan, Yunxiang Pan, Aqeel Ahmed Shah, Ali Dad Chandio, Sadaf Jamal Gilani, May Nasser Bin Jumah, Yusra Fazal, Jun Chen and Zhonghua Shen

Magnetochemistry 2023, 9(3), 68; https://doi.org/10.3390/magnetochemistry9030068 - 27 Feb 2023

Viewed by 1874

Abstract

The wide variety of uses for nanoparticles (NPs) is due to their unique combination of features in a single assembly. The arc melted copper-cobalt ingot sample were qualitatively studied using laser induced breakdown spectroscopy (LIBS). Later, using the fabricated alloy as a target [...] Read more.

The wide variety of uses for nanoparticles (NPs) is due to their unique combination of features in a single assembly. The arc melted copper-cobalt ingot sample were qualitatively studied using laser induced breakdown spectroscopy (LIBS). Later, using the fabricated alloy as a target material for Nd:YAG laser ablation, CuCo₂O₄ NPs were synthesized. The magnetic properties of the synthesized NPs were studied using a vibrating sample magnetometer (VSM). To determine the composition and morphology of the synthesized NPs, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scattering (DLS) techniques were used. The TEM and DLS showed that particles were spherical in shape with an average size of 32 nm and 28 nm, respectively. The antibacterial activity of the synthesized NPs was studied against S. aureus and E. coli strains as positive and negative controls using a standard approach. CuCo₂O₄ nanoparticles exhibited non-mutagenic potential against S. typhimurium TA-98 and TA-100 strains. Furthermore, the magnetic hyperthermia study of CuCo₂O₄ nanofluid was examined using a lab-made apparatus. The specific absorption rates (SAR) of 4.57 and 5.17 W/g were determined for the magnetic field strength of 230 μT and 247 μT, respectively. The study shows antibacterial activity and magnetic hyperthermia potential of the synthesized nanoparticles. Full article

(This article belongs to the Special Issue Advances in Magnetic Nanomaterials and Nanostructures)

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17 pages, 4241 KiB

Open AccessArticle

Fluorescent Magnetic Mesoporous Nanoprobes for Biotechnological Enhancement Procedures in Gene Therapy

by Manuel A. González-Gómez, Román Seco-Gudiña, Pelayo García-Acevedo, Ángela Arnosa-Prieto, Lisandra de Castro-Alves, Yolanda Piñeiro and José Rivas

Magnetochemistry 2023, 9(3), 67; https://doi.org/10.3390/magnetochemistry9030067 - 26 Feb 2023

Cited by 2 | Viewed by 1650

Abstract

In recent years, nanotechnology has deployed a new set of theragnostic tools, including magnetic resonance contrast agents, nano-delivery systems and magnetic hyperthermia treatments in cancer therapy, exploiting not only the small size of nanoparticles, but also relevant nanoscale properties such as superparamagnetism. Specifically, [...] Read more.

In recent years, nanotechnology has deployed a new set of theragnostic tools, including magnetic resonance contrast agents, nano-delivery systems and magnetic hyperthermia treatments in cancer therapy, exploiting not only the small size of nanoparticles, but also relevant nanoscale properties such as superparamagnetism. Specifically, magnetic nanostructures can be remotely manipulated by external magnetic fields, incrementing their possibilities not only for theragnosis, but also for biotech procedures. Genetic engineering processes involve a set of steps like extracting cells from complex environments, their selection and subsequent cultivation or modification by transfection and can benefit from the use of bioconjugated magnetic nanoparticles. Magnetofection of cells with genes or biological material uploaded on superparamagnetic nanoparticles attracted by a magnetic field greatly increases the efficiency, specificity and speed of the biotechnological procedure in gene transfer systems. This article presents a preliminary investigation into the enhanced transfection efficiency of fluorescent magnetic mesoporous silica nanostructures functionalized with mCherry plasmid, which were used to transfect HeLa cells in just 15 min via magnetic transfection. This method was compared to passive transfection (4 h) and conventional gene transfer using the commercial K2 Transfection System (16 h). The results demonstrated that the fluorescent magnetic mesoporous silica nanostructures were similarly effective to the commercial kit, without the need for reagents that increase costs in clinical therapy. Furthermore, viability assays conducted with HeLa cells showed negligible toxicity at concentrations of up to 50 μg/mL. Full article

(This article belongs to the Special Issue Metal Oxide Nanoparticles: Synthesis, Characterization, and Application)

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13 pages, 2803 KiB

Open AccessFeature PaperArticle

NMR of Paramagnetic Proteins: ¹³C Derived Paramagnetic Relaxation Enhancements Are an Additional Source of Structural Information in Solution

by Leonardo Querci, Inês B. Trindade, Michele Invernici, José Malanho Silva, Francesca Cantini, Ricardo O. Louro and Mario Piccioli

Magnetochemistry 2023, 9(3), 66; https://doi.org/10.3390/magnetochemistry9030066 - 26 Feb 2023

Cited by 2 | Viewed by 1325

Abstract

In paramagnetic metalloproteins, longitudinal relaxation rates of ¹³C′ and ¹³C^α nuclei can be measured using ¹³C detected experiments and converted into electron spin-nuclear spin distance restraints, also known as Paramagnetic Relaxation Enhancement (PRE) restraints. ¹³C are less sensitive [...] Read more.

In paramagnetic metalloproteins, longitudinal relaxation rates of ¹³C′ and ¹³C^α nuclei can be measured using ¹³C detected experiments and converted into electron spin-nuclear spin distance restraints, also known as Paramagnetic Relaxation Enhancement (PRE) restraints. ¹³C are less sensitive to paramagnetism than ¹H nuclei, therefore, ¹³C based PREs constitute an additional, non-redundant, structural information. We will discuss the complementarity of ¹³C PRE restraints with ¹H PRE restraints in the case of the High Potential Iron Sulfur Protein (HiPIP) PioC, for which the NMR structure of PioC has been already solved by a combination of classical and paramagnetism-based restraints. We will show here that ¹³C R₁ values can be measured also at very short distances from the paramagnetic center and that the obtained set of ¹³C based restraints can be added to ¹H PREs and to other classical and paramagnetism based NMR restraints to improve quality and quantity of the NMR information. Full article

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

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13 pages, 3049 KiB

Open AccessArticle

A Strong Magnetic Field Alters the Activity and Selectivity of the CO₂RR by Restraining C–C Coupling

by Peichen Wang, Yafei Qu, Xiangfu Meng, Jinwei Tu, Wei Zheng, Lin Hu and Qianwang Chen

Magnetochemistry 2023, 9(3), 65; https://doi.org/10.3390/magnetochemistry9030065 - 26 Feb 2023

Cited by 5 | Viewed by 2180

Abstract

As an external field, a magnetic field can change the electrocatalytic activity of catalysts through various effects. Among them, electron spin polarization on the catalyst surface has attracted much attention. Herein, we investigate the sensitive response behavior of a Cu₂O nanocubes [...] Read more.

As an external field, a magnetic field can change the electrocatalytic activity of catalysts through various effects. Among them, electron spin polarization on the catalyst surface has attracted much attention. Herein, we investigate the sensitive response behavior of a Cu₂O nanocubes to an in situ magnetic field. Under a 3 T strong magnetic field, the total transferred electron quantity in IT test (−1.1 V_RHE) and the current density in the polarization curve increase by 28.7% and 54.7%, respectively, while the onset potential decreases significantly by 114 mV. Moreover, it was found that product selectivity was also altered by the magnetic field. The Faraday efficiency of C₁ increases substantially, along with the inhibition of C₂₊ reaction paths and the HER. Our experimental results and DFT calculation demonstrate that a hybrid magnetic effect accelerates the CO₂RR kinetic and generates spin polarization of the catalyst surface. The polarized surface changes the binding energy of *OCHO/*COOH and inhibits singlet C–C coupling, which restrains the C₂₊ reduction path and thus more CO₂ is reduced to HCOOH. Full article

(This article belongs to the Special Issue Study on the Growth and Performance of Materials under Magnetic Field)

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9 pages, 697 KiB

Open AccessFeature PaperArticle

Superconductivity and Fermi Surface Studies of β^″-(BEDT-TTF)₂[(H₂O)(NH₄)₂Cr(C₂O₄)₃]·18-Crown-6

by Brett Laramee, Raju Ghimire, David Graf, Lee Martin, Toby J. Blundell and Charles C. Agosta

Magnetochemistry 2023, 9(3), 64; https://doi.org/10.3390/magnetochemistry9030064 - 24 Feb 2023

Viewed by 1455

Abstract

We report rf-penetration depth measurements of the quasi-2D organic superconductor

β^{″}

-(BEDT-TTF)

_{2}

[(H

_{2}

O)(NH

_{4}

)

_{2}

Cr(C

_{2}

O

_{4}

)

_{3}

]·18-crown-6, which has the largest separation between consecutive conduction layers of any 2D organic metal with a [...] Read more.

We report rf-penetration depth measurements of the quasi-2D organic superconductor

β^{″}

-(BEDT-TTF)

_{2}

[(H

_{2}

O)(NH

_{4}

)

_{2}

Cr(C

_{2}

O

_{4}

)

_{3}

]·18-crown-6, which has the largest separation between consecutive conduction layers of any 2D organic metal with a single packing motif. Using a contactless tunnel diode oscillator measurement technique, we show the zero-field cooling dependence and field sweeps up to 28 T oriented at various angles with respect to the crystal conduction planes. When oriented parallel to the layers, the upper critical field,

H_{c 2} = 7.6

T, which is the calculated paramagnetic limit for this material. No signs of inhomogeneous superconductivity are seen, despite previous predictions. When oriented perpendicular to the layers, Shubnikov–de Haas oscillations are seen as low as 6 T, and from these we calculate Fermi surface parameters such as the superconducting coherence length and Dingle temperature. One remarkable result from our data is the high anisotropy of

H_{c 2}

in the parallel and perpendicular directions, due to an abnormally low

H_{c 2 ⊥} = 0.4

T. Such high anisotropy is rare in other organics and the origin of the smaller

H_{c 2 ⊥}

may be a consequence of a lower effective mass. Full article

(This article belongs to the Special Issue Functional Molecular Materials Insights—a Themed Issue in Honour of Professor Manuel Almeida on the Occasion of His 70th Birthday)

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15 pages, 2971 KiB

Open AccessReview

Application of Electron Paramagnetic Resonance in an Electrochemical Energy Storage System

by Xiancheng Sang, Xixiang Xu, Zeyuan Bu, Shuhao Zhai, Yiming Sun, Mingyue Ruan and Qiang Li

Magnetochemistry 2023, 9(3), 63; https://doi.org/10.3390/magnetochemistry9030063 - 23 Feb 2023

Cited by 1 | Viewed by 1507

Abstract

The improvement of our living standards puts forward higher requirements for energy storage systems, especially rechargeable batteries. Unfortunately, phenomena such as capacity failure, etc. have been major difficulties in the field of energy storage. Therefore, we need some advanced means to explore the [...] Read more.

The improvement of our living standards puts forward higher requirements for energy storage systems, especially rechargeable batteries. Unfortunately, phenomena such as capacity failure, etc. have been major difficulties in the field of energy storage. Therefore, we need some advanced means to explore the reaction process and mechanisms of the cell. Electron paramagnetic resonance (EPR) has the advantages of a high sensitivity to electrons, lack of damage to samples, quantitative analysis, etc., which can make for a more in-depth exploration of most paramagnetic electrode materials and metal electrode materials. After a brief description of the principle of EPR, this review briefly summarizes the application of EPR to the characterization of transition metal oxide cathode and lithium metal anode electrode materials in recent years, such as showing how to study electrode materials by using EPR in situ and operando. Full article

(This article belongs to the Special Issue Recent Research on Ferromagnetic Materials)

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11 pages, 7672 KiB

Open AccessFeature PaperArticle

A Dy^III Complex of a Pentadentate Schiff Base with Field-Induced Single-Ion Magnet Behaviour

by Julio Corredoira-Vázquez, Paula Oreiro-Martínez, Ana M. García-Deibe, Jesús Sanmartín-Matalobos and Matilde Fondo

Magnetochemistry 2023, 9(3), 62; https://doi.org/10.3390/magnetochemistry9030062 - 23 Feb 2023

Cited by 2 | Viewed by 1051

Abstract

The influence of the solvent in the reaction of dysprosium(III) chloride hydrate with the N₃O₂ ligand H₂L (2,6-bis(2-hydroxyphenyliminomethyl)pyridine) was studied To this end, the new mononuclear chloride complex [Dy(L)Cl(H₂O)₂] (1) was isolated [...] Read more.

The influence of the solvent in the reaction of dysprosium(III) chloride hydrate with the N₃O₂ ligand H₂L (2,6-bis(2-hydroxyphenyliminomethyl)pyridine) was studied To this end, the new mononuclear chloride complex [Dy(L)Cl(H₂O)₂] (1) was isolated in absolute ethanol as solvent, without any evidence of the hydrolysis of the ligand. This clearly contrasts with previous results, where a similar reaction in methanol proceeds with the partial hydrolysis of the Schiff base, and the formation of a new hemiacetal donor to yield [Dy(HL’)₂)][Dy(L)(Cl₂)] (H₂L’ = (6-(2-hydroxyphenyliminomethyl)-2-methoxyhydroxymethyl)pyridine). The single crystal X-ray structure of the chloride complex 1 shows that the Dy^III ion is octacoordinated in a highly distorted N₃O₄Cl environment between triangular dodecahedral and biaugmented trigonal prisms. The full magnetic characterisation of 1 shows that it presents field-induced single ion magnet behaviour, with a thermal energy barrier U_eff of 113.5 K, which is the highest among dysprosium complexes derived from H₂L. Full article

(This article belongs to the Special Issue Magnetic Relaxation in Metal Complexes)

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14 pages, 2744 KiB

Open AccessArticle

Surface-Bulk 2D Spin-Crossover Nanoparticles within Ising-like Model Solved by Using Entropic Sampling Technique

by Catherine Cazelles, Mamadou Ndiaye, Pierre Dahoo, Jorge Linares and Kamel Boukheddaden

Magnetochemistry 2023, 9(3), 61; https://doi.org/10.3390/magnetochemistry9030061 - 23 Feb 2023

Cited by 1 | Viewed by 1206

Abstract

We model the thermal effects in different 2D spin-crossover (SCO) square lattices within the frame of the Ising-like model using Monte Carlo entropic sampling (MCES) method to enhance the scan of macrostates beyond the most probable thermal ones. In fact, MCES allows access [...] Read more.

We model the thermal effects in different 2D spin-crossover (SCO) square lattices within the frame of the Ising-like model using Monte Carlo entropic sampling (MCES) method to enhance the scan of macrostates beyond the most probable thermal ones. In fact, MCES allows access to the metastable states, and it is then well adapted to study thermal hysteresis properties. In this contribution, we distinguish, for the first time, the interaction between molecules located in bulk at the surface and those connecting the bulk and surface regions of an SCO lattice. In addition, an extra ligand field contribution is assigned to surface molecules through an interaction parameter

L

. In the absence of environmental effects on surface nanoparticles, a single thermal hysteresis loop increasing with the lattice size is simulated with a unique bulk and surface equilibrium temperature

T_{e q} = T_{e q}^{b u l k} = T_{e q}^{s u r f}

. When environmental effects are accounted for, a two-step behavior associated with two hysteresis loops of widths ΔT_S (for the surface) and ΔT_B (for the bulk) with an intermediate plateau 14 K wide is obtained in the thermal dependence of the high-spin (HS) fraction for the 6 × 6 lattice. The surface and bulk equilibrium temperatures are then different, both decreasing towards lower values, and the

L

parameter controls the three states’ behavior as well as the hysteresis loop interval. Size effects show that the equilibrium temperature is governed by the surface atoms for a small lattice size (5 × 5) and by the bulk atoms for a large lattice size (7 × 7). Moreover, a change in the size of the lattice results in a variation of the order–disorder (or Curie) temperature, T_O.D_., and the surface equilibrium temperature, T_eq, while only T_O.D. changes in bulk. Full article

(This article belongs to the Special Issue Advances in Molecular Magnetism)

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0 pages, 9067 KiB

Open AccessArticle

Dry Friction Performances of MoN_x Coatings Deposited by High–Power Pulsed Magnetron Sputtering

by Fuqiang Li, Wei Dai, Qimin Wang, Haiqing Li and Zhengtao Wu

Magnetochemistry 2023, 9(3), 60; https://doi.org/10.3390/magnetochemistry9030060 - 23 Feb 2023

Cited by 1 | Viewed by 1331 | Correction

Abstract

A MoN_x coating serves as an effective wear protection layer and is crucial for the investigation of its tribological characteristics at various temperatures. This study examined the tribological characteristics of MoN_x coatings that were deposited through high-power pulsed magnetron sputtering (HiPIMS) [...] Read more.

A MoN_x coating serves as an effective wear protection layer and is crucial for the investigation of its tribological characteristics at various temperatures. This study examined the tribological characteristics of MoN_x coatings that were deposited through high-power pulsed magnetron sputtering (HiPIMS) in an Ar/N₂ environment with varying N₂ partial pressures. The microstructures and mechanical properties of the coatings were elucidated using scanning electron microscopy, grazing-incidence-angle X-ray diffraction, energy-dispersive spectroscopy, and nanoindentation. The dry friction performances of the coatings at different heating temperatures were studied using a ball-on-disk tribometer. The MoN_x coating produced by HiPIMS was composed primarily of fcc−Mo₂N and featured a fine, dense column crystal with a maximum hardness of 28.8 GPa. The MoN_x coatings exhibited excellent lubrication and wear reduction properties at room temperature (RT). The dry friction performances of the MoN_x coatings at elevated temperatures were expected to depend on the growth of the MoO₃ tribolayer. At relatively low temperatures (300 °C and 400 °C), the MoO₃ tribolayer grew slowly and was not enough to provide good lubrication, causing increases in the dry friction of the coatings. However, the δ−MoN phase formed in the MoN_x coating deposited at a high N₂ partial pressure could facilitate the formation of MoO₃ and thus decreased the friction coefficient at 400 °C. At the relatively high heating temperature of 500 °C, however, the MoO₃ tribolayer grew so rapidly that the oxide layer became thick, resulting in an increase in the wear rate. It is believed that tuning the growth rate of MoO₃ via optimizing the composition and structure of the MoN_x coatings might be a useful way to improve the dry friction at various elevated temperatures. Full article

(This article belongs to the Special Issue Magnetron Sputtering Process)

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15 pages, 5227 KiB

Open AccessArticle

Photothermal Hyperthermia Study of Ag/Ni and Ag/Fe Plasmonic Particles Synthesized Using Dual-Pulsed Laser

by Imran Ali, Jun Chen, Saeed Ahmed Khan, Yasir Jamil, Aqeel Ahmed Shah, Abdul Karim Shah, Sadaf Jamal Gilani, May Nasser Bin Jumah, Yusra Fazal, Yunxiang Pan and Zhonghua Shen

Magnetochemistry 2023, 9(3), 59; https://doi.org/10.3390/magnetochemistry9030059 - 22 Feb 2023

Cited by 2 | Viewed by 1355

Abstract

Magneto-plasmonic Ag/Ni and Ag/Fe nanoparticles (NPs) were synthesized in this work using the environmentally safe and contaminant-free dual-pulsed Q-switched Nd:YAG 1064 nm laser ablation method. The optical and magnetic characteristics of synthesized nanomaterials were investigated using a vibrating sample magnetometer and an ultraviolet-visible [...] Read more.

Magneto-plasmonic Ag/Ni and Ag/Fe nanoparticles (NPs) were synthesized in this work using the environmentally safe and contaminant-free dual-pulsed Q-switched Nd:YAG 1064 nm laser ablation method. The optical and magnetic characteristics of synthesized nanomaterials were investigated using a vibrating sample magnetometer and an ultraviolet-visible absorption spectrometer. According to transmission electron microscopy (TEM), the shape of Ag/Ni and Ag/Fe NPs seems to be spherical, with mean diameters of 7.3 nm and 11.5 nm, respectively. X-ray diffraction (XRD) was used in order to investigate and describe the phase structures of the synthesized nanomaterials. The synthesized NPs reached maximum temperatures such as 48.9, 60, 63.4, 70, 75, and 79 °C for Ag/Ni nanofluid and 52, 56, 60, 68, 71, and 72 °C for Ag/Fe nanofluid when these nanofluids were subjected to an NIR 808 nm laser with operating powers of 1.24, 1.76, 2.36, 2.91, 3.5, and 4 W, respectively. Because of the plasmonic hyperthermia properties of nanoparticles, nanofluids display higher temperature profiles than pure water. According to these findings, plasmonic nanoparticles based on silver might be used to treat hyperthermia. Full article

(This article belongs to the Special Issue New Advances in Magnetic–Plasmonic Nanostructured Materials)

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