Pub Date : 2023-10-08DOI: 10.3390/magnetochemistry9100220
Petr Kharitonskii, Elena Sergienko, Andrey Ralin, Evgenii Setrov, Timur Sheidaev, Kamil Gareev, Alexander Ustinov, Nikita Zolotov, Svetlana Yanson, Danil Dubeshko
Artificial glasses containing nanoscale inclusions of iron oxides, including magnetite and hematite, were obtained via the method of the high-temperature melting of rocks. The main factors influencing the magnetic properties of glasses are the composition of the initial charge and the conditions of cooling of the melt. The data of magnetic granulometry and frequency-field dependencies of magnetic susceptibility showed the presence of a sufficiently large superparamagnetic fraction in the samples. Coordinated theoretical modeling using two independent models that take into consideration possible the chemical inhomogeneity of particles and magnetostatic interaction between them made it possible to calculate hysteresis characteristics corresponding to the experiment and to estimate ferrimagnetic concentrations in the samples, including the superparamagnetic fraction.
{"title":"Superparamagnetism of Artificial Glasses Based on Rocks: Experimental Data and Theoretical Modeling","authors":"Petr Kharitonskii, Elena Sergienko, Andrey Ralin, Evgenii Setrov, Timur Sheidaev, Kamil Gareev, Alexander Ustinov, Nikita Zolotov, Svetlana Yanson, Danil Dubeshko","doi":"10.3390/magnetochemistry9100220","DOIUrl":"https://doi.org/10.3390/magnetochemistry9100220","url":null,"abstract":"Artificial glasses containing nanoscale inclusions of iron oxides, including magnetite and hematite, were obtained via the method of the high-temperature melting of rocks. The main factors influencing the magnetic properties of glasses are the composition of the initial charge and the conditions of cooling of the melt. The data of magnetic granulometry and frequency-field dependencies of magnetic susceptibility showed the presence of a sufficiently large superparamagnetic fraction in the samples. Coordinated theoretical modeling using two independent models that take into consideration possible the chemical inhomogeneity of particles and magnetostatic interaction between them made it possible to calculate hysteresis characteristics corresponding to the experiment and to estimate ferrimagnetic concentrations in the samples, including the superparamagnetic fraction.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135251019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-06DOI: 10.3390/magnetochemistry9100217
Athanassios K. Boudalis
The weak intramolecular magnetic interactions within a series of CuII3 complexes based on the trinucleating 2,4,6-tris(di-2-pyridylamino)-1,3,5-triazine (dipyatriz) ligand were investigated via Electron Paramagnetic Resonance (EPR) spectroscopy. X- and Q-band EPR spectroscopy in powders and frozen solutions were recorded and the Q-band spectra were interpreted by a multispin Hamiltonian model comprising exchange, dipolar and hyperfine interactions. The described methodology is suitable for the elucidation of weak intramolecular interactions which are not amenable to analysis via magnetic susceptibility studies.
{"title":"In One Fell Sweep: Modeling Exchange, Hyperfine and Dipolar Interactions from EPR Spectra of Copper(II) Spin Triangles","authors":"Athanassios K. Boudalis","doi":"10.3390/magnetochemistry9100217","DOIUrl":"https://doi.org/10.3390/magnetochemistry9100217","url":null,"abstract":"The weak intramolecular magnetic interactions within a series of CuII3 complexes based on the trinucleating 2,4,6-tris(di-2-pyridylamino)-1,3,5-triazine (dipyatriz) ligand were investigated via Electron Paramagnetic Resonance (EPR) spectroscopy. X- and Q-band EPR spectroscopy in powders and frozen solutions were recorded and the Q-band spectra were interpreted by a multispin Hamiltonian model comprising exchange, dipolar and hyperfine interactions. The described methodology is suitable for the elucidation of weak intramolecular interactions which are not amenable to analysis via magnetic susceptibility studies.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"299 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135351686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-01DOI: 10.3390/magnetochemistry9100216
Radu Jubleanu, Dumitru Cazacu
The superconducting magnet energy storage (SMES) has become an increasingly popular device with the development of renewable energy sources. The power fluctuations they produce in energy systems must be compensated with the help of storage devices. A toroidal SMES magnet with large capacity is a tendency for storage energy because it has great energy density and low stray field. A key component in the creation of these superconducting magnets is the material from which they are made. The present work describes a comparative numerical analysis with finite element method, of energy storage in a toroidal modular superconducting coil using two types of superconducting material with different properties bismuth strontium calcium copper oxide (BSCCO) and yttrium barium copper oxide (YBCO). Regarding the design of the modular torus, it was obtained that for a 1.25 times increase of the critical current for the BSCCO superconducting material compared with YBCO, the dimensions of the BSCCO torus were reduced by 7% considering the same stored energy. Also, following a numerical parametric analysis, it resulted that, in order to maximize the amount of energy stored, the thickness of the torus modules must be as small as possible, without exceeding the critical current. Another numerical analysis showed that the energy stored is maximum when the major radius of the torus is minimum, i.e., for a torus as compact as possible.
{"title":"Design and Numerical Study of Magnetic Energy Storage in Toroidal Superconducting Magnets Made of YBCO and BSCCO","authors":"Radu Jubleanu, Dumitru Cazacu","doi":"10.3390/magnetochemistry9100216","DOIUrl":"https://doi.org/10.3390/magnetochemistry9100216","url":null,"abstract":"The superconducting magnet energy storage (SMES) has become an increasingly popular device with the development of renewable energy sources. The power fluctuations they produce in energy systems must be compensated with the help of storage devices. A toroidal SMES magnet with large capacity is a tendency for storage energy because it has great energy density and low stray field. A key component in the creation of these superconducting magnets is the material from which they are made. The present work describes a comparative numerical analysis with finite element method, of energy storage in a toroidal modular superconducting coil using two types of superconducting material with different properties bismuth strontium calcium copper oxide (BSCCO) and yttrium barium copper oxide (YBCO). Regarding the design of the modular torus, it was obtained that for a 1.25 times increase of the critical current for the BSCCO superconducting material compared with YBCO, the dimensions of the BSCCO torus were reduced by 7% considering the same stored energy. Also, following a numerical parametric analysis, it resulted that, in order to maximize the amount of energy stored, the thickness of the torus modules must be as small as possible, without exceeding the critical current. Another numerical analysis showed that the energy stored is maximum when the major radius of the torus is minimum, i.e., for a torus as compact as possible.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135407654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.3390/magnetochemistry9100215
Gui-Ping Zhu, Shi-Hua Wu, Shu-Ze Zheng, Lai Li, Nam-Trung Nguyen
A significant growth of research on digital microfluidics has been achieved over the past several decades, and the field is still attracting increasing attention for fulfilling relevant mechanisms and potential applications. Numerous studies have been devoted to actively manipulating droplets in a variety of fundamental and applicational scenarios. In this work, the deformation of ferromagnetic fluid droplets is studied under an external uniform magnetic field. The droplets are precisely dispersed on the bottom surface of a container assembled with polymer methacrylate (PMMA) plates. Mineral oil is applied instead of air as the surrounding medium for easy stretching and preventing water solvent evaporation in ferrofluid. The design and processing of the container are firstly carried out to observe the shape and characterize the wettability of the droplets in the immiscible mineral oil medium. Furthermore, the droplets’ deformation and the working mechanism are given under the action of the horizontal uniform magnetic field. At different magnetic field intensities, the droplet is stretched in the horizontal direction parallel to the applied field. Due to volume conservation, the dimension in the height reduces correspondingly. With the coupling effect of magnetic force, viscous force and interfacial tension, the contact angle first increases with the magnetic field and then basically remains unchanged upon magnetization saturation. Consistent with the experimental results, the numerical method clearly reveals the field coupling mechanism and the nonlinear deformation of the sessile droplet.
{"title":"Investigation of Ferrofluid Sessile Droplet Tensile Deformation in a Uniform Magnetic Field","authors":"Gui-Ping Zhu, Shi-Hua Wu, Shu-Ze Zheng, Lai Li, Nam-Trung Nguyen","doi":"10.3390/magnetochemistry9100215","DOIUrl":"https://doi.org/10.3390/magnetochemistry9100215","url":null,"abstract":"A significant growth of research on digital microfluidics has been achieved over the past several decades, and the field is still attracting increasing attention for fulfilling relevant mechanisms and potential applications. Numerous studies have been devoted to actively manipulating droplets in a variety of fundamental and applicational scenarios. In this work, the deformation of ferromagnetic fluid droplets is studied under an external uniform magnetic field. The droplets are precisely dispersed on the bottom surface of a container assembled with polymer methacrylate (PMMA) plates. Mineral oil is applied instead of air as the surrounding medium for easy stretching and preventing water solvent evaporation in ferrofluid. The design and processing of the container are firstly carried out to observe the shape and characterize the wettability of the droplets in the immiscible mineral oil medium. Furthermore, the droplets’ deformation and the working mechanism are given under the action of the horizontal uniform magnetic field. At different magnetic field intensities, the droplet is stretched in the horizontal direction parallel to the applied field. Due to volume conservation, the dimension in the height reduces correspondingly. With the coupling effect of magnetic force, viscous force and interfacial tension, the contact angle first increases with the magnetic field and then basically remains unchanged upon magnetization saturation. Consistent with the experimental results, the numerical method clearly reveals the field coupling mechanism and the nonlinear deformation of the sessile droplet.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136343653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnetic tunnel junction (MTJ) sensors have been one of the excellent candidates for magnetic field detection due to their high sensitivity and compact size. In this paper, we design a magnetometer with in situ magnetic feedback consisting of an MTJ sensor. To analyze and evaluate the detectivity of the MTJ magnetometer, a noise model of the MTJ sensor in the magnetometer without magnetic feedback is first developed. Then, the noise model of the MTJ magnetometer with in situ magnetic feedback is also established, including the noises of the MTJ sensor and the signal conditioning circuit, as well as the feedback circuit. The equivalent noise model of the MTJ magnetometer with in situ magnetic feedback is evaluated through nonlinear fitting for the noise voltage spectrum. Although the noise generated by the MTJ sensor is much greater than that of the signal conditioning circuit, the noise introduced by the feedback coils into the MTJ sensor is slightly more than twice that generated by the MTJ sensor itself. The measurement results show that the detectivity of the MTJ magnetometer with in situ magnetic feedback reaches 526 pT/Hz1/2 at 10 Hz. The equivalent noise analysis method presented in this paper is suitable for the detectivity analysis of magnetometers with magnetic feedback.
{"title":"Equivalent Noise Analysis and Modeling for a Magnetic Tunnel Junction Magnetometer with In Situ Magnetic Feedback","authors":"Aiyu Dou, Ru Bai, Yucheng Sun, Jiakun Tu, Chuanjia Kou, Xin Xie, Zhenghong Qian","doi":"10.3390/magnetochemistry9100214","DOIUrl":"https://doi.org/10.3390/magnetochemistry9100214","url":null,"abstract":"Magnetic tunnel junction (MTJ) sensors have been one of the excellent candidates for magnetic field detection due to their high sensitivity and compact size. In this paper, we design a magnetometer with in situ magnetic feedback consisting of an MTJ sensor. To analyze and evaluate the detectivity of the MTJ magnetometer, a noise model of the MTJ sensor in the magnetometer without magnetic feedback is first developed. Then, the noise model of the MTJ magnetometer with in situ magnetic feedback is also established, including the noises of the MTJ sensor and the signal conditioning circuit, as well as the feedback circuit. The equivalent noise model of the MTJ magnetometer with in situ magnetic feedback is evaluated through nonlinear fitting for the noise voltage spectrum. Although the noise generated by the MTJ sensor is much greater than that of the signal conditioning circuit, the noise introduced by the feedback coils into the MTJ sensor is slightly more than twice that generated by the MTJ sensor itself. The measurement results show that the detectivity of the MTJ magnetometer with in situ magnetic feedback reaches 526 pT/Hz1/2 at 10 Hz. The equivalent noise analysis method presented in this paper is suitable for the detectivity analysis of magnetometers with magnetic feedback.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-27DOI: 10.3390/magnetochemistry9100213
Gulsara D. Kugabaeva, Kamila A. Kydralieva, Lyubov S. Bondarenko, Rose K. Baimuratova, Dmitry Yu. Karpenkov, Ekaterina A. Golovkova, Pavel N. Degtyarenko, Nina D. Golubeva, Igor E. Uflyand, Gulzhian I. Dzhardimalieva
Bimetallic FeCo and FeNi nanoparticles attract much attention due to their promising magnetic properties and a wide range of practical applications as recording and storage media, catalytic systems in fuel cells, supercapacitors, lithium batteries, etc. In this paper, we propose an original approach to the preparation of FeCo- and FeNi/N-doped carbon nanocomposites by means of a coupled process of frontal polymerization and thermolysis of molecular co-crystallized acrylamide complexes. The phase composition, structure, and microstructure of the resulting nanocomposites are studied using XRD, IR spectroscopy, elemental and thermal analysis, and electron microscopy data. The main magnetic characteristics of the synthesized nanocomposites, including the field dependences and the ZFC-FC curves peculiarities, are studied. It is shown that the obtained FeCo/N-C nanocomposites exhibit exchange bias behavior at low temperatures. In turn, FeNi/N-C nanocomposites are ferromagnetically ordered.
{"title":"Polymer-Assisted Synthesis, Structure and Magnetic Properties of Bimetallic FeCo- and FeNi/N-Doped Carbon Nanocomposites","authors":"Gulsara D. Kugabaeva, Kamila A. Kydralieva, Lyubov S. Bondarenko, Rose K. Baimuratova, Dmitry Yu. Karpenkov, Ekaterina A. Golovkova, Pavel N. Degtyarenko, Nina D. Golubeva, Igor E. Uflyand, Gulzhian I. Dzhardimalieva","doi":"10.3390/magnetochemistry9100213","DOIUrl":"https://doi.org/10.3390/magnetochemistry9100213","url":null,"abstract":"Bimetallic FeCo and FeNi nanoparticles attract much attention due to their promising magnetic properties and a wide range of practical applications as recording and storage media, catalytic systems in fuel cells, supercapacitors, lithium batteries, etc. In this paper, we propose an original approach to the preparation of FeCo- and FeNi/N-doped carbon nanocomposites by means of a coupled process of frontal polymerization and thermolysis of molecular co-crystallized acrylamide complexes. The phase composition, structure, and microstructure of the resulting nanocomposites are studied using XRD, IR spectroscopy, elemental and thermal analysis, and electron microscopy data. The main magnetic characteristics of the synthesized nanocomposites, including the field dependences and the ZFC-FC curves peculiarities, are studied. It is shown that the obtained FeCo/N-C nanocomposites exhibit exchange bias behavior at low temperatures. In turn, FeNi/N-C nanocomposites are ferromagnetically ordered.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135579824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-22DOI: 10.3390/magnetochemistry9100212
Andrey N. Dmitriev, Elena A. Vyaznikova, Galina Yu. Vitkina, Antonina I. Karlina
To study the influence of sinter basicity on the microstructure, phase composition, and physicochemical and metallurgical properties, samples of agglomerates with different basicities were sintered and investigated. A comprehensive study of the structure, composition, chemical, and metallurgical properties of the sinter was conducted, and the optimum values for these properties were determined. The results of the mineralogical transformations that occurred during the sintering process are also presented. The magnetite contained in the concentrate partially dissolves in the silicate component and flux during agglomeration, forming a complex silicate SFCA with the general formula M14O20 (M–Ca, Si, Al, and Mg), which is the binder of the ore phases of the agglomerate. The proportion of ferrosilicates of calcium and aluminum in the sinter depends on the basicity of the sinter charge, and the morphology of the SFCA phase depends on the cooling rate of the sinter. The more CaO in the sinter charge, the more SFCA phase is formed in the sinter, and slow cooling results in the growth of large lamellar and dendritic SFCA phases.
{"title":"A Study of the Structure and Physicochemical Properties of the Mixed Basicity Iron Ore Sinter","authors":"Andrey N. Dmitriev, Elena A. Vyaznikova, Galina Yu. Vitkina, Antonina I. Karlina","doi":"10.3390/magnetochemistry9100212","DOIUrl":"https://doi.org/10.3390/magnetochemistry9100212","url":null,"abstract":"To study the influence of sinter basicity on the microstructure, phase composition, and physicochemical and metallurgical properties, samples of agglomerates with different basicities were sintered and investigated. A comprehensive study of the structure, composition, chemical, and metallurgical properties of the sinter was conducted, and the optimum values for these properties were determined. The results of the mineralogical transformations that occurred during the sintering process are also presented. The magnetite contained in the concentrate partially dissolves in the silicate component and flux during agglomeration, forming a complex silicate SFCA with the general formula M14O20 (M–Ca, Si, Al, and Mg), which is the binder of the ore phases of the agglomerate. The proportion of ferrosilicates of calcium and aluminum in the sinter depends on the basicity of the sinter charge, and the morphology of the SFCA phase depends on the cooling rate of the sinter. The more CaO in the sinter charge, the more SFCA phase is formed in the sinter, and slow cooling results in the growth of large lamellar and dendritic SFCA phases.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136094445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.3390/magnetochemistry9090211
Linh Doan
As novel methylene blue adsorbents, polyvinyl alcohol and activated charcoal were used to modify the surface of superparamagnetic iron oxide nanoparticles. The adsorption capacity after 69 h was 26.50 ± 0.99–40.21 ± 1.30 mg/g, depending on the temperature (333.15, 310.15, and 298.15 K) and the initial concentration of methylene blue, which was between 0.017 and 0.020 mg/mL. Based on thermodynamics parameters, the adsorption process can be considered to be spontaneous endothermic physisorption. Kinetics studies show that the pseudo-second-order model was the best-fitted model. Adsorption isotherm studies show that the best-fitted models were the Langmuir, Langmuir, and Temkin and Pyzhev isotherm models when adsorbing MB at 333.15, 310.15, and 298.15 K, respectively.
{"title":"Surface Modifications of Superparamagnetic Iron Oxide Nanoparticles with Polyvinyl Alcohol and Activated Charcoal as Methylene Blue Adsorbents","authors":"Linh Doan","doi":"10.3390/magnetochemistry9090211","DOIUrl":"https://doi.org/10.3390/magnetochemistry9090211","url":null,"abstract":"As novel methylene blue adsorbents, polyvinyl alcohol and activated charcoal were used to modify the surface of superparamagnetic iron oxide nanoparticles. The adsorption capacity after 69 h was 26.50 ± 0.99–40.21 ± 1.30 mg/g, depending on the temperature (333.15, 310.15, and 298.15 K) and the initial concentration of methylene blue, which was between 0.017 and 0.020 mg/mL. Based on thermodynamics parameters, the adsorption process can be considered to be spontaneous endothermic physisorption. Kinetics studies show that the pseudo-second-order model was the best-fitted model. Adsorption isotherm studies show that the best-fitted models were the Langmuir, Langmuir, and Temkin and Pyzhev isotherm models when adsorbing MB at 333.15, 310.15, and 298.15 K, respectively.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136373256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-13DOI: 10.3390/magnetochemistry9090210
Dmitry A. Estyunin, Anna A. Rybkina, Konstantin A. Kokh, Oleg E. Tereshchenko, Marina V. Likholetova, Ilya I. Klimovskikh, Alexander M. Shikin
We investigated the magnetic properties of the antiferromagnetic (AFM) topological insulator MnBi2Te4 with a partial substitution of Mn atoms by non-magnetic elements (AIV = Ge, Pb, Sn). Samples with various element concentrations (10–80%) were studied using SQUID magnetometry. The results demonstrate that, for all substitutes the type of magnetic ordering remains AFM, while the Néel temperature (TN) and spin-flop transition field (HSF) decrease with an increasing AIV = Ge, Pb, Sn concentration. The rate of decrease varies among the elements, being highest for Pb, followed by Sn and Ge. This behavior is attributed to the combined effects of the magnetic dilution and lattice parameter increase on magnetic properties, most prominent in (Mn1−xPbx)Bi2Te4. Besides this, the linear approximation of the experimental data of TN and HSF suggests higher magnetic parameters for pure MnBi2Te4 than observed experimentally, indicating the possibility of their non-monotonic variation at low concentrations and the potential for enhancing magnetic properties through doping MnBi2Te4 with small amounts of nonmagnetic impurities. Notably, the (Mn1−xPbx)Bi2Te4 sample with 10% Pb substitution indeed exhibits increased magnetic parameters, which is also validated by local-probe analyses using ARPES. Our findings shed light on tailoring the magnetic behavior of MnBi2Te4-based materials, offering insights into the potential applications in device technologies.
{"title":"Comparative Study of Magnetic Properties of (Mn1−xAxIV)Bi2Te4 AIV = Ge, Pb, Sn","authors":"Dmitry A. Estyunin, Anna A. Rybkina, Konstantin A. Kokh, Oleg E. Tereshchenko, Marina V. Likholetova, Ilya I. Klimovskikh, Alexander M. Shikin","doi":"10.3390/magnetochemistry9090210","DOIUrl":"https://doi.org/10.3390/magnetochemistry9090210","url":null,"abstract":"We investigated the magnetic properties of the antiferromagnetic (AFM) topological insulator MnBi2Te4 with a partial substitution of Mn atoms by non-magnetic elements (AIV = Ge, Pb, Sn). Samples with various element concentrations (10–80%) were studied using SQUID magnetometry. The results demonstrate that, for all substitutes the type of magnetic ordering remains AFM, while the Néel temperature (TN) and spin-flop transition field (HSF) decrease with an increasing AIV = Ge, Pb, Sn concentration. The rate of decrease varies among the elements, being highest for Pb, followed by Sn and Ge. This behavior is attributed to the combined effects of the magnetic dilution and lattice parameter increase on magnetic properties, most prominent in (Mn1−xPbx)Bi2Te4. Besides this, the linear approximation of the experimental data of TN and HSF suggests higher magnetic parameters for pure MnBi2Te4 than observed experimentally, indicating the possibility of their non-monotonic variation at low concentrations and the potential for enhancing magnetic properties through doping MnBi2Te4 with small amounts of nonmagnetic impurities. Notably, the (Mn1−xPbx)Bi2Te4 sample with 10% Pb substitution indeed exhibits increased magnetic parameters, which is also validated by local-probe analyses using ARPES. Our findings shed light on tailoring the magnetic behavior of MnBi2Te4-based materials, offering insights into the potential applications in device technologies.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"187 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135740553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-12DOI: 10.3390/magnetochemistry9090209
Joana Soares Regadas, Sílvia Rodrigues Gavinho, Sílvia Soreto Teixeira, Juliana Vieira de Jesus, Ana Sofia Pádua, Jorge Carvalho Silva, Susana Devesa, Manuel Pedro Fernandes Graça
Bioglasses have been used throughout the past century as a biomaterial in the bone regeneration field. However, recent studies have attempted to use them as a therapeutic material as well, mainly in the treatment of osteosarcomas. The most widely recognized bioglass is the 45S5 Bioglass, invented by Larry Hench et al., which presents higher bioactivity. A possible application of this bioglass in the treatment of osteosarcomas can be accomplished by adding specific ions, such as iron, that will allow the use of magnetic hyperthermia and Fenton reaction as therapeutic mechanisms. In this study, a 45S5 Bioglass containing 10%mol of Fe2O3 was produced using the melt-quenching method. A group of samples was prepared by changing the overall ball milling time, from 1 h up to 48 h, to analyze the effects of iron in the bioactive glass matrix and evaluate the influence of particle size on their physical and biological properties. The studied bioglasses showed no evidence of changes in the amorphous structural nature compared to the 45S5 Bioglass. The data of the impedance spectroscopy study revealed that the addition of Fe2O3 can increase the standard rate constant of the Electro-Fenton reaction, with the sample milled for 12 h showing the most promising results. The reduction in the particle size influenced the cytotoxicity and the bioactivity. The samples with lower particle sizes showed a higher level of cytotoxicity.
{"title":"Influence of the Particle Size on the Electrical, Magnetic and Biological Properties of the Bioglass® Containing Iron Oxide","authors":"Joana Soares Regadas, Sílvia Rodrigues Gavinho, Sílvia Soreto Teixeira, Juliana Vieira de Jesus, Ana Sofia Pádua, Jorge Carvalho Silva, Susana Devesa, Manuel Pedro Fernandes Graça","doi":"10.3390/magnetochemistry9090209","DOIUrl":"https://doi.org/10.3390/magnetochemistry9090209","url":null,"abstract":"Bioglasses have been used throughout the past century as a biomaterial in the bone regeneration field. However, recent studies have attempted to use them as a therapeutic material as well, mainly in the treatment of osteosarcomas. The most widely recognized bioglass is the 45S5 Bioglass, invented by Larry Hench et al., which presents higher bioactivity. A possible application of this bioglass in the treatment of osteosarcomas can be accomplished by adding specific ions, such as iron, that will allow the use of magnetic hyperthermia and Fenton reaction as therapeutic mechanisms. In this study, a 45S5 Bioglass containing 10%mol of Fe2O3 was produced using the melt-quenching method. A group of samples was prepared by changing the overall ball milling time, from 1 h up to 48 h, to analyze the effects of iron in the bioactive glass matrix and evaluate the influence of particle size on their physical and biological properties. The studied bioglasses showed no evidence of changes in the amorphous structural nature compared to the 45S5 Bioglass. The data of the impedance spectroscopy study revealed that the addition of Fe2O3 can increase the standard rate constant of the Electro-Fenton reaction, with the sample milled for 12 h showing the most promising results. The reduction in the particle size influenced the cytotoxicity and the bioactivity. The samples with lower particle sizes showed a higher level of cytotoxicity.","PeriodicalId":18194,"journal":{"name":"Magnetochemistry","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135886210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：