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Low‐temperature magnetic evolution of troilite sample, extracted from the Cape York IIIA octahedrite meteorite, was investigated by employing macroscopic magnetic measurement, Mössbauer spectroscopy, scanning electron microscopy (SEM) and backscattered electrons (BSE) microscopy, X‐ray diffraction (XRD), electron microprobe analysis (EMA), and atomic absorption spectrometry (AAS). The study identified a magnetic transition at ≈70 K manifested itself in a similar manner as previously reported for troilite from the Bruderheim L6 chondrite meteorite. The data show that this transition is unlikely driven by impurity such as chromite and seems to be rather an intrinsic property of troilite. In this study, we unambiguously exclude the relation of this transition to the structural rearrangement like the Morin transition in hematite. Similarly, in‐field Mössbauer data do not support the change of the canting angle in the spin structure of FeS above and below the transition. Mössbauer, XRD, and magnetic data, newly measured also for troilite from the Bruderheim L6 chondrite, demonstrate that both studied troilite samples exhibit nearly the same magnetic and structural characteristics. Thus, the nature of the transition occurring at ≈70 K in both samples has identical characteristics and its detection can be used as a simple general marker for highly stoichiometric FeS systems. Key Points Zero‐ and in‐field Moessbauer troilite data Essence of magnetic transition in troilite Generalization of transition phenomenon

We synthesized ZnFe 2 O 4 and CoFe 2 O 4 nanoparticles and investigated their magnetic and electromagnetic behaviors at room temperature. X-ray diffraction analyses indicated that these materials having average crystallite sizes of 22–31 nm, and their crystal structure belongs to the cubic-spinel class. While ZnFe 2 O 4 exhibits soft magnetic behavior, with M s  = 88 emu/g and H c  = 130 Oe, CoFe 2 O 4 exhibits hard magnetic behavior, with M s  = 65 emu/g and H c  = 620 Oe. Investigations into the complex permittivity and permeability dependent on the frequency ( f ) and thickness ( t ) revealed remarkable changes in their values at frequencies f  = 12–16 GHz for both samples. In the range f  = 13.5–13.8 GHz, reflection loss magnitudes of devices based on ZnFe 2 O 4 – and CoFe 2 O 4 – with t  = 2.25–2.75 mm were about 11.3–14.2 dB, corresponding to electromagnetic wave absorption of 90–95%. Considering loss tangents, we found that both dielectric and magnetic losses contributed to the electromagnetic dissipation in the investigated materials.

The structural, morphological and magnetic properties of MFe2O4 (M = Co, Ni, Zn, Cu, Mn) type ferrites produced by thermal decomposition at 700 and 1000 °C were studied. The thermal analysis revealed that the ferrites are formed at up to 350 °C. After heat treatment at 1000 °C, single-phase ferrite nanoparticles were attained, while after heat treatment at 700 °C, the CoFe2O4 was accompanied by Co3O4 and the MnFe2O4 by α-Fe2O3. The particle size of the spherical shape in the nanoscale region was confirmed by transmission electron microscopy. The specific surface area below 0.5 m2/g suggested a non–porous structure with particle agglomeration that limits nitrogen absorption. By heat treatment at 1000 °C, superparamagnetic CoFe2O4 nanoparticles and paramagnetic NiFe2O4, MnFe2O4, CuFe2O4 and ZnFe2O4 nanoparticles were obtained.

In the current study we have obtained Co2FeSi glass-coated microwires with different geometrical aspect ratios, ρ = d/Dtot (diameter of metallic nucleus, d and total diameter, Dtot). The structure and magnetic properties are investigated at a wide range of temperatures. XRD analysis illustrates a notable change in the microstructure by increasing the aspect ratio of Co2FeSi-glass-coated microwires. The amorphous structure is detected for the sample with the lowest aspect ratio (ρ = 0.23), whereas a growth of crystalline structure is observed in the other samples (aspect ratio ρ = 0.30 and 0.43). This change in the microstructure properties correlates with dramatic changing in magnetic properties. For the sample with the lowest ρ-ratio, non-perfect square loops are obtained with low normalized remanent magnetization. A notable enhancement in the squareness and coercivity are obtained by increasing ρ-ratio. Changing the internal stresses strongly affects the microstructure, resulting in a complex magnetic reversal process. The thermomagnetic curves show large irreversibility for the Co2FeSi with low ρ-ratio. Meanwhile, if we increase the ρ-ratio, the sample shows perfect ferromagnetic behavior without irreversibility. The current result illustrates the ability to control the microstructure and magnetic properties of Co2FeSi glass-coated microwires by changing only their geometric properties without performing any additional heat treatment. The modification of geometric parameters of Co2FeSi glass-coated microwires allows to obtain microwires that exhibit an unusual magnetization behavior that offers opportunities to understand the phenomena of various types of magnetic domain structures, which is essentially helpful for designing sensing devices based on thermal magnetization switching.

This current study examines the magnetic behavior of a mixed CrI 3 monolayer nanosystem using Monte Carlo simulations. The main objective was to examine the impact of variations in ferrimagnetic coupling parameters ( J σS ), external magnetic field ( H ) and crystal field (| D |) on the blocking temperature. The analysis reveals the emergence of a compensation temperature for | D | = 2 and 3. In addition, the hysteresis behavior analysis highlights how changes in J σS , D and T affect the magnetic behavior of the system. Decreasing J σS values show similar trends, with additional loops and magnetization plateaus attributed to negative J σS values. These results deepen our understanding of the magnetic property of CrI 3 monolayer nanosystem and pave the way for applications in advanced magnetic materials and devices.

The synthesis of Fe/TiO 2 nanocomposite soft magnetic materials, incorporating Cu, Fe 2 O 3 , and Cu/Fe 2 O 3 ;, was achieved using the mechanical alloying technique. Advanced characterization methods, including Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), and Vibrating Sample Magnetometer (VSM), were employed for a comprehensive investigation of structural, morphological, and magnetic properties of the nanocomposite at different synthesis stages. The crystallite size reaches its minimum value, while the lattice strain (ε) attains its maximum value in the FeCu/TiO 2 nanocomposite, measuring 26.85 nm and 0.35%, respectively. Coercivity, magnetic remanence, and squareness ratio of Fe/TiO 2 showed an upward trend with increasing milling time, reaching peak values after 5 h of milling. The FeTiO 2 nanocomposite achieved maximum values for coercivity, magnetic remanence, and saturation magnetization. Notably, the squareness ratio demonstrated notable values for both FeTiO 2 and FeCuTiO 2 .

Transition magnetic metals (Fe, Ni, Co) were inserted into sodium titanate nanotubes subjected to calcination. In the calcination process at 400 °C, the nanotubular structure of the samples with magnetic species breaks down, while at 800 °C the formation of TiO 2 nanoparticles occurs mainly in the anatase and rutile phases. Optical studies revealed that the Fe 3+ , Ni 2+ and Co 2+ ions insertion promoted red shift in UV–Vis and the samples, showed smaller energy gap than NaTiNT. In addition, the samples calcined at 400 °C showed higher conductivity due to the greater number of oxygen defects. All samples exhibited ferromagnetic behavior at room temperature in low magnetic fields. The ferromagnetic behavior for these materials may originate from the interaction between the ions intercalated in the titanate lattice from the defects of oxygen incorporated in the nanotubes by the calcination process and from the transition from Ti 4+ to Ti 3+ in some sites of the nanotube structure. Graphical Abstract

Nd 0.9 Zn 0.1 FeO 3 was prepared in a single-phase with an average crystallite size of 25.82 nm using a citrate combustion technique. The energy dispersive X-ray assures the chemical formula of the sample. The elemental mapping of Zn-doped NdFeO 3 illustrates the good homogeneous distribution of the elements in the sample. Nd 0.9 Zn 0.1 FeO 3 has antiferromagnetic properties with weak ferromagnetic components and has good UV absorbance. The values of the band gap for the direct and indirect transitions are 1.473 eV and 1.250 eV, respectively. The adsorption of nickel(II), cobalt(II), chrome(VI), cadmium(II), and lead(II) ions has been studied at pH 7. The highest removal efficiency (η = 73.72%) was observed for the lead ions from water. The current study has examined the kinetics, recoveries, and mechanisms of utilizing Nd 0.90 Zn 0.10 FeO 3 to remove Pb 2+ ions from water. The optimum conditions for the absorbing Pb 2+ are pH 7 and a contact time of 60 min. The Freundlich isotherm model is the best model for the absorption of Pb 2+ ions. While, the pseudo-second-order kinetic model describes the kinetic adsorption data. The sample has a good efficiency for removing Pb 2+ ions from water several times.

This study explored the fascinating field of high-performance nanoscale metallic multilayer composites, focusing on their magnetic, optical, and radiation tolerance properties, as well as their thermal and electrical properties. In general, nanoscale metallic multilayer composites have a wide range of outstanding properties, which differ greatly from those observed in monolithic films. Their exceptional properties are primarily due to the large number of interfaces and nanoscale layer thicknesses. Through a comprehensive review of existing literature and experimental data, this paper highlights the remarkable performance enhancements achieved by the precise control of layer thicknesses and interfaces in these composites. Furthermore, it will discuss the underlying mechanisms responsible for their exceptional properties and provide insights into future research directions in this rapidly evolving field. Many studies have investigated these materials, focusing on their magnetic, mechanical, optical, or radiation-tolerance properties. This paper summarizes the findings in each area, including a description of the general attributes, the adopted synthesis methods, and the most common characterization techniques used. The paper also covers related experimental data, as well as existing and promising applications. The paper also covers other phenomena of interest, such as thermal stability studies, self-propagating reactions, and the progression from nanomultilayers to amorphous and/or crystalline alloys. Finally, the paper discusses challenges and future perspectives relating to nanomaterials. Overall, this paper is a valuable resource for researchers and engineers interested in harnessing the full potential of nanoscale metallic multilayer composites for advanced technological applications.

Here, we report synthesis and investigations of bulk and nano-sized La(0.7−x)EuxBa0.3MnO3 (x ≤ 0.4) compounds. The study presents a comparison between the structural and magnetic properties of the nano- and polycrystalline manganites La(0.7−x)EuxBa0.3MnO3, which are potential magnetocaloric materials to be used in domestic magnetic refrigeration close to room temperature. The parent compound, La0.7Ba0.3MnO3, has Curie temperature TC = 340 K. The magnetocaloric effect is at its maximum around TC. To reduce this temperature below 300 K, we partially replaced the La ions with Eu ions. A solid-state reaction was used to prepare bulk polycrystalline materials, and a sol-gel method was used for the nanoparticles. X-ray diffraction was used for the structural characterization of the compounds. Transmission electron spectroscopy (TEM) evidenced nanoparticle sizes in the range of 40–80 nm. Iodometry and inductively coupled plasma optical emission spectrometry (ICP-OES) was used to investigate the oxygen content of the studied compounds. Critical exponents were calculated for all samples, with bulk samples being governed by tricritical mean field model and nanocrystalline samples governed by the 3D Heisenberg model. The bulk sample with x = 0.05 shows room temperature phase transition TC = 297 K, which decreases with increasing x for the other samples. All nano-sized compounds show lower TC values compared to the same bulk samples. The magnetocaloric effect in bulk samples revealed a greater magnetic entropy change in a relatively narrow temperature range, while nanoparticles show lower values, but in a temperature range several times larger. The relative cooling power for bulk and nano-sized samples exhibit approximately equal values for the same substitution level, and this fact can substantially contribute to applications in magnetic refrigeration near room temperature. By combining the magnetic properties of the nano- and polycrystalline manganites, better magnetocaloric materials can be obtained.