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We report on the field evolution of the microwave spin wave modes in magnonic crystals made of square antidot lattices etched in a thin film of the Co2MnSi Heusler alloy and having a lateral size s of 200 nm and an edge-to-edge separation d of 600 or 800 nm. The spin wave modes are investigated combining ferromagnetic resonance, Brillouin light scattering experiments, and micromagnetic simulations of the static and dynamic magnetic states as a function of the applied field. We show that for applied fields ≥10 mT, when the magnetization is quasi-saturated across the crystals, the two samples show similar behavior and the two most intense modes in the spin waves spectra correspond to a mode extending in the channels comprised between the antidot and a mode localized in the region between the antidots. For smaller fields, we observe a difference of the measured spectra as a function of d. This is attributed to the fact that for d = 800 nm, the magnetization remains partially uniform in the channel between the antidots because of the Heusler cubic crystal anisotropy, while for d = 600 nm, the magnetic edge domains around the antidots spread into the channels. Moreover, this anisotropy also allows different remanent states when initializing the crystals with a small magnetic field along two perpendicular directions. This leads to an efficient excitation or extinction of the spin wave modes, making possible to achieve reconfigurable microwave devices exploiting an antidot geometry in a metallic ferromagnetic with a low damping coefficient. [ABSTRACT FROM AUTHOR]

Investigating high-performance and stable spintronics devices has been a research hotspot in recent years. In this paper, we employed first-principles methods and Monte Carlo (MC) simulations to explore the structure, electronic, and magnetic properties of monolayer NbSe2, as well as its behavior under carrier concentration modulation. The research on the electronic structure reveals that by introducing an appropriate amount of holes, the material can undergo a transition from metal to a half-metal state, achieving 100% high spin polarization. Investigation of magnetic crystalline anisotropy shows that the magnetic crystal anisotropy energy of 1210 μeV in out-of-plane is beneficial to maintain ferromagnetic order at high temperatures. In addition, doping with suitable carriers can effectively enhance or strengthen the ferromagnetic coupling in NbSe2 so that the magnetization easy axis is shifted. This reveals the potential application prospects of NbSe2 in electronically controlled spintronic devices. Analysis of the Fermi surface shows that both holes and electron doping increase the Fermi velocity of the material. The effect of hole doping is particularly significant, indicating its potential application in Fermi velocity engineering. Under the theoretical framework of the extended two-dimensional Ising model, based on MC simulation, the Curie temperature (TC) of NbSe2 is predicted to be 162 K. The effects of carrier concentration and the magnetic field on the magnetic and thermal properties of monolayer NbSe2 are simulated. The results show that appropriately increasing the hole doping concentration and magnetic field is conducive to obtaining ferromagnetic half-metallic materials with TC higher than room temperature, which provides theoretical support for experimental preparation. [ABSTRACT FROM AUTHOR]

Topological photonics has recently opened up a promising frontier for electromagnetic wave and light manipulation and has made great progress from unique physical concepts to novel practical photonic devices. Numerous works have discussed the realizations of chiral topological photonic states in magnetic photonic crystals with broken time-reversal symmetry; however, limited reports have been discussed to the achievements of antichiral topological photonic states. In this Perspective, we review recent progress in antichiral topological photonic states in magnetic photonic systems for the basic concepts, properties, and applications. Additionally, we provide an outlook for emerging frontier topics, promising opportunities, fundamental challenges, and potential applications for antichiral magnetic topological photonics. [ABSTRACT FROM AUTHOR]

The magnetic structure of K2Co3(MoO4)3(OH)2 is studied in detail. The material has a half-sawtooth one-dimensional (1-D) structure containing two unique Co2+ ions, one in the chain backbone and one on the apex of the sawtooth creating a series of isosceles triangles along the b-axis. These triangles can be a source of magnetic frustration. The ability to grow large single crystals enables detailed magnetic measurements with the crystals oriented in a magnetic field along the respective axes. It has a Curie–Weiss temperature CW of 5.3(2) K with an effective magnetic moment of 4.8(3)μB/Co. The material is highly anisotropic with a sharp antiferromagnetic ordering transition at 7 K with a metamagnetic transition at 2 kOe. Neutron diffraction was used to determine the magnetic structure and revealed a magnetic structure with canted spins along the backbone of the chain while spins along the sawtooth caps maintained a colinear orientation, arranging antiferromagnetically relative to the backbone spins. The parallel chains arrange antiferromagnetically relative to each other along the c-axis and ferromagnetically along the a-axis. [ABSTRACT FROM AUTHOR]

Magnonic crystals with artificial micro/nanomagnetic pattern act as low‐loss information carriers in many microwave devices. The excitation and control of spin waves inside is essential and fundamental in magnonic crystal applications. Herein, permalloy micro‐disk patterns are constructed on a continuous permalloy film, and they succeed in exciting spin waves in this bilayer‐structured magnonic crystal. The spin‐wave modes can be effectively tuned by varying the periodic parameter (P) of upper‐layer disk pattern, which is confirmed by the transition from single‐peak to multi‐peak in ferromagnetic resonance (FMR) spectra with P decreased from 4 to 0.5 μm. The split in FMR spectra is reconstructed by micromagnetic simulation, revealing that three spin‐wave modes are respectively excited by the domain walls of below‐layer continuous film, geometrical restriction of permalloy micro‐disk, and magnetic coupling between neighboring permalloy micro‐disks. The tunable spin‐wave behavior in this bilayer‐structured magnonic crystal presents broad application prospect in programmable spintronic devices at micro/nanoscale. [ABSTRACT FROM AUTHOR]

Single‐molecule toroics are molecular magnets with vortex distribution of magnetic moments. The coupling between magnetic and electric properties such as the magnetodielectric effect will provide potential applications for them. Herein, the observation of significant magnetodielectric effect in a triangular Dy3 crystal with toroidal magnetic moment and multiple magnetic relaxations is reported. The analysis of magnetic and electric properties implies that the magnetodielectric effect is closely related to the strong spin‐lattice coupling, magnetic interactions of Dy3+ ions, as well as molecular packing models. [ABSTRACT FROM AUTHOR]

The spin Seebeck effect was studied in thin films of hexagonal ferrites of W-type SrCo2−xZnxFe16O27 with x = 0, 1, and 2 and Z-type with the composition Sr3Co2Fe24O41. The present data were compared with the previously obtained data on Y-type Ba2Zn2−xCoxFe12O22 with x = 0 and 2. Our work showed that the SSE signal can also be generated in materials with complicated crystal and magnetic structures. Hexaferrites with the magnetic easy plane were selected except for uniaxial W-type with x = 2, for which the highest saturated SSE 0.144 μV/K was observed; however, magnetic field above 1 T must be applied to achieve saturation. For low field application, hexaferrites with easy magnetization in ab-plane are more suitable, namely, Y-type with x = 2 or W-type with x = 1. SSE is suppressed in Co-substituted hexaferrites due to the random distribution of Co among various sites. Therefore, the Co cations interfere with the long-range magnetic ordering and diminish the spin-wave propagation. Additional suppression of SSE might be invoked by the higher magnetic anisotropy of the Co-substituted hexaferrites, which opens a gap in the magnon spectrum and, thus, reduces the contribution of lower energy magnons with longer diffusion length. [ABSTRACT FROM AUTHOR]

The realization and modulation of high-order topological states in three-dimensional (3D) photonic crystals (PCs) hold great significance for practical applications in optical communication, optical information processing, and optical computing. However, they have encountered technological challenges due to the difficulty in achieving a complete bandgap in 3D PCs. To address this issue, we introduce a design for a 3D PC based on the Su–Schrieffer–Heeger (SSH) model that exhibits distinctive topological surface states, topological hinge states, and topological corner states. Furthermore, these three types of topological states can be interconverted through the modulation of magnetic field because the topological states are closed and extremely sensitive to the structure, which are modulated by the magnetic field. This intriguing capability holds potential applications in the manipulation of optical flow, optical signal storage, and magnetic field sensors. [ABSTRACT FROM AUTHOR]

A series of nickel dithiolene molecular crystals [Et3N(CH2)3X][Ni(mnt)2] (1: X = H, 2: X = Cl, 3: X = Br and 4: X = I and Br; mnt2− = maleonitriledithiolate) were prepared by introducing triethylpropylammonium derivatives (X–CH2CH2CH2–NEt3+) into [Ni(mnt)2]− building blocks. 1 crystallizes in a monoclinic system with the space group P21/n at 293 K, and the cations and anions in 1 are arranged in columnar segregated stacks along the a-axis direction. Crystals 2 and 3 also belong to monoclinic systems with space groups P21/n and P21/c, but 4 crystallizes in a triclinic system with the space group P1¯. Interactions between [Ni(mnt)2]− ions in all crystals are antiferromagnetic, and the magnitudes of the interactions are qualitatively consistent with the strength of intermolecular interactions estimated from transfer integrals, where interactions between [Ni(mnt)2]− ions are greater than the others in all crystals. The magnetic measurement data demonstrate that antiferromagnetic behavior was observed in 1 and can be fitted well through the 1D alternating linear chain model. Crystal 2 shows spin dimer magnetic behavior, and the magnetic susceptibilities of 3 and 4 show Curie–Weiss-type paramagnetic character in the whole temperature regions. This study showed that halogen substitution on the cations has significant effects on the arrangement and magnetic behavior of [Ni(mnt)2]−. [ABSTRACT FROM AUTHOR]

The quasi-binary system YbMg2-YbIn2 was studied around the equiatomic composition. In contrast to the ordered rare earth (RE) phases REMgIn (ZrNiAl type), ytterbium forms phases with different structures and pronounced Mg/In mixing (M sites). The structures of YbMg0.75In1.25 (CaLiSn type, P3m1, a = 501.95(7), c = 1087.3(2) pm, wR2 = 0.0490, 790 F2 values, 32 variables) and Yb6Mg6.41In5.59 (Yb6Ir5Ga7 type, P63/mcm, a = 1060.77(14), c = 970.27(16) pm, wR2 = 0.0484, 701 F2 values, 26 variables) were refined from single-crystal X-ray diffractometer data. YbMg0.75In1.25 is an AlB2 superstructure with a tripling of the subcell. The magnesium and indium atoms form three differently puckered layers of M6 hexagons. The Yb6Mg6.41In5.59 structure is derived from the hexagonal Laves phase YbMg2 (MgZn2 type, P63/mmc). A klassengleiche symmetry reduction leads to four crystallographically independent M sites for the rows of corner- and face-sharing tetrahedra which allow a composition close to the equiatomic one. The M–M distances in both structures cover the broad range from 289 to 331 pm, comparable to the sums of the covalent radii. Temperature dependent magnetic susceptibility studies of the polycrystalline YbMg0.75In1.25 and Yb12Mg13In11 samples indicate Pauli paramagnetism with room temperature values of 2.8(1) × 10−3 emu mol−1 (YbMg0.75In1.25) and 5.2(1) × 10−3 emu mol−1 (Yb12Mg13In11). [ABSTRACT FROM AUTHOR]

The discoveries of ferromagnetism down to the atomically thin limit in van der Waals (vdW) crystals by mechanical exfoliation have enriched the family of magnetic thin films [C. Gong et al., Nature 546, 265-269 (2017) and B. Huang et al., Nature 546, 270-273 (2017)]. However, compared to the study of traditional magnetic thin films by physical deposition methods, the toolbox of the vdW crystals based on mechanical exfoliation and transfer suffers from low yield and ambient corrosion problem and now is facing new challenges to study magnetism. For example, the formation of magnetic superlattice is difficult in vdW crystals, which limits the study of the interlayer interaction in vdW crystals [M. Gibertini, M. Koperski, A. F. Morpurgo, K. S. Novoselov, Nat. Nanotechnol. 14, 408-419 (2019)]. Here, we report a strategy of interlayer engineering of the magnetic vdW crystal Fe3GeTe2 (FGT) by intercalating quaternary ammonium cations into the vdW spacing. Both three-dimensional (3D) vdW superlattice and two-dimensional (2D) vdW monolayer can be formed by using this method based on the amount of intercalant. On the one hand, the FGT superlattice shows a strong 3D critical behavior with a decreased coercivity and increased domain wall size, attributed to the co-engineering of the anisotropy, exchange interaction, and electron doping by intercalation. On the other hand, the 2D vdW few layers obtained by over-intercalation are capped with organic molecules from the bulk crystal, which not only enhances the ferromagnetic transition temperature (TC), but also substantially protects the thin samples from degradation, thus allowing the preparation of large-scale FGT ink in ambient environment. [ABSTRACT FROM AUTHOR]

A series of new manganese complexes of general formula 32-Mn4Xn , displaying a highly-reproducible [Mn II2 Mn III2 ] cluster core formation, was observed when tetra-p-adamantylcalix[4]arene 3 was used in combination with N,N′-chelating auxiliary ligands, such as bipy (32-Mn4(bipy)2, bipy = 2,2′-bipyridyl) and phen (32-Mn4(phen)2, phen = 1,10-phenanthroline), as well as with DMF/H2O solvent molecules (32-Mn4(dmf)4, 32-Mn4(dmf)2(H2O)2), acting as O-donor coligands, in the crystalline phase. Single-crystal X-ray diffraction revealed that the involvement of auxiliary ligands in coordination with Mn-ions results in the distortion of their coordination sphere and leads to the controlled compression of the {Mn4}-cluster core of complexes. Moreover, the appearance of adamantyl groups at the upper rim of the macrocyclic backbone of 3 influences the crystalline self-assembly of obtained clusters, providing a preferable "side-to-head" orientation of the cluster molecules within the crystal, leading to the observation of relatively higher {Mn4}⋯{Mn4} distances than those revealed for the earlier reported calix[4]arene supported {Mn4} clusters. All 32-Mn4Xn clusters demonstrated ferromagnetic interactions between the metal atoms within the cluster core independent of the nature of the O-donor or N-donor auxiliary ligands. [ABSTRACT FROM AUTHOR]

In this work, the influences of core–shell structure and cerium (Ce) content on magnetic properties of Nd-Ce-Fe-B permanent magnets were investigated by the finite difference micromagnetic (FDM) simulation method, and the process of magnetization reversals was systematically discussed. For the (Nd1-xCex)2Fe14B-(Dy2Fe14B) core–shell grains with different core sizes, the coercivity (Hcj) dramatically increases with the shell thickness from 0 to 2 nm and then increases slightly with shell thickness increase to 20 nm; for the grains with the same shell thickness, the Hcj decreases with the increase of core size, and it is due to the increase of demagnetization energy. Moreover, the Hcj remarkably deteriorates as the Ce content increases, which is caused by the lower magnetic crystal anisotropy field (HA). The hysteresis loops of core–shell models exhibit excellent squareness with a shell thickness of 2 nm at different Ce proportions. However, a significant two-step demagnetization feature for the model with the thicker shell sizes and higher Ce content results from the different demagnetization abilities of the shell and core. In addition, in the angular distributions of magnetization, the reversal of the core region is later than that of the outer shell, and the applied field required to inverse increases with the shell thickness. The abnormal two-step demagnetization was caused by the twice abrupt changes that occurred in the Zeeman energy (Eext) and total energy (Etot). [ABSTRACT FROM AUTHOR]

Based on the Ising model, using the Monte Carlo method, we examine the magnetic and thermodynamic characteristics of a ferrimagnetic hexagonal nanowire with spin-5/2 and spin-7/2 of alternate layer structure under external and longitudinal crystal magnetic fields, in particular the physical effect of the external magnetic field on compensation behavior. Moreover, the phase diagrams in the ( T , D / J s ), ( T , J int / J s ), and ( T , J σ / J s) planes have been detailed. Consequently, we have obtained single and double compensation temperatures for the determined longitudinal crystal and external field parameters. The magnetizations of type-N, type-Q, and type-M have been found for certain parameter values in our system. This research was compared with other theoretical and experimental findings. [ABSTRACT FROM AUTHOR]

Phosphonate and phosphate ligands have historically received less attention when compared to the widely prevalent carboxylate ligand system. Phosphonates possess multiple donating sites, often leading to the formation of larger aggregates with limited solubility. Conversely, the P−O bond within phosphates is highly susceptible to hydrolysis, resulting in the precipitation of insoluble compounds, particularly when interacting with lanthanide metal ions. However, over the past few decades, various synthetic approaches have emerged for the preparation and characterization of lanthanide complexes involving both phosphonate and phosphate ligands. Consequently, researchers have delved into exploring the magnetic properties of these complexes, such as their potential as single molecule magnets (SMMs) and their ability to exhibit a magnetocaloric effect (MCE). This review will encompass an examination of the crystal structures and magnetic characteristics of lanthanide complexes featuring phosphonate and phosphate ligands. [ABSTRACT FROM AUTHOR]

A surface plasmon resonance (SPR)-based photonic crystal fiber (PCF) magnetic field sensor with hexagonal lattice is proposed. Magnetic fluid is injected into two air holes for magnetic field sensing. In order to obtain the optimal structure of magnetic field sensor, four types of hexagonal PCF models are discussed and compared. The influence of structure parameters d, d 1 , d 2 , t, D, and Λ on sensing characteristics is analyzed when the PCF-3 is determined. The maximum sensitivity and corresponding resolution can reach 1150 pm/Oe and 0.087 Oe, and figure of merit (FOM) is up to 0.0556/Oe in the magnetic range of 30–150 Oe. The maximum wavelength sensitivity is 25000 nm/RIU, when the range of refractive index (RI) is from 1.420 to 1.450. In addition, the temperature sensitivity is only 65 pm/K, indicating small temperature crosstalk. The proposed sensor has the advantages of large FOM, good linearity and simple structure, enabling accurate measurement of magnetic field, especially suitable for weak magnetic field detection. Good performance makes it applicable to industrial production, military affairs, health and environmental monitoring. [ABSTRACT FROM AUTHOR]

In this work, we measured the correlator spectrum of optically cooled nuclear spin system of a bulk n-GaAs crystal in a zero magnetic field. The resulting spectrum is described by two contours, which can be interpreted as the participation of nuclear spins in two types of interactions. We analyzed the measured spectrum in the model for classical magnetic moments in the GaAs lattice. The analysis showed that the main contribution to the high-frequency part of the spectrum is due to the dipole-dipole interaction, and that to the low-frequency part is due to the quadrupole interaction. [ABSTRACT FROM AUTHOR]

The rate of nuclear spin-lattice relaxation is determined by the efficiency of interaction between thermal phonons and nuclear spins. The results on reducing the efficiency of spin–phonon coupling by suppressing the contribution from paramagnetic centers to quadrupole nucleus relaxation are presented. The suppression has been performed by continuous magnetic action at the Larmor frequency. It is shown that, as in the presence of an acoustic field, the rate of spin-lattice relaxation of 23Na nuclei in a sodium fluoride crystal at magnetic saturation of the NMR signal does not change in the region of a negative average spin temperature. In the region of positive spin temperature, the rate of relaxation of 23Na spins significantly decreases and nuclear magnetization recovery with time is described by the sum of two exponentials. The contribution from nuclear spins with a lower efficiency of spin–phonon coupling, corresponding to the exponential with a long relaxation time, increases with increasing saturating field intensity. It is demonstrated that the efficiency of spin–phonon coupling for 19F nuclei, which do not have the quadrupole moment, does not change under the saturation conditions. The results obtained can be used for analyzing the structure of real crystals. [ABSTRACT FROM AUTHOR]

The lattice parameters and the crystal and magnetic structures of Fe2SiO4 have been determined from 10 K to 1453 K by high-resolution time-of-flight neutron powder diffraction. Fe2SiO4 undergoes two antiferromagnetic phase transformations on cooling from room temperature: the first, at 65.4 K, is to a collinear antiferromagnet with moments on two symmetry-independent Fe ions; the second transition, at ~23 K, is to a structure in which the moments on one of the sets of Fe ions (those on the 'M1 site') become canted. The magnetic unit cell is identical to the crystallographic (chemical) unit cell and the space group remains Pbnm throughout. The magnetic structures have been refined and the results found to be in good agreement with previous studies; however, we have determined the spontaneous magnetostrictive strains, which have not been reported previously. In the paramagnetic phase of Fe2SiO4, at temperatures of 70 K and above, we find that the temperature dependence of the linear thermal expansion coefficient of the b axis takes an unusual form. In contrast to the behaviour of the expansion coefficients of the unit-cell volume and of the a and c axes, which show the expected reduction in magnitude below ~300 K, that of the b axis remains almost constant between ~70 K and 1000 K. [ABSTRACT FROM AUTHOR]

A study on 5CB liquid crystal composites with SiO2 nanoparticles and an additional commixture with Fe3O4 nanoparticles using light transmission and SAW measurements is presented. The prepared liquid crystal composites exhibited an interesting memory effect characterized by the hysteresis of both light transmission and SAW attenuation responses investigated in the nematic phase. While in the case of SiO2 nanoparticles as dopants, the liquid crystal composite showed an improvement in the memory effect, the addition of Fe3O4 magnetic nanoparticles resulted in the memory effect decreasing. Additional studies showed a significant shift in both the threshold voltage and nematic–isotropic transition temperature. Measurements in the magnetic field confirmed the increasing memory effect according to that of pure 5CB. The properties of these composites could lead to a potential application for the fabrication of memory devices suitable for information storage. [ABSTRACT FROM AUTHOR]

Sliding-induced subsurface microstructure evolution is believed to be decisive for determining the friction and wear performance of metallic contacts as well as the development of tribo-magnetization. This expects to develop a new prediction method of wear state by elucidating the correlation between subsurface microstructure evolution and corresponding magnetic domain changes. Herein, subsurface microstructure evolution including crystal and magnetic domain under tribological action is investigated experimentally. Our results demonstrate that dislocation mediated plastic deformation decisively influences microstructural changes during tribological contact, further determining the magnetic domain structure. Specifically, sliding-induced plastic deformation causes an increase in the width of magnetic domains, but depth-dependent derived microstructure formed under severe plastic deformation such as the refined grains and sub-grains, in turn, promoted the refinement of magnetic domains and their discontinuity, forming depth-dependent magnetic domain structure. These results are helpful to clarify the evolution of tribo-magnetization and the pinning effect of dislocations on magnetic domains. [ABSTRACT FROM AUTHOR]

The magnetic structure of K2Co3(MoO4)3(OH)2 is studied in detail. The material has a half-sawtooth one-dimensional (1-D) structure containing two unique Co2+ ions, one in the chain backbone and one on the apex of the sawtooth creating a series of isosceles triangles along the b-axis. These triangles can be a source of magnetic frustration. The ability to grow large single crystals enables detailed magnetic measurements with the crystals oriented in a magnetic field along the respective axes. It has a Curie–Weiss temperature CW of 5.3(2) K with an effective magnetic moment of 4.8(3)μB/Co. The material is highly anisotropic with a sharp antiferromagnetic ordering transition at 7 K with a metamagnetic transition at 2 kOe. Neutron diffraction was used to determine the magnetic structure and revealed a magnetic structure with canted spins along the backbone of the chain while spins along the sawtooth caps maintained a colinear orientation, arranging antiferromagnetically relative to the backbone spins. The parallel chains arrange antiferromagnetically relative to each other along the c-axis and ferromagnetically along the a-axis. [ABSTRACT FROM AUTHOR]

Owing to the tunable compositions and versatile functionality, the development of eco-friendly metal-phenolic coordination crystals derivatives is highly anticipated for electromagnetic wave absorption. In this study, three kinds of magnetic hollow carbon spheres (HCSs) with macro-meso-microporous characteristics, including Fe/HCS, Co/HCS, and CoNi/HCS, are successfully fabricated via the co-operative hard template and self-assembling process, in which magnetic particles are encapsulated in carbon shell matrix after the pyrolysis of metal–polyphenol coordination crystals and further subsequent template removal. On the one hand, hierarchical macro-meso-micropores effectively balance the impedance gap between absorbers and air and introduce structural defects or distortion, leading to matched impedance and enhanced dipolar/defect polarization. On the other hand, wrapped magnetic particles provide uncountable hetero-interfaces and induce ferromagnetic resonance, resulting in strengthened interfacial polarization and additional magnetic loss. In particular, enhanced minimum reflection loss (RL,min) and broadband effective absorption bandwidth (EAB) are achieved with only 10 wt.% filler loading. Specifically, the RL,min and EAB values are −57.5 dB and 7.2 GHz for Fe/HCS, −50.0 dB and 5.8 GHz for Co/HCS, and −52.1 dB and 6.7 GHz for CoNi/HCS, respectively. Moreover, this work provides us a modular-assembly strategy to regulate the hollow cavity of absorbers and simultaneously manipulates the chemical components of absorbers to regulate electromagnetic wave absorption performance. [ABSTRACT FROM AUTHOR]

The document titled "Emerging materials in antiferromagnetic spintronics" provides a comprehensive overview of the physics and potential applications of compensated magnets, including antiferromagnets, altermagnets, ferrimagnets, and synthetic antiferromagnets. It is divided into seven thematic groups, covering topics such as topology, spin torques, magnonics, and imaging techniques. The document discusses the latest material developments and offers insights into the fundamental physics of compensated magnets. It also includes articles and perspectives on various topics related to antiferromagnetic materials, such as imaging techniques, ultrafast optics, and the potential of ferrimagnets and synthetic antiferromagnets for hosting topological magnetic textures. The collection provides a valuable resource for researchers interested in the advancements in the field of antiferromagnetic materials. [Extracted from the article]

Some supramolecular polyacrylate‐based liquid crystal polymers (PLCPs) were prepared by polyacrylic acid, a liquid crystal monomer and 3,5‐pyridinedicarboxylic acid. Series of magnetic liquid crystal particles (Fe3O4@PLCPs) with core‐shell structure were prepared by modifying surface of magnetic nanoparticles Fe3O4 by the PLCPs. The Fe3O4@PLCPs showed a saturation magnetization strength above 51.17 emu/g, which is similar to pure magnetic Fe3O4, indicating good magnetism and magnetic field dependence. Series of magnetorheological fluids were fabricated by Fe3O4@PLCPs (using as dispersed phase) and silicone oil (using as carrier liquid). The effects of mesogen, magnetic particle, and the polymer matrix on magnetorheological performance and settling stability were investigated. The magnetorheological fluid based on 10% Fe3O4@PLCP‐1 showed the best performance at an applied magnetic field of 100 mT in this study. Furthermore, the magnetorheological fluids showed excellent settling stability because the density of Fe3O4@PLCPs was lower than that of Fe3O4. The Fe3O4@PLCPs‐based fluids presented certain application potential in the field of magnetic fluid due to the excellent magnetorheological effect and settling stability. [ABSTRACT FROM AUTHOR]

Magnetic structure and crystal symmetry, which primarily determine the time-reversal and inversion symmetry, may give rise to numerous exotic quantum phenomena in magnetic semiconductors and semimetals when arranged in different patterns. In this work, a new layered magnetic semiconductor, Eu3−δZnxSnyAs3, was discovered and high-quality single crystals were grown using the Sn flux. According to structural characterization by x-ray diffraction and atomic-resolution scanning transmission electron microscopy, Eu3−δZnxSnyAs3 is found to crystallize in a hexagonal symmetry with the space group P63/mmc (No. 194). After examining different specimens, we conclude that their stoichiometry is fixed at ∼Eu2.6Zn0.65Sn0.85As3, which meets the chemical charge balance. Eu3−δZnxSnyAs3 is composed of septuple (Eu1−δSnyAs2)-Eu-(ZnxAs)-Eu sequences. The shortest Eu–Eu distance in the system is between two Eu layers separated by ZnxAs along the c-axis. Magnetization measurement shows an antiferromagnetic ordering in Eu3−δZnxSnyAs3 at TN ∼ 12 K, where the magnetic easy-axis is along the c-axis, and Mössbauer spectroscopy observes magnetic hyperfine splitting on Eu and Sn at 6 K. Magnetic anisotropy is significantly different from the ones along the ab-plane in other layered Eu-based magnetic semimetals. Heat capacity measurements confirm the magnetic transition around 12 K. Electrical resistivity measurement indicates semiconductor behavior with a band gap of ∼0.86 eV. Various Eu-based magnetic semiconductors could provide a tunable platform to study potential topological and magnetic properties. [ABSTRACT FROM AUTHOR]

The synthesis, single-crystal structures and magnetic properties of two new double-zigzag-chain cyano-bridged heterobimetallic {[MII(Py-NOH)2][FeIII(Tp*)(CN)3]2}·H2O ([Fe III2 MII]) (Py–NOH = 4-pyridinealdoxime, Tp* = tris(3,5-dimethylpyrazol-1-yl)borohydride, M = Ni (1), Fe (2)) compounds are reported. The crystal structures of both compounds were determined by single-crystal X-ray diffraction. Complexes 1 and 2 are isostructural, with the crystal structure comprising neutral double-zigzag (4,2-ribbon-like) bimetallic chains. The FeIII ion is coordinated by three cyanide carbon atoms and three nitrogen atoms of Tp* anions. However, the MII ion is surrounded by four cyanide nitrogen atoms and two nitrogen atoms from two Py-NOH ligands. The crystal structures and magnetic studies demonstrate that both complexes behave as single-chain magnetics (SCMs) with intrachain ferromagnetic coupling. Furthermore, [Fe III2 NiII] exhibits an excellent coercive field of 0.42 T at 1.8 K, among cyano-bridged 3d transition-metal-based SCMs reported thus far. Preliminary theoretical calculations provide a deep understanding of the magnetic properties of [Fe III2 NiII]. [ABSTRACT FROM AUTHOR]

The reactions of chromium(III) nitrate with M2(cpdc) (cpdc2− – dianion of cyclopropane-1,1-dicarboxylic acid, M = K, Na) and rare-earth metal nitrates taken in a molar ratio of 1 : 3 : 1 yielded heterometallic coordination polymers {[Ln2Cr2(cpdc)6(H2O)9]·8.5H2O}n (1Ln, Ln = Eu, Gd, Tb), crystallizing in tetragonal space group P43212 (P41212). A single crystal X-ray diffraction (XRD) study showed that the crystal structures of these compounds are formed by tris-chelate fragments {Cr(cpdc)3} linked into {Ln–Cr} layers and further into a 3D framework structure due to the bridging coordination of carboxylate groups to Ln atoms. When passing to Ln = Dy, Ho, Y, Er, Yb, the crystals of compounds 2Ln form, where the structure of {Ln–Cr} layers is retained, but the disorder of the interlayer Ln atoms, a decrease in the size of a crystal cell, and a change in the space group to I4 are observed. The use of K2(cpdc) in the syntheses of 1Ln and 2Ln is found to lead to the isolation of a side product, namely, mononuclear complex [Cr(cpdc)(Hcpdc)(H2O)2]·2H2O (3), with the reactions with Na2(cpdc) enabling obtaining only the crystals of heterometallic LnIII–CrIII compounds. Alternating current magnetic susceptibility measurements for the series 1Ln and 2Ln revealed the presence of slow relaxation of magnetization only for 1Eu and 2Y, which is due to the magnetic anisotropy of chromium ions in the presence of magnetic field and their magnetic isolation in a crystal lattice. For 1Eu, 1Gd, 1Tb, 2Dy, and 2Ho, thermal decomposition in an Ar atmosphere was studied. The end product of solid-state thermolysis of 2Dy in air at 1000 °C is shown to be submicron DyCrO3 particles (300–400 nm). [ABSTRACT FROM AUTHOR]

Y3Fe5 –xAlxO12 (х = 0, 0.5, 1.0, 1.5, 2.0) materials prepared by sol–gel synthesis have been characterized by scanning electron microscopy, X-ray diffraction, Raman and Mössbauer spectroscopies, field- and temperature-dependent saturation magnetization measurements, and magnetocaloric measurements in an ac magnetic field. We have examined the effect of aluminum concentration on the magnetic and crystal structures and magnetothermal properties of the garnet ferrite particles. [ABSTRACT FROM AUTHOR]

The influence of diamagnetic substitution on the electronic states of cations and magnetic ordering in CuCr2S4-based solid solutions has been studied by the method of Mossbauer spectroscopy on 57Fe nuclei. It has been found that magnetic dilution of spinel with diamagnetic ions disrupts the connection of 57Fe impurity ions introduced into the crystal lattice with the magnetic structure of the crystal as a whole. Violation of the long-range magnetic order leads to the formation of nanoclusters of various sizes with superparamagnetic properties. [ABSTRACT FROM AUTHOR]

Pr0.67Ba0.33Mn1-xTixO3 (x = 0 and 0.02) were synthesized using a conventional solid-state synthesis method to investigate the effect of Ti substitution on their magnetic and electrical transport properties. All the samples were structurally evaluated by XRD diffraction Rietveld refinement method which showed an increase in unit cell volume with increasing Ni content, indicating that Ti is partially substituted at Mn. Scanning electron microscopy (SEM) and energy dispersive X-tray (EDX) are used to examine the surface morphology and identified elements in the samples' compounds. Fourier transform infrared spectroscopy (FTIR) reveals that all the samples exhibit a transmission band in the range of 590 cm-1 - 610 cm-1. For x = 0, magnetization measurements showed paramagnetic (PM) to ferromagnetic (FM) transition at the transition temperature, TC ~ 213 K. For Ti-substituted samples, ferromagnetic (FM) to PM transition was reduced with Curie temperature (TC), decreasing from 213 K (x = 0) to 205 K (x = 0.02). On the other hand, the M(H) showed the presence of a linear graph for x = 0 and x = 0.02 which may be related to the presence of paramagnetic at room temperature. [ABSTRACT FROM AUTHOR]

The influence of a permanent magnetic field on macro- and nanoscopic properties of triglycine sulfate (TGS) crystals with impurity chromium (TGS-Cr) has been investigated. This work continues the previous studies of magnetically induced effects in ferroelectrics. A specific feature of TGS crystals is the presence of a nanoscale relief on a polar (010) cleavage; this nanorelief is a qualitative characteristic of the crystal defect structure. It is shown that the exposure of a crystal in a magnetic field of 2 T leads to a change in its dielectric properties, accompanied by a long-term transformation of the nanorelief. The results obtained are indicative of a magnetically induced change in the defect crystal structure. A qualitative difference is found between the magnetically induced effects in TGS-Cr crystals and undoped TGS crystals. The relationship between the magnetically induced effects and structural defects is discussed. [ABSTRACT FROM AUTHOR]

Crystal and magnetic structures of R2Ni2In (R = Tb and Ho) have been studied using powder neutron diffraction at low temperatures. The compounds crystallize as orthorhombic crystal structures of the Mn2AlB2 type. At low temperatures, the magnetic moments localized solely on the rare earth atoms form antiferromagnetic structures. The Tb magnetic moments, equal to 8.8 (4) μB and parallel to the c axis, form a collinear magnetic structure described by the propagation vector k = [½,½,½]. This magnetic structure is stable up to the Néel temperature TN = 40 K. For Ho2Ni2In a complex, temperature‐dependent magnetic structure is detected. In the temperature range 6.1–8.6 K, an incommensurate sinusoidal magnetic structure, described by the propagation vector k1 = [0.24, 1, 0.52] is observed, while in the temperature interval 2.2–2.5 K a square‐modulated magnetic structure, related to k2 = (the component along the a axis slightly differs from the commensurate value) and its third harmonics 3k2 = is found. At 3.1–3.7 K as well as below 2 K, a coexistence of both detected magnetic structures is observed. The Ho magnetic moments remain parallel to the c axis in both the sine‐ and square‐modulated magnetic structures. The low‐temperature heat capacity data confirm a first‐order transition near 3 K. [ABSTRACT FROM AUTHOR]

In this paper, a rapid and efficient method for the preparation of scopolamine hydrobromide with high purity was established, named as magnetic field-induced crystallization. Based on the difference in solubility between scopolamine and scopolamine hydrobromide, salifying crystallization was selected and then treated with the synergistic effect of magnetic field to achieve the goal of purifying scopolamine. The influence of crystallization solvents and magnetic field intensity on the crystallization process of scopolamine hydrobromide, as well as the impact of magnetic field on the crystal growth direction, were investigated. The results revealed that treatment under magnetic field led to a shortened induction time (25.64–75.46%), an increased purity of crystals (0.95–2.92%), and an enhanced recovery rate (4.51–10.78%). Furthermore, it was also discovered that magnetic field could destroy hydrogen bonds within the solution, and change the physical properties of the mother liquid, so as to promote the nucleation formation and crystal growth. These findings suggested that external magnetic field could be a promising method for scopolamine preparation. [ABSTRACT FROM AUTHOR]

Wirelessly actuated soft smart materials have great potential applications in real-world actuation and sensing in robotics and biomedical engineering. On the other hand, layered structures can gain more versatile and functional properties then conventional structures. This paper studies the photo- and magneto-responses of a layered beam consisting of liquid crystal elastomers and magnetic responsive elastomers. Based on the finite deformation theory and taking into account the coupling effect of light incidence angle and deformation, governing equation of the layered beam is derived and solved by a new numerical mothed. The results are validated by previous experimental data. It is found that the coupling effect of light incidence angle and the deformation of beam should be taken into account, especially for soft materials with large deformation. For example, neglecting the coupling effect of the light incidence angle and deformation, the maximum deflection of the cantilever beam will be underdetermined by 20.5%, if the light intensity reaches at 1.2 kW/m2. Whether the coupling effect of the light incidence angle and deformation enhances or reduces bending deformation of the beam depends on its boundary conditions and the initial light incidence angle. These results may be useful for designing photo- and magneto-responsive soft robotic and other functional devices. [ABSTRACT FROM AUTHOR]

A crystal symmetry search is crucial for computational crystallography and materials science. Although algorithms and implementations for the crystal symmetry search have been developed, their extension to magnetic space groups (MSGs) remains limited. In this paper, algorithms for determining magnetic symmetry operations of magnetic crystal structures, identifying magnetic space‐group types of given MSGs, searching for transformations to a Belov–Neronova–Smirnova (BNS) setting, and symmetrizing the magnetic crystal structures using the MSGs are presented. The determination of magnetic symmetry operations is numerically stable and is implemented with minimal modifications from the existing crystal symmetry search. Magnetic space‐group types and transformations to the BNS setting are identified by a two‐step approach combining space‐group‐type identification and the use of affine normalizers. Point coordinates and magnetic moments of the magnetic crystal structures are symmetrized by projection operators for the MSGs. An implementation is distributed with a permissive free software license in spglib v2.0.2: https://github.com/spglib/spglib. [ABSTRACT FROM AUTHOR]

Objectives: Anogeissus leiocarpus stem bark is endowed with numerous antidiabetic properties, such as its prognostic value, treatment of organic damages, dyslipidaemia and enhancement of haematopoiesis. In addition to its antioxidant activity on oxidative stress, it accelerated wound healing and has a wide range of safety value. From the purification of its compounds to the points of crystallization it became necessary to analyse the structures for an insight into its mechanisms of actions. Design: Ethanolic extracts were partitioned with ethyl acetate, onto column chromatography packed with silica gel (70-230 mesh) mixed with 95% n-hexane and 5% ethyl acetate; concentrated fractions were loaded onto silica gel-coated thin layer chromatographic plate. Different compounds were observed under UV-light fluorescence and sprayed with sulfuric acid. Similar fractions were pooled, purified to crystals for Nuclear Magnetic Resonance structural analysis. Results: Nuclear Magnetic Resonance revealed fraction A is Lupeol, a pentacyclic triterpene anti-inflammatory compound. Conclusion: Lupeol in the crude ethanolic extract is significant in inflammatory pain of diabetes. [ABSTRACT FROM AUTHOR]

Metal ferrites like nickel ferrite, copper ferrite, zinc ferrite, cobalt ferrite, and other ferrites are highly abundant and used as catalysts in various transformations. However, CaFe2O4 is the most abundant alkali metal ferrite, which is eco-friendly and non-toxic. CaFe2O4 is a superparamagnetic material that can be easily recovered from the reaction media due to its magnetic properties. Therefore, it has been widely used in numerous applications, such as dye degradation, removal of heavy metal ions, transesterification reaction, gas sensing, photocatalytic water splitting, drug delivery, etc. In this review, (1) magnetic properties and crystal structure of spinal CaFe2O4 are discussed, (2) potential applications of CaFe2O4 are discussed, and (3) various synthesis techniques of CaFe2O4 are demonstrated. CaFe2O4 shows photocatalytic properties due to its narrow band gap (1.9 eV), abundant functional group, and high surface area. It is found that CaFe2O4 possesses a remarkable potential for energy and environmental remediation. In this review, we have added the photocatalytic mechanism of various pollutants. At last, future perspectives are given for developing novel, sustainable CaFe2O4 or CaFe2O4-based nanocomposite. [ABSTRACT FROM AUTHOR]

The quasi-binary system YbMg2-YbIn2 was studied around the equiatomic composition. In contrast to the ordered rare earth (RE) phases REMgIn (ZrNiAl type), ytterbium forms phases with different structures and pronounced Mg/In mixing (M sites). The structures of YbMg0.75In1.25 (CaLiSn type, P3m1, a = 501.95(7), c = 1087.3(2) pm, wR2 = 0.0490, 790 F2 values, 32 variables) and Yb6Mg6.41In5.59 (Yb6Ir5Ga7 type, P63/mcm, a = 1060.77(14), c = 970.27(16) pm, wR2 = 0.0484, 701 F2 values, 26 variables) were refined from single-crystal X-ray diffractometer data. YbMg0.75In1.25 is an AlB2 superstructure with a tripling of the subcell. The magnesium and indium atoms form three differently puckered layers of M6 hexagons. The Yb6Mg6.41In5.59 structure is derived from the hexagonal Laves phase YbMg2 (MgZn2 type, P63/mmc). A klassengleiche symmetry reduction leads to four crystallographically independent M sites for the rows of corner- and face-sharing tetrahedra which allow a composition close to the equiatomic one. The M–M distances in both structures cover the broad range from 289 to 331 pm, comparable to the sums of the covalent radii. Temperature dependent magnetic susceptibility studies of the polycrystalline YbMg0.75In1.25 and Yb12Mg13In11 samples indicate Pauli paramagnetism with room temperature values of 2.8(1) × 10−3 emu mol−1 (YbMg0.75In1.25) and 5.2(1) × 10−3 emu mol−1 (Yb12Mg13In11). [ABSTRACT FROM AUTHOR]

Objectives: Anogeissus leiocarpus stem bark is endowed with numerous antidiabetic properties, such as its prognostic value, treatment of organic damages, dyslipidaemia and enhancement of haematopoiesis. In addition to its antioxidant activity on oxidative stress, it accelerated wound healing and has a wide range of safety value. From the purification of its compounds to the points of crystallization it became necessary to analyse the structures for an insight into its mechanisms of actions. Design: Ethanolic extracts were partitioned with ethyl acetate, onto column chromatography packed with silica gel (70-230 mesh) mixed with 95% n-hexane and 5% ethyl acetate; concentrated fractions were loaded onto silica gel-coated thin layer chromatographic plate. Different compounds were observed under UV-light fluorescence and sprayed with sulfuric acid. Similar fractions were pooled, purified to crystals for Nuclear Magnetic Resonance structural analysis. Results: Nuclear Magnetic Resonance revealed fraction A is Lupeol, a pentacyclic triterpene anti-inflammatory compound. Conclusion: Lupeol in the crude ethanolic extract is significant in inflammatory pain of diabetes. [ABSTRACT FROM AUTHOR]

The triangular lattice antiferromagnet (TLAF) has been the standard paradigm of frustrated magnetism for several decades. The most common magnetic ordering in insulating TLAFs is the 120° structure. However, a new triple-Q chiral ordering can emerge in metallic TLAFs, representing the short wavelength limit of magnetic skyrmion crystals. We report the metallic TLAF Co1/3TaS2 as the first example of tetrahedral triple-Q magnetic ordering with the associated topological Hall effect (non-zero σxy(H = 0)). We also present a theoretical framework that describes the emergence of this magnetic ground state, which is further supported by the electronic structure measured by angle-resolved photoemission spectroscopy. Additionally, our measurements of the inelastic neutron scattering cross section are consistent with the calculated dynamical structure factor of the tetrahedral triple-Q state. Skyrmion crystals, where skyrmions are arranged close packed in a triangular lattice arise due to the superposition of three magnetic spin spirals, each with a distinct wave vector, Q. Such skrymion crystals have been found in a diverse array of materials. Here, Park et al find a short wavelength (or dense skyrmion) limit of this skyrmion crystal structure in Co1/3TaS2, a metallic triangular lattice antiferromagnet, in the form of a triple Q magnetic ordering, with four magnetic sublattices.' [ABSTRACT FROM AUTHOR]

Electron paramagnetic resonance (EPR) and optical absorption are used to characterize Cu2+ (3d9) and Cu3+ (3d8) ions in Cu-doped β-Ga2O3. These Cu ions are singly ionized acceptors and neutral acceptors, respectively (in semiconductor notation, they are Cu− and Cu0 acceptors). Two distinct Cu2+ EPR spectra are observed in the as-grown crystals. We refer to them as Cu2+(A) and Cu2+(B). Spin-Hamiltonian parameters (a g matrix and a 63,65Cu hyperfine matrix) are obtained from the angular dependence of each spectrum. Additional electron-nuclear double resonance (ENDOR) experiments on Cu2+(A) ions give refined 63Cu and 65Cu hyperfine matrices and provide information about the nuclear electric quadrupole interactions. Our EPR results show that the Cu2+(A) ions occupy octahedral Ga sites with no nearby defect. The Cu2+(B) ions, also at octahedral Ga sites, have an adjacent defect, possibly an OH− ion, an oxygen vacancy, or an H− ion trapped within an oxygen vacancy. Exposing the crystals at room temperature to 275 nm light produces Cu3+ ions and reduces the number of Cu2+(A) and Cu2+(B) ions. The Cu3+ ions have an S = 1 EPR spectrum and are responsible for broad optical absorption bands peaking near 365, 422, 486, 599, and 696 nm. An analysis of loops observed in the Cu3+ EPR angular dependence gives 2.086 for the g value and 22.18, 3.31, and −25.49 GHz for the principal values of D (the fine-structure matrix). Thermal anneal studies above room temperature show that the Cu3+ ions decay and the Cu2+ ions recover between 75 and 375 °C. [ABSTRACT FROM AUTHOR]

With the concept of topological order of electronic states in crystals being proposed, the pursuit of topological phases in various systems has become an important subject of modern physical science. The existence of antisymmetric Dzyaloshinskii–Moriya interaction caused by spin–orbit coupling in magnetic systems leads to the non-reciprocal propagation of magnons, which is a key factor to realize the magnonic analog of an electronic topological insulator (TI). Here, a two-dimensional magnetic skyrmion crystal (SkX) is introduced as a platform for realizing magnonic TI. It is numerically demonstrated that nonchiral and chiral edge states could exist in different magnonic bandgaps. The nonchiral edge magnons can propagate to both directions simultaneously along the boundary of the SkX with different wavelengths and group velocities. By contrast, chiral edge magnons are topologically protected, resulting in the unidirectional propagation along the boundaries and the robustness against defects or disorders. Furthermore, the chirality and the presence of edge magnons can be manipulated by the polarity of skyrmions and the width of the second magnonic bandgap via the magnetic field. Our findings could provide a skyrmionic paradigm for investigating topological magnonics and even quantum magnonics. [ABSTRACT FROM AUTHOR]