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Generalized gradient approximation with Hubbard potential (GGA + U) within the framework of density functional theory (DFT), the structural and electronic properties, as well as the magnetic ordering of the quadruple perovskites Y2CuGaTM4O12 (TM = Mn and Fe), are studied. Formation energy indicates that Y2CuGaMn4O12 is more stable than the Y2CuGaFe4O12 and the estimated structural parameters are in good accordance with the experiment. The optimized magnetic energy curves show that these compounds have a type I ferrimagnetic order. According to the Heisenberg model, strong long-range Mn+3–O2−–Cu2+–O2−–Mn+3 interactions are mediated by a super exchange mechanism. The susceptibility data shows that these compounds undergo multiple magnetic transitions due to different magnetic interactions (J1 (Cu+2–Cu+2), J2 (Cu+2–Mn+3), and J3 (Mn+3–Mn+3)). The electronic band profiles and density of states shows the half-metallic character of these compounds and Mn d electrons are responsible for their half-metallic nature. Beside this Mn d state electrons are also responsible for magnetism with addition of Cu atoms instead of Ga. DFT and the Heisenberg model's estimated results are confirmed by magnetic susceptibility. These compounds are anticipated to be appropriate for spintronic applications due to their ferrimagnetic nature and high spin polarization near the Fermi level. [ABSTRACT FROM AUTHOR]

To overcome the challenges related to diluted magnetic semiconductors (DMS), significant research efforts are currently underway to develop functional materials to fulfil the requirements of next-generation spintronic devices. This study was planned to investigate a potential DMS material based on Al2CO using first-principles methods. Al2CO is a direct band gap semiconductor with the energy gap of 1.77 eV in such a way that the conduction band minimum is composed of Al 3 s states, whereas the valence band maximum is contributed by p states of carbon and oxygen atoms. The phonon dispersion curves revealed the dynamical stability of Al2CO. The effect of 3d transition metal (TM) dopants doping into the Al2CO on the electronic and magnetic properties was systematically investigated. The cationic site near oxygen is found energetically feasible when compared with the site adjacent to a carbon atom in the host. The dopants produced spin-polarized gap states in an otherwise non-magnetic host. The hybridization of the p states of the host with the d states of dopant pointing to p-d exchange interactions is observed. The doping of Cr in the host exhibited half-metallic nature of the material. To check the magnetic ground state, double doping with the spin-flip configuration of the host was carried out. The results revealed that the entire 3d dopants prefer to adopt antiferromagnetic coupling in Al2CO. The finding demonstrates that Al2CO is a promising host material for creating new DMS to be used in spintronics. [ABSTRACT FROM AUTHOR]

Magnetic nanomaterials showing unique magnetic behaviour have spread their potential applications in various fields. Iron oxide nanomaterials have been developed for their unique properties that they develop at extremely small size. The high surface area to volume ratio, enhanced surface properties, excellent magnetic property with better biocompatibility are the most promising properties of iron oxide nanoparticles (NPs). Hence development of bio-friendly and less toxic iron oxide NPs is the key point of research in recent years. Most importantly, unique physical and chemical properties of magnetite (Fe3O4), maghemite (γ-Fe2O3) and hematite (α-Fe2O3) are significantly important in the field of technological and biological applications. At nanoscale transition metal iron oxide develops superparamagnetism, which is very important and promising for biomedical applications. In the current study Magnetite (Fe3O4) phase of iron oxide has been prepared in the laboratory using the coprecipitation method. In this study less expensive and widely used experimental setup has been designed to observe the size effect in magnetic iron oxide nanoparticles. The structural information was obtained using X-ray diffraction (XRD). XRD result showed the presence of peaks corresponding to magnetite (Fe3O4) phase of iron oxide. The morphology of the particles was studied using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Magnetic properties were studied using vibrating sample magnetometer (VSM). Theoretical discussion on superparamagnetism has also been done. [ABSTRACT FROM AUTHOR]

Condensed matter physics has often provided a platform for investigating the interplay between particles and fields in cases that have not been observed in high-energy physics. Here, using angle-resolved photoemission spectroscopy, we provide an example of this by visualizing the electronic structure of a noncentrosymmetric magnetic Weyl semimetal candidate NdAlSi in both the paramagnetic and ferrimagnetic states. We observe surface Fermi arcs and bulk Weyl fermion dispersion as well as the emergence of new Weyl fermions in the ferrimagnetic state. Our results establish NdAlSi as a magnetic Weyl semimetal and provide an experimental observation of ferrimagnetic regulation of Weyl fermions in condensed matter. A Weyl semimetal formally requires either broken time reversal symmetry or inversion symmetry. One class of Weyl semimetals-the crystal family of NdAlSi-exhibits both. Here, Li et al perform angle-resolved photoemission spectroscopy measurements on NdAlSi, and observe the formation of an additional Weyl fermion as the material becomes ferrimagnetic. [ABSTRACT FROM AUTHOR]

The magnetic properties of trigonal 3C Fe7S8 nanoparticles, synthesized via the thermal decomposition method, are investigated using temperature-dependent zero-field cooled (ZFC) and field-cooled (FC) magnetization (M–T) curves. The M–T data, recorded at 100 and 1000 Oe, reveal magnetic ordering with high Curie transition temperature (TC > 300 K) in the specimen. The magnetization vs. applied magnetic field (M–H) data measured in the temperature range from 7 to 300 K show that the compound exhibits ferrimagnetic ordering. The values of coercivity (HC), saturation magnetization (M60 kOe) and remanent magnetization (MR) appear to increase at lower measuring temperatures. As the result of increasing M60 kOe at lower measuring temperatures, within the temperature range of 7 to 300 K, the maximum energy product (BHmax) has the highest value of 128 kG Oe at 7 K. [ABSTRACT FROM AUTHOR]

The influence of the size of dislocation loops on sublattice ferrimagnetism in graphene is studied. It is shown that graphene and the underlying gold layer with Au/Co dislocation loops of various sizes are characterized by ferrimagnetic ordering within atomic layers. Additional gold adatoms under graphene enhance the induced Rashba spin–orbit coupling in graphene but do not destroy the ferrimagnetic order in graphene. Since gold clusters can remain during the intercalation of gold on the surface of graphene and under graphene, the number and size of clusters after intercalation can be controlled to enhance the induced Rashba interaction and to obtain a topological phase in graphene. [ABSTRACT FROM AUTHOR]

The electrical resistivity, magnetic, and galvanomagnetic properties of the cast and rapid melt quenched Mn3Al Heusler alloy have been studied. Rapid melt quenching was found to result in changing the microstructure of the Mn3Al alloy, which leads to substantial changes in its electronic transport and magnetic properties. It was suggested that for the cast and rapid melt quenched Mn3Al alloy frustrated antiferromagnetic and almost compensated ferrimagnetic state could appear, respectively. It is shown that the preparation and treatment of the Mn3Al compound plays a substantial role in the formation of its electronic and magnetic characteristics. [ABSTRACT FROM AUTHOR]

The magnetic superconductors Dy0.8Er0.2Rh3.8Ru0.2B4 (Tc ~ 5.1 K) and Dy0.6Er0.4Rh3.8Ru0.2B4 (Tc ~ 5.8 K) have been prepared by partially substituting Er for Dy in DyRh3.8Ru0.2B4, and their χ(Т), М(B), and (Т) have been studied in detail. The materials have been shown to undergo an antiferromagnetic transition (at ~3 K) similar to that of the magnetic superconductor DyRh3.8Ru0.2B4. Using magnetic moment vs. magnetic field, M(B), measurements for Dy0.8Er0.2Rh3.8Ru0.2B4 and Dy0.6Er0.4Rh3.8Ru0.2B4 samples and the Bean model, we have obtained the critical current density as a function of field, jc(B), and the reduced pinning force as a function of reduced field, Fp(h), for the Er-containing materials. The superconductors with antiferromagnetic order in their magnetic subsystem (Dy0.8Er0.2Rh3.8Ru0.2B4 and Dy0.6Er0.4Rh3.8Ru0.2B4) have been shown to exhibit the largest deviation from the scaling law for h > 0.4. [ABSTRACT FROM AUTHOR]

Structural properties, electronic band profile along with magnetic ordering of the tri-transition quaternary perovskites CaCu3B2Ir2O12 (B = Mn, Fe, Co and Ni) are investigated through generalized gradient approximation plus Hubbard potential (GGA + U) in the framework of density functional theory (DFT). The estimated structural parameters are well consistent with the experiments and it is indicated from formation energy that CaCu3Mn2Ir2O12 is more stable among the series. The optimized magnetic energy curves reveal the spin glass behavior for CaCu3B2Ir2O12 (B = Mn and Fe) and type-I ferrimagnetic order for CaCu3B2Ir2O12 (B = Co and Ni) compounds. The Heisenberg model estimates the J1 (Cu–B), J2 (B–Ir), and J3 (Cu–Ir) interactions that generate the strong long-range interactions through superexchange mechanism. Furthermore, the electronic band profiles reveal that the 3d electrons of Cu and B are localized and responsible for magnetism while the Ir-5d electrons are delocalized and responsible for metallic nature in the compounds. Magnetic susceptibility verifies the estimated results of DFT and Heisenberg model. Due to spin polarization around the Fermi level, low magnetic moments, magnetization, spin glass, and ferrimagnetic nature of these compounds, it is expected that these materials are suitable for spintronic applications. [ABSTRACT FROM AUTHOR]

We studied some magnetic behaviors of the Ising model in a single-wall mixed spin (σ = ½, S = 1) triangular nanotube using the effective field theory with correlations (EFTC), and the differential operator technique (DOT). The effects of exchange interactions as well as the temperature and the applied field on the magnetic properties of the nanotube, such as isotherm and spontaneous magnetizations, were carefully analyzed. We demonstrated that the low-temperature behavior of the magnetization is very sensitive to the exchange interactions involved, especially in the case of competitional couplings. Besides the phase diagram, unusual phenomena have been discovered, especially for opposite exchange interactions where magnetization plateaus and frustration are observed. Several forms of ferrimagnetism have been revealed for judicious choices of exchange and single-ion anisotropy. One of the most notable effects is the occurrence of magnetization jumps and fractional plateaus due to both the geometry and the competition between exchange couplings, on the one hand, and the applied magnetic field, on the other hand. Such plateaus could provide a path toward potential applications of functional ferrimagnets in spintronics and device regulation. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) magnetic materials promise unconventional properties and quantum phases as well as advances in ultra-compact spintronics. Miniaturization of 2D magnets often reaches a single monolayer but in general can go beyond this limit, as demonstrated by 2D magnetism of submonolayer Eu superstructures coupled with Si. The question is whether the submonolayer magnetism constitutes a general phenomenon. Herein, we demonstrate that regular Eu lattices form a class of 2D magnets displaying various structures, stoichiometries, and chemical bonding. We synthesized and studied a set of Eu superstructures on Ge(001). Their magnetic properties are consistent with the emergence of a magnetic order such as ferro- or ferrimagnetism. In particular, control over the magnetic transition temperature by weak magnetic fields indicates the 2D nature of the magnetism. Taken together, Eu/Ge and Eu/Si superstructures seed a nucleus of the research area addressing the emergence of magnetism in submonolayer chemical species. [ABSTRACT FROM AUTHOR]

The magnetic and magnetic entropy behaviors of the CaBaCo4O7 with Al-doping CaBaCo3.96Al0.06O7 and Ni-doping CaBaCo3.96Ni0.06O7 compound are observed. When compared with the Al-doping, Ni-doping shows that a huge decrease of ferrimagnetism is produced. For Al-doping, the magnetic measurements suggest that spin-glass and ferromagnetic transitions are observed at 25 K and 45 K. For Ni-doping, besides the above two transitions, another peak is observed due to the antiferromagnetic (AFM) phase appearance at ~ 80 K. The plot of H/M vs M2 of the isotherms in the vicinity of the Curie temperature suggests that this phase transition was first-order phase transition for all compounds. With decreasing the temperature, the system enters charge-order state and the negative entropy is observed for CaBaCo4O7 and CaBaCo3.96Al0.04O7 compound. However, unlike the nonmagnetic doping, replacement of Co2+ in the zig-zag ferromagnetic chain by Ni2+ does not truncate the chain, but it perturbs the magnetic interaction through antiferromagnetic exchange with cobalt following Goodenough–Kanamori rules. This possibly reorients the cobalt spins adjacent to the dopant in the chain which modifies ferrimagnetic ground state resulting in competing magnetic states. These are likely responsible for the change in magnetic ground state of CaBaCo4O7, this results in suppression of ferrimagnetic state with the evolution of antiferromagnetism and magnetic frustration. The result suggests that the AFM interaction between the dopant Ni2+ and Co2+ ions has a crucial role in the destabilization of the ferromagnetic structure, whereas the triangular geometry of the cobalt sublattice imposes the appearance of magnetic frustration. [ABSTRACT FROM AUTHOR]

The review considers various groups of Heusler compounds, which can have the properties of a semiconductor, a half-metallic ferromagnet, a spin gapless semiconductor, a topological semimetal, and a non-collinear antiferromagnet. In these Heusler compounds, "conventional" from the point of view of the crystal structure, unusual kinetic and magnetic properties can be observed, which are caused by the features of their electronic structure (e.g., presence of an energy gap for one spin projection) and magnetic state (e.g., strong ferromagnetism, compensated ferrimagnetism). Their magnetic and kinetic characteristics are very sensitive to external influences. Depending on the alloy composition and external parameters, transitions between the considered states can be realized. All this opens up further prospects for controlling the electronic and magnetic characteristics of such compounds and their practical application. [ABSTRACT FROM AUTHOR]

Novel kind lead-free 0–3 type particulate composites of binary ferroelectric and magnetostrictive phase having molar ratio of (1 − x){0.94Na0.5Bi0.5TiO3 (NBT)-0.06Ba0.85Sr0.15Zr0.1Ti0.9O3 (BSZT)} − (x) Ni0.7Zn0.3Fe2O4 (NZFO) [x = 0, 0.1, 0.3, 0.5 & 1] have been investigated. To probe the magnetoelectric response of the (1 − x)(0.94NBT-0.06BSZT−(x)NZFO composites, structural, morphological and magnetoelectric properties were systematically studied. Scanning electron microscopy (SEM) shows the ferrimagnetic phase (NZFO) distribution in the binary ferroelectric, NB (0.94NBT-0.06BSZT) matrix with different micro-structural symmetry. With increasing ferrimagnetic content, the room temperature dielectric study shows an increase in relative permittivity as well as an increase in dielectric loss. The occurrence of spontaneous polarization in all composites is conclusively demonstrated by polarization with respect to electric field (P–E) loops. The M–H curve at room temperature demonstrates the emergence of ferromagnetic long-range ordering as ferrite concentration increases. The magneto-dielectric and magneto-electric characterization techniques have been used as sensitive probing tools to evaluate the degree of magnetoelectric coupling in (1 − x)(0.94NBT-0.06BSZT − (x)NZFO composites. Magneto-dielectric (MD %) shows the maximum 1.81% change at 1 kHz along with high values of magneto-electric coupling coefficients α ~ 366 μV/cm Oe for 50{0.94NBT-0.06BSZT} − 50NZFO composite. These lead-free environmentally friendly ME particulate composites may provide an opportunity for the miniaturization of future ME devices. [ABSTRACT FROM AUTHOR]

Nanoparticles of Ni0.6–xZn0.4CoxFe2O4 were prepared via an aqueous sol–gel auto-combustion route. The Ni–Zn–ferrite system was doped with Co to improve the magnetic properties. Structural determination of the phase and crystallite size was achieved using the X-ray diffraction technique. Spinel cubic (single-phase) nanoparticles were formed at some specific compositions, x = 0.264 and x = 0.528, whereas at other compositions, a partial hematite secondary phase was formed. The values of saturation magnetization depend upon the concentration of the hematite phase; in this situation, the value of magnetic saturation decreases, causing a high spin canting effect that results in a decrease in the net magnetic moment. Further doping of Co2+ ions enhances the magnetic properties because of its high magnetic moment and distributions. Theoretical analysis using the most suitable proposed cation distribution verified the experimental findings. The observed structural and magnetic findings may contribute to improve electromagnetic-interference-shielding and magnetic-recording-device applications. [ABSTRACT FROM AUTHOR]

The magnetic properties of the mixed spin − 1/2 and spin − 1 Ising ferrimagnetic nanotube with a hexagonal lattice in the presence of the crystal field are investigated by means of the finite cluster approximation. We examine the effects of the crystal field, the surface shell, and core coupling parameters where the main attention has been paid to study the magnetizations and also the phase diagrams for both transition and compensation temperatures. In the absence of the crystal field, the compensation behavior exists only in a limited range of surface shell and core couplings. By introducing a crystal field, the compensation behavior is maintained and the tricritical behavior occurs depending on the strength of surface shell coupling. [ABSTRACT FROM AUTHOR]

Exploring two-dimensional (2D) magnetic semiconductors with room-temperature magnetic ordering and electrically controllable spin-polarization is a highly desirable but challenging task for nano-spintronics. Here, through first-principles calculations, we propose to realize such a material by exfoliating the recently synthesized organometallic layered crystal Li0.7[Cr(pyz)2]Cl0.7·0.25(THF) (pyz=pyrazine, THF=tetrahydrofuran). The feasibility of exfoliation is confirmed by the rather low exfoliation energy of 0.27 J m−2, even smaller than that of graphite. In exfoliated Cr(pyz)2 monolayers, each pyrazine ring grabs one electron from the Cr atom to become a radical anion, and then a strong d-p direct-exchange magnetic interaction emerges between Cr cations and pyrazine radicals, resulting in room-temperature ferrimagnetism with a Curie temperature of 342 K. Moreover, the Cr(pyz)2 monolayer is revealed to be an intrinsic bipolar magnetic semiconductor where electrical doping can induce half-metallic conduction with controllable spin-polarization direction. [ABSTRACT FROM AUTHOR]

Multiferroic behaviour in novel kind of ferroelectric (FE)–ferromagnetic (FM) particulate composites of (1−x)PbZr0.95Ti0.05O3(PZT)–(x)Ni0.7Zn0.3Fe2O4 (NZFO) [x = 0.1, 0.2, 0.3 and 0.4] has been studied. The study of FE–FM composites is represented in the context of structural, electrical, magnetic and magnetodielectric properties. X-ray diffraction reveals that both ferroelectric (PZT) and ferrite (NZFO) phases are present in prepared 0–3 type particulate composites. Scanning electron micrographs show the distribution of NZFO in the PZT matrix. Temperature-dependent relative permittivity studies revealed ferroelectric to paraelectric transition at ~ 250 °C. Room-temperature dielectric properties of the system have been studied in a wide range of frequencies (100 Hz to 1 MHz). Polarization versus electric field (P–E) studies at room temperature give conclusive confirmation of the presence of spontaneous polarization in all the composites. Magnetodielectric (MC%) measurements show the maximum 7.74% change at 1 kHz along with high values of magnetoelectric coupling coefficients γ ~ 5.98 × 10–5 (emu/g)−2, χE ~ 53.75 (mV/cm Oe) and χ ~ 16.60 × 10–8 (s/m) for 60PZT–40NZFO composite. [ABSTRACT FROM AUTHOR]

Multiferroic behaviour in novel kind of ferroelectric (FE)–ferromagnetic (FM) particulate composites of (1−x)PbZr0.95Ti0.05O3(PZT)–(x)Ni0.7Zn0.3Fe2O4 (NZFO) [x = 0.1, 0.2, 0.3 and 0.4] has been studied. The study of FE–FM composites is represented in the context of structural, electrical, magnetic and magnetodielectric properties. X-ray diffraction reveals that both ferroelectric (PZT) and ferrite (NZFO) phases are present in prepared 0–3 type particulate composites. Scanning electron micrographs show the distribution of NZFO in the PZT matrix. Temperature-dependent relative permittivity studies revealed ferroelectric to paraelectric transition at ~ 250 °C. Room-temperature dielectric properties of the system have been studied in a wide range of frequencies (100 Hz to 1 MHz). Polarization versus electric field (P–E) studies at room temperature give conclusive confirmation of the presence of spontaneous polarization in all the composites. Magnetodielectric (MC%) measurements show the maximum 7.74% change at 1 kHz along with high values of magnetoelectric coupling coefficients γ ~ 5.98 × 10–5 (emu/g)−2, χE ~ 53.75 (mV/cm Oe) and χ ~ 16.60 × 10–8 (s/m) for 60PZT–40NZFO composite. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate the operation of a Rowland-type concave grating for spin waves, with potential application as a microwave spectrometer. In this device geometry, spin waves are coherently excited on a diffraction grating and form an interference pattern that focuses spin waves to a point corresponding to their frequency. The diffraction grating was created by focused-ion-beam irradiation, which was found to locally eliminate the ferrimagnetic properties of YIG, without removing the material. We found that in our experiments spin waves were created by an indirect excitation mechanism, by exploiting nonlinear resonance between the grating and the coplanar waveguide. Although our demonstration does not include separation of multiple frequency components, since this is not possible if the nonlinear excitation mechanism is used, we believe that using linear excitation the same device geometry could be used as a spectrometer. Our work paves the way for complex spin-wave optic devices—chips that replicate the functionality of integrated optical devices on a chip-scale. [ABSTRACT FROM AUTHOR]

We have studied the electrical-transport, thermophysical, and magnetic properties of the YRh4B4 and HoRh3.8Ru0.2B4 compounds. YRh4B4 has been shown to be a classic type II superconductor with Tc ~ 10 K, whereas the superconducting transition of HoRh3.8Ru0.2B4 (at Tc ~ 6 K) occurs along with its ferrimagnetic transition (Tm ~ 22–23 K). We have measured magnetic irreversibility loops for the YRh4B4 and HoRh3.8Ru0.2B4 compounds and calculated Jc(B) in the Bean model. The reduced pinning force Fp/Fp max as a function of hp = B/Bc2 for YRh4B4 has been shown to obey a "scaling" law, whereas the magnetic superconductor HoRh3.8Ru0.2B4 exhibits a significant deviation from the scaling law for hp > 0.2. [ABSTRACT FROM AUTHOR]

We present an overview of the microscopic theory of the Dzyaloshinskii–Moriya (DM) coupling and related exchange-relativistic effects such as exchange anisotropy, electron-nuclear antisymmetric supertransferred hyperfine interactions, antisymmetric magnetogyrotropic effects, and antisymmetric magnetoelectric coupling in strongly correlated 3d compounds focusing on orthoferrites RFeO3 (R is a rare-earth ion or yttrium Y). Most attention in the paper centers around the derivation of the Dzyaloshinskii vector, its value, orientation, and sense (sign) under different types of the (super)exchange interaction and crystal field. Microscopically derived expression for the dependence of the Dzyaloshinskii vector on the superexchange geometry allows one to find all the overt and hidden canting angles in orthoferrites RFeO3 as well as corresponding contribution to magnetic anisotropy. Being based on the theoretical predictions regarding the sign of the Dzyaloshinskii vector we have predicted and study in detail a novel magnetic phenomenon, weak ferrimagnetism in mixed weak ferromagnets with competing signs of the Dzyaloshinskii vectors. The ligand NMR measurements in weak ferromagnets are shown to be an effective tool to inspect the effects of DM coupling in an external magnetic field. Along with orthoferrites RFeO3 and weak ferrimagnets RFe1 –xCrxO3, although to a lesser extent, we address such typical weak ferromagnets as α-Fe2O3, FeBO3, and FeF3. [ABSTRACT FROM AUTHOR]

Using density functional theory calculations, we found that recently high-pressure synthesized double perovskite oxide Lu 2 NiIrO 6 exhibits ferrimagnetic (FiM) Mott-insulating state having an energy band gap of 0.20 eV which confirms the experimental observations (Feng et al. in Inorg Chem 58:397–404, 2019). Strong antiferromagnetic superexchange interactions between high-energy half-filled Ni + 2 - e g 2 ↑ and low-energy partially filled Ir + 4 t 2 g 3 ↑ t 2 g 2 ↓ orbitals, results in a FiM spin ordering. Besides, the effect of 3d transition metal (TM = Cr, Mn, and Fe) doping with 50% concentration at Ni sites on its electronic and magnetic properties is explored. It is established that smaller size cation-doping at the B site enhances the structural distortion, which further gives strength to the FiM ordering temperature. Interestingly, our results revealed that all TM-doped structures exhibit an electronic transition from Mott-insulating to a half-metallic state with effective integral spin moments. The admixture of Ir 5d orbitals in the spin-majority channel are mainly responsible for conductivity, while the spin minority channel remains an insulator. Surprisingly, a substantial reduction and enhancement of spin moment are found on non-equivalent Ir and oxygen ions, respectively. This leads the Ir ion in a mixed-valence state of + 4 and + 5 in all doped systems having configurations of 5 d 5 ( t 2 g 3 ↑ t 2 g 2 ↓ ) and 5 d 4 ( t 2 g 2 ↑ t 2 g 2 ↓ ), respectively. Hence, the present work proposes that doping engineering with suitable impurity elements could be an effective way to tailor the physical properties of the materials for their technological potential utilization in advanced spin devices. [ABSTRACT FROM AUTHOR]

Recent results showed that the ferrimagnetic compensation point and other characteristic features of Tb/Co ferrimagnetic multilayers can be tailored by He+ ion bombardment. With appropriate choices of the He+ ion dose, we prepared two types of lattices composed of squares with either Tb or Co domination. The magnetization reversal of the first lattice is similar to that seen in ferromagnetic heterostructures consisting of areas with different switching fields. However, in the second lattice, the creation of domains without accompanying domain walls is possible. These domain patterns are particularly stable because they simultaneously lower the demagnetizing energy and the energy associated with the presence of domain walls (exchange and anisotropy). For both lattices, studies of magnetization reversal show that this process takes place by the propagation of the domain walls. If they are not present at the onset, the reversal starts from the nucleation of reversed domains and it is followed by domain wall propagation. The magnetization reversal process does not depend significantly on the relative sign of the effective magnetization in areas separated by domain walls. [ABSTRACT FROM AUTHOR]

The polycrystalline samples of Al1.5Mn1.5O4, MgAl0.5Mn1.5O4 and MgGa0.5Mn1.5O4 were prepared using a standard ceramic method and characterized by X-ray diffraction and magnetic measurements. The cationic distributions were determined by the combination of the Rietveld refinement and the tabulated cation-oxygen distances in spinel compounds. The results obtained were compared with those calculated using a thermodynamic calculation according to the O'Neill model. The Al1.5Mn1.5O4 compound is characterized by its cationic distribution with a high occupancy rate of the magnetic ions Mn2+ in the A sites, in agreement with the experimental magnetic moment. This compound presents a ferrimagnetic behavior at T < 23.5 K. The MgAl0.5Mn1.5O4 and MgGa0.5Mn1.5O4 compounds have almost the same distribution of magnetic manganese cations in both A and B sites, with a weak presence of the magnetic ions Mn2+ in the A sites, justified by the refinement Rietveld, thermodynamic calculation and the hyperbolic form of the inverse magnetic susceptibility above 23.2 K. Both compounds have almost the same magnetic behavior at low temperature T < 23.2 K, typical of a spin glass. This behavior is attributed to the strong presence of diamagnetic ions on the A sites and the magnetic disorder in B sites. [ABSTRACT FROM AUTHOR]

This work focuses on the study of the influence of the insertion layer (IL) on the magnetic properties of thin films of Co-Tb. Thin films of Ta (5 nm)/Co1−xTbx (20 nm)/Cu (3 nm)/Co1−xTbx (20 nm)/Ta (5 nm) as well as Ta (5 nm)/Co1−xTbx (40 nm)/Ta (5 nm) with x = 0.10 and 0.15 were grown on a silicon substrate using DC magnetron sputtering. The X-ray diffraction patterns indicate the amorphous nature of all prepared films. The measurement of surface roughness of Ta (5 nm)/Co1−xTbx (20 nm) and Co0.85Tb0.15 (20 nm)/Cu (3 nm)/Co0.85Tb0.15 (20 nm) films using 3D optical profilometer indicates a high surface roughness. The measured out-plane and in-plane magnetic hysteresis (M-H) curves indicate that Ta/Co1−xTbx (40 nm)/Ta films (i.e., without any IL) exhibit nearly magnetic isotropic behavior. However, Ta/Co1−xTbx (20 nm)/Cu (3 nm)/Co1−xTbx (20 nm)/Ta films exhibit in-plane magnetic anisotropy. The in-plane anisotropy was found to be significant for the case of x = 0.10 film with larger effective anisotropy constant (Keff). The values of saturation magnetization and squareness (Sq) of films are found to decrease with Cu insertion layer and it is likely due to the worsening of the Co-Tb/Cu interface. The post-annealing of the Co-Tb films with Cu IL helps to improve the value of MS and Keff but it reduces the HC and the squareness of the hysteresis curve. [ABSTRACT FROM AUTHOR]

Recently, many theoretical studies have projected that the Mn-doped ZrO2 compounds can exhibit long-range ferromagnetism. This study is to understand the magnetic property of Mn-doped monoclinic zirconia, Zr1−xMnxO2 (x = 0, 0.05, 0.10, 0.15, and 0.20), prepared at equilibrium condition, using solid-state reaction route. The structural property of these samples was studied using X-ray diffraction, and it is observed that all Mn-doped compounds are crystallized into monoclinic symmetry. The magnetic property measurements show that the pure ZrO2 compound exhibit paramagnetic behavior. However, all Mn-doped compounds exhibit ferrimagnetic ordering with a magnetic irreversibility behavior. The magnetic irreversibility in these compounds can be explained in terms of competition between ferrimagnetic and anti-ferromagnetic interactions. The coercivity and the area under hysteresis loop of all Mn-doped compounds are found to increase with the increase of Mn doping. The influence of final sintering temperature on the magnetic property is also studied, and it indicates that the samples prepared at a lower sintering temperature (1200 °C) exhibits better squareness of M-H loop, but with a decreased magnetic moment in comparison to the samples prepared at 1550 °C. [ABSTRACT FROM AUTHOR]

In the present work for the first time, we report in-depth structural, electrical, optical and magnetic properties of a family of cobalt chromate nanoparticles with 5 mol% Bi3+ substitution of the average crystallite size of 15 nm, fabricated by a solution combustion method using urea and glucose as a fuel. Co0.95Bi0.05Cr2O4 shows a single phase with spinel cubic structure with a space group of Fd3m with a lattice parameter of 8.334 Å. The morphology of the family of Bi3+-doped CoCr2O4 shows a highly porous nature. Transmission electron microscopy (TEM) shows samples are in nano size, i.e. 22 nm with well crystalline nature. The energy gap was estimated by using UV spectrum and found in the range of 3.86 eV. Temperature-dependent dielectric constant (ε′), dielectric loss (ε″) and loss tangent (tan δ) are explained by using Maxwell–Wagner and Koop's phenomenological theory. The evolution of magnetic behaviour was studied as a function of temperature and magnetic field to study the magnetic transitions such as paramagnetic to long-range collinear ferrimagnetism transitions, and it was found at 98 K and non-collinear ferrimagnetism at 26 K. M−H loop at 300 K nearly shows a paramagnetic phase at 98 K, and it clearly suggests that samples exhibit superparamagnetic nature. [ABSTRACT FROM AUTHOR]

Nanoscale [Tb–Co/Ti]n and [Tb–Co/Si]n multilayers were designed and prepared by the rf-sputtering technique. Their structure and magnetic properties have been experimentally studied. Low-angle X‑ray diffraction studies confirmed that a well-defined layered structure was formed in all investigated cases. The change in the magnetic properties of multilayers with a decrease in the thickness of the Tb–Co layers was due to both the size effect and the influence of the material of the non-magnetic spacers, namely the reduction of the Co atom moment because of the electron charge transfer from atoms of the Ti or Si spacers to atoms of the cobalt. [ABSTRACT FROM AUTHOR]

Thin films of Co1−xTbx (x = 0.10, 0.12, and 0.15) alloy have been prepared by a co-sputtering process using dc magnetron sputtering. The measurement of temperature variation of magnetization indicates that these films exhibit ferrimagnetism with Curie temperature (TC) much above the room temperature. The M–T curves under zero-field-cooled and field-cooled conditions indicate that Co0.85Tb0.15 film exhibits non-collinear sperimagnetic ordering due to competition between exchange interaction and perpendicular magnetic anisotropy. An increase of coercivity, squareness, and change of magnetic isotropy to magnetic anisotropy behavior with the increase of Tb composition was observed. Particularly, Co0.85Tb0.15 is found to exhibit perpendicular magnetic anisotropy. The relative reversal in these films follows the Kondorsky model. The post-annealing of the films helps to improve the squareness of the hysteresis curve, but it reduces the coercivity. [ABSTRACT FROM AUTHOR]

Magnetism, electronic structure, elastic and thermal properties of Mn2YAl (with Y = Cr, V) have been investigated. The optimized lattice parameters, bulk modulus, and cohesive energy have been obtained. These alloys have the ferrimagnetic state as the most stable magnetic configuration, since the calculations showed a strong Mn-V antiferromagnetic coupling leading to the ferromagnetism of the Mn sublattices. A small and itinerant magnetic moment of Mn at the A site is found, which is antiparallel to the moment of Y at the B position in Mn2YAl (with Y = Cr, V) compounds. The calculated total spin moments are integral values and increase from − 2 μB/f.u. for Mn2VAl to – 1 μB/f.u. for Mn2CrAl with increasing the number of valence electrons. Band structure and total and partial density of states could be calculated via applying the modified Becke Johnson approximation (mBJ). Based on these results, Mn2YAl (with Y = Cr, V) are half-metallic ferrimagnets with the energy gap lies in the majority spin direction and a high-spin polarization (100%). The main difference between these two compounds is that the band gap is increased by 48% (0.210 eV for Mn2CrAl and 0.401 eV Mn2VAl). Elastic anisotropies, brittleness, and thermodynamic properties are determined for the Mn2YAl (with Y = Cr, V). The slight difference in the spatial distributions of Young's moduli of Mn2YAl (with Y = Cr, V) reflects the small differences for the elastic anisotropies of the alloys under consideration. The mechanical stability of Mn2YAl (with Y = Cr, V) alloys are studied based on the elastic constants. The thermal properties are studied and investigated using the quasi-harmonic model, in addition, the temperature effect on heat capacities at constant pressure and volume, entropy, and thermal expansion are analyzed and discussed. [ABSTRACT FROM AUTHOR]

The anomalous physical properties of dysprosium iron garnet Dy3Fe5O12 or DyIG single crystals have been revisited at low temperatures. This paper presents results of experimental investigation based on specific heat, magnetization, and Faraday rotation measurements. The distinguishing features are the occurrence of two types of anomalies in the temperature dependences of some judicious quantities. The first one coincides with the previous first-order spin reorientation transition at TSR = 15 K where the iron sublattice magnetization vector MFe changes from the <111> axis at high temperature toward the low angular phases below TSR. The second one takes place around the "low-temperature Belov point" TB = 42 K, confirming what had already been predicted previously about the paraprocess effect in this ferrimagnet. The results are compared with previous findings and discussed taking into account the coexistence of some concomitant phenomena such the magnetodielectric and Schottky effects which cause anomalies, respectively near TSR and TB. [ABSTRACT FROM AUTHOR]

CoFe2O4 has been attracting attention for its ferrimagnetism applicable to spin transfer, resonance imaging, drug delivery etc. CoFe2O4 thin films were synthesized on Si(100) substrates by using a sol–gel deposition process. The CoFe2O4 specimen produced by post-annealing in air at 800 °C showed flat surface and polycrystalline grains with no secondary phase. The specimen exhibited magnetic hysteresis curve with magnetization up to 415 emu/cm3 and coercivity of 1.7 kOe. Such a large magnetization implies migration of a number of Co2+ ions from octahedral to tetrahedral sites of the spinel lattice. The distribution of Co2+ ions among tetrahedral and octahedral sites of CoFe2O4 was estimated by curve-fitting analysis on the Raman scattering spectrum of the specimen. The result suggests 30% of the Co2+ ions residing in the tetrahedral sites. The coexistence of Co2+ ions in both tetrahedral and octahedral sites of CoFe2O4 was also detectable by using Co 2p X-ray photoelectron spectroscopy. Highlights: CoFe2O4 thin films with high crystalline quality have been fabricated on Si(100) substrates by using a sol–gel technique and post-annealing in air at 800 °C. Thin-film CoFe2O4 specimen exhibits magnetization (415 emu/cm3) that is larger than theoretical value (380 emu/cm3) expected for pure inverse spinel CoFe2O4. The enhanced magnetization of CoFe2O4 is ascribed to the migration of Co2+ ions to the tetrahedral sites of the spinel lattice. The inversion parameter of CoFe2O4 is estimated to be 0.70 through a curve-fitting analysis on the Raman scattering spectrum of the specimen. [ABSTRACT FROM AUTHOR]

Using first-principle calculations, the structural, electronic, and magnetic properties of the Ca2FeMoO6 double perovskite compound is investigated. Different spin-ordering: ferrimagnetic (FiM), ferromagnetic (FM), and anti-ferromagnetic (AFM1 and AFM2) using the generalized gradient approximation (GGA) and GGA + U (Hubbard Coulomb onsite correction) are evaluated to determine the theoretical ground state. The value of the Hubbard Coulomb U parameter is varied from 1 to 4 eV. The ground state is found to be a FM spin-ordering within the GGA approach and FiM spin-ordering within the GGA + U approach (where U ≥ 3 eV) which is the experimental preferred configuration. We obtain the FiM spin-ordered half semiconducting state within the GGA + U approach for the Ca2FeMoO6 compound. Within the GGA + U (where U ≥ 3 eV) approach, the FM phase maintains a half-metallic character with a net magnetic moment of 4 0 μB, whereas the FiM phase have a spin gapless semiconducting (SGS) behavior at U = 3 eV, and an insulating character at U = 4 eV, with a net magnetic moment of 4 0 μB. The main features found in the density of states profile show that the hybridization of the Fe and Mo d orbitals play an important role in determining the electronic and magnetic character of this compound. [ABSTRACT FROM AUTHOR]

The ferrimagnetic systems have been extensively investigated because of their fascinating properties. In this paper, the mixed spin-7/2 and spin-3 Ising system with periodic boundary conditions on a square lattice has been studied using the Monte Carlo simulation within the Metropolis algorithm; the Hamiltonian of the system includes the interaction between the first nearest neighbors and the crystal fields Δ7/2 and Δ3 generated by the spin-7/2 and spin-3, respectively. The ground-state phase diagram of the system has been established. On the other hand, the impact of the single-ion anisotropies on the compensation temperature has been shown. Several topologies of the total magnetization have been found for this system. [ABSTRACT FROM AUTHOR]

Using the effective field theory with correlations, we have studied the phase diagrams and the thermal variations of total magnetization (mT) in a graphene-like Ising bilayer film with nonequivalent planes, consisting of two A (spin-1/2) and B (spin-1) planes with an applied transverse field in the B plane. We have investigated the effects of an applied transverse field and the interplane exchange interaction on the magnetic properties. Many interesting behaviors, such as various types of mT curves and the re-entrant phenomena, have been obtained, depending on the selections of physical parameters. [ABSTRACT FROM AUTHOR]

First principles calculations based on density functional theory is used to study the structural, electronic, and magnetic properties of novel CoFeNbZ (Z = Al, Si, Ge, Sn) quaternary Heusler alloys with the full-potential linearized augmented plane wave (FP-LAPW) method. The exchange-correlation effects are treated using generalized gradient approximation (GGA) to study the structural properties. With GGA as the exchange-correlation potential, CoFeNbAl and CoFeNbSn are half-metallic with 100% spin polarization, whereas CoFeNbSi and CoFeNbGe are nearly half-metallic with high spin polarization of 90.06 and 98.28% respectively. For CoFeNbAl and CoFeNbSn, the spin-flip gap increases with the use of modified Becke-Johnson potential. Using this approximation, CoFeNbGe is a half-metal with a spin-flip gap of 0.303 eV. The magnetic properties indicate that all the compounds follow the Mt = Zt - 24 Slater-Pauling rule. The half-metallic behavior is maintained over a relatively wide range of lattice constants against hydrostatic strain. The transport properties of half-metallic CoFeNbZ (Z = Al, Ge, Sn) compounds are reported. Our present work has the potential to trigger the design of quaternary Heusler alloys with applications in spintronic devices. [ABSTRACT FROM AUTHOR]

In this work, the structural and magnetic properties in ZnCr2−xGaxO4 were investigated. In ZnCr2−xGaxO4, Ga3+ ions substitute partial Cr3+ ions and occupy the B sites. ZnCr2O4 undergoes a paramagnetic-antiferromagnetic transition at 12 K. In ZnCr2−xGaxO4, the antiferromagnetic short-range correlation occurs below 60 K above T N . The Ga3+ doping weakens the antiferromagnetic nearest-neighbor exchange interaction (J1) and induces ferromagnetic next-nearest-neighbor exchange interaction (J2) among the B site magnetic ions. The generation of the ferromagnetic J2 is ascribed to structure distortion induced by the Ga3+ doping. [ABSTRACT FROM AUTHOR]

In this work, the structural and magnetic properties in ZnCr2−xGaxO4 were investigated. In ZnCr2−xGaxO4, Ga3+ ions substitute partial Cr3+ ions and occupy the B sites. ZnCr2O4 undergoes a paramagnetic-antiferromagnetic transition at 12 K. In ZnCr2−xGaxO4, the antiferromagnetic short-range correlation occurs below 60 K above T N . The Ga3+ doping weakens the antiferromagnetic nearest-neighbor exchange interaction (J1) and induces ferromagnetic next-nearest-neighbor exchange interaction (J2) among the B site magnetic ions. The generation of the ferromagnetic J2 is ascribed to structure distortion induced by the Ga3+ doping. [ABSTRACT FROM AUTHOR]

Mesoporous Fe3O4 nanoparticles were synthesized by a solvothermal method, via a mixed solvent of ethylene glycol (EG) and deionized water, using iron chloride and urea as the precursors. The phase, morphology, and pore structure are investigated by the characterization of X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 isotherm adsorption–desorption. The results show that the amount of water in the mixed solvent plays vital role in controlling the size of Fe3O4 nanoparticles, specific surface area, and pore size. Additionally, solid Fe3O4 nanospheres were prepared using only EG as solvent, while α-Fe2O3 nanosized polyhedrals were obtained with only water as solvent. The mesoporous Fe3O4 nanoparticles show a ferromagnetic behavior, with saturation magnetizations (Ms) of 78–82 emu g− 1 and coercivities (Hc) ranging from 13–58 Oe. The α-Fe2O3 nanoparticles also exhibit a weak-ferrimagnetic character, with a remanent magnetization (Mr) of 0.24 emu g− 1, and Hc of 558 Oe. [ABSTRACT FROM AUTHOR]

Magnetic powders containing ferrimagnetic Mn4C phase and antiferromagnetic MnO phase were prepared from a Mn-C alloy by using the laser ablation method. The Mn-C alloys were composed of Mn4C and α-Mn(C) solid solution, which decomposed into Mn4C and Mn23C6 during laser ablation. The Mn clusters precipitated from the Mn(C) solid solution were spontaneously oxidized into MnO when exposed to air, forming an exchange bias system of Mn4C/MnO with ferrimagnetic/antiferromagnetic interfaces. The exchange bias field (22.3 mT at 5 K) of the Mn4C/MnO micro-powders, which show irregular shapes and a wide size distribution in the range of ~ 100 nm to ~ 20 μm, decreases with increasing temperature. Both the interface spins and the surface spins contribute to the exchange bias effect in these powders. The coercivity of the laser-ablated micro-powders reached up to ~ 150 mT at 5 K and ~ 40 mT at 400 K, respectively. [ABSTRACT FROM AUTHOR]

The effects of two different single-ion anisotropies on the magnetization of the mixed (7/2, 5/2) Ising ferrimagnetic system on a square lattice are investigated by the use of Monte Carlo simulation. The ground-state phase diagram is obtained. Compensation points are detected for certain values of the crystal fields. Different types of magnetization curves are available. [ABSTRACT FROM AUTHOR]

The phase transition, phase diagrams, and magnetizations of an Ising bilayer film with non-magnetic inter-layers are investigated by the use of the effective field theory with correlations. The system is consisted of two magnetic layers where upper and lower layers are consisted of spin-1/2 atoms and spin-1 atoms with a single-ion anisotropy. It is examined how the system may exhibit the tricritical behavior and some characteristic features of ferrimagnetism. The effects of non-magnetic layers on the magnetic properties are clarified. [ABSTRACT FROM AUTHOR]

The magnetic properties (phase diagrams and magnetizations) of a mixed-spin Ising ferrimagnetic bilayer film on the graphene honeycomb lattice where two (A and B) layers separated by a number of nonmagnetic layers are investigated by the use of the effective field theory with correlations. The systems are consisted of two (spin-1/2 and spin-1) magnetic atoms where spin-1 atoms have a single-ion anisotropy. The effects of an indirect exchange interaction between the A and B layers are examined. Some characteristic behaviors have been found in the system, when the single-ion anisotropy takes a large negative value. Some characteristic phenomena of ferrimagnetism, have been found in the thermal variation of magnetization. [ABSTRACT FROM AUTHOR]

Single-phase polycrystalline samples of Y3−xSmxFe5O12 (x = 0.0-3.0) were prepared by using a solid-state reaction method. The lattice constant is found to increase from 12.372 Å for x = 0.0 to 12.524 Å for x=3.0. The substitution of Sm3+ at Y3+ site is confirmed from the red shift of Raman F2g mode. Magnetization loops measured at room temperature and the analysis of initial magnetization curves show that saturation magnetization value decreases with an increase in Sm concentration due to the possible antiferromagnetic interaction. On the other hand, temperature variation of magnetization plots shows that all the samples exhibit ferrimagnetic transition with transition temperature in the range of 550 K for x = 0.0 to 573 K for x=3.0. The dielectric constant increases upon Sm substitution, and the analysis of impedance and dielectric spectra shows the contribution of both grains and grain boundaries. [ABSTRACT FROM AUTHOR]

The phase diagram and total magnetization of an Ising bilayer film with nonmagnetic interlayers are investigated by the use of the effective field theory with correlations. The system is consisted of two spin-1/2 magnetic layers where one of them is canted from the easy-axis (or z-) direction due to an applied transverse field, and they are coupled by an indirect exchange interaction. It is examined whether the system may exhibit some characteristic features of ferrimagnetism, such as a compensation point. The effects of nonmagnetic layers on them are clarified. [ABSTRACT FROM AUTHOR]

A novel V2O5-ZnO-B2O3 (VZB) glass was introduced into the Li0.42Zn0.27Ti0.11Mn0.1Fe2.1O4 (LiZnTiMn) ferrites for advancing low-temperature cofired ceramics technology and fabricating microwave ferrite devices by the multilayer process. The results reveal that the addition of VZB glass is an effective way to improve the densification, microstructure, and ferrimagnetic properties of the LiZnTiMn ferrites. The relationship among dopant amount, sintering mechanism, and structural distribution characteristic was established, tailoring the foundation of ferrimagnetic performance of low-temperature fired LiZnTiMn composites. The resulting VZB glass as flux promotes the microstructural uniformity and compactness and also provides the optimized physical properties of low-temperature sintered LiZnTiMn composites. An appropriate amount of VZB glass (~0.5 wt%) could enhance the saturation magnetization (from 52.2 to 72.3 emu/g) and remanence ratio of saturation induction (from 0.76 to 0.85) and reduce the coercivity of magnetic induction intensity (from 685 to 199 A/m) of the ferrite composites sintered at ~900 °C. Moreover, the ferromagnetic resonance linewidth of LiZnTiMn composites doped with 0.5 wt% VZB glass decreased from 860 to 195 Oe because of the combined effect of good uniformity and low porosity. Thus, with a low-temperature sintering process, the VZB glass could be a promising additive for achieving low-loss LiZnTiMn ferrite used in microwave devices. [ABSTRACT FROM AUTHOR]

Ytterbium (Yb) substituted magnesium ferrite materials (MgYbxFe2−xO4 with x = 0.00, 0.025, 0.050, 0.075, 0.10) have been prepared by the Sol–gel method. XRD analysis revealed that the prepared samples are cubic spinel with single phase till the content ‘x’ equals 0.05. At higher content x ≥ 0.075, Yb substituted samples possessed YbFeO3 phase along with the cubic spinel phase. A significant decrease of ~34.7 nm in crystallite size is noted in response to the increase in Yb substitution level. The room temperature dc resistivity increases gradually from 3.47 × 107 to 2.63 × 108 Ω-cm as the substitution of Yb is increased. Temperature dependent DC electrical resistivity of all the samples exhibits semiconducting behavior. Yb substituted materials can be suitable to limit the eddy current losses for microwave applications. VSM indicated the existence of an appreciable fraction of ferrimagnetic properties at room temperature. The saturation magnetization of the samples decreases from 60 to 33 emu/g. Saturation magnetization and remanence decreased while coercivity increased with Yb substitution. [ABSTRACT FROM AUTHOR]

Uniform, large, spherical, hierarchical CoFeO spinel particles have been successfully prepared by a modified polyol method using NaBH and NaOH, revealing controlled size, shape, and morphology with high crystallinity in a certain microscale range. Their inverse ABO-type crystal structure was intensively studied by x-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Using stock solutions of CoCl and FeCl precursors in 1:2 ratio, CoFeO particles were formed well with high crystallinity in the best inverse spinel structure in space group Fd-3m. The fascinating ferrimagnetic and hysteretic properties of the as-prepared hierarchical CoFeO spinel particles were investigated by vibrating-sample magnetometry (VSM) at room temperature (RT). The results confirm formation of hierarchical CoFeO microscale particles with inverse-spinel ABO-type structure and high magnetization by modified polyol method with heat treatment. [ABSTRACT FROM AUTHOR]

We report the effects of Fe doping on the BiS-based superconductor BiOS. It has been found that the superconducting transition temperature ( $$T_{\text{C}}^{\text{onset}}$$ ) is slightly enhanced by Fe doping. The magnetic susceptibility results reveal the coexistence of superconductivity and long-range ferrimagnetism in these samples. A new magnetic transition temperature T (Verwey transition) from the M-T curves at ~112 K is observed. The isothermal magnetization curves ( M-H) indicate a weak ferrimagnetism, which is probably due to the antiparallel ordering of Fe and Fe magnetic moments. The coexistence of superconductivity and ferro/ferrimagnetism makes bismuth oxysulfide superconductor a platform for understanding superconductivity from a new perspective. [ABSTRACT FROM AUTHOR]