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Yttrium Iron Garnet (YIG) ferrites, characterized by their superior magnetic and dielectric attributes, are instrumental in advancing the development of microwave devices, particularly in enhancing high-frequency performance, integration, and miniaturization. This paper synthesizes YIG ferrite materials with the composition Bi 0.6 Y 1.4-x Ca 1+x Fe 4.5-x V 0.5 Ge x O 12 (x = 0.10 to 0.50, incrementing by 0.10) through the solid-state sintering method. It delves deeply into the mechanism by which Ca2+-Ge4+ ions substitution regulates the magnetic properties of BiV-YIG. The microstructural and magnetic properties of the samples were systematically tested and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometry (VSM), and TE106 perturbation method. At a substitution content of x = 0.50, the substitution of Ge4+ ions for the Fe3+ ions at the d-site transforms the material from ferrimagnetic to paramagnetic, and the saturation magnetization of the sample drops to 132.74 G. By calculating the ferromagnetic resonance (FMR) linewidth using the law of approach to saturation, the study elucidates the negative impact of low saturation magnetization on FMR linewidth. The mechanisms proposed in this paper provide theoretical and experimental bases for reducing the FMR linewidth of high dielectric constant Bi-substituted YIG, paving the way for developing high-dielectric, low-loss YIG ferrite materials for microwave devices. [ABSTRACT FROM AUTHOR]

We prepared ultrafine MnCo 2 O 4 particles using a facile sol–gel autocombustion method. The structural and vibrational characterizations confirmed the formation of a pure cubic spinel phase in as-synthesized MnCo 2 O 4 particles. The surface morphology analyses revealed the porous structure with an average particle size of 5 nm and uniform distribution of manganese (Mn), cobalt (Co), and oxygen (O) in the particles. We observed the presence of multiple valence states of Mn and Co, occupying both tetrahedral and octahedral sites, enhancing our insight into the material's electronic properties and structural configuration. Our magnetization studies unveiled a Curie Temperature (T C) of 185 K with ferrimagnetic ordering below T C , resulting in substantial magnetization (9.8 emu/g) and coercivity (3.46 kOe) at 2 K and weak magnetic behavior above T C. This is attributed to the finite size and surface effects. Furthermore, the incorporation of MnCo 2 O 4 nanoparticles and graphene oxide into a polyurethane foam matrix resulted in an excellent sound absorption coefficient of 90 % at 2000 Hz. This outstanding acoustic performance underscores the versatile applications of MnCo 2 O 4 nanoparticles in diverse noise mitigation applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This research is focused on designing new ceramic oxides with the spinel structure for a potential application as sensitive temperature and magnetic field sensors. In this respect, the mixtures of ferrimagnetic NiFe 2 O 4 with low-resistive Ni 0.66 Cu 0.41 Mn 1.93 O 4 semiconductor (molar coefficient α = 1 / 5 and 1 / 2) were prepared using the chemical co-precipitation technique followed by a low-temperature sintering of the cold-pressed powders. For the prepared materials, a variation of the electrical conductivity σ dc with temperature T (in the range 50 K–400 K) is quantitatively analyzed using different theoretical concepts of the charge carrier hopping transport occurring in disordered materials with strong electron-phonon interaction. It has been shown that an increase in α from 0 to 1 / 2 causes a step-like change of the dc electrical conductivity and, simultaneously, a gradual change in the magnetization M determined in the saturation state. The temperature coefficient of resistance T C R of the prepared ceramics takes the values from −0.6%/K (at 400 K) to −19.6%/K (below 100 K). The highest absolute value of the magneto-resistance coefficient M R determined at 150 K (and at magnetic field 7 T) registered for ceramic oxide with α = 1 / 2 was found to be 3.4%. [ABSTRACT FROM AUTHOR]

This research is driven by a desire to create composite films that combine the ferrimagnetic capabilities of pure and La/Nd substituted Sr 3 Co 2 Fe 24 O 41 Z-hexaferrites with the multifunctional features of ferroelectric polymers. A flexible magnetoelectric (ME) polymer composite films, with Sr 3 Co 2 Fe 24 O 41 (SF), Sr 2.85 La 0.15 Co 2 Fe 24 O 41 (SF–La) and Sr 2.85 Nd 0.15 Co 2 Fe 24 O 41 (SF-Nd) as the ferrimagnetic material and poly vinylidene fluoride-hexafluoropropylene (PH) as a ferroelectric component, were synthesized using solution casting method. In the current case, two steps have been used to synthesize ferroelectric and ferrimagnetic composites films: first, SF, SF-La and SF-Nd hexaferrite samples were synthesized using solid state reaction method and then 20% weight percentage of these hexaferrites were incorporated into the PH matrix using solution casting method to form composite film. In order to find the traces of collaborative interactions between the two phases, the structural, magnetic, and ferroelectric properties of these composite samples have been studied. The XRD data confirm the formation of SF, SF-La and SF-Nd hexaferrite dispersed in a piezoelectric copolymer PH matrix. The changes in the ferroelectric properties in different magnetic fields demonstrated the existence of ME coupling in the composite films. The inclusion of PH enhanced the magnetoelectric coupling of composite films. The maximal value of magnetoelectric coupling coefficient (α ME) observed is 0.213, 1.227, 3.403 and 9.797 mV cm−1 Oe−1 for SF, PHSF, PHSF-La and PHSF-Nd, respectively. There is approximately 46-time increase in the maximum value of magnetoelectric coupling coefficient (α ME) in PHSF-Nd (9.797 mV/cm.Oe) composites as compare to pure SF (0.213 mV/cm.Oe). [ABSTRACT FROM AUTHOR]

The magnetic properties of the Co 1-x Fe x Cr 2 S 4 solid solutions for compositions adjacent to CoCr 2 S 4 were investigated using various techniques, including magnetization measurements and AC susceptibility. The results revealed that substituting Fe for Co in the CoCr 2 S 4 compound led to changes in the magnetic behavior, such as the presence of ferrimagnetic ordering and the emergence of a cluster spin glass phase. The study found that the temperature of the ferrimagnetic transition (T C) decreased with increasing Fe concentration, indicating the influence of iron on the magnetic properties of the solid solutions. Additionally, the discovery of a cluster spin glass phase for specific compositions (x = 0, 0.1, 0.2, 0.4) suggests complex magnetic behavior in these materials. In summary, the study offers valuable insights into the magnetic properties of Co 1-x Fe x Cr 2 S 4 solid solutions and highlights the potential for tuning their magnetic behavior through compositional variations. [ABSTRACT FROM AUTHOR]

The ferrimagnetic nodal-line semiconductor Mn 3 Si 2 Te 6 , featuring a quasi-two-dimensional crystal structure, has attracted significant attention owing to its rich physical properties. Here, we systematically investigate the magnetic properties of its isostructural compound, Mn 3 Si 2 Se 6. The magnetism of this material is attributed to the Mn atoms, which exhibit antiferromagnetic interactions among the Mn atoms. The competition between antiferromagnetic exchange interactions results in an overall ferrimagnetic state, with a second-order transition from paramagnetic to ferrimagnetic occurring at 68 K. Critical exponents are derived using various common experimental techniques, including the modified Arrott plot, Kouvel-Fisher method, and critical isotherm analysis. The results indicate that the magnetism of Mn 3 Si 2 Se 6 closely aligns with the mean-field model, with critical exponents β , γ , and δ determined as 0.475(3), 1.059(3), and 3.20(1), respectively, at the critical temperature of 68.3(2) K. Moreover, the curves of the magnetic entropy change − Δ S M (T , H) exhibit a peak around T c , with − Δ S M max amounts to 4.61 (3.63) J kg−1 K−1 for H ∕∕ ab (∕∕ c) with a field change of 7 T. The estimated magnetic entropy value near T c through specific heat is remarkably saller than the expected spin entropy of Mn2+ ions, indicating the presence of short-range interactions in the paramagnetic region. • The competition exchange interactions result in an overall ferrimagnetic state in Mn 3 Si 2 Se 6. • Magnetism of Mn 3 Si 2 Se 6 aligns with the mean-field model. • Specific heat analysis reveals short-range interactions in Mn 3 Si 2 Se 6 's paramagnetic region. [ABSTRACT FROM AUTHOR]

• Review on recent progress in magnetic properties of SrM magnet & it's applications. • Reviewed various synthesis processes and their effect on magnetic properties of SrM. • Covered substitutional behavior of various elements on magnetic properties of SrM. • Attempted to cover the possibility of SrM-based magnet in numerous applications. • The review paper is motivated towards an alternative to rare-earth permanent magnet. Hard magnets (HMs) are significant components in various applications like rotating machines, telecommunication, computer devices, sensors, and many more. In the HM group, permanent magnets are extensively used due to their high energy product, though they are costly and contain rare earth (RE) elements. Advancements in the magnetic properties of non-RE-based hard magnets can fulfill the technology gap between non-RE and expensive RE-based hard magnets. Hexaferrite magnets represent the largest magnet group being used nowadays by volume, in which strontium hexaferrite (SrM) is a widely used non-RE hard magnet. It is the most faithful base magnet in terms of abundance and economic balance, which requires more or less reformation and advancement in the aspect of magnetic properties. SrMs are ferrimagnetic materials, and their magnetic properties are inherently linked to the microstructures. It can be upgraded to attain high (BH) max and high curie temperature by refining its magnetic properties. Improvement in its M s and H c , even mildly, could open up the possibilities of large-scale immersion of strontium hexaferrite-based magnets in the vast field of permanent magnet applications. In the past several years, enormous improvement has been made toward enhancing the physical and magnetic properties of SrM. Identifying the synthesis parameters as well as the microstructural changes is essential for designing and improvisation of magnets. The current progress in the magnetic properties of SrM (especially high M s and high H c) by synthesis parameters and different substituting elements is briefly covered in this review, along with the applications and future aspects of Sr-hexaferrite-based magnets. [ABSTRACT FROM AUTHOR]

We used Monte Carlo simulation to study the magnetic properties and compensation behavior of a ferrimagnetic mixed-spin (3 / 2 ; 1 / 2) Ising system in a graphene bilayer. The effects of exchange interactions, crystal field, external magnetic field and temperature on the total magnetization, partial magnetizations, magnetic susceptibility, phase diagram and hysteresis behavior of the system were examined. Interesting results were obtained in this work, such as the compensation behavior and the multi-loop hysteresis phenomenon for specific values of the system's physical parameters. Our results conform to those of other theoretical studies. • The compensation and critical behaviors of a Graphene Bilayer were investigated. • Different total magnetization profiles are observed in this ferrimagnetic system. • The effect of various physical parameters on hysteresis behavior was presented. [ABSTRACT FROM AUTHOR]

The mean-field approximation based on the Gibbs-Bogoliubov inequality and Monte Carlo simulations based on the Metropolis method in the Blume–Emery–Griffiths model were used to successfully examine a hexagonal Ising nanowire with spin-1. It was found that the model displays fascinating phase diagrams in various planes of interest by using both methods. The investigation of magnetic hysteresis cycles also exhibits interesting properties. The model not only presents first- and second-order phase transition lines, but also the tricritical and isolated critical points, multi-compensation temperatures, and magnetic hysteresis behavior with one to eight cycles. • The mean-field approximation based on the Gibbs-Bogoliubov inequality is applied. • The Monte Carlo simulations based on the Metropolis method is employed. • Spin-1 Blume–Emery–Griffiths model for hexagonal Ising nanowire is investigated. • First- and second-order transitions, tricritical and isolated critical points are found. • Multi-compensation and magnetic hysteresis with one to eight cycles are observed. [ABSTRACT FROM AUTHOR]

We report here the studies of structural and magnetic properties of two equiatomic quaternary Heusler alloys CoCrVZ (Z = Al, Ga). Both the alloys crystallize in LiMgPdSn type crystal structure (space group #216) with B2 (CoCrVAl) and A2 (CoCrVGa) type anti-site disorder between elemental sites. Intended stoichiometry was confirmed from the compositional analysis. The temperature dependence of dc magnetic susceptibility and the low temperature moment values show a nearly compensating ferrimagnetic behaviour at low temperatures for both the alloys. The inverse of dc magnetic susceptibility starts to deviate from the Curie–Weiss law below 220 K and 164 K for the alloys containing Al and Ga respectively. The Arrott plots confirms the absence of long range order down to 2 K. Further analysis of the dc and ac susceptibility shows that the observed behaviour is due to the presence of Griffiths like phase in these alloys. • Systematic study shows that CoCrVZ (Z = Al, Ga) Heusler alloys crystallize in LiMgPdSn type structure (space group #216) with 50% B2 (CoCrVAl) and 25% A2 (CoCrVGa) type anti-site disorders. • The presence of disorder leads to the reduction of magnetic moment and a nearly compensated ferrimagnetic behaviour at low temperatures. • The presence of Griffiths like phase is inferred for both the alloys. [ABSTRACT FROM AUTHOR]

This study investigates the magnetocaloric potential of the Al 50 Cr 21-x Mn 17+x Co 12 (x=0, 4, 8 at%) high-entropy alloy (HEA) series using integrated experimental and theoretical approaches. Structural analysis by X-ray diffraction and scanning electron microscopy indicate a dual phase containing B2 and body-centered cubic (BCC) structures. Magnetic characterization shows an approximately linear decrease in saturation magnetization and Curie temperature with increasing Cr content. Curie temperatures calculated by Monte Carlo simulations suggest that the measured magnetic properties originate from the B2 phase rather than the BCC phase. The enhanced magnetocaloric effect with decreasing Cr content highlights the attractiveness of HEAs in magnetocaloric applications. • Al 50 Cr 21-x Mn 17+x Co 12 (x=0, 4, 8 at%) high-entropy alloys were prepared by arc melting. • The phase and chemical composition analysis indicates a dual phase containing B2 and BCC structures. • Calculated T C s suggest that the measured magnetic properties originate from the B2 phase rather than the BCC phase. • Tunable TC and magnetization with decreasing Cr were confirmed through measurement of TC and hysteresis loops. • The magnetocaloric effect was quantified by measuring the adiabatic temperature change and magnetic entropy change. [ABSTRACT FROM AUTHOR]

This work utilizes a multi-scale computational approach combining first-principles density functional theory (DFT) and Monte Carlo statistical simulations to provide fundamental insights into the impacts of vanadium (V) doping on the structural, electronic, magnetic, and thermodynamic properties of wurtzite zinc sulfide (ZnS). 2 × 2 × 2 ZnS supercells with controlled V doping concentrations from 12.5%–25% substituting zinc sites were constructed. The introduction of V dopants induces systematic expansions in lattice parameters and cell volume, attributed to the larger ionic radius of V 2 + than Zn 2 + , while the average compressibility shows minimal variation. However, V incorporation is found to soften ZnS by over 15% at higher dopant contents, increasing compliance and anisotropy. Stable ferromagnetic spin couplings emerge, mediated by host carriers without precipitating V secondary phases. The band structure develops half-metallic electronic properties with the lifting of spin degeneracy and preferential spin-up band metallicity induced by V-3d and S-3p hybridization effects. This results in 100% spin polarization at the Fermi level. Monte Carlo simulations based on a tight-binding Hamiltonian constructed from maximally localized Wannier functions to accurately calculate the exchange interactions between V spins successfully reproduce the magnetic phase transition behavior. The results confirm high Curie temperatures exceeding 300 K at 25% V, attributable to the significant strengthening of short-range ferromagnetic couplings over antiferromagnetic interactions. The integrated computational approach provides fundamental insights into the microscopic origin of carrier-mediated ferromagnetism in V-doped wurtzite ZnS dilute magnetic semiconductors. The systematic first-principles calculations and statistical mechanics modeling establish clear structure–property relationships linking V doping configurations and concentrations to tuned mechanical response, enhanced stability, electronic structure modifications, spin polarization, and magnetic ordering temperatures in ZnS. The results present design pathways and predictive capabilities to guide experimental efforts toward emerging high-performance magnetic materials for spintronic technologies. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present work, [Co (1-(x + y)) Mg x Ni y ][Cr 2 ]O 4 (CMNCr)(where, x = y = 0, 0.10, 0.20) NPs are examine in detail by using experimental results. Solution combustion method is adopted to prepare the CMNCr NPs. Experimental results were studied to understand structure (using XRD), microstructure (using SEM) and magnetic behaviour (using SQUID). The structural analysis was confirmed a single-phase spinel cubic structure with singular structural distortions associated with Mg–Ni doping and the generation of metal vacancies. SEM micrographs of all samples reveal their highly porous nature. EDS was utilized to examine the elemental analysis of the samples. The formation of spinel cubic structure without impurity were also confirmed by Fourier-transform infrared (FTIR) spectroscopy and the same tool is used to investigate the absorption bands related to the A-site and B-site. For all samples, paramagnetic phase to ferrimagnetic phase transition observed at T C and conical spiral spin order transition observed at T S. The curie temperature is found to be 98 K, 89 K, and 85 K for [Co][Cr 2 ]O 4 , [Co 0.8 Mg 0.1 Ni 0.1 ][Cr 2 ]O 4 and [Co 0.6 Mg 0.2 Ni 0.2 ][Cr 2 ]O 4 samples, respectively. The spiral transition temperature is found to be 26 K, 14 K and 8 K for [Co][Cr 2 ]O 4 , [Co 0.8 Mg 0.1 Ni 0.1 ][Cr 2 ]O 4 and [Co 0.6 Mg 0.2 Ni 0.2 ][Cr 2 ]O 4 samples, respectively. All of the samples exhibit paramagnetic behaviour above T C. The negative magnetization effect were observed in [Co 0.6 Mg 0.2 Ni 0.2 ][Cr 2 ]O 4 NPs. 20% of Mg and 20% of Ni substitution to Co site in [Co][Cr 2 ]O 4 leads to the evident magnetization reversal at the compensation temperature with an applied magnetic field of 100 Oe. The M − H loop at 10 K exhibits large coercivity due to the spiral spin ordering. This phenomenon of negative magnetization in the material results in a stable state of magnetization in the material, which has significant applications in the field of magnetic storage devices. [ABSTRACT FROM AUTHOR]

Copper-containing ferrimagnetic glass-ceramic with the following composition: 24.7% SiO 2 -8.5% CaO-13.5% Na 2 O-3.3% P 2 O 5 -31% Fe 2 O 3 -14% FeO–5CuO (wt%) was synthesized by means melt and quenching process both in powder and bulk form. The obtained samples were characterized and compared by means morphological, compositional and structural analyses. The magnetic properties and the ability to release heat were also investigated together with the antimicrobial properties towards S. aureus strain. The obtained results showed that copper introduction and the annealing process influenced the nucleation of crystalline phases; in particular the samples produced in powder form evidenced a low amount of magnetite and thus a reduced hysteresis area and ability to produce heat when exposed to an alternating magnetic field. While Cu-containing samples in the bulk form maintained the magnetic and calorimetric properties of pristine glass-ceramic. Preliminary evaluation of antibacterial properties demonstrated Cu-doped samples were not able to reduce the bacterial proliferation and thus the need to optimize the copper introduction process. [ABSTRACT FROM AUTHOR]

Structural, magnetic, and optical properties along with N 2 absorption-desorption features of Sm3+–Dy3+ ions co-substituted BaSr hexaferrite microspheres (HFMSs) engineered through a hydrothermal gel approach were investigated. The microstructural and morphological features were examined by powder X-ray diffraction (XRD), surface area and pore size distribution (BET), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), and transmission electron microscopy (TEM) techniques. Rietveld analysis proved the purity of products. The BET revealed a slight variation in textural characteristics with increasing Sm3+–Dy3+ substitution. The surface area (11–16 m2/g) exhibits a pore volume of ~0.07 cm3/g and average pore size distributions of 26.6 nm. The 300 K and 10 K field-dependent hysteresis loops were registered. Remanent magnetizations (M r) and coercive fields (H C) are in a range of 29.15–34.05 emu/g and 1420–5391 Oe at 300 K, respectively. The estimated saturation magnetizations (M s) vary between 53.22 emu/g and 71.08 emu/g, and magneton numbers (n B) are in a range of 10.51–13.93 μ B. At 10 K, the M r = 35.18–46.83 emu/g, H C = 1487–4760 Oe, M s = 81.82–99.17 emu/g, and n B = 14.83–19.44 μ B , which are greatly higher compared to room temperature. All magnetic parameters exhibit strong ferrimagnetic features of pristine Sr 0 · 5 Ba 0 · 5 Fe 12 O 19 and Dy3+ and Sm3+ co-doped HFMSs at both temperatures. Squareness ratios (SQRs), which are very close to 0.50 assign the single domain uniaxially symmetric structured HFMSs. δ M type of remanence plots was applied to specify the intensity and type of interparticle interactions as a function of the externally magnetic field, H. The Schuster-Kubelka-Munk theory provides to estimate direct energy band gaps (E g). Undoped or co-doped HFMSs have a very narrow magnitude of E g data between 1.795 and 1.865 eV depending on the couple ion concentrations. [ABSTRACT FROM AUTHOR]

Polycrystalline samples of DyCo 9 Si 4 with the tetragonal LaFe 9 Si 4 -type structure have been synthesized by arc melting and high-temperature annealing. Results of the magnetization M and specific heat C p measurements show the existence of two magnetic anomalies at T C = 40 K and T m = 20 K. The transition at T C = 40 K is attributed to the ferromagnetic transition of the Co sublattice. The magnetic moments of Dy3+ appear to align gradually below T C , and almost fixed below T m , at which a broad maximum in C p has been observed. Field-dependent M at T = 2 K up to H = 7 T suggested that the magnetic moment of Dy3+ is coupled antiferromagnetically with those of Co, forming a ferrimagnetic structure. Magnetization measurements up to 50 T at low temperatures using a pulse magnet demonstrated a spin-flip transition around H = 20 T, above which the magnetic moments of Co and Dy are in parallel. The spin-flip transition becomes broad with increasing temperature but still remains at T C = 40 K, indicating a strong antiparallel coupling between Co and Dy moments even in the paramagnetic state. The magnetocaloric effect was evaluated from C p and M , and also from the sample-temperature variation in the quasi-adiabatic process with the pulsed magnetic field. The maximum entropy change for the field change from 5 to 0 T was observed at around T = T m with the value Δ S = 5 J/kg K. The maximum temperature of Δ S shifts to higher temperatures in high magnetic fields, resulting in the large value of Δ S = 24 J/kg K at T ∼ T C by the field change from 50 to 0 T. The present results demonstrate that the pulsed-field measurement is a powerful method to evaluate the magnetocaloric effect of materials. ● Physical properties of DyCo 9 Si 4 are reported for the first time. ● Step-like increase of the magnetization curve is observed at low temperature. ● Antiparallel coupling of Dy/Co magnetic moments remains in the paramagnetic state. ● Pulsed field measurement enables a quick and reliable magnetocaloric evaluation. ● Large magnetocaloric effect of 24 J/kg K is observed at T = 40 K. [ABSTRACT FROM AUTHOR]

Magnetic properties of multicomponent alloys depend sensitively on the degree of atomic order on the different crystallographic sites. Here we report the contrast between the magnetic properties of bulk and thin-film samples of the Heusler alloy V 2 FeAl. Arc-melted bulk ingots show no site preference of the elements (A2 structure), whereas magnetron-sputtered thin-film samples display a degree of atomic ordering with a tendency towards XA-type order. Electronic structure calculations favour ferrimagnetic XA-type order, and the effect of different pairwise atomic disorder on the element specific and net magnetic moments are evaluated to reproduce experimental observations. XA-type thin-films with iron moment of 1.24 μ B determined by X-ray magnetic circular dichroism are in agreement with calculation, but the measured net moment of 1.0 μ B per formula unit and average vanadium moment are smaller than expected from calculations. The measured Curie temperature is approximately 500 K. Films with a higher degree of disorder have a lower T C , close to 300 K, with a net moment of only 0.1 μ B at low temperature. The large calculated vanadium moments are destroyed by partial disorder on 4 d vanadium sites. By contrast, the arc-melted and annealed bulk alloy with a fully-disordered A2 structure shows no spontaneous magnetization at any temperature; it is a Pauli paramagnet with dimensionless susceptibility χ v = 2.95 × 10-4. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The electronic, magnetic, and optical properties of MnFe 2 O 4 are studied through first-principles calculations. • The intricate chemical interactions of Mn-O and Fe-O bonds grounded in the multi-orbital hybridizations are thoroughly investigated in this article. • The optical properties, with a particular focus on prominent peaks that exhibit direct correlations with band transitions and spin configurations are an appealing research. • Various computational methods, encompassing local-density approximations (LDA), LDA + U, Perdew, Burke, Ernzerhof (PBE), and PBE + U, are considered to compare the electronic band gap and magnetic moments of MnFe 2 O 4. MnFe 2 O 4 represents a notable spinel ferrite material that synergistically combines the benefits of both Fe- and Mn-based materials. This compound emerges as a potential candidate for diverse applications encompassing biomedical techniques like thermotherapy, energy storage mechanisms such as lithium-ion batteries and supercapacitors, and advancements in optoelectronics and optical devices. Comprehensive first-principles calculations have been employed to delve into the structural, electronic, magnetic, and optical properties of MnFe 2 O 4. The intricate chemical interaction of Mn-O and Fe-O is elucidated via charge and spin features. This study meticulously examines distinct energy bands, spatial charge distributions, specific van Hove singularities, and configurations separated by spin orientation. Preliminary findings categorize the material as a semiconductor exhibiting ferrimagnetic traits. Among the computational methodologies utilized, including local-density approximations (LDA), LDA + U, Perdew, Burke, Ernzerhof (PBE), and PBE + U, the latter method shows a band gap of 1.017 eV, in contrast to the narrower gaps identified by alternative approaches. Crucially, the pronounced multi-orbital interactions spanning [4s, 3 d x 2 - y 2 , 3d xy , 3d yz , 3d xz , 3 d z 2 ] and [2s, 2p x , 2p y , 2p z ] offer insights into the fundamental physicochemical interactions of Fe-O and Mn-O. This article also presents and deliberates on the optical properties, emphasizing peaks that correlate directly with band structures and spin configurations. [ABSTRACT FROM AUTHOR]

Ab initio calculations are used in the present study to analyze the structural, magnetoelectronic, mechanical, thermal, thermoelectric, optical and thermodynamic properties of AMnBi 2 compounds (where A = Ca and Sr). The calculations use the density functional theory involving the Full Potential –Linearized Augmented Plane. Wave and the Monte Carlo simulation. We have used the Generalized Gradient Approximation (GGA) with Perdew-Burke-Ernzerhof (PBE) functional for modelling the exchange-correlation potential with Hubbard correction (GGA + U) was employed. The bulk modulus, its first derivative, and the optimal lattice parameters have been found. Both compounds display metallic nature. The electronic transport coefficients have been calculated. The entropy, thermal expansion coefficient, Debye temperature, and heat capacities C v and C p are calculated. The elastic constants at zero pressure, the bulk modulus B, and the shear modulus G have been evaluated. The Young's modulus and Poisson's ratio of two compounds have been performed. The Debye temperature is also approximated from the average sound velocity. The Néel temperature, magnetization, and hysteresis cycles are found. [ABSTRACT FROM AUTHOR]

The influence of external pressures on the structural and magnetic properties of the FeNi alloy is elucidated using density functional theory (DFT) and Monte Carlo simulation. Utilizing a range of pressures, the study showcases compressive behavior in lattice constants, with both a and c exhibiting reductions. A sharp decline in magnetic moments is recorded at a critical pressure of 54 GPa. Indicating a magnetic phase transition from ferro to paramagnetic phase. Beyond this critical pressure, dynamical instability becomes evident, attributable to the aforementioned magnetic phase transition. Further examination of exchange interaction parameters reveals that while Fe–Fe interactions exhibited a consistent decrease with pressure, the FeNi and NiNi interactions remained relatively stable across the examined pressure range. At pressures close to 0 GPa, the Curie temperature (T C) was found to be around 838 K. As the external pressure is applied, a consequential decline in T C is witnessed, suggesting a significant sensitivity of the magnetic phase transition to external pressures. In particular, this study indicates that the FeNi alloy is sensitive to external pressures, emphasizing some relation between structural and magnetic properties. [Display omitted] • A comprehensive examination of the influence of external pressure on the properties of the FeNi alloy has been conducted. • A magnetic phase transition from a ferromagnetic to a paramagnetic state has been observed at a critical pressure of 54 GPa. • There is a decrease in the Curie temperature as the applied external pressure is increased. [ABSTRACT FROM AUTHOR]

Cobalt ferrite (CoFe 2 O 4) nanoparticles have been synthesized using two different wet-chemical methods: co-precipitation and solvothermal. Mesoporous cobalt ferrite nanoparticles were prepared using the co-precipitation method with 4, 6, and 8 wt% of Pluronic P123 and with the solvothermal method with 10, 15, and 20 wt% of PEG-4000. X-ray diffractometry confirmed the formation of a single-phase spinel structure. The saturation magnetization of the nanoparticles increased from 48 to 64 emu/g as the P123 concentration increased from 4 to 8 % wt, and decreased from 72 to 62 emu/g as the PEG-4000 concentration increased from 10 to 20 % wt. Generally, the samples synthesized by the solvothermal method had a higher specific surface area than those prepared by the co-precipitation method. In comparison to other samples, the 10 % PEG-4000 sample had the highest specific surface area and showed the highest level of dye degradation (93 %). The findings demonstrated that the concentration of Pluronic P123 and PEG-4000 had an impact on the saturation magnetization and specific surface area of the nanoparticles. [Display omitted] • Pure CoFe2O4 was successfully synthesized utilizing two separate chemical processes: solvothermal and co-precipitation. • The microstructure of the cobalt ferrite nanoparticles produced by both procedures is spherical and porous. • The solvothermal method yielded samples with a larger specific surface area than the co-precipitation method. • The magnetic properties in the system rises as P123 grows and falls as PEG-4000 increases. • Cobalt ferrite nanoparticles were ferrimagnetic, with saturation magnetization ranging from 42 to 72 emu/g. [ABSTRACT FROM AUTHOR]

The physical properties of the double perovskite A 2 BB'O 6 are closely related to the B-site cationic arrangement, which directly affects the crystal morphology, magnetic coupling and electronic structure. Herein, the impact of B-site antisite defects on the magnetic and electronic properties of double perovskite Pb 2 FeOsO 6 has been investigated using spin-polarized first-principles calculations. Our calculations demonstrate that B-site ordered Pb 2 FeOsO 6 is a ferrimagnetic semiconductor with the saturated magnetic moment of ~2.27 μ B f.u.−1, mainly generated from B-site Fe and B′-site Os antiferromagnetic coupling. With the introduction of B-site antisite defects, the crystal lattices nearly maintain the original structure of the ordered Pb 2 FeOsO 6 , although the internal atomic arrangements are reconstructed. Nevertheless, the saturated magnetic moment is sharply reduced in Fe/Os disordered configurations, which originates from the additional Os–Os and Fe–Fe antiferromagnetic coupling, and consequently induces Os–Os, Os–Fe and Fe–Fe spins interaction competition. Further electronic structure analyses indicate that the B-site antisite defects do not alter the semiconducting performance of Pb 2 FeOsO 6. Our study sharpens the understanding of the effects of cationic ordering on the physical properties of double perovskites and provides an alternative avenue for tailoring their characteristics. This work illustrates the nonnegligible effect of B-site atomic disorder on the atomic distribution, spin interaction arrangements and electronic transport properties in double perovskite Pb 2 FeOsO 6. Image 1 [ABSTRACT FROM AUTHOR]

• LaFeO 3 and Al-Ti doped LaFeO 3 are prepared by solid state reaction method. • Magnetic properties are enhanced in doped sample. • Dielectric and ferroelectric properties of LAFTO are improved compared to that of LFO. • Coefficient of magnetocapacitance (MC) is strengthened in LAFTO. • Ab initio calculations of LFO and LAFTO are carried out using density functional theory. In order to enhance the magnetoelectric property of LaFeO 3 , we have considered co-substitution of Al3+ and Ti4+ in La3+ and Fe3+ sites. Rietveld refinement of the observed XRD patterns confirms that the pristine (LaFeO 3 , LFO) crystallizes in orthorhombic Pbnm (centrosymmetric) space group whereas the doped samples (La 0.9 Al 0.1 Fe 0.9 Ti 0.1 O 3 , LAFTO) crystallizes in orthorhombic Pna 2 1 (non-centrosymmetric) space group due to co-doping of Al3+- Ti4+ in LFO. Analysis of magnetic data confirms the antiferromagnetic phase of LFO and LAFTO possess ferrimagnetic spin structure with enhanced magnetization. Besides this ferroelectric polarization at room temperature is also improved in the co-doped sample of LAFTO (Pmax = 0.25 µC/cm2). Spontaneous polarization is predicted from first principle calculation for LAFTO to be ~ 12.31 µC/cm2. The dielectric loss factor of LAFTO reduces significantly and the dielectric strength is also enhanced compared to that of LFO. Experimental results are in agreement with these findings extracted from ab initio calculations using density functional theory. The present doped sample LAFTO has improved magnetic, dielectric, ferroelectric properties and magnetoelectric coupling compared to that of LFO, would have the high potential for applications in multiferroic devices. [ABSTRACT FROM AUTHOR]

A detailed study has been carried out of the static and dynamic magnetic properties of ferrimagnetic spinel MgFe 1.2 Ga 0.8 O 4 nanoparticles (NPs), including the measurements of low-field dc -magnetization M (T) under zero-field-cooled (ZFC) and field-cooled (FC) conditions and ac -susceptibility χ ac (T) at different frequencies (f) and amplitudes of the ac -field (H ac). Below, a Curie temperature (T C), a clear magnetic irreversibility (M ZFC (T) ≠ M FC (T)), as well as a broad peak in both M ZFC (T)– M FC (T) magnetizations have been observed. At T ≪ T C , the two distinct, frequency-dependent peaks at T p1 ≈ 9 K and T p2 ≈ 14 K in the imaginary part of the ac -susceptibility χ ac '' (T) have been found. Their positions have been consistent with those of the anomalies detected on the temperature dependence of the magnetic contribution to the heat capacity C mag (T), and a sharp decrease of the M ZFC (T) magnetization near ≈ 10–20 K. It was revealed that the fitting of the frequency dependence of the peaks' positions (T p1 (f) and T p2 (f)) in the imaginary part of ac -susceptibility χ ac '' (T) using the Neel-Arrhenius law yields unphysical values of the relaxation time (τ 0) and, therefore, these results ruled out a possibility of an existence of superparamagnetic (SPM) clusters in the system. On the other hand, the T p1 (f) and T p2 (f) dependences followed both the Vogel-Fulcher law and the power law. These observations indicate that, a complex magnetic state in MgFe 1.2 Ga 0.8 O 4 , realized in the low temperature region, may likely be related to a progressive freezing of magnetic clusters. [ABSTRACT FROM AUTHOR]

Di-phase 0.66BaTiO 3 –0.33Co 0.8 Zn 0.2 Fe 2 O 4 ceramic composites with randomly mixed phases have been obtained by conventional sintering method (CM) and Spark Plasma Sintering (SPS). The impact of sintering method on the structural, microstructural and functional properties is comparatively analysed. The dielectric properties are dominated by the BaTiO 3 phase, with contributions from the interfaces mostly on the dielectric relaxation properties, while the ferrimagnetic character of the composite is derived from the ferrite phase as a sum property. Both CM and SPS ceramics show bi-tunable character, i.e. their permittivity can be modified by the application of both electric and magnetic fields. A high dielectric nonlinearity is mostly characteristic to the ceramics with larger grains. The electrical tunability tends to reduce by the application of a magnetic field an almost is cancelled in the SPS ceramic. The two types of ceramics show opposite signs of their magnetocapacitance properties, indicating that they have different origins. A microwave filter realised with these two types of ceramics have been tested. With increasing magnetic field from 0 to 1.9 kOe (above the magnetic coercive field), the resonance frequency can be up/down shifted, as result of the positive/negative magnetoelectric coupling. [ABSTRACT FROM AUTHOR]

Terbium (Tb) and Thulium (Tm) co-doped strontium hexaferrites (SHFs), with composition SrFe 12-2x Tb x Tm x O 19 (0.00 ≤ x ≤ 0.04), were prepared via sol-gel auto-combustion method. The effect of Tb3+ and Tm3+ (as co-dopants) on SHFs were investigated in detail. XRD pattern of the prepared SHFs revealed the formation of M-type SHFs. A secondary phase of Fe 2 O 3 starts to appear for x ≥ 0.02. The optical band gaps (E g) of the prepared SHFs were widened with the increase in doping levels. Mössbauer study showed that the Tm3+ and Tb3+ ions have the preference to occupy 12k and 2a octahedral sites. M(H) measurements were recorded at room temperature (RT; T = 300 K) and low temperature (T = 10 K). The hysteresis loops of various SHFs revealed their ferrimagnetic (FM) nature at both RT and 10 K. Magnetic parameters including saturation magnetization (M s), remanence (M r), coercivity (H c), squareness ratio (SQR = M r /M s) and magnetic moment ( n B ) were determined. Compared to the pristine (undoped) sample, lower content of Tm3+ and Tb3+ co-substitution (x = 0.01) improves significantly the magnetic properties of SHFs. With further increasing co-substitution contents (x > 0.01), an impurity phase appears and as a result the magnetization reduces. The observed SQR values of the proposed SHFs above 0.5 clearly indicated their single domain character with uniaxial magnetocrystalline anisotropy. Our systematic synthesis strategy and characterization may constitute a basis for achieving high quality co-doped SHFs in a customized way. [ABSTRACT FROM AUTHOR]

The ferrite having the general chemical formula Mg 1-x Zn x Fe 2-x Cr x O 4 (x = 0.0, 0.1, 0.3, 0.5 and 0.7) prepared by the solid state technique. The XRD analysis depicted the presence of single phase cubic spinel structure. They showed an increasing trend of lattice parameter with the expansion of the spinel lattice which resulted from the partial incorporation of larger radii. The FT-IR absorption bands are observed at 590 and 430 cm−1 for tetrahedral and octahedral location. These bands are shifting toward 604.7 and 474.15 cm−1 for Zn–Cr substitution due to the change in Me–O covalence. DC electrical resistivity has found to show the highest magnitude 107 Ω cm at x = 0.1, decreases with further increase in content. The hysteresis curves measured at 300 K demonstrate the coercivity and it varies from 146.33 to 9.427 Oe for increasing the content which confirms decreasing the grain size as well as soft ferrimagnetic material. • XRD patterns revealed that the cubic spinel structure and pure phased. • The FT-IR spectrum shows characteristic features of spinel structure. • The maximum saturation magnetization value (58.718 emu/g) registered at x = 0.1. • DC electrical resistivity has found to show the highest magnitude 107 Ω cm at x = 0.1. [ABSTRACT FROM AUTHOR]

• Gd-content gradients influence PMA in both "+δ" and "−δ" samples. • "+δ" has lower H C due to closer T comp , suggesting different Gd-content. • Reversal of AHE loop near T comp indicates sublattice dominance shift. • Decrease in H SF suggests weakened exchange interaction near T comp. • Strong ΔR XY at ± 4 kOe and ± 30 kOe for "−δ" indicates enhanced PMA. Ferrimagnetic rare-earth (RE) – transition-metal (TM) alloys are considered small ferromagnets with antiferromagnetic exchange in sublattices, which makes them a preferable choice for future ultrafast memory-related applications. Here, we explore the magnetic properties of two GdFeCo thin films with tailored vertical composition gradients, achieved by gradually varying Gd concentration across the film thickness. The temperature-dependent magnetic behavior of these films is investigated using anomalous Hall effect (AHE) measurements and SQUID magnetometry. Both films exhibit perpendicular magnetic anisotropy with distinct coercivities, indicating variations in their magnetic properties. The films show RE-dominant behavior at 300 K. Moreover, for the positive composition gradient (+δ) film, the compensation temperature is around 350 K, while the film with a negative gradient (−δ) exhibits a compensation temperature above 400 K. Furthermore, the spin-flop behavior and AHE sign reversal provide insights into the sublattice dominance and exchange interactions within the films. The magnitude of ΔR XY (the difference in AHE resistance at different magnetic fields) is shown to be sensitive to the composition gradient, indicating stronger perpendicular magnetic anisotropy for the "−δ" sample. This study demonstrates the potential of composition engineering to tailor the magnetic characteristics of ferrimagnetic materials for specific spintronics applications. [ABSTRACT FROM AUTHOR]

We report a systematic experimental and theoretical study of half-metallic Heusler alloys Mn 2 V 1−x Co x Al (x = 0, 0.25, 0.5, 0.75, 1). In this study, using the arc-melting method and optimizing annealing temperatures, we succeed to synthesize Mn 2 V 1−x Co x Al (x = 0, 0.25, 0.5, 0.75, 1) alloys with evident L2 1 (or XA) order. A near compensated ferrimagnetic moment of 0.02 μB/f.u. at 5 K is observed with the Co concentration of 0.5 which is consistent with the S-P rule. In addition, we systematacially investigate the effects of Co concentration on electronic structure of Heusler alloys Mn 2 V 1−x Co x Al (x = 0, 0.25, 0.5, 0.75, 1) using first-principles calculations, and found that the half-metallic characteristic persists for all Co concentrations. In line with our experimental results, employing appropriate atomic site occupation, we obtained a full compensated ferrimagnetic moment of 0 μB/f.u. for stoichiometric Mn 2 V 0.5 Co 0.5 Al alloy. In addition, the robustness of half-metallic properties for compensated ferrimagnet Mn 2 V 0.5 Co 0.5 Al with the variation of atomic disorder are investigated and the results indicate that the Mn-Al swapping weakly destroys the half-metallic properties and the compensated ferrimagnet Mn 2 V 0.5 Co 0.5 Al alloy maintains the high spin polarization under the effect of B2 disorder. • Mn 2 V 1−x Co x Al (x = 0, 0.25, 0.5, 0.75, 1) alloys with evident L2 1 (or XA) order are fabricated successfully. • Magnetic properties can be regulated by component ratio of Co and V. • A full compensated ferrimagnetic moment of 0 μB/f.u. for stoichiometric Mn 2 V 0.5 Co 0.5 Al alloy is obtained. • Half-metallic properties of Mn 2 V 0.5 Co 0.5 Al is robust against atomic disorder. [ABSTRACT FROM AUTHOR]

We report the structural stability and half-metallicity of the half-Heusler alloy CoMnSe via the density functional theory (DFT). The γ -phase ferromagnetic of CoMnSe is more energetically stable than other phases. The electronic and magnetic properties show that the CoMnSe is a false half-metal ferromagnetic with 98.10% spin polarization and a total magnetic moment of 4 μ B . This value is in good agreement with the Slater-Pauling rule and available data using the GGA method, whereas the GGA+U method shows it is a ferrimagnetic metal with 95.73% spin polarization, and the total magnetic moment is 4.01 μ B. The effects of Bulk strain and axial strain demonstrate that the relative change of total magnetic moment M t o t and spin polarization P of CoMnSe is almost negligible, indicating that the half-metallicity is strong against Bulk strain and axial strain. Using Monte Carlo simulations, a transition ferromagnetic-paramagnetic response is also studied. • CoMnSe alloy is mechanically and thermodynamically stable. • CoMnSe does not undergo martensitic transformation. • CoMnSe is found to be falsely half-metallic using GGA, while it is metallic using GGA+U. • The high spin polarization and Curie temperature make CoMnSe suitable for spintronic. [ABSTRACT FROM AUTHOR]

Due to interesting properties such as perpendicular magnetic anisotropy (PMA), ferrimagnetism, etc., rare earth-transition metal(RE-TM) alloys attract considerable attention in ultrafast and terahertz spintronics applications. The magnetic properties of RE-TM alloys strongly depend on their composition and vary with temperature. Here, we model crystallographically amorphous ferrimagnetic TbCo using atomistic spin dynamics(ASD) simulations to study their temperature dependence on magnetic properties by varying the compositions. In this study, we investigate the temperature dependence of magnetisation, uniaxial anisotropy, and coercivity values of amorphous Tb x Co 100 − x for the composition range Tb 18 Co 82 to Tb 36 Co 64. The monte carlo method is used to calculate the temperature dependence of magnetisation and calculate the magnetisation compensation temperature(T M) and curie temperature(T c) values for different compositions. The temperature dependence of uniaxial anisotropy is calculated from the angular dependence of free energy curves calculated at different temperatures using constrained monte carlo methods. Further, we evaluate the temperature dependence of coercivity values by calculating the magnetic hysteresis at different temperatures using the LLG Heun method. The results show the magnetic properties of amorphous TbCo can be easily tuned by varying their composition and have a strong temperature dependence. These highly tunable magnetic properties make them promising candidates for spintronics applications. [Display omitted] • RE-TM alloy thin films are interesting for ultrafast and terahertz spintronics applications. • RE-TM alloys are known for their intrinsic PMA, Ferrimagnetism and compensation temperatures. • The temperature dependence of M s , K u and H c of amorphous TbCo is studied using ASD simulations. • Magnetic properties of RE-TM alloys strongly depend on their temperature and composition. [ABSTRACT FROM AUTHOR]

• Ferrimagnetic mixed spin (3/2,1) Ising for zigzag and armchair graphene-like nanoribbons (GNRs) is investigated using the finite cluster approximation FCA. • Transition reentrance is revealed for both GNRs for lower J co strength. • Double compensation points are identified for the armchair GNR under the effect of the shell crystal field. • The core crystal field may lead for both zigzag and armchair GNRs, to a tricritical behavior. Graphene-like nanoribbon structures (GNRs) in which singular magnetic properties emerge because of the graphene-cutting process, may offer unique opportunities for future technological development such as spintronics. Using the finite cluster approximation, research has been implemented on some magnetic and critical characteristics of a mixed spin-3/2 and spin-1 Ising ferrimagnetic graphene-like nanoribbon with two typical edges, namely armchair, and zigzag. We investigate the influences of such aspects as crystal fields, exchange couplings, and temperature on phase diagrams and magnetizations. Tricritical as well as compensation behaviors have been demonstrated under the effect of the above physical parameters. In particular, only armchair GNR may exhibit double compensation points. Meanwhile, an unexpected reentrant transition has been discovered for both GNRs, which is mainly due to the finite size effect. [ABSTRACT FROM AUTHOR]

The effects of Fe substitution on the structural and magnetic properties of the HoCo 12- x Fe x B 6 (0 ≤ x ≤ 2) series of intermetallic compounds have been studied. All of the compounds form in the rhombohedral SrNi 12 B 6 -type structure, the lattice constants increasing linearly with x. These compounds are ferrimagnets with a small transition metal magnetic moment and exhibit a spin reorientation transition. The Curie temperature decreases from 147 K for x = 0–105 K for x = 2. The Fe for Co substitution leads also to a progressive decrease of the spontaneous magnetization. The spin reorientation transition temperature is significantly reduced upon Fe for Co substitution whereas the compensation temperature is much less sensitive to the Fe composition. • Ferrimagnetic ground state. • Compensation point. • Spin reorientation transition. • Magnetocrystalline anisotropy. • Monotonic decrease of T C , T SR and M S upon Fe for Co substitution. [ABSTRACT FROM AUTHOR]

In3+-substituted Co 0.9 Cu 0.1 Fe 2 O 4 with various small fractions of In3+ was prepared by the sol-gel autocombustion method. The phase purity was verified by X-ray diffraction, the selected-area electron diffraction pattern, and Raman spectroscopy. The chemical composition was estimated and determined by inductively coupled plasma atomic emission spectroscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The surface morphology and particle size of the compositions were analyzed by scanning electron microscopy and transmission electron microscopy, respectively. Mössbauer spectroscopy studies confirmed the ferrimagnetic nature of the material. Magnetic investigations were conducted at 300 and 5 K to determine the magnetic parameters. The saturation magnetization and coercivity were found to decrease on In3+ substitution. The Curie temperature showed a noticeable decrease with In3+ substitution because of dilution of magnetic interactions. Dielectric studies were performed with respect to frequency and temperature. • Preparation of In-substituted Co-Cu ferrite by sol-gel autocombustion. • Detailed characterization of this material by various techniques. • Effect of In substitution on the magnetic properties at 300 and 5 K. • DC resistivity increased and dielectric constant decreased with In substitution. • The In substitution allowed tuning of the magnetic and dielectric properties. [ABSTRACT FROM AUTHOR]

The composition dependent magnetic structure in epitaxial BaFe 12-x Sc x O 19 (0 ≤ x ≤ 2.1, BaScM) thin films have been investigated. Results show that with increasing Sc3+ content, the out-of-plane c -axis lattice constants of BaScM films increase but do not follow the Vegard's law. The changes in hysteresis loops indicate a variation of magneto-crystalline anisotropy from the uniaxial-type for BaFe 12 O 19 to the near-planar type for BaFe 10.2 Sc 1.8 O 19. The remanent magnetic domains change from a mixture of dots and maze-like structure to more maze-like structure as the Sc3+ content increases. The above magnetic results can be explained by a composition dependent magnetic structure transition from collinear-type ferrimagnetic magnetic structure to the non-collinear conical magnetic structure which appears at Sc3+ content x ≥ 0.6. The ZFC/FC curves further show that the conical magnetic structure transition temperature (T cone) of the films increases with the Sc3+ content until x ≥ 2.1. The above results may help better apply BaScM films in the electromagnetic devices. • With increasing Sc3+ content, lattice constant c increases but doesn't follow the Vegard's law. • With increasing Sc3+ content, magnetocrystalline anisotropy of the film changes from uniaxial-type for to conical-type. • With increasing Sc3+ content, magnetic domains change from a mixture of dots and maze structure to more maze-like structure. • The conical magnetic structure transition temperature (T cone) increases with the Sc3+ content until x ≥ 2.1. [ABSTRACT FROM AUTHOR]

Theoretical calculations were performed to investigate the effect of isovalent substitution of Fe with Ga on the magnetic and ferroelectric properties in BiFeO 3 doped with 16.6% and 8.3% Ga. Such substitution will break the G-type anti-ferromagnetic order and enhance the magnetism of BiFeO 3 by forming a stable ferrimagnetic order. The doped system maintains robust spontaneous polarization that is sufficiently large for practical applications at room temperature. The findings explain experimentally observed magnetism. The coexistence of magnetism and ferroelectricity in the doped BiFeO 3 render it a candidate material for application to information storage and spintronics devices. • The coexistence of magnetism and ferroelectricity is observed in Ga-doped BiFeO 3. • The substitutional doping establishes a ferrimagnetism in BiFeO 3 matrix. • The Ga-doped BiFeO 3 material still maintains robust ferroelectricity. [ABSTRACT FROM AUTHOR]

Di-phase ferroelectric-ferrite composites with the same composition close to the percolation limit (0.66BaTiO 3 -0.33CoFe 2 O 4) and with different phase arrangements (randomly mixed phases and tri-layer structures) have been consolidated by using spark plasma sintering and their properties were comparatively analyzed. The intrinsic effective dielectric constant has been estimated by using finite element method and a value almost ten times higher was predicted for the randomly mixed composite, as result of different field distributions inside the ferrite and ferroelectric phases. At room temperature, experimental permittivity contains an intrinsic behavior overlapped onto a very strong extrinsic component determined by the interfaces and by local charge inhomogeneity. The extrinsic dielectric behavior has been discussed in terms of thermally activated relaxation mechanisms developed in both types of investigated structures, as revealed by the temperature-dependence impedance spectroscopy. The magnetic properties are derived as "sum property" from the ferrimagnetic character of CoFe 2 O 4 and show the lowest magnetization for the randomly mixed composites and a weak magnetic anisotropy when the magnetic field was applied in-plane or out-of-plane in the layered structure. Due to the different levels of interface doping specific to the different types of interfaces, the magnetic Curie temperature of the two composites ranges from 720 K in the randomly mixed structure to 746 K for the layered one. The ferroelectric P (E) loops and a modest ME coefficient of 14 mVOe−1cm−1 at 100 Hz were determined only for the layered structure, due to the high leakage and to the small grain size (below 200 nm) in the ferroelectric BaTiO 3 component. • Randomly mixed and tri-layered structure composites were comparatively investigated. • Role of the phase arrangement on the dielectric properties was predicted by FEM. • Experimental dielectric data contains a strong influence from extrinsic phenomena. • Magnetic properties slightly depend on the phase arrangement. [ABSTRACT FROM AUTHOR]

In this paper, the ferrimagnetic mixed-spin (3/2, 5/2) Ising model was established to investigate the magnetic and thermodynamic properties of a nanoisland bilayer system with graphene-like structure by Monte Carlo simulation. We have analyzed the magnetization of the system and two sublattices, susceptibility, internal energy and hysteresis loops in detail. We have obtained the phase diagrams of the blocking temperature T B affected by the effects of various physical parameters. The triple hysteresis behavior has been observed, which originates from the competition among various physical parameters. Our results are comparable with those of other theoretical and experimental research. • The ferrimagnetic mixed-spin (3/2, 5/2) graphene-like nanoisland bilayer in the longitudinal magnetic field has been investigated. • Magnetization, susceptibility and internal energy have been discussed. • The phase diagrams of blocking temperature have been obtained under the influence of various physical parameters. • The triple hysteresis behavior have been found for certain physical parameters. [ABSTRACT FROM AUTHOR]

In this work, we study the magnetic properties of a borophene core-shell structure with spins σ = 5/2 and S = 3/2, using Monte Carlo simulations. We start by discussing the ground state phase diagrams corresponding to several physical parameters. Then the magnetizations and the susceptibilities have been analyzed. Besides, we explore the thermal magnetization behavior under the effect of the reduced exchange coupling interactions. Furthermore, we investigate the presence of the compensation temperature induced by the presence of a core shell structure and resulted from the variation of the reduced coefficient coupling. Finally, the variation of the total magnetizations as a function of the reduced exchange coupling interactions, the crystal and the external fields has been discussed. • Monte Carlo Simulations is used to investigate the magnetic properties of the core-shell Borophene. • The ground state phase diagrams are established. • The effect of exchange coupling interactions and magnetic external and crystal fields are analyzed. • The existence of compensation Temperature is studied. • The hysteresis cycles are explored. [ABSTRACT FROM AUTHOR]

• The mechanical and magnetic properties of AlM2B2 have been investigated. • The low hardness indicates a delamination deformation. • In AlM 2 B 2 the magnetism ferro- to antiferromagnetic with increasing Mn content. • AlFeMnB 2 shows a ferrimagnetic exchange interactions. • DFT calculations indicate weakening of the magnetic interactions upon substitution. The mechanical and magnetic properties of the newly discovered MAB-phase class of materials based upon AlFe 2 B 2 were investigated. The samples were synthesised from stoichiometric amounts of all constituent elements. X-ray diffraction shows that the main phase is orthorhombic with an elongated b -axis, similar to AlFe 2 B 2. The low hardness and visual inspection of the samples after deformation indicate that these compounds are deformed via a delamination process. When substituting iron in AlFe 2 B 2 with manganese, the magnetism in the system goes from being ferro- to antiferromagnetic via a disordered ferrimagnetic phase exhibited by AlFeMnB 2. Density functional theory calculations indicate a weakening of the magnetic interactions among the transitions metal ions as iron is substituted by manganese in AlFe 2 B 2. The Mn-Mn exchange interactions in AlMn 2 B 2 are found to be very small. [ABSTRACT FROM AUTHOR]

Magnetic properties of a superlattice that consists of three square layers with Ising spins σ = 1 / 2 , s = 1 and q = 5 / 2 , are investigated by means of standard Monte Carlo simulations and Mean Field Theory. The Hamiltonian model comprises contributions of intralayer and interlayer exchange interactions and the applied external magnetic field. Effects of the external magnetic field on magnetic behaviors have been thoroughly studied in the presence of thermal excitation. Ground state and thermal phase diagrams are numerically computated by both methods. Ground state phase diagrams of the system exhibit one ferromagnetic phase (1/2, 1, 5/2) and three ferrimagnetic ones: (−1/2, 1, 5/2), (−1/2, −1, 5/2) and (−1/2, 1, −5/2). A number of interesting phase diagrams and phenomena have been found, including hysteresis behaviors. [ABSTRACT FROM AUTHOR]

Abstract La 0.5 Sr 0.5 Fe (1-x) Cr x O 3 perovskite-type of oxides, 0.0 ≤ x ≤ 1, were prepared by the wet-chemical co-precipitation method and characterized by the X-ray diffraction (XRD), EDX, X-ray photoelectron spectroscopy (XPS), FT-IR, VSM and UV-VIS spectra. This study proved that these samples have orthorhombic perovskite structure in nano-metric scale and ferrimagnetic behavior. The crystal lattice volumes (V), crystallite size (R) and strain (ε) were decreased with increasing the Cr content x , whereas the density (D), porosity (P) and specific surface area (S) were increased. The analysis of XPS measurements revealed that the iron Fe is represented in three different equivalences (Fe2+, Fe3+ and Fe4+) while the chromium Cr is represented as metallic element (Cr0), Cr3+, Cr6+ and Cr 2 O 3 phase. In addition the oxygen O 1 S is appeared as the Lattice Oxygen O2− and the surface adsorbed Oxygen O−. The existence of Cr6+ and O− candidate these samples to have good catalytic effect. The main absorption bands of perovskite were observed in IR spectra and assigned to their corresponding sites and bonds. The saturation magnetization M S of the samples was decreased with increasing the Cr content x. There are two characteristic peaks of Cr6+ appeared with introducing the Cr doping in coincide with the stability of the energy band gap values (E g) with Cr doping. [ABSTRACT FROM AUTHOR]

The double perovskite Sr2CrIrO6 has very important characteristics for spintronic applications. It is a ferrimagnetic material distinguished by its high Curie temperature. This manuscript presents a model representing the double perovskite Sr2CrIrO6 in order to simulate and to predict its magnetic properties. This compound contains only two magnetic atoms, namely: Cr (S = 3/2) and Ir (σ = 2). Our simulations are done using the Monte Carlo method under the Metropolis algorithm. We present the behavior of the magnetization and the susceptibilities as a function of the temperature. Also, we discuss the effect of the physical parameters such as the coupling exchange interactions, the crystal field and the external magnetic field. To complete this study, we have presented the ground state by exposing the different phase diagrams in different planes of the physical parameters. Moreover, we establish the magnetic hysteresis loops of this compound. • We study the magnetic properties of the double perovskite Sr2IrCrO6. • We perform Monte Carlo simulations to investigate the magnetic properties of the double perovskite Sr2IrCrO6. • The effect of the physical parameters is studied and discussed. • The hysteresis loops are also presented for specific values of the physical parameters. [ABSTRACT FROM AUTHOR]

Abstract Magnesium and calcium co-substituted Ba M-type nanohexaferrite (NHFs) is fabricated via sol-gel auto-combustion technique. The phase formation was proved by XRD powder pattern, FESEM and HR-TEM. Magnetic properties of Ba 1-2x Ca x Mg x Fe 12 O 19 (x ≤ 0.1) NHFs investigated by Mossbauer Spectroscopy. The variations in line width, quadrupole splitting, isomer shift, the cation distribution of Ca2+ and Mg2+ ions and hyperfine magnetic field values were estimated. The AC magnetic susceptibility and ZFC-FC measurements were also performed for the Ba 1-2x Ca x Mg x Fe 12 O 19 (x = 0.02 and 0.08) NHFs. The M FC -M ZFC results do not show blocking temperature peak, indicating the ferrimagnetic (FM) behavior of prepared products. Different models including Neel-Arhenius (N-A), Vogel-Fulcher (V-F) and critical slowing down (CSD) were tested to evaluate the AC-magnetic susceptibility behaviors. It is demonstrated that the magnetic interactions are important for x = 0.02 NHFs. [ABSTRACT FROM AUTHOR]

Abstract Herein, we have systematically illustrated the specific impact of Ce-Zn co-substituted M-type strontium hexaferrites on its microstructure and magnetic properties. An evident phase pattern change process and performance improvement are observed from a series of systematic measurements. The results of X-ray diffraction show that the single phase can be obtained when x = 0.00–0.30, the other unexpected diffraction peaks of hematite (α -Fe 2 O 3) will appear in the patterns as x > 0.3. Scanning electron microscopy exhibits that all samples formed the uniform plane hexagonal structures with different substitution contents. FT-IR spectra verify the confirmation that M-type hexagonal structure has been formed thoroughly. M (T) curve displays the ferrimagnetic behavior of temperature dependent magnetization. And vibrating sample magnetometer indicates both M s and H c can be improved significantly, indicating an excellent performance in novel recording devices. Highlights • Ce-Zn co-substitute M-type strontium hexaferrites is reported initially. • EDX verifies the expected formula of Sr 1- x Ce x Fe 12- x Zn x O 19 hexaferrites. • FTIR spectroscopy confirms the structure of the sample. • Both M s and H c are much higher than un-substituted one. [ABSTRACT FROM AUTHOR]

Abstract The magnetic properties of tetragonal structure of stoichiometric NiMn alloy is investigated using density functional theory within the local spin density approximation. The system studied here, is a free standing film. The effect of thickness and epitaxial strain on the magnetic and structural properties is examined. It is found that while the magnetic moments of Mn surface atoms vary depending on the number of layers being odd (3.60 μ B) or even (3.55 μ B) the magnitude of the magnetic moment for surface Ni atoms is constant (0.11 μ B). By applying epitaxial strain on the slabs, it was observed, for the first time, that the magnetic phase of NiMn films changes from "A-type-like" ferrimagnetic for compressive strains to "G-type-like" ferrimagnetic for tensile strains. Highlights • Effect of thickness and epitaxial strain on the magnetic structure of NiMn films are investigated. • Surface buckling phenomenon for different thicknesses is studied. • A magnetic phase transition from A-type-like ferrimagnetic to G-type-like ferrimagnetic was observed by applying epitaxial strain. [ABSTRACT FROM AUTHOR]

Abstract Tetragonal Heusler alloys with high coercivity field (H C), low saturation magnetic moment and high Curie temperature (T C) have been considered as promising candidates for spin transfer torque (STT) applications. In this paper, tetragonal Heusler alloys Mn 3- x Cr x Ga have been designed and realized in experiments by adjusting the ratio of Mn/Cr and selecting suitable heat treatment conditions. It has been found that Mn 3- x Cr x Ga (x = 0, 0.2, 0.3, 0.4, 0.5, 0.6 and 1) alloys exhibited multiple phase structures. As x > 0.5, both as-spun and as-annealed ribbons show pure B 2-type body-centered cubic (b.c.c.) structure. The D 0 22 -type tetragonal Heusler structure starts to appear in the matrix of cubic B 2 structure as x = 0.5 in as-annealed ribbon samples, and gradually develops to pure tetragonal structure as x = 0.3. There is a significant structure difference between as-annealed and as-spun ribbons as x ≤ 0.2. Cu 3 Au-type face-centered cubic (f.c.c.) structure is observed for as-spun ribbons, while the annealed ribbons show pure tetragonal structure. The pure tetragonal Heusler alloys have hard-ferrimagnetic properties with H c higher than 258 kA/m, accompanied by a high T C , large magnetic remanence (B r) and low magnetic moment at room temperature, which are important factors for spin-transfer torque applications. Our work reveals the tunability of the magnetic and structural properties of Heusler alloys by changing the ratio of doping elements, providing a guidance for further searching for tetragonal Heusler alloys. Highlights • Multiple pure phases of entire Mn 3- x Cr x Ga alloy series were obtained by distinct composition and heat treatment methods. • First-principles calculations of structural stability were used to interpret the experimental results. • Tetragonal Heusler alloys Mn 3- x Cr x Ga with potential application prospects were realized. [ABSTRACT FROM AUTHOR]

Highlights • Dependence of μ ij , q ij , and α ij in BiFeO 3 on arbitrary orientations is investigated. • Anisotropy characteristics of μ ij , q ij , and α ij in BiFeO 3 are presented. • The optimal orientations for achieving the largest μ ij ′ , q ij ′ , and α ij ′ are specified. Abstract Through coordinate transformation approach, crystal orientation dependences of magnetic properties have been investigated in the three dimensional space for bismuth ferrite (BiFeO 3). Permeabilities μ 11 ′ , μ 33 ′ , piezomagnetic constants q 31 ′ , q 33 ′ , and magnetoelectric coefficients α 12 ′ , α 31 ′ along arbitrary orientations were presented based on magnetic and crystalline asymmetry characteristics of trigonal BiFeO 3 below the Neel temperature. μ 11 ′ is a constant while the max μ 33 ′ = μ 11 ′ = 2.68 lies in [ n k 0] axes. q 31 ′ and q 33 ′ show very similar orientation dependences with their absolute maximas (10−13 m/A) both lying in directions at ϕ = 30°, 90°, and 150° inside XOY plane. α 12 ′ and α 31 ′ show the contrary orientation dependences with their maximas (120 mV/cm Oe) existing along [0 0 1] and [ n k 0] axes, respectively. The results suggest that by adopting optimal directions, the magnetic parameters of BiFeO 3 could be optimally used. [ABSTRACT FROM AUTHOR]

Highlights • Effect of volume change on anisotropy. • Spin reorientation transition. • High volume stability of the magnetic properties. • Moderate decrease of the Curie temperature with increasing pressure. Abstract The magnetic properties of HoCo 12 B 6 ferrimagnetic compound are investigated versus the magnetic field, temperature and pressure. The magnetic phase diagram exhibits three remarkable temperatures: the ordering temperature T C , the spin reorientation temperature T SR and the compensation temperature T COMP at 147 K, 76 K and 47 K respectively. In HoCo 12 B 6 intermetallic system the spontaneous magnetization resulting from the antiparallel coupling of the magnetic moments of Ho and Co sublattices is pressure insensitive at lowest temperatures whereas it decreases with pressure at temperature range above T SR. The mean Co magnetic moment is small (<0.5 µ B) in the studied compound and exhibits a weak pressure dependence. In addition, significant pressure effects have been observed on both the spin reorientation transition and the Curie temperatures. A value of dT C /dp = −3.5 ± 0.4 K GPa−1 is dominated by the Co sublattice contribution. The spin reorientation transition temperature is also found to decrease versus pressure dT SR /dp = −4.2 ± 0.4 K GPa−1. The compensation temperature where the Ho and Co sublattices have the same magnitude but opposite direction does not vary significantly with applied pressure in the investigated pressure range (up to 1 GPa). The results of pressure dependence of the magnetic properties are compared to earlier results on other R-Co-B borides. HoCo 12 B 6 compound confirmed the remarkably high volume stability of the magnetic properties of the RCo 12 B 6 compounds with the itinerant character of magnetism and low values of both the T C and magnetization. [ABSTRACT FROM AUTHOR]

Highlights • Magnetic H - T phase diagram of a Fe/Gd ferrimagnetic superlattice is obtained. • Collinear, twisted and surface twist magnetic states are identified. • Two spectral branches of ferromagnetic resonance are observed. • The observed modes correspond to different types of non-uniform precession in Gd. Abstract Static and dynamic magnetic properties of a ferrimagnetic Fe (35 Å) / Gd (50 Å) 12 superlattice were investigated in a wide 4–300 K temperature range using magneto-optical Kerr effect (MOKE) and ferromagnetic resonance (FMR) techniques. The multilayer structure was sputtered on a transparent glass substrate which made it possible to perform MOKE measurements on both Fe and Gd terminated sides of the superlattice. These experiments allowed us to detect a transition between field-aligned and canted magnetic states on both sides of the film and to distinguish between the bulk and surface twisted phases of the superlattice. As a result, the experimental H - T magnetic phase diagram of the system was obtained. FMR studies at frequencies 7–36 GHz demonstrated a complex evolution of absorption spectra as temperature decreased from room down to 4 K. Two spectral branches were detected in the sample. Theoretical simulations show that the observed spectral branches correspond to different types of inhomogeneous resonance modes in the multilayer with non-uniform magnetization precession inside Gd layers. [ABSTRACT FROM AUTHOR]