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With humongous demand for data storage and processing, two‐dimensional (2D) ferromagnetic‐based materials, is emerged as the next‐generation nanoelectronic devices due to their low power consumption and optimal memory and processing capabilities. BiFeO3 as a single‐phase multiferromagnetic material is expected to find potential applications in electromagnetic devices. Herein, 2D room‐temperature ferromagnetic BiFeO3 is obtained with the help of supercritical carbon dioxide (SC CO2). The rhombic phase of BiFeO3 is converted to cubic with the creation of Ov and Fe2+ defects over the SC CO2 treatment, leading to significant ferromagnetic enhancement. More importantly, it is found that SC CO2 can destroy the cycloidal spin structure of BiFeO3 leading to an increase in the Fe─O─Fe bond angle, which generates stronger superexchange interactions. Ultimately, the saturation magnetization strength of BiFeO3 is increased by nearly 23 times. A new strategy is provided for ferromagnetic induction in 2D materials, which is favorable for promoting their practical applications on device architectures in the future. [ABSTRACT FROM AUTHOR]

We develop a strong coupling approach towards quantum magnetism in Mott insulators for Wannier-obstructed bands. Despite the lack of Wannier orbitals, electrons can still singly occupy a set of exponentially localized but nonorthogonal orbitals to minimize the repulsive interaction energy. We develop a systematic method to establish an effective spin model from the electron Hamiltonian using a diagrammatic approach. The nonorthogonality of the Mott basis gives rise to multiple new channels of spin-exchange (or permutation) interactions beyond Hartree–Fock and superexchange terms. We apply this approach to a Kagome lattice model of interacting electrons in Wannier-obstructed bands (including both Chern bands and fragile topological bands). Due to the orbital nonorthogonality, as parameterized by the nearest-neighbor orbital overlap g, this model exhibits stable ferromagnetism up to a finite bandwidth W ∼ U g , where U is the interaction strength. This provides an explanation for the experimentally observed robust ferromagnetism in Wannier-obstructed bands. The effective spin model constructed through our approach also opens up the possibility for frustrated quantum magnetism around the ferromagnet-antiferromagnet crossover in Wannier-obstructed bands. [ABSTRACT FROM AUTHOR]

Transition metal perovskite oxide membranes and their unique properties have attracted great attention recently and have been developed into one of the research frontiers in condensed matter physics and materials science. Free of constraint imposed by the underlying substrate, freestanding membranes exhibit extraordinary structural tunability and flexibility far exceeding the bulk materials and epitaxial films clamped on substrates, which substantially extends the explorable regime in the phase diagrams. Moreover, high‐quality oxide membranes, even down to a single unit cell, can be synthesized and stacked/integrated with any materials for novel artificial heterostructures and electronic applications. The exceptional structural tunability and stacking ability in oxide membranes provide new knobs to explore the spontaneous symmetry breaking in oxides, providing a fertile playground for emergent primary ferroic/multiferroic properties and electronic applications. Here, the recent progress is briefly reviewed and the promising outlook for future research in ferroic perovskite oxide membranes and their applications is discussed. [ABSTRACT FROM AUTHOR]

Spinel type Mn 3 O 4 oxide ceramics possess intriguing magnetodielectric properties, but traditional processing routes can be frustrated by limited high temperature phase stability. Using a low temperature (≤400 °C) electric field assisted processing route (Cool-SPS), a highly cohesive Mn 3 O 4 ceramic is achieved. Reactive manganese oxide-hydroxide precursor powder is converted into the targeted Mn 3 O 4 with a single step process under strategically selected conditions. Detailed X-ray diffraction studies, including variable temperature and atmosphere measurements, plus in-situ monitoring of processing parameters, have been combined to map and optimize SPS processing parameters. The microstructure evolution from precursor to ceramic was examined by electron microscopy, while extensive magnetic and dielectric measurements were performed to study the complex physical behavior of Mn 3 O 4 at low temperature (<43 K). The efficacy of this Cool- SPS processing approach for Mn 3 O 4 is demonstrated by the observed ceramic properties, including a hysteretic magnetic-field dependent dielectric response which supports the existence of a magnetoelectric coupling. [ABSTRACT FROM AUTHOR]

The efficiency of hydrogen evolution reaction (HER) takes an important influence on electrochemical water electrolysis, yet it still delivers sluggish kinetics mainly due to the high kinetic energy barriers. Herein, Cu 1 Ni 5 Fe 2 -Layered double hydroxides/reduced graphene oxide (denoted as Cu 1 Ni 5 Fe 2 -LDHs/rGO) with heterogeneous Cu atoms incorporated into Ni 6 Fe 2 -LDHs/rGO is constructed through a hydrothermal method and doping strategy in this works, wherein the subtle lattice distortion is availably regulated and optimized by Cu2+ Jahn-Teller effect, offering more active sites for HER. As benefits of the subtle lattice distortion and the spin exchange interaction, Cu 1 Ni 5 Fe 2 -LDHs/rGO displays ferromagnetism at room temperature and shows superior alkaline HER properties with a relatively low overpotentials of 50 mV at 10 mA cm−2 in 1.0 M KOH. The low Tafel slope of 38 mV dec−1 implies Cu 1 Ni 5 Fe 2 -LDHs/rGO owns an ultra-fast HER kinetic. This study can offer a new strategy to construct high efficient HER catalysts based on transition metal NiFe-LDHs. [Display omitted] • A new preparation, it is first time to fabricate Cu 1 Ni 5 Fe 2 -LDHs/rGO. • The subtle lattice distortion is optimized by the Cu2+ Jahn-Teller effect. • Cu 1 Ni 5 Fe 2 -LDHs/rGO displays ferromagnetism at room temperature. • Cu 1 Ni 5 Fe 2 -LDHs/rGO shows an ultra-fast HER kinetic with a low Tafel slope of 38 mV dec−1. [ABSTRACT FROM AUTHOR]

Ferromagnetism in 2D materials has attracted tremendous interest from the scientific community thanks to its potential for the design of magnetic materials with unique properties. The presence of a ferromagnetic element in a 2D material can improve the existing properties and offer new ones, giving rise to the development of manifold applications. This review focuses on recent advances and perspectives of 2D materials that bear at least one ferromagnetic element (iron, cobalt, nickel) as i) structural constituent, ii) dopant atom, or iii) adjacent atom through proximity effect. By describing in detail the magnetic properties that have emerged so far, their potential to form next‐generation 2D magnets is discussed. Moreover, the contribution of such 2D materials is analyzed in various applications (electrochemical, photochemical, optical, and electronic), aiming to explore further functionalities and capabilities of ferromagnetic elements, apart from their magnetic nature. Special attention is given to gadolinium and other rare earth elements that display a ferromagnetic order even at ultra‐low temperatures and form part of 2D structured materials, with particularly appealing properties deriving from their 4f electrons. [ABSTRACT FROM AUTHOR]

Nickel-doped magnesium cubic spinel ferrite nanoparticles (NPs) were prepared through the microwave combustion method (MCM). The structure of magnesium ferrite normal spinel is obtained from XRD analysis. The average crystallite size is between 26 and 17 nm. The elemental compositions and oxidizing states of Ni2+ doped MgFe2O4 ferrites were evaluated by using XPS analysis. The morphology of spinel nanoparticles was studied using HR-SEM images. The energy dispersive X-ray method is used for ensuring the presence of elements and the band gap value 2.09, 2.02, 1.85, and 1.82 eV have been obtained using the tau'c relation. The magnesium spinel structure is confirmed in the band at 434 and 561 cm−1 which corresponds to the stretching vibration of the octahedral site (Mg2+–O2−) and tetrahedral site (Fe3+–O2−) respectively. From the hysteresis loops the magnetic features viz. Hc, Mr, and Ms were determined. Further dielectric studies and AC conductivity of the prepared samples are performed. [ABSTRACT FROM AUTHOR]

The rapid development of 2D magnetic materials has opened new possibilities in the field of spintronics. CrTe2, a 2D material with perpendicular magnetic anisotropy (PMA) and ferromagnetic transient temperature near room temperature, holds promise for various applications. However, the underlying mechanism responsible for its global magnetism remains unclear. This work focuses on investigating the magneto‐transport properties of ultra‐thin CrTe2 Field Effect Transistor (FET) under the influence of top gate biases. The application of gate voltage ranging from 25 to −15 V tunes its coercivity (HC) and Curie temperature (TC) (from 152 to 191 K). Notably, a linear correlation is observed between the TC and the hole concentration (np1/3$n_{\mathrm{p}}^{1/3}$) in the CrTe2 film, indicating the involvement of the Ruderman–Kittel–Kasuya–Yosida interaction. This experimental analysis sheds light on the mechanism of the CrTe2's ferromagnetism and paves the way for future advancements and applications in this material. [ABSTRACT FROM AUTHOR]

In this study, pure and europium-doped (2%, 4%, 6%, and 8%) cerium oxide (CeO2) nanoparticles (NPs) were employed for efficient dye removal through photocatalytic approach. XRD and TEM confirmed the formation of pure CeO2 nanoparticles, while XPS and Raman spectroscopy were used to analyze the electronic properties and lattice defects, such as oxygen vacancies. The presence of lattice defects, which increased with the concentration of Eu, was found to be responsible for the enhanced degradation of Rose Bengal dye (82.4% for 8% Eu-doped sample) in 75 min. FTIR confirmed the chemical composition of the synthesized sample. The band at 617 cm−1, corresponding to the symmetrical stretching vibration mode of (Ce–O-Ce) or (Ce–O-Eu). The magnetic properties of synthesized samples were examined using VSM, revealing an increase from 4.48 to 11.0 emu/g in magnetization. This enhancement was attributed to F-center exchange mechanism (FCE), resulting from the presence of oxygen vacancies. These findings contribute to the development of advanced materials for sustainable wastewater treatment and spintronics. [ABSTRACT FROM AUTHOR]

This review reports the latest trends in the ceramic composite matrix used for the magnetoelectric (ME) effect. In the last few years, ME composite has become the center of attraction for use in various electrically and magnetically coupled devices. The growth and use of electronic components everywhere have propulsively accelerated the exploration of self-powered electronic and sensor network devices. ME is a feasible technique for addressing difficulties of traditional batteries such as short life span and frequent recharge difficulties. Self-charging multiferroic components have been found for the constant working of mobile electronics that use multiferroic composites in response to magnetoelectric energy transformation. Researchers have rigorously studied the rigid and flexible magnetoelectric composites for their suitability in applications. This paper gives a comparative study between rigid and flexible magnetoelectric composites based on their properties and provides knowledge about the materials for such types of composites. It reviews the latest polymer-based ME materials as well as the related fabrication and polarization methods. The review finally encapsulates the applications in biomedicine, ranging from mechanical energy harvesters to sensors and actuators.

Nickel ferrite nanoparticles doped with zinc were synthesized at a lower reaction temperature of 180 °C. The research delved into their structural, optical, dielectric, and magnetic properties. These nanoparticles exhibited a distinct cubic spinel structure, with crystallite sizes ranging from 33 to 51 nm. FTIR analysis revealed metal oxide stretching vibrations between 400–600 nm. FESEM and HR-TEM examinations unveiled irregularly shaped nano-particles. XPS analysis disclosed the chemical states of Zn2+, Fe3+, and Ni2+ ions. Mossbauer spectra exhibited two sextet patterns related to tetrahedral (A) and octahedral (B) sites, plus a weak doublet pattern. Magnetic tests showed a decrease in saturation magnetization (Ms) but an increase in remanent magnetization (Mr) and coercivity (Hc) values upon doping.

Employing a self-combustion method supported by egg white, pure and Fe-doped ZnO/C nanoparticles successfully biosynthesized. XRD, FTIR, Raman, SEM/EDS and TEM measurements were used to characterize the pure and doped systems. The materials under investigation’s optical, surface and magnetic characteristics were recognized. Only one zinc oxide crystalline phase exhibiting a hexagonal shape comparable to wurtzite was present in the systems of pure and Fe-doped ZnO/C. Due to the variation in ionic radii, doping ZnO/C system with iron ions resulted in a decrease in unit cell volume; it revealed that ions of iron had been integrated into the lattice of zinc oxides. FTIR analysis shows characteristic vibration modes related to ZnO and that of carbon groups, confirming the formation of the ZnO/C system. In a perfect match with the IR data, which represent two bands at 1120 and 1399 cm−1 attributed to carbon groups, the Raman analysis shows that in the freshly manufactured materials, sp2 and disordered G and D carbon bands have both graphitized. Fe-doping of the ZnO/C system with different amounts of iron ions resulted in the change in the size and agglomeration of the particle’s system. The doped ZnO/C system has a surface area smaller than that of the pure system due to the decrease in both the mean pore radius and the total pore volume. Doping the ZnO/C system with 2 and 5 mol% Fe2O3 resulted in optical band gaps expanding from 3.17 eV to 3.27 eV and 3.57 eV, respectively. Due to the doping with iron ions, a magnetic transition from a fully diamagnetic state to a slightly ferromagnetic state was detected.

We systematically investigate the unoccupied electronic states, crystal structure, and magnetism of V- and Mn-doped ZnO nanocrystals (NCs). Post-annealing treatment at 300 ° C converts diamagnetic V 5 + into magnetic high-spin V 3 + ions, which leads to room-temperature ferromagnetism for the V-doped NCs. In contrast, ferromagnetism does not occur for the Mn-doped NCs. Oxygen 1 s x-ray absorption spectroscopy reveals that the unoccupied metal-oxygen hybridized state lies near the bottom of the conduction band for the V-doped NCs but lies far above it for the Mn-doped NCs. Therefore, the ferromagnetism in a ZnO-based diluted magnetic semiconductor system can be understood within the framework of the n -type carrier-mediated ferromagnetism model. [ABSTRACT FROM AUTHOR]

Using state-of-the-art first-principles electronic-band-structure calculations alongside density functional theory, we investigated the structural, elastic, electronic, and magnetic properties of LiMnZ2 (Z = Se, Te) compounds with a trigonal structure. Initially, we determined the equilibrium lattice structure and atomic positions, which aligned well with experimental values. Ferromagnetism was shown to be more favorable than the non-magnetic state. The elastic constants, cohesive energies, and formation energies indicated that the studied compounds were mechanically stable in the experimentally determined trigonal lattice. The analysis of spin-polarized band structures and density of states revealed that both LiMnZ2 compounds exhibited perfect half-metallic characters. The total spin magnetic moment per formula unit adhered to the Slater–Pauling rule, being exactly 4 μΒ, mainly concentrated at the Mn atoms due to the strong spin polarization of the Mn d orbitals. We anticipate that our results will prompt further experimental and computational studies for the application of these layered materials in practical devices.

Here, by using angle-resolved photoemission spectroscopy, we showed that Bi2−xCrxSe3 single crystals have a distinctly well-defined band structure with a large bulk band gap and undistorted topological surface states. These spectral features are unlike their thin film forms in which a large nonmagnetic gap with a distorted band structure was reported. We further provide laser-based high resolution photoemission data which reveal a Dirac point gap even in the pristine sample. The gap becomes more pronounced with Cr doping into the bulk of Bi2Se3. These observations show that the Dirac point can be modified by the magnetic impurities as well as the light source.

In this study, ferroelectric Pb(Fe1/2Nb1/2)O3 with an antiferromagnetic polymorph at and below 150 K was converted into a room-temperature magnetoelectrically active multiferroic with soft ferromagnetism by disrupting the existing antiparallel spin alignment of Fe ions through the heavy replacement of Fe by Ni. To maximize the induced soft-ferromagnetic properties and the consequent nonlinear magnetoelectric coupling, the substitution level of Ni should be controlled such that the individual Ni ions are separated from one another to avoid mutual spin cancellation. The induced magnetoelectric coupling was found to originate from the collective contribution of oppositely canted pairs of spins in two nearby Fe3+ ions, which counterbalances the relatively smaller spin moment of the in-between Ni ions. The non-material specific nature of this strategy implies that it can be used in the development of new room-temperature multiferroic perovskite oxides. [ABSTRACT FROM AUTHOR]

High-temperature ferromagnetism has always been a classic and interesting subject, especially in spin gapless semiconductor PbPdO 2 with exotic properties. Here, a combination of theoretical and experimental studies was employed to clarify the origin of high Tc. First, based on first-principles calculations, electronic band structures of PbPd 0.875 Co 0.125 O 2 at different Co substitution positions were studied. Our results indicate that Co atoms tend to form an antiferromagnetic ground state due to the Co–O–Co (180 °) indirect exchange effect, while ferromagnetism is favored in Co-doped PbPdO 2 when a unique molecular field effect induced band crossover and p – d coupling occurs. It is revealed that metallic or semiconductor properties have an important connection with ferromagnetism or antiferromagnetism. Subsequently, a Monte Carlo simulation was carried out based on the first-principles results to predict the ferromagnetism of PbPd 0.875 Co 0.125 O 2. Finally, the moment-magnetic field and moment-temperature curves were also measured for PbPd 0.875 Co 0.125 O 2 samples, which was found well consistent with the theoretical findings. The ground state of PbPd 0.875 Co 0.125 O 2 was confirmed to be ferromagnetic. Our results well explain the origin of high-temperature ferromagnetism in diluted magnetic semiconductors and provide new approaches for the design of future high Tc spintronic devices. [ABSTRACT FROM AUTHOR]

We report the thermal expansion, critical behavior, magnetocaloric effect (MCE), and magnetoresistance (M R) on the polycrystalline Mn 1.4 Fe 3.6 Si 3 compound around the ferromagnetic transition. A large negative volume thermal expansion (α V ∼ − 20 × 10 − 6 K − 1 ) is observed across the transition temperature with a strong anisotropic variation of lattice parameters in the a b -plane. The anisotropic magnetoelasticity arises from the competition between magnetic ordering and structural deformation that could be responsible for the large MCE (Δ S m ≃ − 6 J/Kg K) across the magnetic transition in this compound. The large and negative M R (∼ − 3 % in 80 kOe) is also observed at the transition temperature which can be attributed to the suppression of spin disorder. Furthermore, the Rhodes–Wolfarth ratio (RWR > --> 1) and identical field dependence of M R and MCE isotherms indicate the itinerant character of the 3 d electrons. The critical exponents determined from the analysis of magnetization and MCE are consistent with the quasi-two-dimensional (2D) Ising model with long range exchange interactions that decays as J (r) ∼ r − 3.41 . This unconventional quasi-2D Ising character with long-range interactions can be ascribed to strong a b -plane anisotropy and the delocalized 3 d electrons in the studied compound. [ABSTRACT FROM AUTHOR]

Abstract Finding materials exhibiting superconductivity at room temperature has long been one of the ultimate goals in physics and material science. Recently, room-temperature superconducting properties have been claimed in a copper substituted lead phosphate apatite (Pb10-xCux(PO4)6O, or called LK-99) (Lee et al. in J. Korean Cryst. Growth Cryst. Technol. 33:61, 2023; Lee et al. in The first room-temperature ambient-pressure superconductor, 2023; Lee et al. in Superconductor Pb10-xCux(PO4)6O showing levitation at room temperature and atmospheric pressure and mechanism, 2023). Using a similar approach, we have prepared LK-99 like samples and confirmed the half-levitation behaviors in some small specimens under the influence of a magnet at room temperature. To examine the magnetic properties of our samples, we have performed systematic magnetization measurements on the as-grown LK-99 like samples, including the half-levitated and non-levitated samples. The magnetization measurements show the coexistence of soft-ferromagnetic and diamagnetic signals in both half-levitated and non-levitated samples. The electrical transport measurements on the as-grown LK-99 like samples including both half-levitated and non-levitated samples show an insulating behavior characterized by the increasing resistivity with the decreasing temperature.

The complex electronic structure of metallic ferromagnets is determined by a balance between exchange interaction, electron hopping leading to band formation, and local Coulomb repulsion. By combining high energy and temporal resolution in femtosecond time-resolved X-ray absorption spectroscopy with ab initio time-dependent density functional theory we analyze the electronic structure in fcc Ni on the time scale of these interactions in a pump-probe experiment. We distinguish transient broadening and energy shifts in the absorption spectra, which we demonstrate to be captured by electron repopulation respectively correlation-induced modifications of the electronic structure, requiring to take the local Coulomb interaction into account.

Abstract The main objective of the review was to investigate the ferromagnetism of diluted magnetic semiconductors made of Mn‐doped GaAs. Manganese‐doped gallium arsenide has recently become an important field of research because of its potential applications in the fields of spintronics and magnetic devices. The magnetic moment caused by adding manganese to the GaAs crystal structure causes a low‐temperature ferromagnetic behavior. The main factor that affects the ferromagnetic properties of Mn‐doped gallium arsenic is manganese concentration. Understanding the relationship between Mn concentration and magnetic properties is important for material optimization in specific applications. It was found that Mn‐doped GaAs exhibit paramagnetic behavior below a specific critical concentration. However, the substance is transformed into a ferromagnetic state over the maximum concentration. The Curie temperature is an important additional factor influencing the ferromagnetic properties of Mn‐doped GaAs. The temperature at which a material ceases to exhibit ferromagnetic behavior is known as the Curie temperature. The Curie temperature of a material depends on its Mn concentration, thin film thickness, and degree of disturbance. A reduction in magnetic resistance increases the concentration of Mn‐treated gallium arsenic and increases its rate as it reaches its maximum value. High Curie temperatures are the result of stronger magnetic interactions resulting from higher manganese concentrations. The specific heat capacity of Mn‐doped gallium arsenide is influenced by its magnetic and structural contribution.

Intercalation of transition metal dichalcogenides with magnetic elements has been the subject of increasing research interest, aiming to explore novel magnetic materials with anisotropy and spin-orbit coupling. In this paper, two magnetic samples with varying Fe content have been prepared using different growth conditions via the chemical vapor transport method. A comprehensive investigation of the magnetic properties of the materials has been conducted using the Physical Property Measurement System (PPMS, EvercoolⅡ-9T, Quantum Design). The results reveal distinct features in the studied materials. Fe0.12TaSe2 exhibits significant ferromagnetism with a Curie transition temperature of 50 K. However, its in-plane magnetism is weak and no significant hysteresis loop is observed below the Curie temperature. On the other hand, Fe0.25TaSe2 exhibits antiferromagnetism without any hysteresis loop and has a Néel temperature up to 130 K. This finding is quite different from the intercalated iron in FexTaS2, where only an antiferromagnetic state occurs with x larger than 0.4. Our study thus provides updated insights into the magnetic properties of this new system and serves as a reference for future investigations of TaSe2 compounds with varying iron content.

The structural, magnetic, ferroelectric, dielectric, magneto-dielectric and optical properties of W/Co co-substituted tungsten bronze Ba4Sm2Fe2Nb8-3x(W2Co)xO30 (0 ≤ x ≤ 0.3) ceramics were studied in detail. All the samples can be indexed with the tetragonal structure with the space group of P4bm. The room-temperature ferromagnetism with rather high ferromagnetic Curie temperature Tc was obtained in all compositions. The co-doping of W/Co ions obviously optimized the ferromagnetism and ferroelectricity. The composition x = 0.2 showed a superior multiferroicity with the remnant magnetization Mr of 0.15 emu/g and the remnant polarization Pr of 2.1μC/cm2 as well as the Tc of 886 K. The low-temperature relaxation was related to the thermal process of oxygen vacancies, while the another one around 300 K was ascribed to the localized hopping of electrons. The relative increment of magneto-dielectric constant (MDC) obeyed with the square term of magnetization in Ginzburg-Landau theory, implying the existence of intrinsic magneto-electric coupling effect. A relatively large MDC of 0.17 % was achieved in pure sample. In addition, two direct inter-band transitions with the narrow band gaps of ∼2.0 eV and ∼2.5 eV were demonstrated.

We have conducted a study that focuses on designing a quasi-1D ultrathin and long ferromagnetic nanowires array with excellent linearity. The purpose of this design is to test the presence of Majorana zero modes in pairs over a long distance and the influence of the lateral interaction. Specifically, we investigate the magnetic properties of a one-unit cell thick MoSX nanowire array, where dopant X (H, C, N, O, and F. etc) is utilized, to assess its suitability for our intended purposes. Our findings reveal that the edge magnetization of the optimized MoSX nanowires is comparable to that of 3d transition metals with the Curie transition temperature surpassing room temperature. Our study indicates that the ferromagnetism of the optimized MoSX nanowires is unlikely to be eliminated when placed on an s-wave superconductor due to lattice mismatch. By conducting comparative case studies of various dopants, we establish a connection between the source of magnetism in the nanowires and internal electric fields, charge perturbation, spin-orbital coupling and p-d hybridization. The strong exchange interaction, robust spin-orbital coupling and large local magnetic moment exhibited by long and ultrathin room-temperature ferromagnetic nanowires open up avenues for diverse topological applications.

The present study reports the new functionality of room temperature ferromagnetism (RTFM) in non-magnetic Cadmium (Cd) doped BaTiO3 nanostructures, contrary to pure diamagnetic BaTiO3. TEM images show that grain size reduces with Cd doping. XPS analysis indicates that cation vacancies induce RTFM in Cd doped BaTiO3. Magnetic study reveals that pure BaTiO3 exhibits diamagnetic like signature, while Cd doped BaTiO3 show ferromagnetic feature with saturation magnetization (Ms ~ 9.70x10-3emu/g), remanent magnetization (Mr ~ 0.22x10-3emu/g) and coercive field (Hc ~ 42.54 Oe), respectively. The current investigation also indicates that the induced RTFM could meet the demand of developing spintronic applications. [ABSTRACT FROM AUTHOR]

The flexible electronics have application prospects in many fields, including as wearable devices and in structural detection. Spintronics possess the merits of a fast response and high integration density, opening up possibilities for various applications. However, the integration of miniaturization on flexible substrates is impeded inevitably due to the high Joule heat from high current density (1012 A/m2). In this study, a prototype flexible spintronic with device antiferromagnetic/ferromagnetic heterojunctions is proposed. The interlayer coupling strength can be obviously altered by sunlight soaking via direct photo-induced electron doping. With the assistance of a small magnetic field (±125 Oe), the almost 180° flip of magnetization is realized. Furthermore, the magnetoresistance changes (15~29%) of flexible spintronics on fingers receiving light illumination are achieved successfully, exhibiting the wearable application potential. Our findings develop flexible spintronic sensors, expanding the vision for the novel generation of photovoltaic/spintronic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] Magnetic semiconductors with both electron charge and spin features exhibit tremendous potential in spintronics. Although defective transition-metal dichalcogenides are promising with induced room temperature (RT) magnetic moments, impacts of the defect type and underlying mechanisms remain unclear. Herein, two strategies involving elemental substitution and epitaxial growth have been explored to synthesize alloyed and hybrid MoSe 2-x S x with lattice distortion and artificial interfaces respectively. Both experimental measurements and first-principle calculations demonstrate induced magnetism in the resultant MoSe 2-x S x with the magnetization intensity closely associated to the atomic structure. The alloyed MoSe 2-x S x exhibits satisfactory structural stability and atomic magnetic moments due to the Mo 4d orbital splitting induced by lattice distortion. Nevertheless, both enhanced RT ferromagnetism and thermomagnetic stability can be achieved for the hybrid MoSe 2-x S x resulted from stronger localized spin polarization at the MoSe 2 /MoS 2 interfaces. As such the work not only sheds light on the mechanisms underlying defect-induced ferromagnetism in transition-metal dichalcogenides, but also proposes an interface engineering strategy to induce significant ferromagnetism for multi-fields including spintronics, multiferroics and valleytronics. [ABSTRACT FROM AUTHOR]

Undoped porous WO 3 nanofilms with large surface area were fabricated on porous anodic alumina substrates by magnetron sputtering. The nanofilms exhibited significant room-temperature ferromagnetism, at least one order of magnitude stronger than other reported undoped WO 3 films. By controlling the oxygen partial pressure and the sputtering time during the deposition process, the saturation magnetization of the samples could be tuned over a large range, from 0.1 to 21.7 emu/cm3. Obvious magnetic anisotropy was found in the porous samples, indicating that the magnetic behavior is related to the regular pore structure perpendicular to the surface. Moreover, the first theoretical evidence that the Curie temperature of the sample is higher than room temperature was provided. When annealed in argon, the WO 3 nanofilms turned black and showed a combination of a narrowed bandgap and enhanced ferromagnetism. These interesting phenomena are explained based upon the concept of hydrogen-like impurity states associated with oxygen vacancies. [ABSTRACT FROM AUTHOR]

Rutile TiO 2 exhibits RTFM when it contains intrinsic defects or when external elements are doped into the material, which makes it an crucial substrate material for advancement of spintronics. By utilizing electron irradiation, intrinsic defects can be generated in rutile TiO 2 , and the type and concentration of defects can be controlled by adjusting the energy and fluence of the electron beam. In this study, rutile TiO 2 samples were subjected to electron irradiation at different fluences, and the resulting microstructure, magnetism, and optical properties were characterized. The findings reveal that all the samples exhibit RTFM, and the changes of M S and N S are similar with the variations of the concentration of V O. This serves as direct evidence that the intrinsic defects in rutile TiO 2 can induce RTFM and confirms that electron irradiation can regulate the RTFM of rutile TiO 2. [Display omitted] • The change of M S and N S are similar with the variations of the electron fluence. • The intrinsic defect V O present in rutile TiO 2 can induce RTFM. • 0.5 MeV electron irradiation can regulate the RTFM of rutile TiO 2. [ABSTRACT FROM AUTHOR]

NiO nanoparticles are synthesized by vacuum arc sputtering. The effect of the synthesis parameters on the structural and magnetic properties of samples is studied. X-ray diffraction analysis confirms a polycrystalline structure of the nanoparticles prepared under all deposition conditions; however, the preferred orientation of crystallites depends on the deposition conditions. The magnetic behavior correlates with the crystallite size of NiO nanoparticles. Condensates with a particle size of 4–6 nm demonstrate superparamagnetic behavior, which changes into antiferromagnetic as the particle size increases. [ABSTRACT FROM AUTHOR]

In the context of developing next-generation information technology, two-dimensional materials with inherent ferromagnetism, a Curie temperature above room temperature, and significant magnetic anisotropy hold great promise. In this work, we employed first-principles calculations to investigate a novel two-dimensional Janus structure, namely SVAN2 (A = Si, Ge). Our findings reveal that these structures are not only dynamically and thermally stable, but also exhibit semiconductor properties alongside their ferromagnetic states. The Janus SVSiN2 monolayer exhibits an in-plane easy axis, while the SVGeN2 monolayer shows an out-of-plane easy axis, both characterized by a significant magnetic anisotropy energy (129 and 172 μeV, respectively). Notably, through Monte Carlo simulation, we found that the Curie temperature of the SVSiN2 monolayer is 330 K, which is higher than room temperature. Finally, by applying biaxial strain and an external electric field, we successfully regulated the electronic properties of the SVAN2 (A = Si, Ge) monolayers, enabling a transition from semiconductor to half-metallic behavior. These remarkable electronic and magnetic properties make the Janus SVAN2 (A = Si, Ge) monolayers promising candidate materials for spin electron applications. [ABSTRACT FROM AUTHOR]

Primary ferroicities like ferroelectricity and ferromagnetism are essential physical properties of matter. Multiferroics, with coexisting multiple ferroic orders in a single phase, provide a convenient route to magnetoelectricity. Even so, the general tradeoff between magnetism and polarity remains inevitable, which prevents practicable magnetoelectric cross-control in the multiferroic framework. Here, an alternative strategy, i.e., the so-called alterferroicity, is proposed to circumvent the magnetoelectric exclusiveness, which exhibits multiple but noncoexisting ferroic orders. The natural exclusion between magnetism and polarity, as an insurmountable weakness of multiferroicity, becomes a distinct advantage in alterferroicity, making it an inborn rich ore for intrinsic strong magnetoelectricity. The general design rules for alterferroic materials rely on the competition between the instabilities of phononic and electronic structures in covalent systems. Based on primary density functional theory calculations, Ti-based trichalcogenides are predicted to be alterferroic candidates, which exhibit unique seesaw-type magnetoelectricity. This alterferroicity, as an emerging branch of the ferroic family, reshapes the framework of magnetoelectricity, going beyond the established scenario based on multiferroicity. [ABSTRACT FROM AUTHOR]

Ferromagnetism can be characterized by various distinct phenomena such as non-zero magnetization (inducing magnetic attraction/repulsion), diagonal piezomagnetism, nonreciprocal circular dichroism (such as Faraday effect), odd-order (including linear) anomalous Hall effect, and magneto-optical Kerr effect. We identify all broken symmetries requiring each of the above phenomena, and also the relevant magnetic point groups (MPGs) with those broken symmetries. All ferromagnetic point groups, relevant for ferromagnets, ferrimagnets, and weak ferromagnets, can certainly exhibit all these phenomena, including non-zero magnetization. Some of the true antiferromagnets, which are defined as magnets with MPGs that do not belong to ferromagnetic point groups, can display these phenomena through magnetization induced by external perturbations such as applied current, light illumination, and uniaxial stress, which preserve the combined symmetry of spatial inversion together with time reversal. Such MPGs are identified for each external perturbation. Since high-density and ultrafast spintronic technologies can be enabled by antiferromagnets, our findings will be essential guidance for future magnetism-related science as well as technology. [ABSTRACT FROM AUTHOR]

Triple negative breast cancer (TNBC) phenotype accounts for its significant resistance to chemotherapy and other therapeutic procedures. So, the establishment of better and effective therapeutic procedures has become a challenge during recent years. Doxorubicin is a potent chemotherapeutic candidate but its prominent side effects can be subsided via its combination with nanocarriers. So, the present study was aimed to design ascorbic acid modified biopolymeric EDC/NHS-modified magnetic nanoparticles (MNP@MNP@AA-EDC/NHS-DOX for doxorubicin drug delivery to the triple negative breast cancers cell lines of MDA-MB-231, MDA-MB-468 and HCC1937. Monodisperse Fe3O4 MNPs were prepared by chemical co-precipitation method. According to the SEM and DLS results, MNP@AA-EDC/NHS-DOX, MNPs@AA, MNP@AA-MNP@AA-EDC/NHS and MNP@AA-EDC/NHS-DOX had average particle diameter of 53, 79 and 95 nm, respectively. While, XRD analysis showed that the MNP material had the strongest Fe crystal peak, while surface modified MNP@AA-EDC/NHS-DOX did not alter the characteristic properties of MNPs. VSM magnetization analysis revealed that MNP@AA-EDC/NHS-DOX exhibited sufficient paramagnetic potential in the presence of external magnetic field. The TG analysis showed that thermal decomposition capacity of present nanocomposites was: MNPs > MNP@AA-EDC/NHS > AA-MNPs > MNP@AA-EDC/NHS-DOX. AA-modified MNPs did not completely lose their thermal stability as compared to other modifications. Alamar blue analysis revealed that the bare MNPs did have non-significant cytotoxicity in MDA-MB-231, MDA-MB-468 and HCC1937 cell lines (p > 0.001). While, MNP@AA-EDC/NHS-DOX at 0.1, 1.0 and 10 µg/mL DOX concentrations showed significantly lowered cell survival percentages as compared to the free DOX regimens after 24 and 72h. While, HCC1937 cell line had the most accumulation of free (1.42 > 0.93 > 0.9 pg DOX/cell) and conjugated DOX (2.64 > 2.2 > 1.91 pg DOX/cell) after 6 h of incubation period as compared to MDA-MB-468 and MDA-MB-231, respectively (* p < 0.05). Present results provide a new insight into the design of paramagnetic targeted drug delivery nanocomposite system to overcome the obstacles and side effects of conventional chemotherapeutic agents. [ABSTRACT FROM AUTHOR]

The present study reports the new functionality of room temperature ferromagnetism (RTFM) in non-magnetic Cadmium (Cd) doped BaTiO3 nanostructures, contrary to pure diamagnetic BaTiO3. TEM images show that grain size reduces with Cd doping. XPS analysis indicates that cation vacancies induce RTFM in Cd doped BaTiO3. Magnetic study reveals that pure BaTiO3 exhibits diamagnetic like signature, while Cd doped BaTiO3 show ferromagnetic feature with saturation magnetization (Ms ∼ 9.70x10-3 emu/g), remanent magnetization (Mr ∼ 0.22x10-3 emu/g) and coercive field (Hc ∼ 42.54 Oe), respectively. The current investigation also indicates that the induced RTFM could meet the demand of developing spintronic applications. [ABSTRACT FROM AUTHOR]

Lanthanum oxide (Lanthana-La2O3) doped with Fe and Co nanoparticles was synthesized by a co-precipitation method. These synthesized samples were systematically characterized and studied using several measuring techniques: X‐ray fluorescence (XRF), X-ray diffraction (XRD), and UV-visible optical spectroscopy. Moreover, magnetization measurements were performed to study the elemental content analysis, crystalline structure, and optical bandgap and created ferromagnetic magnetic properties respectively. These measurements were aimed to investigate the structural and optical properties and the possibility of the creation of room-temperature ferromagnetic (RT-FM) properties in a host lanthana ceramic doped by Fe and Co ions, which could transform the La2O3 ceramic into a dilute magnetic semiconductor (DMS). The bandgap of the synthesized lanthana nanoparticles (NPs) was found to be significantly redshifted (~50–60%) by Fe/Co doping. The main objective of the present study is to investigate the significant effect of hydrogenation on the ferromagnetic properties of Fe- and Co-doped lanthanum-oxide ceramics. The results in this work indicate that the hydrogenation of the host NPs played an essential role in creating the RT-FM properties. The experimental results also showed that the magnetization obtained in La2O3 doped with Co ions was enhanced approximately by about three times higher than when Fe ions were doped. The obtained results were reported and discussed. [ABSTRACT FROM AUTHOR]

This paper presents a dual gravity model for a (2+1)‐dimensional system with a limit on finite charge density and temperature, which will be used to study the properties of the holographic phase transition to paramagnetism‐ferromagnetism in the presence of Horndeski gravity terms. In our model, the non‐zero charge density is supported by a magnetic field. As a result, the radius ρ/B$\rho /B$ indicates a localized condensate, as the Horndeski gravity parameter is increased, that is represented by γ. Furthermore, such condensate shows quantum Hall‐type behavior. This radius is also inversely related to the total action coefficients of our model. It is observed that increasing the Horndeski parameter decreases the critical temperature of the holographic model and leads to the harder formation of the magnetic moment at the bottom of the black hole. However, when removing the magnetic field, the ferromagnetic material presents a disorder of its magnetic moments, which is observed through the entropy of the system. The authors also found that at low temperatures, spontaneous magnetization and ferromagnetic phase transition. [ABSTRACT FROM AUTHOR]

Employing a self-combustion method supported by egg white, pure and Fe-doped ZnO/C nanoparticles successfully biosynthesized. XRD, FTIR, Raman, SEM/EDS and TEM measurements were used to characterize the pure and doped systems. The materials under investigation's optical, surface and magnetic characteristics were recognized. Only one zinc oxide crystalline phase exhibiting a hexagonal shape comparable to wurtzite was present in the systems of pure and Fe-doped ZnO/C. Due to the variation in ionic radii, doping ZnO/C system with iron ions resulted in a decrease in unit cell volume; it revealed that ions of iron had been integrated into the lattice of zinc oxides. FTIR analysis shows characteristic vibration modes related to ZnO and that of carbon groups, confirming the formation of the ZnO/C system. In a perfect match with the IR data, which represent two bands at 1120 and 1399 cm−1 attributed to carbon groups, the Raman analysis shows that in the freshly manufactured materials, sp2 and disordered G and D carbon bands have both graphitized. Fe-doping of the ZnO/C system with different amounts of iron ions resulted in the change in the size and agglomeration of the particle's system. The doped ZnO/C system has a surface area smaller than that of the pure system due to the decrease in both the mean pore radius and the total pore volume. Doping the ZnO/C system with 2 and 5 mol% Fe2O3 resulted in optical band gaps expanding from 3.17 eV to 3.27 eV and 3.57 eV, respectively. Due to the doping with iron ions, a magnetic transition from a fully diamagnetic state to a slightly ferromagnetic state was detected. [ABSTRACT FROM AUTHOR]

In this study, highly c-axis-oriented ZnO:TM (TM = Co, Fe, and Mn) thin films doped with different doping levels (x = 0–10 at%) of TM were grown by chemical (sol-gel) and physical (magnetron sputtering) film deposition methods. These films were scrutinized by XRD, AFM, FESEM, EDX, XPS, Uv-Vis spectrophotometer, and VSM magnetometer. All the films have a powerful preferential c-axis orientation with a hexagonal polycrystalline structure. Comparatively, the stronger c-axis orientation and higher crystalline quality were observed for the chemically fabricated films than those physically derived. The chemically derived films had relatively higher roughness and it was decreased with increasing TM doping concentration. Compared to the ZnO, an increment in the crystallinity of chemically derived films was observed with an enhanced TM doping ratio, whereas a decrement in physically derived films was observed. The existence of Zn, Mn, Co, Fe, and O atoms and Zn2+, Co2+, Mn2+, and Fe2+ ions were determined. Optical analysis revealed that the transmittance of chemically derived ZnO:TM thin films was relatively higher than physically produced, and the optical band gap of the films produced by both techniques was in good agreement with each other except for the ZMO. Magnetic measurements showed a clear room temperature ferromagnetic behavior for the ZnO:Mn and ZnO:Fe films. In contrast, paramagnetic behavior was observed for the chemically and physically produced ZnO:Co films. Among all films, the highest ferromagnetic response was obtained for the ZnO:Fe films due to their high crystallinity and purity. These outcomes reflect the produced films have great potential to be promising materials for optoelectronic and spintronic applications. [ABSTRACT FROM AUTHOR]

During cooling, conventional martensitic transformation can only be realized from austenite to martensite. Recently, a so-called reentrant martensitic transformation attracted much interest due to an additional transformation from martensite to austenite during further cooling. Obviously, materials with this reentrant transformation will increase the number of physical effects and possible applications. However, until now, only bulk samples have been available, which are not suitable for applications in micro-devices. In this work, we focus on the Co-Cr-Ga-Si system and examine the suitability of this system for the growth of thin films. We observed that the films grow epitaxially on MgO (100) substrates and exhibit a martensitic transformation if deposited at a sufficiently high temperature or with an additional heat treatment. Films within the austenite state are ferromagnetic while films within the martensitic state just exhibit a very low ferromagnetic order. We sincerely make a statement that our work is arranged in the scientific way with highly novelty. So far, the research and reports on reentrant martensitic materials are very less. We make a starting in thin films to arouse enthusiasm for research on this novel shape memory materials. Although we could not observe a reentrant martensitic transformation in the additional experiments due to the limited conditions, we consider our work as a substantial advance in science since we present for the first time a route to prepare epitaxial films from this emerging material, which allowed analyzing its functional properties. So, we think our work is at the high novelty. We consider our manuscript relevant for the broad interdisciplinary readership of Science and Technology of Advanced Materials. First, it is relevant for material scientists, as it addresses reentrant martensite as an emerging class of functional materials. Second, it is interesting for physicist, as our epitaxial films enable probing the underlying mechanism driving a reentrant transition. Third, it is interesting for engineers, as reentrant films are required for microsystems based on this multifunctional material. We thank you for your consideration and your time. We hope that our work is now acceptable for publication in Science and Technology of Advanced Materials. [ABSTRACT FROM AUTHOR]

2D intrinsic magnetic materials possess unique physical properties distinct from bulk materials, providing an ideal research platform for the development of low‐dimensional spintronics. The traditional approach to developing new materials involves a "trial‐and‐error" method, which is inherently flawed due to long development cycles and high costs. In recent years, with the rapid improvement in computational power, the high throughput (HTP) first‐principles calculation based on density functional theory (DFT) and machine learning (ML) method have provided a highly effective means for the design of novel intrinsic ferromagnetic materials and the study of their magnetic properties. This article reviews the recent research progress in 2D ferromagnetic materials, with particular emphasis on the significant role played by HTP first‐principles calculations and ML in the exploration and fabrication of two‐dimension ferromagnetic (2DFM) materials. Finally, the future development and challenges of 2DFM materials are discussed. [ABSTRACT FROM AUTHOR]

The cobalt nanoparticles (Co NPs) incorporated into mesoporous graphene (Co/MG) were prepared via electrostatic interaction between cobalt hydrate ion and exfoliated graphene oxide, further utilizing tri-block co-polymer P123 as a soft-template for the self-assembly process, followed by carbothermal reduction in an argon atmosphere. The particle size and crystal phase of the Co/MG were confirmed by HR-TEM and XRD, which showed the formation of a face-centered cubic cobalt phase and well-dispersed Co NPs with a narrow size distribution of (10.8 ± 3.5) nm. In addition, most of the Co NPs structures in Co/MG were only slightly oxidized, with remaining Co metal. The EDS and TGA verified the contents of cobalt inside MG. The Raman spectra showed restoration of the graphitic structure after Co NPs were introduced to MG. Further, pore parameters exhibited that the synthesized Co/MG maintained its mesoporosity (SBET = (683 ± 99) m2 g−1), suggesting Co NPs were well embedded into the MG structure. The magnetic properties of the Co/MG were measured and implied that the obtained sample has ferromagnetic behavior at 300 K with an excellent value of saturation magnetism (154.3 emu g−1; 1.88 wt% Co). The results demonstrated that even small amounts of Co NPs can be influenced by an external magnetic field. [ABSTRACT FROM AUTHOR]

The bulk, pristine sp2 carbons, such as graphite, carbon nanotubes, and graphene, are usually assumed to be typical diamagnetic materials. However, over the past two decades, there have been many reports about the ferromagnetism in these sp2 carbon materials, which have attracted intense interest for basic research and potential applications. In this review, we focus on the evidence and developments of the emergent ferromagnetism in sp2 carbon revealed by nine kinds of experimental methods: magnetic force microscopy (MFM), magnetization measurements with physical property measurement system (PPMS), X-ray magnetic circular dichroism (XMCD), scanning tunneling microscopy (STM), miniaturized magnetic particle inspection (MPI), anomalous Hall effect (AHE), mechanical deflection of carbon nanotube cantilevers, magnetoresistance, and spin-related devices (spin field effect transistor and spin memory). The advantages, conclusions, challenges, and future of these methods are discussed. The ferromagnetism in sp2 carbon will open a door to explore exotic physical phenomena and lay the basis for the development of integrated circuit of spintronics, which is fundamentally different from charge-based conventional electronics. [ABSTRACT FROM AUTHOR]

Manganites doped with potassium ions La1 –xKxMnO3, where х = 0.0, 0.1, and 0.15, have been obtained by extraction-pyrolytic method at low temperature. The compounds have been studied by X-ray powder diffraction, electronic paramagnetic and ferromagnetic resonances. Unit cell parameters of La1 –xKxMnO3 samples have been calculated. According to magnetic resonance spectroscopy, La1 –xKxMnO3 exhibits phase delamination into paramagnetic and ferromagnetic phases. The fraction of the latter phase increases when temperature decreases. The temperature of transition from paramagnetic into ferromagnetic phase (Curie temperature, TC) for La1 –xKxMnO3 is –17.4, –13.7, and –4.8°С at х = 0.0, 0.1, and 0.15, respectively. The reason of symbate change in TC and potassium ion concentration in La1 –xKxMnO3 is supposed to be the change in the content of ferromagnetic pairs Mn3+–О2––Mn4+ in the manganites. [ABSTRACT FROM AUTHOR]

MAX phases are a class of intrinsically nanolaminated materials, which combine features of metals and ceramics, owing to the alternating metallic and covalent bonding between atomic layers. Magnetic MAX phases have been known for a decade, but ferromagnetism at room temperature in this highly anisotropic system has been elusive, limiting their value as magnets in practice. Here, we show that a MAX phase with a strong ferromagnetic response is obtained by substituting Mn with Cr on the M-site in the well-known Mn2GaC. The ferromagnetic response is observed in ( M n 1 − x C r x ) 2 GaC with 0.06 < x < 0.29 up to temperatures well exceeding room temperature (489 K). The strongest magnetization is achieved with x = 0.12, reaching a saturation moment of 1.25 μB and a remanence of 0.67 μB per M-atom at 3 K and maintaining 0.90 and 0.44 μB per M-atom, respectively, at 300 K. This is the first experimental report of a significant ferromagnetic response in a MAX phase at room temperature. The results open the door to the use of MAX phases in a broad range of applications, from bulk magnets in power electronics to spintronic devices. [ABSTRACT FROM AUTHOR]