First-principles calculations within the spin polarized density functional theory (SP-DFT) were used to study the stability, electronic and magnetic properties of a vdW heterostructure by stacking a MXene (Ca 2...

Transition metal telluride compositions are explored extensively for their unique magnetic behavior. Few-layered chromium telluride (Cr2Te3) exhibits a near-room-temperature phase transition, where the material can be effectively used in applications such as magnetic refrigeration. Compared to existing magnetocaloric materials, Heusler alloys, and rare-earth-based alloys, the large-scale synthesis of mechanically exfoliated Cr2Te3 involves less complexity, resulting in a stable composition. Compared to existing tellurides, Cr2Te3 exhibited a large change in magnetic entropy (|ΔSM|) of 1.88 J kg-1 K-1 at a magnetic field of 4 T. A refrigeration capacity (RC) of ∼82 J kg-1 was determined from the change in magnetic entropy versus temperature curve. The results were comparable with those for existing Cr-based compounds. First-principles density functional theory (DFT) confirmed the magnetic properties of Cr2Te3, including a near-room-temperature Curie temperature, TC, consistent with experimental results. Structural transition was also observed using first-principles DFT, which is responsible for the magnetic behavior.

High entropy oxides (HEOs), composed of five or more metal cations in a single‐phase oxide structure, are rapidly emerging as advanced materials for diverse applications due to their remarkable structural and novel functional properties. However, the influence of size on their physical properties remains largely unexplored. In this article, we systematically explore the size effects on the structural, electronic, dielectric, and magnetic properties of spinel‐structured (NiMnFeAlZn) 3 O 4 HEO powders synthesized via ball‐milling under ambient conditions, followed by controlled heat treatment ( T A ). Structural analysis confirms a M 3 O 4 spinel structure with crystal size ( D ) varying from ∼11 to ∼69 nm as T A increases to 1000°C. Electronic properties reveal mixed‐valence states for Ni, Mn, and Fe, site preferences for Zn and Al, and a nonmonotonic trend in oxygen vacancies (O Vs ), that is, initially increasing upto 700°C and then decreasing with further increasing T A . Dielectric studies show colossal dielectric (), peaking at 4.44 × 10 4 for 4 Hz for T A at 700°C and correlating closely with electronic properties and O Vs . Magnetic studies reveal enhanced saturation magnetization, increased blocking and Curie temperatures, and reduced coercivity with increasing D . These findings establish close correlations between D , O Vs , and multifunctional properties, positioning spinel HEOs for potential applications in electromagnetic interference‐shielding, spintronics, and capacitive devices.

ABSTRACT We investigate the influence of hydrostatic pressure on the physical properties of monolayer for spintronics applications. A phase transition from a ferromagnetic half‐metal to a ferromagnetic semiconductor is unveiled at 4.6 GPa, accompanied by a transition from a non‐polar (1T) to a polar (1H) structure. We demonstrate that hydrostatic pressure elevates the Curie temperature above room temperature (for example, 618 K at 5 GPa) and enhances the magnetic anisotropy energy (for example, 731 per formula unit at 5 GPa). A significant Dzyaloshinskii‐Moriya interaction is present in the 1H structure (due to the broken spatial inversion symmetry) and increases with the hydrostatic pressure. Together with the observation of in‐plane electric polarization (for example, 1.1 pCcm −1 at 5 GPa), this positions the 1H structure as a pioneer in the class of 2D materials. Exploiting the phase transition of monolayer , a single‐material magnetic tunnel junction is proposed and an outstanding tunneling magnetoresistance ratio is demonstrated.

Lead-free BiFeO3-based ceramics have emerged as compelling candidates for high-power energy storage applications, owing to their exceptional combination of high Curie temperature and large spontaneous polarization. However, their widespread adoption has been hindered by intrinsic limitations including low breakdown strength and substantial hysteresis losses. Herein, we propose a strategy of local structural perturbations that significantly enhances the energy storage performance of BiFeO3-based ceramics through the introduction of (Bi2/9La2/9Sm2/9)ZrO3 (BLSZ). This approach effectively suppresses hysteresis loss and delays polarization saturation by reducing polarization anisotropy and domain-switching barriers, while simultaneously enhancing breakdown strength through highly disordered atomic arrangements with localized lattice distortion and grain refinement. Consequently, the optimized BiFeO3-based ceramic delivers a high energy density of 7.4 J cm-3, surpassing most previously reported BiFeO3-based dielectrics. This study highlights the significant potential of BiFeO3-based ceramics for advanced energy storage while providing crucial design guidelines for high-performance dielectric materials.

Oxygen octahedral rotation is essential for hybrid improper ferroelectrics (HIFs), but interlayer rumpling will compete with oxygen octahedron rotation, leading to the suppression of ferroelectricity in layered perovskite materials containing trivalent cations at the B-site. In the present work, single-phase dense La2Sr(Sc1−xInx)2O7 ceramics with double-layered Ruddlesden–Popper structures have been prepared, and the presence of room-temperature HIF is evidenced by the ferroelectric hysteresis loops. The polar A21am phase is adopted at room temperature, and it will transform into a nonpolar Amam phase above the Curie temperature. The Curie temperature increases linearly with the content of In3+ cation and with decreasing tolerance factor, whereas the ferroelectric polarization decreases with the substitution of In3+ cation at the B-site owing to the suppression of oxygen octahedral rotation. The present work demonstrates the room-temperature HIF in La2Sr(Sc1–xInx)2O7 ceramics and emphasizes the essential role of tolerance factor in determining the Curie temperature.

Ferroelectric metals, traditionally considered mutually exclusive, face enduring challenges owing to screening effects of itinerant electrons on ferroelectric order. However, in certain van der Waals (vdW) heterostructures, two-dimensional materials with distinct structural and physical properties can be alternatingly arranged in layers, retaining their individual characteristics and thereby enabling the coexistence of ferroelectricity and metallicity. Here, we report the coexistence of robust in-plane ferroelectricity and exceptional metallicity in a natural vdW superlattice (SnSe)_{1.16}(NbSe_{2}) crystal, exhibiting high-density carriers (>10^{21} cm^{-3}), superconductivity (T_{c} ∼3.25 K), and Curie temperature up to 383K. The weak-coupling electronic and phononic natures stabilize in-plane ferroelectricity against screening by high-density carriers, confirming the decoupled electron mechanism. Moreover, we demonstrate the first ferroelectric memristor, where the metallic channel conductance is manipulated through polarization dynamics. Our Letter establishes a universal platform for designing multi-order parameters quantum-confined materials, and opens new avenues for energy-efficient functional electronics.

Harnessing atomic ordering through order-disorder transition is a powerful strategy to tailor electric polarization and functionality. However, most reported order-disorder ferroelectrics exhibit low Curie temperatures, narrow thermal hysteresis, and limited tunability, restricting their potential in nonvolatile memory technologies. Here, we identify VOCl2 as a new van der Waals order-disorder ferroelectric with site disorder, exhibiting an exceptionally wide thermal hysteresis (ΔT = 220 K) and a high Curie temperature (Tc = 440 K), associated with lattice expansion across the disorder to order transition. Moreover, the sensitivity of V4+ cations to structure distortions allows efficient polarization tuning under hydrostatic pressure, where pressure irreversibly induces the in-plane polarization at 2.3 GPa, and then drives a reversible polarization switching from in-plane to out-of-plane at 8.0 GPa. Such a giant thermal hysteresis and unusual polarization switching of VOCl2 open new opportunities for programmable phase-change devices with a broad operating window.

Abstract The high Curie temperature (Tc) flaky FeCo alloy with high dielectric and magnetic losses has great potential application for preparing high-temperature (＜773 K) absorbing materials, excepting for the disadvantages of easy to be oxidized and excessive complex permittivity. In this work, the flaky FeCo was wrapped by the NiCo2O4 nanoparticles (NiCo2O4@flaky FeCo) via a hydrothermal method and subsequently calcination process. The NiCo2O4 layer formed on the surface effectively prevents the oxidation of flaky FeCo and reduces the complex permittivity. The NiCo2O4@flaky FeCo treated at elevated temperature (773 K) for 24 h (NiCo2O4@flaky FeCo-773 K) maintains moderated complex permittivity and desirable higher complex permeability. As a result, remarkable microwave absorption performance can be achieved in the NiCo2O4@flaky FeCo-773K. Specially, the optimum reflection loss (RLmin) value reaches −47.78 dB at 8.0 GHz and the effective absorption bandwidth (RL＜−10 dB) is up to 7.52 GHz with the matching thickness of 1.9 mm, covering the whole Ku band. The corresponding maximum RCS reduction values of 17.09 dBm2 is also realized. The designed NiCo2O4@flaky FeCo is expected as valuable absorber, which has the potential to be applied at elevated temperature environment.

Abstract Rare-earth compounds present a fertile ground for two-dimensional (2D) spintronics, distinguished by their localized 4 f electrons and strong spin-orbit coupling. However, integrating these materials into functional devices remains severely constrained by the absence of scalable synthesis protocols for high-quality, continuous ultrathin films. Here, we surmount this constraint via a robust two-step sulfurization strategy, enabling the fabrication of waferscale, continuous, and atomically thin (~1.5 nm) Sm 2 S 3 films. Comprehensive characterizations confirm their exceptional large-area uniformity, strict stoichiometry, and high crystallinity. In contrast to their bulk counterparts, which display only weak low-temperature ordering, these 1.5 nm films exhibit robust ferromagnetism with a Curie temperature of ~126 K. This scalable synthesis unlocks a critical materials platform for exploring 4 f -electron-driven quantum phenomena and next-generation spintronic applications.

Computational investigation of high Curie temperature, magnetic anisotropy and optical properties of new Zr based half-Heusler compounds.

The influence of vanadium substitution on the structure, elastic, mechanical, and magnetic behavior of lithium ferrite (Li0.5+xVxFe2.5−2xO4; x = 0.00–0.2) was systematically studied. X-ray diffraction (XRD) was used to investigate the crystal structure, and infrared spectroscopy (IR) was used to determine the cation distribution between the two ferrite sublattices, in addition to the elastic and mechanical behavior of Li0.5+xVxFe2.5−2xO4 ferrites. X-ray analysis revealed a monotonic decrease in lattice parameter from 8.344 Å to 8.320 Å with increasing V5+ content, confirming lattice contraction and stronger metal–oxygen bonding. Despite a moderate increase in porosity (from 6.9% to 8.9%), the elastic constants C11 and C12 increased, indicating improved stiffness and reduced compressibility. The derived Young’s, bulk, and rigidity moduli rose with the doping of V5+. Correspondingly, the longitudinal, shear, and mean velocities (Vl, Vs, and Vm) increased. The Debye temperature also showed a linear rise from 705 K to 723 K with V5+ doping, directly reflecting enhanced lattice stiffness and phonon frequency. Furthermore, both the saturation magnetization (MS) and the initial permeability (μi) increased up to V5+ concentration x = 0.1 and then decreased. Curie temperature (TC) decreased with increasing V5+ concentration, while both the saturation magnetization (MS) and the initial permeability (μi) increased up to V5+ concentration x = 0.1 and then decreased, while the coercivity (HC) showed the reverse trend. These results confirm that V5+ incorporation significantly enhances the Li ferrite, improving its elastic strength, lattice energy, thermal stability, and magnetically controlling properties and making them suitable for a variety of daily uses such as magneto-elastic sensors, high-frequency devices, and applications requiring mechanically robust ferrite materials.

High Curie temperature and perpendicular magnetic anisotropy in Mn-doped MoSe2 monolayer induced by O and S impurities

Abstract The magnetocaloric properties and critical behavior of the Cd-doped Mn 5 Ge 2.7 Cd 0.3 alloy are systematically investigated for near-room-temperature magnetic refrigeration applications. The polycrystalline sample was synthesized by arc melting followed by annealing, and its magnetic properties were characterized using vibrating sample magnetometry. Temperature-dependent magnetization measurements reveal a second-order magnetic phase transition with a Curie temperature of ∼318 K. Critical exponents derived from modified Arrott plots and Kouvel–Fisher analysis yield β = 0.474, γ = 0.941, and δ = 2.985, which deviate significantly from standard universality classes, suggesting the presence of long-range magnetic interactions influenced by Cd doping. The maximum magnetic entropy change (|Δ S M |) reaches 6.757 J·kg −1 ·K −1 under a 5 T field change, with a relative cooling power of 284.85 J·kg −1 . A universal curve constructed from rescaled entropy change data confirms the second-order nature of the transition. The results demonstrate that Cd doping effectively tailors the critical behavior of Mn 5 Ge 2 -based alloys. The combination of a near-room-temperature T C , a competitive refrigerant capacity, and the hysteresis-free nature of its second-order transition positions this material as a promising candidate for efficient and reliable magnetic cooling applications.

We present a comprehensive study of Eu3InO, a compound with a cubic inverse perovskite structure (Pm3-msymmetry), usingab initiocalculations. The system adopts a ferromagnetic ground state, with nearest-neighbor (NN) exchange (J1= 0.2108 meV) and a stronger next-NN exchange (J2= 1.7142 meV), resulting in an estimated Curie temperature (TC= 243.14 K) that exceeds the experimental value of 185 K. The dominance ofJ2overJ1indicates the significant role of longer-range magnetic coupling, consistent with indirect exchange interactions mediated by conduction electrons in metallic 4f systems. Eu3InO exhibits intriguing electronic features, like Fermi surface topology indicative of nesting possibility and a nodal ring in thekz=0plane. The topological characteristics contribute to non-zero Berry curvature and anomalous Hall conductivity. Additionally, surface state and constant energy contour plot reveal a nodal ring along the (001) surface. Our findings position Eu3InO as a promising material for magnetoelectronics and spintronics.

Two-dimensional van der Waals magnets are highly promising for next-generation spintronics. The ferromagnetic material Fe3GaTe2 is especially interesting due to its high Curie temperature. Here we demonstrate highly efficient current-induced domain wall motion in Fe3GaTe2 racetracks via spin-transfer torque that gives rise to the highest domain wall velocity yet reported for any van der Waals magnet. The spin polarization of the conduction electrons was measured via superconducting point-contact measurements revealing that 100% of their spin angular momentum is transferred to the domain walls. The very low threshold current density plus the very high mobility of the domain walls is attributed to the structural perfection of the two-dimensional magnet. We further demonstrate an electrically readable memristive racetrack device with more than four data bits, via precise domain wall positioning. Our work demonstrates that van der Waals magnets are compelling for emerging spintronic applications from room temperature to cryogenic temperatures.

Magnetic hyperthermia (MH), which leverages the ability of magnetic nanoparticles (MNPs), located in the tumor, to generate heat upon exposure to an alternating magnetic field (AMF), has long been synonymous with cancer therapy. However, recent advancements highlight emerging applications of MH beyond oncology, including neuromodulation, tissue engineering, biosensing, catalysis, and environmental remediation. All these applications intelligently harness the same principle to achieve a wide range of new functionalities in MNPs besides local heating, including drug release, eradication of pathogens, manipulation of cell membranes, mechanical responses for novel non-invasive therapies, boosting chemical reactions, intensifying processes and degrading or desorbing pollutants like CO2, just to name a few. This review provides a comprehensive overview of the latest breakthroughs in non-cancer applications of MH. While some fields, ranging from infection control and organ cryopreservation to nanorobotics in biomedicine, require non-toxic biocompatible and biodegradable MNPs (iron oxides) and AMFs restricted to radiofrequencies in the range of 100-300 kHz and an appropriate field intensity (few tens of kA m-1) to avoid tissue damage, some other areas, like sustainable catalysis, sensing, etc., open up the possibility of using diverse chemical elements besides iron (e.g., cobalt, nickel, carbon) mainly in the form of alloys, and AMFs of higher frequencies (well above 300 kHz) and amplitudes (well above 10-20 kA m-1). Indeed, engineering of MNPs with suitable catalytically active elements (gold, nickel, ruthenium, palladium, etc.), support materials (silica, aluminium/magnesium oxide, etc.) or surface coating with appropriate (bio)molecules (enzymes, RNA/DNA fragments, etc.) is crucial for each application, as well as considering the effect of local temperature (for instance, achieving the Curie temperature, Tc, of the nanomaterial, provoking the de-swelling of polymers, activating/deactivating enzymes or boosting the efficiency of a catalytic process). Furthermore, this work discusses the current limitations and future directions required to expand the reach of MH. Finally, this review serves as a critical resource for researchers seeking to harness MH beyond cancer treatment and integrate it into novel scientific and technological frontiers.

Recently, newly developed organic ferroelectric materials have garnered significant interest due to their suitability for electronic applications. Among these materials, diisopropylammonium bromide (dipaBr) stands out for its remarkable properties, exhibiting a spontaneous polarization of 23 μC/cm2 and a high Curie temperature of 425K, making it a promising candidate for practical applications. In this investigation, the nonlinear optical behavior of pristine and halogen-substituted diisopropylammonium bromide crystals was explored using density functional theory, aiming to elucidate the influence of chemical doping on the material's optical characteristics. The unmodified dipaBr structure was initially geometrically optimized, followed by a systematic replacement of the bromide anion with halogen atoms fluorine (F), chlorine (Cl), and iodine (I) to examine the resulting alterations in electronic configuration, molecular polarizability, and first hyperpolarizability (β), which are pivotal descriptors of second-order NLO effects. The computed NLO parameters reveal that the dipole moments for pristine and halogen-doped dipaBr are 18.96 D, 17.50 D, 10.18 D, and 11.41 D, respectively, as derived from the LANL2DZ basis set using CAM-B3LYP functional. The nonlinear optical properties of pristine diisopropylammonium bromide (dipaBr) and its halogen-doped derivatives were investigated using Density Functional Theory (DFT). The computations were carried out using the B3LYP functional with the 6-31 + G(d), 6-311 + + G(d,p), and LANL2DZ basis sets, together with the CAM-B3LYP functional employing the 6-311 + + G(d,p) and LANL2DZ basis sets. The computational outputs were visualized using Gauss View 6 software. Halogen incorporation led to notable modifications in the electronic band gap and charge density distribution, with a marked increase in dipole moment and β values, particularly for the F- and I-substituted systems. Furthermore, the thermodynamic parameters of pristine and halogen-doped diisopropylammonium bromide are systematically analyzed.

Magnetothermal stimulation is key in biomedical applications like tumor ablation, drug delivery, and regenerative therapies. A common method involves injecting magnetic particles that heat under an alternating magnetic field (AMF). However, uncontrolled heating can damage healthy tissues. Maintaining temperatures below 45°C is critical. Using materials with a Curie temperature (Tc) near this limit offers a self-regulating solution, as magnetization-and thus heating-drops sharply at Tc. This study explores Mn0.65Fe1.30P0.65Si0.37 (MCM), a magnetocaloric material composed of non-toxic elements and featuring a tunable Tc. It is engineered to exhibit a Tc of 43°C, close to the safe physiological threshold. MCM particles are encapsulated in a wax matrix to form a composite that responds to AMF exposure. Heat generated by MCM particles triggers the wax phase transition, while the obtained Tc enables the composite to achieve self-limiting thermal regulation under magnetic field exposure. Biocompatibility tests using human umbilical vein endothelial cells (HUVECs) show over 90% cell viability in direct and indirect contact. Stability tests in phosphate buffers at 37°C confirm controlled degradation over 28 days. These results demonstrate that MCM is a promising, burn-free magnetic material for safe, localized heating, supporting its use in self-regulating, temperature-responsive biomedical systems.

Bismuth-layered structure ferroelectrics (BLSFs), exemplified by CaBi2Ta2O9 (CBTa), exhibit exceptional thermal stability at high temperatures with a high Curie temperature. This attribute renders them highly promising candidates for piezoelectric sensors, transducers, non-volatile ferroelectric memory, etc. working in extreme environments. However, CBTa ceramic suffers from the following intrinsic limitations: spontaneous polarization confined within the ab-plane of the unit cell and a large coercive field, leading to severely suppressed piezoelectric activity (d33 ≈ 5.4 pC N-1). To address these challenges, a synergistic strategy integrating ion doping and hot forging is proposed to fabricate textured CBTa-based ceramics. Systematic characterization reveals that hot forging induces preferential grain orientation, effectively aligning polar domains while maintaining the layered perovskite structure. This optimization achieves significant enhancement in piezoelectric response (d33 ∼ 21.8 pC N-1) and direct-current resistivity (ρ > 1 × 107 Ω cm at 600 °C) without compromising TC (∼922 °C). Notably, the textured ceramics retain 95% of their initial piezoelectric performance after depoling at 900 °C for 2 h, underscoring their outstanding thermal stability. This work establishes a microstructure-engineering paradigm for tailoring electromechanical properties in BLSFs, bridging the gap between intrinsic material limitations and application-driven performance requirements.