Defect-induced magnetism (DIM) in otherwise nonmagnetic wide-band oxides had recently been explored in order to prepare oxide dilute magnetic semiconductor (O-DMSs) as the next-generation spintronic materials. In this context, effect of morphology-dependent surface-disorder and cationic-site defects in tailoring ferromagnetic behaviour and Raman vibrational modes were investigated systematically in series of indium (In)-substituted SnO 2 thin films fabricated by pulsed laser deposition (PLD) in oxygen-deficient Argon (Ar) atmosphere. Surface morphology of the SnO 2 :In films had been changed as nanospheres (NSs), nanoflowers (NFs), nanoflakes (NFLs) and nanowires (NWs) with varying Ar pressure of 1, 10, 100 and 1000 Pa respectively. With increase of deposition pressure, crystallite size and thickness of the film decreased whereas surface disorder had enhanced considerably. Spectroscopic evidence revealed that both Sn vacancy ( V Sn ), oxygen vacancy ( V O ) defects were stabilized with enhanced surface disorder with the films. ESR spectroscopy indicated the presence of two major paramagnetic defect centres comprising Lande g -factor ~ 2.003, assigned to singly ionized V O + defect whereas other ‘ g ’ value about 1.89 were due to V Sn defects or its complex with Vo defects. Being enriched with substantial paramagnetic defects, In-doped SnO 2 films exhibited enhanced high- T C ferromagnetism. NWs of In:SnO 2 exhibited superior ferromagnetic signal with magnetic moment ~ 11.1 emu/cm 3 and Curie temperature ~ 570 K. We attribute RKKY type magnetic interaction between magnetic of isolated V Sn or associated defects complex like ( V Sn - Vo ) mediated through the holes introduced due to In Sn defects as the origin of FM in In:SnO 2 thin films. Therefore, the study depicts the promotion of cation vacancy defects by monitoring growth atmospheric conditions can be an effective way to achieve the oxide-based dilute magnetic semiconductors (O-DMSs) for spintronics applications.

Spintronics has emerged as a revolutionary frontier in the pursuit of faster, more energy-efficient, and technologically advanced electronics. However, the transmission distance of conventional ferromagnetic spin-orbit torque is typically limited to <10 nm, posing a critical challenge for spin current transport. Here we grow Mn3Sn films with a 30° canted magnetic octupole moment oriented out of plane, in which the Kagome spin structure is fully perpendicular to the film surface. By introducing a spin-orbital coupled amorphous Pt overlayer, we demonstrate the electrical switching dynamics of magnetic octupoles in Kagome antiferromagnetic Mn3Sn. Remarkably, perpendicular spin currents reverse Mn3Sn layers up to 60 nm thick. The switching efficiency of Mn3Sn/Pt bilayers increases with antiferromagnetic thickness, peaking near 40 nm before decreasing, reflecting a long spin diffusion length sustained by twin topological spin structures. Direct observation of magnetic octupole dynamics further validates the presence of such twin spin orders. Moreover, our theoretical analysis reveals that twin topological spin canting intrinsically supports ultralong-distance octupole switching. These findings establish antiferromagnetic Mn3Sn as a robust platform for efficient spin transport and highlight the pronounced long-range nature of spin-orbit torque enabled by twin spin order.

This paper reports magnetic microscopy using high-sensitivity room-temperature tunnel magnetoresistance (TMR) devices for thin geological sections. The sensitivity region of the TMR sensor has dimensions of 178 µm (L) × 0.1 µm (W) × 100 µm (H), consisting of two TMR devices. Magnetic images were obtained for a vertically magnetized Hawaii basalt thin section in two sensor configurations, with the sensor length aligned parallel to the X- (lift-off = 174 μm) and Y-axes (lift-off = 200 μm), without introducing anisotropic distortion in the magnetic images. Although the magnetic images obtained with a scanning SQUID microscope (SSM) were similar, slight discrepancies were observed in the high-spatial-resolution region. A magnetic point source (50 μm × 50 μm) with a perpendicular magnetization film was prepared for evaluation. The SSM measurements showed a clear magnetic dipole at an angle of approximately 1° from the vertical direction. The FWHMs for both the SSM and TMR sensors increased linearly with lift-off. However, the peak magnetic fields, magnetic moments, and dipole tilts of the TMR sensor were significantly larger than those of the SSM sensor. This discrepancy may be due to the vertical extent of the active region of the TMR sensor, as well as due to sensor noise and drift.

Abstract We review the recent progress achieved, using resonance chiral theory, in the hadronic contributions to the muon anomalous magnetic moment. These include the hadronic vacuum polarization, either using $$e^+e^-$$ e + e - or $$\tau$$ τ decays into hadron final states as input; and the hadronic light-by-light part, where in addition to previous results on the lightest pseudoscalar and tensor-poles contributions, we first present the evaluation of the pseudoscalar box using this formalism. We also discuss the scalar, axial-pole and other subleading pieces. The results obtained are consistent with the White Paper 2 values, with comparable precision.

Functional renormalization group study of anomalous magnetic moment in a low energy effective theory

The primary requirement for achieving spin-selective electron transfer in a nanojunction possessing a magnetic system with zero net magnetization is to break the symmetry between the up and down spin sub-Hamiltonians. Circumventing the available approaches, in the present work, we put forward a new mechanism for symmetry breaking by introducing a bias drop along the functional element. To demonstrate this, we consider a clean magnetic chain with antiparallel alignment of neighboring magnetic moments. The junction is modeled within a tight-binding framework, and spin-dependent transmission probabilities are evaluated using wave-guide theory. The corresponding current components are obtained through the Landauer-Büttiker formalism. Selective spin currents, exhibiting a high degree of spin polarization, are obtained over a wide bias region. Moreover, the bias-dependent transmission profile exhibits negative differential resistance, another important aspect of our study. We examine the results under three different potential profiles, one linear and two non-linear, and in each case, we observe a favorable response. This work may offer a new route for designing efficient spintronic devices based on bias-controlled magnetic systems with vanishing net magnetization.

The broadband electromagnetic wave absorption (EWA) of soft magnetic alloys (SMAs) is severely constrained by the rapid decay of their magnetic loss at gigahertz frequencies. To address this issue, an intergranular coupling strategy guided by the magnetic exchange length (Lex) is proposed in this study. Doping with Cu systematically increases Lex in SMAs from 12.7nm to 19.1nm, thereby enhancing the collective precession of magnetic moments over a larger spatial range. This Cu doping concurrently reduces the effective magnetic anisotropy (Keff) from 9.2 to 8.6kJm-3 and increases the magnetic exchange strength by 25%. These coordinated changes effectively shift the resonance peak to 12.0GHz and amplify the magnetic loss. As a result, the optimized alloy achieves an effective absorption bandwidth (EAB) of 8.1GHz at a minimal thickness of 1.8mm, representing a 47.1% improvement over its Cu-free counterpart. This work pioneers the use of Lex-driven mechanisms for regulating magnetic loss and establishes a fundamental framework for enhancing the broadband EWA performance of SMAs through targeted resonance modulation.

We explore the effects of Mn substitution on GeO2in its bulk rutile structure, using density functional theory with both generalized gradient approximation and the PBE0r hybrid functional. Our objective is to assess the potential emergence of half-metallic (or semiconducting) ferromagnetism. For pure rutile GeO2, the experimental wide band gap (4.68 eV) is accurately reproduced by PBE0r using only a small fraction (7%) of the exact exchange. Ordered substitutional bulk alloysGe1-xMnxO2were examined atx = 0.5, 0.25, and 0.17, of Mn concentrations. Atx = 0.5, the system is predicted to be a half-metallic ferromagnet with a magnetic moment of 3µBper tetragonal unit cell. At lower Mn concentrations (x = 0.25 and 0.17) the alloys remain semiconducting, with Mn ions in a high-spin configuration. These findings highlight the reliability and efficiency of the PBE0r functional in describing ultra-wide-gap oxides and indicate that Mn-doped GeO2bulk systems deserve further theoretical and experimental attention.

Rhenium disulfide (ReS₂) and related two-dimensional transition metal dichalcogenides (TMDCs) have emerged as promising candidates for spintronic applications, primarily due to the possibility of tailoring their magnetic and electronic properties through defect engineering. In this work, we carry out a comprehensive first-principles investigation of eighteen intrinsic point defects in monolayer ReS₂, including single vacancies, vacancy complexes, and antisite defects, under both Re-rich and S-rich growth conditions. Our results reveal a much richer defect-induced magnetic landscape than previously reported, indicating that magnetism in ReS₂ is not limited to defects involving rhenium atoms alone. In particular, we find that the emergence of magnetic moments is highly sensitive to the specific defect site and local atomic environment. Notably, theV2Redefect exhibits contrasting magnetic behavior depending on its configuration, being magnetic in one case while remaining nonmagnetic in another. Several defect configurations are found to significantly modify the electronic structure, leading to semiconductor-to-half-metal transitions in case ofV1Re+3Sdefect and/or semiconductor-to-half-semiconductor transitions with pronounced bandgap narrowing in case of other defect configurations. These changes are expected to have implications for charge transport and carrier recombination processes. Importantly, we identify previously unexplored defect configurations in ReS2that exhibit robust and stable magnetic moments. By linking defect formation energetics and changes in the electronic structure, this study provides fundamental insight into how defect type and spatial arrangement induces magnetic ordering. Overall, our findings highlight the potential of defect-engineered ReS₂ monolayers for future spintronic and quantum device applications.

To enhance the wide-temperature-range magnetocaloric performance of (Mn,Fe)2(P,Si) alloys, the effects of Mg-Co co-doping on their structural and magnetocaloric properties were systematically investigated. Mn1.05−yCoyFe0.9P0.5Si0.48Mg0.02 alloys were prepared by the arc melting method. The results show that Mg-Co co-doping can tune the lattice parameters and ferromagnetic coupling between Mn and Fe atoms. The Mn1.03Co0.02Fe0.9P0.5Si0.48Mg0.02 alloy exhibited an effective refrigeration capacity of 425.4 J·kg−1 and an effective working temperature span of 52 K. During the temperature-induced ferromagnetic transition, coupling between the magnetic moment of Fe-Si layers and the crystal lattice drives a magnetoelastic transition, leading to a giant magnetocaloric effect. The Mg-Co co-doping strategy effectively tunes the crystal structure and local electron density distribution of the Fe-Si layer, thereby influencing the total magnetic moment and magnetothermal properties of the alloys.

Here, we present the results of a combined computational and experimental study of magnetic and structural properties of a Heusler compound Mn2PtIn. In particular, we analyze the effect of biaxial strain on tetragonal distortion and magnetic properties of this alloy. It is shown that the ground state of this material corresponds to tetragonal symmetry, with possible non-collinear magnetic alignment. At the same time, our calculations indicate that this system may also exhibit ferrimagnetic alignment of magnetic moments. Analysis of exchange couplings indicates that ferrimagnetic alignment is more likely to be realized in practice. The interplay between these two magnetic phases may be achieved by strain engineering and thus may have practical applications in spintronics. The sample prepared by arc melting crystallizes in the tetragonal structure and exhibits ferrimagnetic/non-collinear magnetic ordering, with a saturation magnetization of 1.5 μB/f.u., a coercivity of 2 kOe, and a Curie temperature of 350 K. In addition, a pronounced splitting between the zero-field-cooled (ZFC) and field-cooled-warming (FCW) curves and an exchange bias effect arising from the interaction of magnetically inhomogeneous regions are observed.

This study examines the magnetic, optical, structural and electronic properties of Zn x Co[Formula: see text]Fe 2 O 4 ([Formula: see text]–1.0, with 0.25 steps) ferrites using DFT calculations with the CASTEP code. The simulated X-ray diffraction (XRD) patterns for these ferrites showed increases in lattice constants (8.301–8.491 Å), d-spacings (2.326–2.461 Å), unit cell volumes (571.994–612.176 Å 3 ) and hopping lengths ([Formula: see text]–7.353 Å; [Formula: see text]–6.004 Å) as the Zn[Formula: see text] content grew. Meanwhile, the X-ray density (5.451–5.233[Formula: see text]g/cm 3 ) decreased with increasing Zn[Formula: see text]. The ferrites exhibited properties typical of direct-band gap semiconductors, with the band gap widening from 1.688 to 2.139[Formula: see text]eV as Zn[Formula: see text] content increased. Density-of-states calculations indicated that these materials exhibit desirable spin polarization, suggesting their potential for spintronics. The Hirschfeld analyses revealed that the magnetic moment and saturation magnetization increased from 4.737 to 4.233 [Formula: see text] and from 112.665 to 97.974[Formula: see text]emu/g, respectively, with increasing Zn[Formula: see text] content. The optical properties of Zn x Co[Formula: see text]Fe 2 O 4 ([Formula: see text] 0.0, 0.25, 0.5, 0.75, 1) fall within the visible spectrum, making them suitable for optoelectronic uses. This comprehensive theoretical work offers valuable insights into the structure-property relationships of these ferrites, highlighting their potential for magnetic and optoelectronic applications, as well as multifunctional uses, due to their advantageous structural, optical, magnetic and electronic properties.

A variety of lightweight, high-precision engineering approaches are urgently required to decrease the density of metallic components exhibiting zero thermal expansion (ZTE). Scandium, the lightest rare-earth element, plays a unique role in the emergent quantum orders of Kagome metals. Here, we report the controlled design of interplanar magnetic order and thermal expansion in a family of Kagome (Sc,Ti)Fe2 compounds. Optimizing the Sc-Ti-Fe ternary composition enables ZTE behavior up to room temperature (αl=+0.18×10-6 K-1, 112-300K) in Sc0.4Ti0.6Fe2.4, together with a relatively low density of 6.56g/cm3, which is much smaller than that of the documented ZTE alloys. Scanning transmission electron microscopy, Mössbauer spectroscopy, neutron powder diffraction, and theoretical calculations reveal that the extra positive magnetic exchange interactions of antisite Fe stabilize strong in-plane ferromagnetic order and suppresses spin reorientation from in-plane to out-of-plane upon heating. Local magnetic moments of Fe(2a) and Fe(6h) sites decrease successively over a wider temperature range, thus yielding such ZTE performance. The nearly isotropic ZTE of the ingot indicates its practical potential for advanced functional applications.

Hydrogels do not have observable responses to external magnetic fields as they are conventionally thought to be diamagnetic. These materials require additives for magnetic control, limiting biomedical applications due to potential side effects. Here we show that calcium cations can induce strong paramagnetism of hydrogels rich in groups containing carbon-oxygen double bonds, including alginate, carboxymethyl chitosan, polyacrylamide and N-isopropyl acrylamide. Both experiments and computations reveal that the ubiquitous presence of net magnetic moments, the key to paramagnetism, is induced by the unexpected coupling of a single calcium cation and one carbonyl group under large calcium cation excess conditions. The paramagnetic phenomenon is also observed in the endogenous biomolecule sodium hyaluronate with calcium cations. We further demonstrate the applications of the strongly paramagnetic alginate-calcium hydrogel as a contrast agent in magnetic resonance imaging and a carrier in magnetic drug delivery. Our findings provide insights into the origin of magnetism and advance magnetism-related biomedical innovations.

A novel mixed-ligand copper(II) complex, [Cu(Asp)(bpy)]·nH₂O, incorporating aspartic acid (Asp) and 4,4′-bipyridine (bpy), was synthesized and extensively characterized to elucidate its redox, magnetic, thermal, and spectroscopic properties. Fourier-transform infrared spectra confirmed coordination through the carboxylate oxygen of Asp and the nitrogen atoms of bpy, forming a mixed N,O-donor environment around the Cu(II) center. UV–Visible spectroscopy revealed d–d and metal-to-ligand charge transfer transitions, while fluorescence spectra displayed emission quenching due to the paramagnetic Cu(II) ion, confirming effective metal–ligand interaction. The complex exhibited an effective magnetic moment (μeff) of 2.46 Bohr magnetons, consistent with a single unpaired electron in a distorted octahedral geometry. Thermogravimetric analysis indicated a multi-step decomposition pattern with stability up to 350 °C, suggesting strong metal–ligand coordination and potential thermal robustness. Electrochemical investigations using cyclic voltammetry demonstrated a quasi-reversible Cu(II)/Cu(I) redox couple, with diffusion-controlled kinetics and ligand-induced stabilization of the Cu(I) oxidation state. Molar conductivity measurements indicated the formation of a neutral complex, further confirming complete coordination. Collectively, these findings establish the structural integrity and multifunctional nature of the Cu–Asp–bpy complex. Owing to its redox reversibility, paramagnetic character, and high thermal stability, the complex shows promise for applications in electrocatalysis, redox-active materials, and bioinspired electron-transfer systems. This study provides valuable insight into how synergistic N,O-ligand coordination can modulate copper redox chemistry and enhance functional stability for potential catalytic and electronic applications. These findings collectively demonstrate that the Cu–Asp–bpy complex possesses a stable Cu(II)/Cu(I) redox couple and high thermal durability, making it a promising candidate for electrocatalytic and bioinspired electron-transfer applications. IUBAT Review—A Multidisciplinary Academic Journal, 8(2): 82-104

With growing demand for cooling and rising interest in eco-friendly solutions, researchers are focusing on the development of advanced cooling technologies, including those utilizing the magnetocaloric effect by means of magnetocaloric materials. Such development necessitates a thorough understanding of these types of materials. In this context, a density functional theory (DFT) study of neodymium orthophosphate (NdPO4) was conducted by employing the GGA + U + SOC approximation. The compound's electronic and magnetic properties, investigated in the monoclinic monazite structure, revealed an antiferromagnetic configuration, which can be described as two antiparallel sublattices, while electronic structure analysis showed a direct band gap energy of 3.39 eV, indicating an insulating behavior. To probe its magnetic properties, sum rules applied to X-ray magnetic circular dichroism (XMCD) and X-ray absorption spectra (XAS) near the M5,4 edges coupled to pure DFT calculations yielded a total magnetic moment of 1.4 μB, where 2.92, -1.64, and 0.105 μB are the spin, orbital, and dipolar term contributions, respectively. Additionally, NdPO4 shows a modest magneto-crystalline anisotropy with the b-axis identified as the hard and the ac plane as the easy magnetization directions. Finally, the superexchange was found to be very weak; however, it remains the driving mechanism over dipole-dipole interaction, especially between nearest neighbors, while driving the transition temperature around 0.32 K.

Electron paramagnetic resonance (EPR) is a technique for studying the microscopic structures by detecting the transitions of the spin magnetic moments of unpaired electrons. Since its discovery by E. K. Zavoisky in 1944, EPR has evolved from a tool for analyzing atomic structures in physics into a core characterization method in the fields of chemistry, biology, and materials science. In surface chemistry, due to its high sensitivity to the local environment, EPR has become a unique technique for elucidating surface-active sites, free radical intermediates, and defect structures. However, for many chemists, EPR testing and analysis, which are based on mathematical and physical principles, is not an easy field to engage in due to its high level of specialization. Some introductory textbooks provide excellent and comprehensive explanations of the basic knowledge, and recent work reports have also demonstrated the continuously developing magnetic resonance spectroscopy methods. Nevertheless, they are not intended to provide a brief and clear overview through a wide range of examples. To bridge the knowledge gap between EPR spectroscopists and chemists unfamiliar with EPR, this work reviews the progress in the application of EPR in surface chemistry, discussing its principles, applications, innovative cases and future challenges. It is hoped that nonprofessionals would gain certain knowledge and technical accumulation from this work, thereby promoting the development of surface chemistry.

To demonstrate multiferroic heterostructures with a giant converse magnetoelectric (CME) effect, we propose a material design strategy based on utilizing the control of orbital magnetic moments. Following this strategy, we focus on a multiferroic heterostructure composed of (211)-oriented metastable body-centered cubic (bcc) ferromagnetic Co3Mn, which is predicted to exhibit a significant change in magnetic anisotropy due to in-plane piezostrain. By inserting an appropriate Fe/V layer, we experimentally obtain a highly (211)-oriented bcc Co3Mn layer on piezoelectric Pb(Mg1/3Nb2/3)O3-PbTiO3(011). Using this structure, we reproducibly show a giant CME effect with repeatable and nonvolatile magnetization vector switching. Our proposal is one of the important strategies toward the development of room-temperature electric-field-controlled spintronic devices with ultra-low powerconsumption.

Dynamical response of noncollinear spin systems at constrained magnetic moments

The quantum anomalous Hall effect (QAHE) is a hallmark of topological quantum states, which has attracted significant attention due to its dissipationless transport characteristics. This study theoretically investigates the dynamic modulation of QAHE in two-dimensional noncollinear antiferromagnetic (NAFM) kagome organic–metal framework Sc3C6O6 under both resonant and non-resonant schemes via Floquet engineering. First-principles calculations demonstrate that in monolayer Sc3C6O6, the NAFM state exhibits superior magnetic stability compared to the collinear ferromagnetic state, while possessing a symmetry-protected Dirac point below the Fermi level, and this characteristic differentiates it from the lower-energy but topologically trivial antiferromagnetic state. Circularly polarized light (CPL) dynamically breaks mirror symmetry (M), thereby opening a topologically non-trivial bandgap and generating quantized anomalous Hall conductance. By rotating the magnetic moments, we obtained three typical configurations: Type-I (e.g., ϕ=0°) exhibits stable QAHE; Type-II (e.g., ϕ=60°) is topologically trivial; Type-III (e.g., ϕ=150°) enables optically tunable edge states. Further investigation under low-energy CPL (ℏω=0.2 eV) reveals chiral-inverted edge channels and higher optical modulation sensitivity, with the required light intensity for quantization reduced by 25% compared to the high-energy regime. Notably, the propagation direction of the surface states is strictly locked to the light helicity; switching the chirality of circular polarization enables reversal of both the edge state direction and the sign of the Chern number. This work establishes Sc3C6O6 as an ideal NAFM platform for studying non-equilibrium topological states and provides a feasible strategy for manipulating QAHE in frustrated magnets. This work establishes Sc3C6O6 as an ideal NAFM platform for studying non-equilibrium topological states and provides a feasible strategy for manipulating QAHE in frustrated magnets.