In-situ plasma processing serves as a cost-effective strategy for modulating surface structure while simultaneously functionalizing material surface, owing to the low-contamination environment and its capability to induce strong surface-substrate interaction. However, current research primarily focuses on correlating plasma discharge parameters with the resultant surface morphology and facet orientation, often overlooking the dynamic evolution of critical parameters during plasma processing, particularly the surface thermal field. This leads to suboptimal surface structure modulation, thereby limiting the practical applicability of plasma-based surface engineering. Herein, we introduce a facile cooling-mediated N2 plasma processing strategy to directly engineer iron nitride nano-framework on Fe surface, while concurrently modulating the surface facets. Operando plasma diagnostics, combined with numerical simulations, are employed to unravel the role of the surface-thermal field in governing the formation of catalytically favorable facets. Given the strong dependence of hydrogen evolution reaction (HER) behavior on surface structure, the resultant iron nitride frameworks via cooling-mediated plasma processing (cFeNC) exhibit improved catalytic performance compared to those fabricated through conventional thermally preserved plasma (hFeN). Density functional theory (DFT) calculations further confirm that the enhanced catalytic behaviors of cFeNC arise from the preferential exposure of highly reactive facets. Our strategy presents a cost-effective pathway for facet engineering of nitride surfaces, providing a promising route towards advanced electrocatalytic materials. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Distinct material phase modulation is widely regarded as a key strategy for tailoring the surface properties of nano-frameworks. Plasma has emerged as an effective method for in situ phase modulation directly on substrate surfaces. However, the persistent vertical bombardment of reactive species in a conventional plasma system inevitably leads to excessive surface etching, thereby compromising the distinction and quality of surface structural engineering. Herein, we introduce a novel magnetically confined plasma strategy that enables the unique phase modulation of iron nitride nano-frameworks on iron substrates. By varying the magnetic field strength, the resultant iron nitride phase transitions from orthorhombic Fe2N to trigonal Fe2N, with a well-defined exposed facet, is achieved. In contrast, the conventional plasma nitridation predominantly yields hexagonal FeN. Operando plasma diagnostics and numerical simulations are employed to elucidate the underlying mechanism governing phase modulation. The superior distinction of phase modulation via magnetically confined plasma processing is further validated by comparing with conventional plasma nitridation under varying discharge parameters. Such apparent structural differences of nitrides via magnetically-confined plasma are confirmed through the corresponding electrocatalytic performance evaluation and theoretical calculations. Such an approach offers a promising pathway for the distinct structural engineering of nitrides directly on the substrate surface toward improved electrocatalytic behavior.

Plasma-substrate interactions have attracted considerable attention for their potential in optimizing surface structure modulation. However, most studies focus on initial discharge parameters, while the fundamental influence of plasma environment on the intrinsic properties of the substrate during processing has been largely overlooked, limiting the precision of surface structural control. Here, we report a novel phenomenon: the ferromagnetism collapse of metallic Ni during low-pressure glow discharge plasma processing. The intrinsic ferromagnetic behavior of Ni is transformed into the diamagnetic state during plasma processing and it is reversed back to ferromagnetic state once the plasma is switched off. Such transition in magnetic behavior of Ni is observed under N2, O2 and H2 plasma environments. Through the combination of operando plasma diagnostics and numerical simulations, it is demonstrated that reactive species in different plasmas are adsorbed on substrate surface under the confinement of plasma sheath. Such adsorption significantly reduces the ferromagnetic stability of Ni, leading to the ferromagnetism collapse. Such discovery provides new insights into plasma-substrate interactions and offers a comprehensive scientific basis for understanding and controlling the surface magnetic properties of Ni during plasma processing.

Spin transfers in magnetic multilayers offers a promising pathway toward ultrafast, energy-efficient spintronic devices. In this study, we investigate the interfacial spin pumping and temperature-dependent spin current exchange in a Cr1.12Te2/Cu/Ni80Fe20 (Py)(FM1/NM/FM2) trilayer structure. Using broadband and cryogenic ferromagnetic resonance (FMR) measurements, we investigate key magnetization dynamical parameters, including the effective Gilbert damping factor, effective magnetic fields, interfacial spin mixing conductance, and spin current density. Efficient spin angular momentum transfers from Py to Cr1.12Te2 are observed at room temperature. At lower temperatures, the enhanced linewidth reflects temperature dependent spin pumping effects occurring at distinct precession frequencies of the ferromagnetic layers. Notably, the absence of interfacial Damping indicates that spin pumping can be modulated by controlling the net spin current flow. These findings offer critical insight into temperature-dependent tunable spin transport mechanisms in magnetic multilayers, highlighting their potential for next-generation spintronic applications.

M-type hexaferrites have continued to attract attention over the years due to their potential applications in microwave devices, magneto-optical systems, magnetic recording media, and permanent magnets. Here, we present a comprehensive investigation of the physical properties of M-type hexaferrites with nominal composition Sr0.54Ca0.46AlxFe12-xO19 (x = 2.0, 4.0, 5.5, and 6.5) hexaferrites, designated as SCAFO-2, SCAFO-4, SCAFO5.5 and SCAFO-6.5, synthesized via the solid-state reaction method. The formation of high-purity M-type hexagonal ferrite phases was confirmed by X-ray diffraction (XRD), and the structural parameters were quantitatively determined using Rietveld refinement of the diffraction patterns. Magnetic measurements reveal that the highest saturation magnetization Ms = 55.01 emu/g at 5 K and 34.57 emu/g at 300 K respectively for the synthesized strontium hexaferrite material with 2% aluminum substitution. Additionally, the coercivity (Hc) exhibits a monotonic increase with increasing Al content, rising from 5.61 kOe at x = 2.0 to a peak of 14.16 Oe at x = 4.0, followed by a decline at x = 5.5. The micromagnetic simulations, revealing that the resonance frequency increases with Al content, reaching a maximum at x = 5.5 (f = 250 GHz), followed by a decline at x = 6.5. This study provides a comprehensive understanding of the structure property relationships in Sr0.54Ca0.46AlxFe12-xO19, demonstrating their strong potential for magneto-optical and sub-terahertz applications and establishing M-type hexaferrites as promising materials for future advanced technologies.

Highly crystalline hematite (alpha-Fe2O3) nanostructures (NSs) with distinct morphology hold vital significance, not only for fundamental knowledge of magnetic properties but also offering potential applications from biomedical to data storage to semiconductor industry, etc. alpha-Fe2O3 NSs with various shapes are examined to reveal the intrinsic relationship between the shape anisotropy and magnetic properties. Herein, different morphologies of alpha-Fe2O3 NSs, such as spherical, cubic, plate-like, rhombohedral, and hexagonal bipyramid are synthesized, by controlled hydrothermal method. The impact of shape and size on the optical and structural characteristics through UV-vis absorption spectroscopy and X-ray diffraction is analyzed. Advanced nanomaterial techniques such as transmission electron microscopy are utilized to explore and confirm the morphology and size of NSs. Subsequently magnetic properties of the alpha-Fe2O3 NSs, such as magnetic saturation (M-s), coercivity (H-c), and remanent magnetization (M-r), are measured. Careful analysis of magnetic data reveals Morin transition around 200 K for cubic, plate-like, and rhombohedral samples, whereas the spherical and hexagonal bipyramid samples illustrate the superparamagnetic behavior in the temperature range of 150-300 K. Finally, the antibacterial characteristics of NSs against Escherichia coli using a microplate reader for monitoring the bacterial growth are investigated.

The present study explored the correlation between microstructure and magnetic properties of CoCrCuFeNiTi HEA coatings prepared on Si substrate using plasma surface alloying technology. The coatings exhibited a mixture of Fe2Ti, FeCr, FCC, BCC phase and the amorphous/crystalline structure. The mircrostructure changed with the deposition duration, resulting in different coercivity. The crystalline part of the coating deposited for 1.0 h contained up to 81.9 % of Fe2Ti and more amorphous structure, causing a coercivity of 53.1 Oe. Fe2Ti showed a preferred orientation along the (201) direction, leading to columnar structure in the coatings and the vertical growth of columnar structure caused an increase in coating thickness. As the deposition duration increased to 1.5 h, a reduction of Fe2Ti and amorphous structure, as well as an increase of defects such as grain boundaries allowed the coercivity to increase to 104.5 Oe. FCC, FeCr, and BCC phase increased as increase of deposition duration, and the relative content of BCC phase increased to a maximum of 8.3 % at a deposition duration of 2.0 h. An increase of grain size and nonuniform distribution of different phases in coating led to a reduction of coercivity to 82.9 Oe. However, the vertical growth of the columnar structure made the coating to exhibit obvious shape anisotropy and the coercivity increased to 118.3 Oe when deposition duration was 3.0 h. The coercivity of HEA coating prepared by plasma surface alloying technology were sensitive to microstructure, and the deposition duration needed to be controlled to obtain the desired coercivity.

Rust removal via glow-discharge plasma has attracted considerable attention owing to its dry environment with little contaminant, environmental-friendliness and treatment rapidity. The plasma-rust interaction process has been studied over the years, but a crucial influencing factor, the surface temperature of the iron substrate, remains inadequately controlled during plasma processing, leading to suboptimal rust removal performance and an ambiguous mechanism. Here, we innovatively modulate the rust-reducing performance on iron (Fe) surface via controlling surface thermal field during plasma processing along with the elucidation of rust reduction mechanism. Coupled with operando plasma diagnostics along with numerical simulation, it is confirmed that plasma processing with the cooling component introduction causes the insufficient surface thermal field on Fe substrate and hence results in partial Fe2O3 reduction towards porous Fe3O4 with little metallic phase formation. Comparatively, excessive thermal field results in exorbitant surface kinetic and thereby resulting in compact layer formation with inner FeO on Fe surface. Such phenomenon is ascribed to the initially achieved H2O vapor constraint within oxide to achieve FeO. We found that appropriate thermal field, where the Fe surface temperature is neither too high or too low, can remove rust effectively owing to synergistic effect of thermal field and porous structure formation. Our work is to provide a novel plasma-based pathway to effectively modulate surface oxide reduction.

Plasma-based surface modulation has gained attention in preparing electrode materials for high-performance electrocatalysis, but most methods involve multiple steps, typically a wet chemical synthesis followed by plasma treatment, limiting their further scalability. Solely plasma-driven surface structure control of electrocatalysts remains challenging due to the unclear dynamic factors during the plasma discharge, which extend beyond the known values of the initial set of plasma discharge parameters. Herein, we develop a cooling-mediated plasma strategy, enabling one-step modulation of the structure/phase of the metal electrocatalyst directly on its surface. With nickel as the substrate, a controlled surface thermal field during nitrogen plasma processing yields a distinct morphology and facet exposure of the resultant nitrides, attributed to the differential distribution of reactive N-species and varied surface dynamics of Ni, as verified by in situ plasma diagnostics and numerical simulations. Based on electrocatalytic performance testing and density functional theory (DFT) simulations, plasma-tailored nano-structures, under controlled surface temperature of the electrocatalyst through the use of a cooling component, deliver improved hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities. Our strategy offers a cost-effective approach for structural engineering in electrocatalysis.

Low-temperature plasmas, also known as non-thermal plasmas, are partially ionized gases whose electron temperatures are much higher than those of the ions and neutrals. Furthermore, gaseous molecules are partly dissociated, and the degree of dissociation is orders of magnitude larger than that calculated from the Boltzmann distribution at a given gas temperature. This distinguishing characteristic allows low-temperature plasma (LTP) to have diverse uses in many fields, including medical and biological, agriculture, environmental, and electronics and semiconductor applications. Applications of LTP have been increasing worldwide, but in this particular topic, we will focus on the advances in LTP applications in Asia.

Achieving electrical control of ferromagnets without magnetic fields is crucial for the dense integration of nanodevices in modern memory and computing technologies. Current methods using spin orbit torques from the spin Hall effect and interfacial Rashba effect are limited to in-plane magnetized ferromagnets. Out-of-plane antidamping torque is essential for the electrical only control of ferromagnets with perpendicular magnetic anisotropy. In this work, we report the observation of out-of-plane polarized spin currents in platinum/permalloy bilayers, linked to interfacial perpendicular magnetic anisotropy at the interface between two metallic layers, as revealed by polarized neutron reflectometry. In-plane angle-resolved spin-torque ferromagnetic resonance measurements characterized the out-of-plane damping-like torque, constituting about 12% of the total torque in ultrathin Pt films, which vanishes when platinum thickness exceeds 4 nm, confirming its interfacial origin. This interfacial perpendicular magnetic anisotropy-induced torque is significant compared to the bulk spin Hall effect, which can be obtained in a typical heavy metal/ferromagnet bilayer. This advancement holds promise for enhancing the efficiency and reliability of spin orbit torque magnetic random-access memory (SOT-MRAM), spin Hall oscillators, and other spintronic devices.

Magnetic nanoparticles and nanochains hold significant importance in data storage and biomedical applications due to their small size, high aspect ratio, and distinctive reversal properties. However, these properties are significantly affected by the surface morphology and fine orientational features of the particles. This study systematically examines the magnetic reversal and hysteretic properties of Ni nanostar-chains and their constituent particles, focusing on the surface characteristics and geometric configurations resulting from chemical synthesis. The investigation reveals the influence of surface roughness, manifested as spikes, on the reversal landscape. Additionally, it delves into the impact of structural properties of self-assembled nanochain clusters on the reversal behaviour. The findings offer valuable insights into fundamental magnetic phenomena in chemically synthesized magnetic nanostructures, emphasizing their morphological and geometric characteristics. This approach details minute features of nanostructures, paving the way for advancements in computer memory and biotechnology applications.

Heteroatom doping and vacancy introduction, typical orbital polarization strategies, play pivotal roles in enhancing electrocatalytic H2 production of transition metal dichalcogenide (TMD). Plasma serves as an indispensable technique to efficiently tailor doping and vacancy. However, it is difficult to simultaneously modulate doping-defect proportion to precisely control the orbital polarization due to the ambiguous plasma-substrate interaction. Coupled with theoretical prediction, we design facile pulsed plasma processing to precisely modulate the surface proportion of N-doping and S-vacancy on layered WSSe via meticulously controlling the surface temperature. The resultant S-vacant N-doped WSSe (VNWS) exhibits enhanced electrocatalytic behavior in diversified-pH media, compared with N-doped WSSe with little defects via continuous plasma treatment. Operando plasma diagnostics further substantiates the influence of surface heating on plasma parameters and the precise surface modulation of WSSe. The work highlights the pivotal role of controlled surface temperature during plasma processing in creating high-performance VNWS electrocatalyst with optimized vacancy-dopant proportion.

We explore the effect of magnetic anisotropy on the interplay between spin current and parametric instability in magnetization dynamics, crucial for developing efficient nonlinear spintronics devices. The parametric instability is induced by the Suhl process where a uniform mode magnon excites two counter-propagating parametric magnons. We experimentally demonstrate direction-specific spin current generation via spin pumping from these parametrically excited magnons in a thin bilayer of [110]-oriented yttrium iron garnet and platinum (Pt), utilizing the facet-dependent magnetocrystalline anisotropy and magnetodipolar interaction. The facet-symmetry and the shape anisotropy modulate the magnonic dispersion relation as well as the magnon-scattering process which determines the spin pumping efficiency. Analyzing the in-plane angular dependence of spin pumping-induced inverse spin Hall effect voltage, we demonstrate anisotropic control of the spin pumping efficiency of the parametric magnons. Our findings provide critical insights to enhance control in magnonic logic devices.

In this study, atmospheric pressure AC needle-to-needle bare electrode discharge coupled with a nebulized sample injection was developed for elemental analysis (Ni, Cu, Cd, and Pb). The effects of various parameters-including carrier gas composition, nebulizer gas flow rate, organic additives, solution pH, discharge power, and discharge gap-on the discharge mode and analytical performance were systematically investigated. Oxygen was identified as the optimal carrier gas due to its low background noise in the optical emission spectrum and favorable plasma properties. Importantly, the transition state between streamer and glow-like discharge was found to be most favourable for elemental analysis. Under optimized conditions (2.2 L min-1 nebulizer gas flow rate, 2% methanol additive, 3 mm discharge gap, and 15 kV applied voltage), the device achieved sensitive limits of detection (LODs) for Ni (0.38 mg L-1), Cu (0.05 mg L-1), Cd (0.09 mg L-1), and Pb (0.24 mg L-1), with relative standard deviations (RSDs) <= 6.1% (n = 10), demonstrating its potential for portable and rapid elemental analysis applications.

A facile facet reconfiguration has been considered as an essential issue for nitride coating in promoting surface protection behaviour. Compared to physical-chemical methods to achieve heterogeneous coating, plasma nitridation strategy is regarded as a favourable technique to in-situ deliver nitride protecting layer, but it is difficult to precisely control surface framework through plasma technique due to complicated interaction environment. To simply achieve nitride coating with favourable surface protection behaviour, we design a novel auxiliary insulator-confined plasma system to directly achieve hydrophobic iron nitride nano-coral (hFeNC) with desirable corrosion- and wear-resistant properties by controlling surface heating process during plasma nitridation. The resultant hFeNC nano-framework delivers corrosion rate of 1.2 mpy, 4- and 9-times lower than that of solid iron nitride film (sFeN) via normal plasma and initial Fe in NaCl condition, respectively. Operando plasma diagnostics along with numerical simulation further confirm the effect of surface heating on typical plasma parameters as well as the iron nitride nano-frameworks, indicating surface heating as the key factor responsible for the favourable surface protection coating.

The world as we know today has shifted towards sustainable and clean energy through the development of novel hydrogen production facilities. To fulfill the demand for a cleaner future, improvements in carbon capture technology have become an essential enabler for the growing hydrogen economy and reduction in carbon footprint. The Dense Plasma Focus (DPF) device was utilized as an alternative means of growing nanostructured carbon from low partial pressure methane gas with assistance from a heated catalyst, namely stainless steel (ANSI 304) substrates. The carbon material synthesized has been characterized andanalyzed to be multiwalled carbon nanotubes that are mostly vertically aligned forests on the substrate. Raman spectroscopy confirms the nature of the type of carbon nanostructured material from the presence of D, G and D$\prime$ peaks as well as from the overtones, with graphitization quality (I G / I D ) ratio to be within 0.907 to 1.023. The carbon nanotube forest was found to have grown with a bulk film thickness between 3 to 4 µm and an average diameter of about 12.8 to 14.6 µm. Further work done on optimizing the parameters has resulted in highly vertically aligned carbon nanotubes achieved at a gas pressure centered around 12.0 mbar, while no growth was observed at the highest operated pressure of 30 mbar. Operating at theoptimized parameters with a single shot generated the highest gas-to-solid carbon conversion rate which was deduced from the high anisotropy value of $\approx$ 250 from the carbon nanotube. Hence, we successfully demonstrated that the DPF device can easily convert carbon-based gaseous precursors into solid storable carbon materials at relatively low gas pressures on commonly accessible and low-cost stainless-steel substrates, making it a suitable alternative candidate for carbon capture applications.

SmCo5/Co core-shell nanoparticles are studied for their ability to improve magnetic properties like coercivity and exchange-bias effects. The core-shell structure helps enhance these properties by allowing better control over the magnetic behaviour of the core, shell, and their interface. These nanoparticles can maintain strong magnetization, high coercivity, and improved energy efficiency. The structure allows for adjustable magnetic properties, giving insights into the core, shell, and their interactions effect on the overall magnetism. We use atomistic magnetic simulations with VAMPIRE software to study the magnetization reversal, coercivity, and Curie temperature in two different combination of exchange-coupled bi-magnetic hard/soft ferromagnetic core/shell nanoparticle. In the first configuration, SmCo5 is the hard magnetic core and Co is the soft magnetic shell. The core size (dc) varies from 0 to 4 nm, while the overall particle size stays around 5 nm. The results show that changing the shell thickness affects the microscopic interface pinning mechanism. Whether SmCo5 is the core with Co as the shell, or vice versa, the coercivity shows little change with variations in shell thickness, but it increases significantly compared to individual Co or SmCo5 nanoparticles. The findings confirm that the core-shell structure depends on the materials, core size, and temperature. We also investigate how the finite-size effect influences the Curie temperature of SmCo5 and Co nanoparticles using M-T graphs. The results show that the maximum energy product (BH)max strongly depends on core size. The SmCo5/Co core-shell nanoparticle combination boosts magnetic performance by utilizing SmCo5’s high magnetic strength for permanent magnets and the Co shell’s thermal stability for enhanced magnetization. This synergy makes them suitable for applications in permanent magnets, recording media, and biomedical uses.

Mutually coupled spin Hall nano-oscillators (SHNO) can exhibit binarized phase state, offering pathways to realize Ising machines and efficient neuromorphic hardware. Conventionally, phase binarization is achieved in coupled SHNOs via injecting an external microwave at twice of the oscillator frequency in presence of a biasing magnetic field. However, this technology poses potential challenges of higher energy consumption and complex circuit design. Moreover, fabrication-induced mismatch in SHNO dimensions may hinder mutual synchronization. Addressing these challenges, we demonstrate purely DC current-driven mutual synchronization and phase binarization of two non-identical nanoconstriction SHNOs without biasing magnetic field and microwave injection. We thoroughly investigate these phenomena and underlying mechanisms using micromagnetic simulation. We further demonstrate the bias field-free synchronized SHNO pair efficiently performing a reservoir computing benchmark learning task: sin and square wave classification, utilizing current tunable phase binarization. Our results showcase promising magnetization dynamics of coupled bias field-free SHNOs for future computing applications.