Multilayer graphene-coated Co-based amorphous wires were fabricated by repeated PMMA-assisted transfer processing. Torsional deformation was introduced at different stages of shell construction to investigate the influence of fabrication sequence on the giant magnetoimpedance (GMI) effect. For the non-torsion series, the maximum GMI ratio increased from 165% for the as-spun wire to 302% after three graphene-coating cycles. A further enhancement to 353% was achieved when torsion was introduced after partial shell formation, whereas only a marginal improvement was observed when torsion was applied to bare amorphous wires. Magnetic measurements revealed concurrent reductions in coercivity and peak field together with a systematic evolution of the optimal operating frequency. These correlated changes suggest that progressive shell construction modifies the near-surface magnetic state via electromagnetic boundary modulation, while torsion introduced after partial shell formation provides additional interfacial strain tuning of the graphene-modified near-surface magnetic state, further optimizing low-field circumferential permeability. The results indicate that fabrication-sequence control provides an effective approach for tailoring the GMI response of composite amorphous wires and offers potential for the development of high-sensitivity magnetic sensing devices.
Bacterial contamination remains a critical safety concern in platelet transfusion, and there is an urgent demand for decontamination technologies that eliminate contaminating bacteria without damaging platelet viability and physiological function. Herein, Fe3O4-QCS-PEI-Cu-apt microparticles with enlarged magnetic cores were rationally fabricated to improve aptamer immobilization, aiming at targeted bacterial elimination via near-infrared (NIR) irradiation while maintaining platelet function. Fluorescence assays confirmed their specific targeting capability toward Staphylococcus aureus (S. aureus) without binding to platelets. Magnetic separation experiments demonstrated that the aptamer-functionalized microparticles could efficiently capture and remove 91.35% of S. aureus from platelets. NIR irradiation of the Fe3O4-QCS-PEI-Cu core induced marked bactericidal activity against S. aureus in suspension, as determined by plate counting and LIVE/DEAD staining. This antibacterial ability originated from the intrinsic photo-responsive property of the composite rather than from aptamer-mediated recognition, and could be easily extended to bacteria captured by aptamer-functionalized particles. Comprehensive biocompatibility evaluations, including morphological observation, hematological parameter analysis, CD62P expression detection, and thromboelastography (TEG) were performed. And the results demonstrated that there were no significant changes in platelet morphology, count, activation state, or overall hemostatic function, apart from an increase in the α angle. This platform achieves efficient targeted NIR-triggered antibacterial efficacy while maintaining excellent platelet compatibility, offering a promising strategy to enhance the safety of platelet transfusion.
La0.8Ce0.2Fe9.2Co0.6Si1.2/Fe bulk composites were fabricated via spark plasma sintering (SPS), and the effects of Fe powder content on the phase composition, microstructure, magnetic properties, mechanical properties, and thermal conductivity of the composites were investigated. The Fe powder content alters the α-Fe phase content in the composites. During SPS, atomic diffusion occurs between the Fe powder and the La0.8Ce0.2Fe9.2Co0.6Si1.2 matrix, which reduces the compositional homogeneity of the desired 1:13 phase and induces the formation of thermal decomposition (TD) structures in particles adjacent to the Fe powder. As Fe powder content increases from 0 wt% to 15 wt%, the maximum magnetic entropy change ((−ΔSM)max) of the composites decreases from 8.11 to 5.78 J∙kg−1∙K−1 under 2 T. Interestingly, the α-Fe phase significantly enhances the mechanical strength and thermal conductivity (λ) of the composites. The composite with 15 wt% Fe (S15) forms a continuous α-Fe network structure and possesses the best mechanical and thermal properties: the (σbc)max reaches 1463 MPa, and the λ at 300 K is 20 W·m−1·K−1. Owing to their balanced magnetic, mechanical, and thermal performances, the La0.8Ce0.2Fe9.2Co0.6Si1.2/Fe composites exhibit distinctive and balanced properties, making them promising candidates for near-room-temperature magnetic refrigeration applications.
Magnetic shape memory alloys based on the Ni–Mn–Ga system are of strategic interest for aerospace and robotics applications due to their ability to respond to both thermal and magnetic stimuli. However, the NASA Shape Memory Materials Database a key resource for the community exhibits significant gaps in functional parameters, with up to 93.7% of records missing critical properties such as the Curie temperature, and over 88% lacking complete magnetic data. To address this limitation, this study proposes a data imputation strategy based on a stacking ensemble comprising twelve machine learning models (LGBM, XGBoost, CatBoost, GradientBoosting, RandomForest, MLP, BayesianRidge, KNN, SVR, GPR, MICE, and AutoEncoder), optimized via Optuna and evaluated using ten random seeds with 10 repetitions each. The approach was applied to reconstruct missing entries in NASA’s database. For heat treatment 1, the method achieved coefficients of determination (R2) of 0.95 for duration (h) and 0.88 for temperature (°C), respectively. For the phase transformation temperatures (Mf, Ms, As, and Af), the method yielded R2 values of 0.83, 0.82, 0.79, and 0.80, respectively. Magnetic properties saturation magnetization and maximum magnetic field were imputed with an R2 of 0.92. In contrast, the Curie temperature exhibited limited predictive performance (R2 = 0.15–0.35), primarily due to insufficient data availability. Overall, the proposed methodology integrates machine learning based imputation with physically supported constraints, providing a viable alternative to enhance the completeness and utility of materials databases.
We studied the electronic origin of the NMR nuclear magnetic shieldings (σ) of compounds containing the following transition metal atoms: M= Zn, Cd, Hg, Co, Rh, Cr, Mo, W. The electronic mechanisms that underlie the relativistic effects on those shieldings were assessed with the LRESC–Loc model, which permits one to quantify the set of leading relativistic electronic mechanisms responsible for such effects in terms of well-known non-relativistic operators, and also allows for the determination of which molecular orbitals (MOs) are involved in each of those mechanisms. These MOs are such that the chemist’s intuition associated with core, lone-pair (LP), and bonding MOs is satisfied. The LRESC model is a reliable semi-relativistic methodology that has been shown to reproduce, in a semiquantitative manner, the magnetic shieldings and experimental chemical shifts of transition metals in a large set of molecules. Several new features appear in the shieldings analyzed. Trends in the total shieldings within a given family of compounds depend on relativistic effects—the spin-orbit mechanism is one of the most involved—though, within it, one must consider the Fermi contact (FC) and the spin-dipolar (SD) mechanisms. We found that the contributions that are due to partially filled d atomic orbitals (AOs) become too large when the electron correlation is not properly included. This is overcome in our case using density functional theory. A large influence of lone-pairs of π-type on σ(M) is also seen in some of the molecules studied.
The helical-channel magnetohydrodynamic (MHD) thruster is a silent underwater propulsion device free of rotating mechanical components, which fundamentally eliminates the inherent mechanical noise induced by blades and shaft systems in conventional propeller-driven thrusters. Taking a 10 T-class superconducting helical-channel MHD thruster as the research object, this work establishes a three-dimensional numerical simulation model with bidirectional electromagnetic-fluid coupling via Maxwell–Fluent, filling the research gap of systematic optimization of helical pitch angles in existing low-magnetic-field numerical investigations. A composite magnetic circuit configuration consisting of main coils and compensation coils is adopted, achieving a magnetic field uniformity of 90.13% within the effective working section and markedly alleviating magnetic field attenuation at both ends of the flow channel. Three schemes with helical pitch angles of 23.00°, 17.66°, and 14.29° are quantitatively compared to analyze the effects of helical pitch angle on current density, static pressure, total pressure, radial/axial flow velocities and three-dimensional helical streamlines. Under the rated design mass flow rate of 15.5 kg/s, the scheme with the small pitch angle of 14.29° delivers a thrust of 262.56 N and an electromagnetic efficiency of 7.23%; compared with the large pitch angle scheme of 23.00°, its thrust is improved by 28% and electromagnetic efficiency rises by 53%. Reducing the helical pitch angle extends the effective coupling distance between seawater and the electromagnetic field, optimizes the uniformity of radial current distribution, suppresses eddy currents and Joule heat loss, converts more electromagnetic energy into fluid pressure energy, and thus greatly improves the energy utilization efficiency of the propulsion system. This study provides quantitative design references for the structural optimization and engineering prototype development of low-noise superconducting underwater propulsion equipment, and supports the engineering application of helical-channel magnetohydrodynamic thrusters.
Low-field nuclear magnetic resonance (NMR) is widely used for nondestructive characterization of petroleum-related porous media, including pore-structure evaluation, fluid identification, relaxation analysis, wettability assessment, and displacement monitoring. Conventional NMR signal models usually rely on the quasi-static approximation, in which the detected magnetic field is assumed to respond instantaneously to Bloch-governed nuclear magnetization. However, classical electrodynamics requires electromagnetic fields generated by time-dependent magnetization sources to depend on the source state at a retarded time. In this study, a retarded magnetic-dipole formulation is developed to evaluate finite-propagation-time effects in low-field NMR signal modeling. The analysis shows that the correction appears mainly as a phase shift governed by the dimensionless parameter ϵ=ω0L/v, where ω0 is the Larmor angular frequency, L is the characteristic source–receiver distance, and v is the effective electromagnetic propagation velocity, with v=c in free space. Relaxation-induced amplitude corrections are generally smaller. Numerical examples demonstrate that the quasi-static approximation is well justified when ϵ≪1, as typically satisfied in laboratory core NMR. For extended-scale configurations, including unilateral, borehole, underground, and surface NMR, larger propagation paths and medium-dependent electromagnetic properties may increase \epsilon and produce systematic phase deviations. This work provides a theoretical criterion for assessing the validity range of the quasi-static approximation in low-field NMR applications for petroleum-related porous media.
The Zeta-Minimizer Theorem provides a fully deductive variational foundation for the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. Starting from three primitive thermodynamic axioms and the helical geometry of the phase functional, a multi-extent dynamical system is constructed that simultaneously treats the electrochemical reaction coordinates and the adsorption extents of the participating species at the solid–electrolyte interface. The combined Hessian of the phase functional yields a complete spectrum of relaxation rates whose eigenvalues and eigenvectors emerge directly from the solid blackbox constants Ck and the helical partition functions of the reactive species. Adiabatic elimination of the fast surface modes produces an effective single-extent description in which voltage (or overpotential) appears as the conjugate variable, exactly analogous to the role of pressure in the corresponding gas-phase ammonia synthesis framework. The resulting nonlinear rate law is thermodynamically consistent at all conditions, recovers the Butler–Volmer and Tafel forms as well-defined limiting cases, and incorporates the effects of temperature, dilution, and catalyst-specific interface constants without empirical activation energies or adjustable reaction orders. The framework therefore unifies equilibrium, kinetics, and modal dynamics of HOR and ORR within a single variational structure, offering a parameter-light, first-principles alternative to classical empirical electrocatalytic rate expressions while preserving transparent contact with established limiting laws.
In this work, the SiO2-added MnZn power ferrites have been prepared by the conventional ceramic method, and the effect of stress on initial permeability and power loss has been investigated. With increasing SiO2 content, initial permeability firstly increases and then decreases, whereas power loss firstly decreases and then increases. The sample with 50 ppm SiO2 additive exhibits optimal magnetic performance, including the highest initial permeability and the lowest power loss. This optimal sample also exhibits the wide-temperature characteristics of power loss. Initial permeability decreases and power loss increases under the applied stress. The sample with 75 ppm SiO2 additive exhibits the best stress insensitivity of initial permeability and power loss. Through the loss separation method, it is revealed that magnetic hysteresis loss is more sensitive whereas eddy current loss remains almost unchanged with stress. An appropriate addition of SiO2 reduces the stress sensitivity of the initial permeability and power loss of MnZn ferrites.
Spin-spray deposition is a low-temperature route for preparing crystalline ferrite films, but the actual liquid-film temperature has not been isolated from the nominal heater temperature. NiZn ferrite films were deposited at liquid-film temperatures of 87.6, 90.1, 92.7, and 95.0 °C. As the temperature increased, the (222) Lotgering factor fL decreased from 0.32 to 0.01, the triangular morphology weakened, and the growth rate declined. Ms remained nearly constant at 429–442 kA m−1, whereas μ′max increased from 44 to 83 and fr decreased from 465 to 260 MHz. The structural and magnetic trends are consistent with a shift from surface-confined (222)-oriented growth toward less-oriented growth and a corresponding permeability–frequency trade-off. Unlike our previous studies of substrate and oxidant effects, this work isolates the measured liquid-film temperature and establishes its quantitative relationship with texture and dynamic magnetic response. This parameter provides a practical means of selecting the operating window of spin-sprayed NiZn ferrite cores for integrated high-frequency inductors.
Fracture size governs fluid mobility in shale, yet its direct quantification remains challenging. Nuclear Magnetic Resonance (NMR) transverse relaxation time (T2) offers a unique, non-destructive probe of fracture size distributions; however, a physically grounded conversion from transverse relaxation time to pore radius r (T2−r) is essential to translate NMR signals into quantitative geometric constraints on fluid mobility. This study introduces a capillary-constrained experimental method for T2−r transformation into shale fractures. The workflow uses computed tomography (CT) scanning to extract fracture geometry. The gas-displacing-water process is precisely controlled by integrating the pore capillary pressure and back-pressure feedback algorithm. The NMR-CT conversion method performed in this study differs significantly from the T2−r transformation based on conventional MICP. Differential spectral analysis isolates fracture-specific T2 responses, and least-squares fitting derives the T2−r conversion. Constraining displacement pressure and controlling segmental pressure are effective methods for ensuring the accuracy of fracture displacement. By emphasizing the governing role of capillary pressure during displacement, this method achieves accurate fracture-targeted displacement and reliable T2−r mapping. The results significantly advance the use of NMR for quantifying fracture size and evaluating fluid transport in shale.
Iron powder cores are widely used in cost-sensitive low- to medium-frequency applications because of their high saturation magnetisation, low cost and favourable formability. However, the low electrical resistivity of iron powders favours continuous conductive pathways between adjacent particles, leading to high-frequency eddy-current loss and heat accumulation. To combine electrical insulation, interfacial stability, magnetic-property retention and thermal diffusion in a single coating, a synergistic insulation/thermal-conduction coating based on thiol-functionalised boron nitride was designed for iron-based magnetic powder cores. Hexagonal boron nitride was surface-modified through ultrasonic activation followed by grafting with a mercaptosilane coupling agent, forming covalent linkages on the boron nitride surface. The resulting functionalised nanosheets were deposited onto water-atomised iron powders through interfacial interactions between nitrogen- and sulfur-containing functional groups and the iron surface. A coating content of 5 wt.% produced a relatively continuous and uniform interfacial layer with limited agglomeration, enabling the magnetic powder cores to combine interparticle insulation, loss reduction, magnetic-property retention and thermal transport. The optimised core exhibited a volume resistivity of 58.7 Ω·m and a total core loss of 81.2 kW/m3 at 10 mT and 100 kHz, corresponding to a 20.8% reduction relative to the pure iron core. The sample retained a saturation magnetisation of 201.4 emu/g and an effective permeability of 67.5 at 100 kHz, while achieving a thermal conductivity of 55.2 W/(m·K) and a thermal impedance of 0.215 K·m2/W. Loss-separation analysis indicates that the continuous insulating layer restricts interparticle induced-current pathways and suppresses high-frequency eddy-current loss, while the two-dimensional boron nitride framework promotes internal thermal diffusion.
The microscopic pore structure and fluid occurrence laws of tight oil reservoirs are intricate, leading to relatively low oil production rates. The T1-T2 two-dimensional nuclear magnetic resonance (2D NMR) technique presents significant advantages for fluid identification and the quantitative characterization of fluids and pore spaces in these reservoirs. Nonetheless, systematic and in-depth investigations into its experimental measurements remain scarce. A comprehensive review of both domestic and international literature on T1-T2 2D NMR measurement techniques was conducted for oil reservoirs. The fundamental principles, data acquisition and inversion mechanisms of 2D NMR technology were elucidated. Additionally, the signal distribution laws of hydrogen-containing components under varying test parameters were summarized. The relationship between NMR experimental testing and reservoir characteristics was explored, elucidating the mechanism of the T1-T2 spectra. Building upon this foundation, the strategic optimization of data acquisition and inversion methodologies, along with critical parameters for T1-T2 NMR measurements, significantly enhanced the precision of NMR datasets and the fidelity of 2D NMR spectral imaging. These advancements provide a theoretical basis and technical support for the characterization of rock and fluid in tight oil reservoirs.
[MnIII(pyrol)3(tren)] {(Hpyrol)3tren = tris(1-(2-azolyl)-2-azabuten-4-yl)amine)} is a mononuclear spin-transition compound switching between high spin (HS, S = 2) and low spin (LS, effective S = 1) around 47 K, preserving I4 & strns;3d symmetry. Its magnetic anisotropy is studied by calculating the atomic susceptibility tensor from the refinement of polarized neutron powder diffraction. The analysis reveals that the weakly prolate-type atomic magnetic anisotropy in the HS state abruptly switches to uniaxial needle-shaped/Ising-type anisotropy in the LS state. However, the overall magnetic anisotropy of the unit cell remains isotropic due to the cubic nature of the crystal symmetry. Irreversible coexistence of mixed spin states HS/LS is observed in the vicinity of the cooperative spin crossover, where the average magnetic moment of Mn3+ shows a hysteretic temperature variation. This hysteretic mixing of HS and LS at intermediate temperatures suggests complex growth and nucleation of HS and LS domains. The study demonstrates that polarized powder neutron diffraction is a unique and powerful tool for describing complex magnetic anisotropies and magneto-structural correlations in molecular-based magnetic materials.
This study systematically investigates the gas-liquid phase transition heat transfer characteristics and volatilization loss behavior of magnetic liquid sealing devices under high-temperature and high-speed operating conditions. A magneto-thermal flow-coupled numerical model was established using ANSYS Maxwell (2025 R1) and Fluent (2025 R1) software to simulate and analyze the influence of rotational speed, solid content, and shaft diameter on the temperature distribution and gas-phase evolution of the magnetic liquid within the sealing gap. An experimental platform was also constructed for validation. The research indicates that increasing rotational speed significantly intensifies the vaporization of magnetic liquid, with bubbles migrating towards lower-concentration regions. The influence weight of rotational speed on phase transition is greater than that of shaft diameter. Under identical temperature fields, the phase transition interface morphology and the proportion of gas-liquid two-phase regions among magnetic liquids with different solid contents are highly similar. However, high-solid-content magnetic liquid can inhibit phase transition due to dense particle packing. Increasing shaft diameter notably expands the vaporization region, easily forming through-leakage channels.
Annealing is a critical step in the fabrication of soft magnetic composites (SMCs), and precise coordination of annealing atmosphere and temperature is essential for optimizing their performance. In this study, FeSiCr SMCs were annealed under three different atmospheres (air, nitrogen, and argon) across a range of temperatures, and the effects of the annealing atmosphere on their microstructure and soft magnetic properties were systematically investigated. The results demonstrate that annealing in an inert atmosphere, particularly argon, within the temperature range of 450-750 degrees C, yields superior magnetic properties compared with air annealing. After annealing under argon at 550 degrees C, the effective magnetic permeability (mu e) reached 47.5, and the power loss (Pcv) was 1457.3 kW/m3 at 1000 kHz and 30 mT. These improvements are primarily attributed to effective stress relaxation and the substantial retention of the polyvinyl butyral (PVB) insulating layer. With further increases in annealing temperature, the magnetic properties deteriorate rapidly due to the complete decomposition of PVB and the formation of conductive chromium carbides. Under such conditions, air annealing exhibits distinct advantages. Selective oxidation of FeSiCr occurs, leading to the formation of a dense chromium oxide insulating layer that enhances magnetic performance (after annealing at 850 degrees C, mu e = 47.9, Pcv = 1632.0 kW/m3). Moreover, the mechanical properties were significantly improved, with the radial crush strength increasing from 22.36 N in the unannealed state to 330 N after annealing. These results indicate that the comprehensive performance of SMCs can be effectively tailored through the appropriate selection of annealing atmosphere and temperature, providing valuable guidance for the design and optimization of high-performance SMCs.
The structural and magnetic properties and band structure results of HoCo3-xSix compounds are reported. First-principles GGA+U+SO calculations, compared with magnetometry experiments, provide deep insight on the magnetic properties of the HoCo3 compound. They show that HoCo3 is a robust ferrimagnet, with strongly localized Ho-4f moments in excellent agreement with neutron data and itinerant Co-3d magnetism, where inclusion of the interstitial contribution brings the Co moments into very good agreement with the experimental data. The electronic structure reveals sharp Ho-4f states well below EF, exchange-split Co-3d bands crossing EF, and noticeable Ho-5d-Co-3d hybridization that mediates the antiparallel Ho-Co coupling and explains the non-negligible interstitial moment, providing a consistent microscopic picture that supports the experimentally observed increase in magnetization upon Co-Si substitution. Metamagnetic transitions are shown in magnetization isotherms. The observed transitions are broad and can be explained by the distribution of internal magnetic fields which arises from differences in the local environments of cobalt atoms. The magnetic properties were correlated with the theoretical results. Two transitions were revealed below room temperature, one due to a transition to a noncollinear magnetic structure and the other due to a temperature-induced metamagnetic transition.
Hydrogen (H-2) storage in subsurface formations has recently gained attention as a promising large-scale energy storage solution. Although previous studies have revealed distinct displacement behaviors between H-2 and other gases such as nitrogen (N-2) and carbon dioxide (CO2) in high-permeability sandstones, the mechanisms governing H-2 migration in tight formations remain largely unexplored. To provide experimental observations that may help improve the understanding of H-2 migration in tight reservoirs, we conducted H-2 flooding experiments on a tight sandstone sample from the Ordos Basin under pore fluid pressures of 0.5, 1, and 2 MPa. Dynamic core flooding processes were monitored using a low-field nuclear magnetic resonance (NMR) analysis system. The capillary number (Nc) in this work ranged from 1.7 & times; 10(-9) to 3.4 & times; 10(-9), indicating a capillarity-dominated flow. H-2 saturation in the tight sandstone increased from 41.9% to 53.3% and then to 57.7% with increasing pore fluid pressure. Under a pore fluid pressure of 0.5 MPa, H-2 initially displaced water in small pores (T-2 < 10.5 ms), leading to prolonged fluctuations in water content over 136 min before significant displacement occurred in large pores (10.5 ms < T-2 < 6579.3 ms). In contrast, at a pore fluid pressure of 2 MPa, the water in large pores was more significantly impacted, with a marked decrease in water saturation observed after 8 min of flooding. These findings provide direct experimental evidence of pressure-dependent and pore-scale selective displacement patterns of H-2 in tight sandstone, offering new insights into the fluid dynamics that control hydrogen injectivity and storage efficiency in low-permeability reservoirs.
Polyalphaolefin (PAO)-based magnetic fluids are widely used in precision transmission systems for their excellent rheological and lubricating properties, but their stability and magnetic controllability under high-temperature and high-shear conditions remain a key challenge. In this work, a PAO2-based magnetic fluid was prepared via coprecipitation using a sequential modification strategy involving oleic acid and alkenyl succinimide. An energy competition model under multi-field coupling was established using the magnetothermal energy ratio (lambda) and Mason number (Mn) to elucidate the system's rheological behavior. The fluid shows significant shear-thinning behavior under zero magnetic field; a 60 kA/m magnetic field increases the relative viscosity by over 4 times at 5 s-1, while the magnetoviscous effect becomes weak at shear rates over 500 s-1 (corresponding approximately to Mn = 1). With increasing temperature, the field-induced viscosity enhancement decreases progressively as thermal disturbance becomes increasingly important. This work reveals the multi-field coupling rheological mechanism, and the results suggest that the OA/T154 modification strategy is a feasible route for obtaining a PAO-based magnetic fluid that remains dispersible and magnetically responsive under the tested conditions. The study provides theoretical and experimental support for the design of intelligent lubricating materials.
Cobalt/copper (Co/Cu) multilayers are prototypical systems for giant magnetoresistance (GMR)-based spintronic devices, where interfacial quality and spin-dependent scattering critically determine performance. In this work, Co/Cu multilayers were fabricated by pulsed laser deposition (PLD) on SITAL ceramics, Si(100), and BK7 substrates, with 10, 20, and 40 bilayer repetitions, in order to elucidate the interplay between microstructure, interfacial diffusion, and magnetotransport properties. Systematic characterization combining atomic force microscopy (AFM), scanning electron microscopy (SEM), SIMS/SNMS depth profiling, vibrating sample magnetometry (VSM), and Hall effect measurements reveals that PLD enables controlled multilayer growth with low background roughness and well-defined periodic structures, despite the presence of characteristic particulates. A clear dependence of the GMR response on both bilayer number and substrate type is observed. Increasing the number of repetitions enhances spin-dependent scattering at Co/Cu interfaces, leading to a progressive increase in the magnetoresistance amplitude, reaching similar to-14% for 40-period multilayers on SITAL substrates. This enhancement is attributed to the higher interface density and improved interfacial coherence, as confirmed by SIMS/SNMS analysis showing reduced interdiffusion in thicker stacks. In parallel, Hall effect measurements indicate a reduction in carrier density and an increase in carrier mobility with increasing multilayer thickness, consistent with improved charge transport stability. A pronounced substrate effect is demonstrated: SITAL-supported multilayers exhibit enhanced GMR sensitivity (up to similar to 44%.T-1) due to increased diffuse spin-dependent scattering at rougher interfaces, whereas Si(100) substrates promote smoother growth, improved structural coherence, and more stable electronic transport. While sputtering typically enables smoother interfaces and higher GMR ratios, PLD offers enhanced flexibility in tailoring interfacial morphology and diffusion processes, which can lead to improved sensitivity under specific conditions. These results establish PLD as a versatile route for tailoring Co/Cu multilayers, enabling controlled optimization of the trade-off between sensitivity and structural quality for advanced spin-valve and magnetic sensor applications.
