Component Layers Research Articles

Flammability and Mechanical Testing of Sandwich Composite for Rolling Stock Structural Applications

Components made of composite materials are being increasingly used in the construction of rolling stock. Currently, the use of components made of composite materials as train structural elements is increasingly being considered. Non-structural components made of composites are most often found inside rail vehicles (e.g., the interior lining), while structural components made of sandwich composite materials can be used for the roof, sidewalls, and underframe constructions. This article provides a description of an innovative sandwich composite developed for a metro’s underframe, as well as the production process and preparation of the composite specimens. The main parts of the work are flammability and mechanical (static and fatigue) tests of the innovative sandwich composite. The scope of the flammability tests included the testing of the fire properties using the radial plate method, the optical density of smoke, and the content of toxic gases. The mechanical strength of the sandwich composite was examined during a flexural (three-point bending) test and a fatigue strength under a given dynamic load. The results presented in the article are very significant, both in terms of flammability and the mechanical strength tests. In order to produce large-size train components, appropriately large patches of component layers of the composite are required; this may pose production problems.

Structural features of bimetallic composites of the Me-Al type (Cu, Ni, Nb), obtained by ball milling of powder mixtures and consolidation by torsion under pressure

A comparative study of the features of the microstructure of bimetallic composites of the Me-Al (Cu, Ni, Nb) type, obtained by ball milling of powder mixtures and consolidation by torsion under pressure in Bridgman anvils, was carried out. In all systems studied in this work, the formation of a nanoband structural state is observed, the elements of which are elongated predominantly along the direction parallel to the anvil plane. It has been established that in local areas characterized by the absence of the aluminum component, an SMC state without a nanolaminate structure is formed. An analysis of the features of structure formation was carried out taking into account the comparison of the characteristics of powder systems components (melting point, shear modulus and stacking-fault energy). It was shown that low shear modulus of aluminum, compared to other components, in combination with a higher homologous temperature, provides it high accommodative ability. It has been suggested that under conditions of torsion under pressure, the aluminum component, being a kind of solid lubricant, ensures slipping and flattening of stronger layers of the second component, which contributes to the formation of a nanolaminate structure in the metal‑aluminum systems under consideration.

Characterization of mechanical and temperature effects on delamination and basic strength behaviors of PVC coated PUR foam substrate used in bus dashboard

This study focuses on the delamination and characterization of different loadings and temperature conditions of polyvinyl chloride (PVC)-coated polyurethane (PUR) foam component layers commonly used in bus dashboards. The method was developed through mechanical and thermal tests.The study involves the examination of primer and no primer PVC-coated PUR components using SEM (Scanning Electron Microscope), tensile-compression, three-point bending, primer characterization, peel, PUR material thermal expansion, and thermal tests. Physical and material tests were conducted to determine the mechanical properties of PVC and PUR foam and the material properties of the primer. Fourier transform infrared spectroscopy (FTIR) analysis was also conducted to identify the functional groups present in the PVC, PUR, and primer materials, helping to understand the material interactions.Some tests produced the expected results, while others did not. The primer characterization and three-point bending tests were unsuccessful due to sample foam breakage. However, tensile-compression tests, peel tests, thermal expansion tests, and thermal tests yielded the desired outcomes. During thermal testing of primed samples, it was observed that the samples shortened and bent as the primer material melted and began to separate from the PVC and PUR layers. This bending and swelling were attributed to the difference in thermal expansion coefficients between the melting primer material and the PVC and PUR layers. The results demonstrate that PVC-coated PUR components can be effectively separated, and they also highlight opportunities for design modifications to improve the durability of bus dashboards.

Аналіз розподілу температури у двошаровій композитній циліндричній оболонці зумовленої конвективним теплообміном на її зовнішній поверхні

A non-stationary thermal conductivity problem for a two-layer cylindrical shell is formulated. The materials of the constituent layers of the shell are assumed to be homogeneous and isotropic. This shell is convectively heated by the external environment. The system of linear two-dimensional equations for the integral temperature characteristics summed over the component layers of the shell was used as the initial system of equations of the problem under consideration. When obtaining this system, the hypothesis of a linear distribution of temperature along the thickness of the entire shell was applied. On the basis of the developed two-dimensional mathematical model of thermal conductivity for layered cylindrical shells, a general solution to the thermal conductivity problem for a two-layered cylindrical shell was obtained. A temperature distribution was found for such a shell, which is locally convectively heated by the external environment in a rectangular region on the outer surface. For the numerical analysis, a metal-ceramic cylindrical shell was considered, the inner layer of which is made of tungsten, and the outer layer is made of ceramics. Under such a structure and conditions of heat exchange with the external environment for the considered shell, the effect of its geometric parameters and thermophysical characteristics of the materials of its component layers on the temperature field on the outer surface of the shell was investigated. The revealed new qualitative and quantitative regularities can be used to estimate temperature fields in composite elements of layered structures and in structures with one-sided coatings. The dependences of temperature distributions on geometric parameters and thermophysical characteristics obtained in this work are the basis of the theoretical basis for the analysis of temperature regimes of metal-ceramic cylindrical shells. In particular, metal-ceramic dental crowns to predict their temperature regimes are modeled by the two-layer metal-ceramic cylindrical shells described above, which are locally convectively heated by the external environment

High Piezoelectric Performance of KNN-Based Ceramics over a Broad Temperature Range through Crystal Orientation and Multilayer Engineering.

Uninterrupted breakthroughs in the room temperature piezoelectric properties of KNN-based piezoceramics have been witnessed over the past two decades; however, poor temperature stability presents a major challenge for KNN-based piezoelectric ceramics in their effort to replace their lead-based counterparts. Herein, to enhance temperature stability in KNN-based ceramics while preserving the high piezoelectric response, multilayer composite ceramics were fabricated using textured thick films with distinct polymorphic phase transition temperatures. The results demonstrated that the composite ceramics exhibited both outstanding piezoelectric performance (d33~467 ± 16 pC/N; S~0.17% at 40 kV/cm) and excellent temperature stability with d33 and strain variations of 9.1% and 2.9%, respectively, over a broad temperature range of 25-180 °C. This superior piezoelectric temperature stability is attributed to the inter-inhibitive piezoelectric fluctuations between the component layers, the diffused phase transition, and the stable phase structure with a rising temperature, as well as the permanent contribution of crystal orientation to piezoelectric performance over the studied temperature range. This novel strategy, which addresses the piezoelectric and strain temperature sensitivity while maintaining high performance, is well-positioned to advance the commercial application of KNN-based lead-free piezoelectric ceramics.

Study of the microhardness ensuring the contact endurance of structural materials

The strength of the working surfaces of gears depends on the mechanical properties of the material and the quality of parts. We present the results of studying the strength of materials and working surfaces of a gear mechanism due to structural changes attributed to chemical and thermal treatment. The surface strength of the gears of gas turbine engines was studied. Nitrocementation and ion nitriding were used for chemical and thermal treatment of the contacting surfaces of steel samples under study (20Kh3MVF-Sh, 16Kh3NVFMB-Sh, 18Kh2H4MA, and 12Kh2H4A). Changes in the microhardness of the component layers (diffusion, transition and basic) of the toothed crown were analyzed. Metallographic analysis of the structure of materials was carried out to describe the factors determining the surface strength of working surfaces. Systematized data on the change in the microhardness of materials obtained experimentally in conditions of mass production are presented. Presented experimental results on changes in the mechanical properties of materials are based on data on the microhardness and structural state of the surface layers of the working profiles of gears. A comparative assessment of the surface strength of the studied samples during contact interaction was performed. The dependence of the surface strength on the multifactorial volumetric structure and structure formation of the material in the process of operation is determined. It is shown that the method of surface saturation forms the structure of a material with different mechanical properties accompanied with the formation of a transition zone having characteristic distinctive values of the hardness. The results obtained can be used in the design of gears, taking into account changes in the mechanical properties and structure of materials to ensure the necessary operational requirements.

Green recycling of end-of-life photovoltaic modules via Deep-Eutectic solvents

Sustainable End-of-life (EOL) photovoltaic (PV) modules recycling is essential for achieving resource conservation and alleviating environmental issues. Ethylene vinyle acetate (EVA) adhesive films separation is a prerequisite for the realization of valuable component recovery of PV modules. However, the conventional wet chemical separation processes are usually accompanied by the challenges of low separation efficiency, high toxicity and difficult multiple recycling. Herein, a green, biodegradable, low-cost and recyclable deep eutectic solvent (DES) is firstly developed to efficiently separate EVA films in EOL PV modules. The high temperature stability and the acidic characteristic of DES can facilitate the separation of EVA film between component layers. At 175 ℃, the warping effect caused by the differential thermal contraction between the module component layers creates favorable conditions for the efficient reaction and separation by the DES. Additionally, the acidic medium reacts with the aluminum electrode layer of PV cells, which further enhances the separation efficiency of EVA films. The EVA separation rate reached 100%, the separation rate of the EVA containing aluminum (Al) up to 98.4% after 12.5 h at 175 ℃. Moreover, the developed DES exhibits excellent recyclable performance, the EVA separation rate remained 100% after 10 cycles. Compared to the traditional solvent toluene, DES has advantages in terms of economics, environmental impact, and efficiency. This strategy of design a green, biodegradable, low-cost and recyclable solvent to replace traditional solvents, and provides a promising route to efficiently separate EVA films in EOL PV modules.

Mapping climate suitability index for rainfed cultivation of medicinal plants by developing an AI-based probabilistic framework

The Climate Suitability Index (CSI) can increase agricultural efficiency by identifying the high-potential areas for cultivation from the climate perspective. The present study develops a probabilistic framework to calculate CSI for rainfed cultivation of 12 medicinal plants from the climate perspective of precipitation and temperature. Unlike the ongoing frameworks based on expert judgments, this formulation decreases the inherent subjectivity by using two components: frequency analysis and Particle Swarm Optimization (PSO). In the first component, the precipitation and temperature layers were prepared by calculating the occurrence probability for each plant, and the obtained probabilities were spatially interpolated using geographical information system processes. In the second component, PSO quantifies CSI by classifying a study area into clusters using an unsupervised clustering technique. The formulation was implemented in the Lake Urmia basin, which was distressed by unsustainable water resources management. By identifying clusters with higher CSI values for each plant, the results provide deeper insights to optimize cultivation patterns in the basin. These insights can help managers and farmers increase yields, reduce costs, and improve profitability.

Hydrophobic deep eutectic solvents as novel media for the recycling of waste photovoltaic modules

Disposing of end-of-life photovoltaic (PV) modules has posed a significant environmental challenge due to the absence of proficient and sustainable recycling technologies. Separating PV modules, which are ethylene–vinyl acetate (EVA)-bonded layers, including glass, solar cells (i.e., silicon wafers), and backsheets, establishes a foundation for effectively reclaiming valuable resources from PV modules. Removing EVA encapsulation is critical for disassembling PV modules; nonetheless, effective and feasible technology is currently limited. Conventional EVA dissolving agents (e.g., benzene and trichloroethylene) are highly toxic and effective only for non-cross-linked segments of EVA. Thus, developing efficient and environmentally benign reagents for PV waste recycling is urgently needed. Herein, a novel recycling route employing deep eutectic solvents (DESs) with switchable hydrophilicity has achieved successful separation of the component layers within PV modules. Complete separation of the glass and backsheet bonded by the EVA film was achieved under atmospheric pressure and moderate temperature conditions (80 °C for 2 h) by hydrophobic DESs composed of menthol and decanoic acid ([Men][DecA] (1:1)). [Men][DecA] effectively induced EVA swelling, concurrently accelerating EVA dissolution by substituting the acetate groups in the side chains of EVA with the hydroxyl groups of the DES. The superior PV module disintegration can be attributed to the exceptional EVA dissolution ability of the [Men][DecA] framework, and the achieved high solid–liquid ratio (40 g/L) for EVA in [Men][DecA] is beneficial for industrial processes. Furthermore, the reusability of [Men][DecA], which is endorsed by its switchable hydrophilicity, introduces a sustainable platform for PV module disintegration, thereby facilitating the large-scale recycling of PV waste.

Correlative Microscopy Analysis for Battery Materials

Lithium batteries (LB) are in high demand for a diverse range of applications, such as automotive industry, consumer electronics, wearable and medical devices, grid storage, etc. Each application demands a specific set of performance advantages, such as high capacity and/or energy density, long cycle life, superior electrochemical stability. Therefore, there is no one-size-fits-all for a LB chemistry and its form factor. Battery performance advantages rely on optimization of the battery components, including active materials, electrolyte, separator, binder system, and current collectors. For meaningful device optimization, electrochemical battery testing needs to be combined with a deep understanding of the material and device microstructure. Physical and chemical characterization on the material- and electrode-level is needed to establish root-cause relationships with battery performance. Properties of the interfaces between layers of the battery components often define the device characteristics. Critical information is usually buried beneath the surface of a material specimen or encapsulated in a closed-form device. Microstructural defect identification in the battery needs to be followed by a targeted defect study. Different battery form factors and chemistries make it hard to streamline root-cause analysis.Recently, a commercial focused-ion beam scanning electron microscope was developed with an integrated fs-laser mill attached to the load lock of the microscope, opening the door to new and more powerful analysis approaches in energy materials research. Applications include rapid access to deeply buried structures for high resolution imaging and analytics, large area cross-section preparation, and massive material ablation for sample preparation of structures; e.g. FIB-SEM tomography, TEM, APT, or X-ray nanoCT. Additionally, each of these methods may be correlatively guided by prior imaging, with techniques like 3D X-ray microscopy (XRM), to enable targeted analysis and preparation. The non-destructive nature of 3D XRM makes it an ideal tool for microstructural defect identification in LB. Laser mill allows researchers to combine non-destructive X-ray defect identification with electron microscopy methods for targeted defect characterization. This approach can be used for various battery types and form factors.By combining the laser mill with 3D X-ray microscopy, this platform enables comprehensive analysis of energy materials at the nanoscale. We illustrate these concepts with application examples, and use cases demonstrating the utility of the approach.

Biomimetic design and integrated biofabrication of an in-vitro three-dimensional multi-scale multilayer cortical model

The lack of accurate and reliable in vitro brain models hinders the development of brain science and research on brain diseases. Owing to the complex structure of the brain tissue and its highly nonlinear characteristics, the construction of brain-like in vitro tissue models remains one of the most challenging research fields in the construction of living tissues. This study proposes a multi-scale design of a brain-like model with a biomimetic cortical structure, which includes the macroscopic structural features of six layers of different cellular components, as well as micrometer-scale continuous fiber structures running through all layers vertically. To achieve integrated biomanufacturing of such a complex multi-scale brain-like model, a multi-material composite printing/culturing integrated bioprinting platform was developed in-house by integrating cell-laden hydrogel ink direct writing printing and electrohydrodynamic fiber 3D printing technologies. Through integrated bioprinting, multi-scale models with different cellular components and fiber structural parameters were prepared to study the effects of macroscopic and microscopic structural features on the directionality of neural cells, as well as the interaction between glial cells and neurons within the tissue model in a three-dimensional manner. The results revealed that the manufactured in vitro biomimetic cortical model achieved morphological connections between the layers of neurons, reflecting the structure and cellular morphology of the natural cortex. Micrometer-scale (10 μm) cross-layer fibers effectively guided and controlled the extension length and direction of the neurites of surrounding neural cells but had no significant effect on the migration of neurons. In contrast, glial cells significantly promoted the migration of surrounding PC12 cells towards the glial layer but did not contribute to the extension of neurites. This study provides a basis for the design and manufacture of accurate brain-like models for the functionalization of neuronal tissues.

Exploring the thermomechanical and dynamical mode switch transition of a reversible solid oxide cell

Reversible solid oxide cells (r-SOCs) are regarded as a solution form of clean energy generation towards a green hydrogen energy transition. However, during transportation, installation, and operation, they are required to withstand dynamic conditions as they face thermal, mechanical, and vibrational effects. Assessing the interplay of the thermomechanical and dynamical impacts on r-SOC materials during the mode-switch from electrolysis to fuel cell operation is the subject of this current comprehensive study. Advanced FEM-based homogenisation techniques have been harnessed in predicting and evaluating the detailed transients during static and dynamic loading. The intricate 3D thermal profiles throughout the transient reversible dual-modus operation from a typical r-SOC study have been derived using advanced image processing. Orthotropic material properties were incorporated into a unified macroscopic scale model by deriving the complex 3D microstructure geometry characteristics of the cell materials and component layers. The comprehensive thermomechanical and pre-stressed modal analysis results showed that the static and dynamic forces in fuel cell mode are more pronounced, whereas, in electrolysis operation, the dynamical behaviour highly depends on geometrical and operating conditions. Smaller component size shows higher natural frequencies and more intense vibration, leading to higher deformation attributed to complex mode shapes and reduced flexural rigidity. These insights are essential for optimizing r-SOC design parameters, enhancing their dynamic and structural reliability throughout their dual-mode operation lifespan.

Interfacial behavior and damage mechanism of Al-B4C/Al laminated composites under ballistic impact

The present study involved the fabrication of Al-B4C/Al laminated composites with a strong bonding interface using an integrated (or one-step) hot-pressed sintering method followed by hot rolling. A comprehensive analysis of the mechanical properties and interface behavior of Al-B4C/Al laminated composites under various loading conditions, particularly focusing on ballistic impact. Findings indicate that the laminated composite exhibits a high-strength interface bonding (greater than 318 MPa) facilitated by the continuous Al matrix, with no interlayer delamination occurring even after Charpy impact failure and ballistic penetration. The integrated interface promotes coordinate deformation between different component layers, enhancing the comprehensive mechanical performance of the Al-B4C/Al laminated composites. Moreover, the integrate interface of the Al-B4C/Al laminated plate enables a higher absorption of impact energy from projectiles, increasing by 10% and 70% compared to the monolithic and unbonded stacked plates, respectively.

Optimized mechanical properties of the hot forged Ti–6Al–4V alloy by regulating multiscale microstructure via laser shock peening

The hot forged Ti–6Al–4V alloy demonstrates well constructed microstructure and balanced mechanical properties, which promotes its wide application in aviation field. However, its relative poor resistance to wear and foreign object impact usually leads to the cumulative damage, causing sudden failure and serious accident. Laser shock peening (LSP) is a novel surface plastic deformation technique, which could strengthen the surface layer of components through gradient grain structure. Nevertheless, the specific mechanism of microstructure evolution and mechanical properties enhancement of LSP processed hot forged Ti–6Al–4V alloy is still obscure, and its corresponding explanation would help the wide application. In the present research, the hot forged Ti–6Al–4V alloy was processed by LSP to regulate its superficial microstructure and improve mechanical properties, helping to understand the inner mechanism. The results reveal that LSP could simultaneously result in the merging of ultrafine α-Ti grains and refinement of coarse α-Ti grains, which reconstruct the dual-size grain structure. The crystal tilting and transformation promoted by the generation and movement of dislocations benefit the merging of ultrafine grains. Due to the different slip systems in dual phases, β-Ti phases exhibit much greater response to slip under surface plastic deformation, which are enforced to deform and construct the shell structure by sliding and phase transformation, while the α-Ti phases act as the core to synergistically construct ‘core-shell’ like structure. The increase of LSP impact time promotes the well wrapping of the ‘core-shell’ like structure and strengthens it by abundant dislocations, which also forms the gradient grain structure from surface to inner. Since the microstructure regulation and crystal defects engineering, the LSP improves the surface damage resistance and mechanical properties of the hot forged Ti–6Al–4V alloy obviously. Such results indicate a new technology to increase the properties of the hot forged Ti–6Al–4V alloy component further.

Adapted Design Process for Continuous Fiber-Reinforced Additive Manufacturing-A Methodological Framework.

Continuous fiber-reinforced material extrusion is an emerging additive manufacturing process that builds components layer by layer by extruding a continuous fiber-reinforced thermoplastic strand. This novel manufacturing process combines the benefits of additive manufacturing with the mechanical properties and lightweight potential of composite materials, making it a promising approach for creating high-strength end products. The field of design for additive manufacturing has developed to provide suitable methods and tools for such emerging processes. However, continuous fiber-reinforced material extrusion, as a relatively new technology, has not been extensively explored in this context. Designing components for this process requires considering both restrictive and opportunistic aspects, such as extreme anisotropy and opportunities for functional integration. Existing process models and methods do not adequately address these specific needs. To bridge this gap, a tailored methodology for designing continuous fiber-reinforced material extrusion is proposed, building on established process models. This includes developing process-specific methods and integrating them into the process model, such as a process selection analysis to assess the suitability of the method and a decision model for selecting the process for highly stressed components. Additionally, a detailed design process tailored to continuous fiber-reinforced material extrusion is presented. The application of the developed process model is demonstrated through a case study.

Enhanced strength-ductility synergy in pure Cu through the design of alternating coarse-grained and nanostructured layers

Heterogeneous micro/nano laminated structure (HM/NLS) design has emerged as a promising strategy for circumventing the strength-ductility trade-offs in nanostructured metals. However, most of reported HM/NLSed metals are mainly prepared from two dissimilar metals, which make it challenging to fully understand the deformation mechanisms of HM/NLS due to the complicated coupling of microstructural and compositional difference between component layers. Here, a series of HM/NLSs, consisting of alternating coarse-grained (CGed) and nanostructured (NSed) layers with varied thickness ratio (RCGed/NSed) of CGed layers to NSed layers, have been designed and introduced into pure Cu, which aim to exclude the influence of compositional difference between component layers and investigate the effect of microstructural difference on the deformational behavior of HM/NLSed metals independently. The effects of RCGed/NSed on the mechanical property of HM/NLSed Cu were investigated and an optimized strength-ductility synergy was achieve when RCGed/NSed = 2:3. Loading-unloading-reloading tests and in situ EBSD characterization reveal that the huge microstructural discrepancy between the neighboring CGed and NSed layers promotes dislocations accumulation and produces strong back stress strengthening during plastic deformation, thereby achieving a high yield strength ∼296 MPa and large uniform elongation of ∼18%. The results of this work will provide a viable approach for fabricating high-performance HM/NLSed metals and deepen the understanding of the underlying deformation mechanisms of HM/NLSed metals.

Influence of interface on deformation compatibility of a heterogeneous Cu/Al nanoscale multilayer

The incompatible deformation among the constituent layers usually results in extremely low tensile ductility in nanoscale metallic multilayers. Here, molecular dynamics simulations are conducted to investigate the deformation compatibility of a heterogeneous Cu/Al multilayer with various interface structures under compression. The results show that, by selecting an appropriate thickness of thin interlayers, the heterogeneous Cu/Al nanolayered composite with (1¯1¯1) interface exhibits excellent compatible deformation between the soft and hard layers while the homogeneous counterpart does not. The excellent deformation compatibility of the heterogeneous structure originates from the presence of the thin soft interlayer that can enhance the dislocation activities of the hard layers. Unlike that with (1¯1¯1) interface, the heterogeneous structure with (001) interface shows obvious incompatible deformation among the component layers. Such a scenario can be attributed to the stable dislocation network on the (001) interface, making the dislocations in the soft phase difficult to cross the interface into the hard phase. These findings may deepen our understanding of the deformation compatibility of heterogeneous nanoscale metallic multilayers.

Image reconstruction based on TV-L1 model for planar array capacitance defect detection

Planar array capacitive imaging is an emerging nondestructive testing (NDT) technology with broad application prospects. The severe ill-posed inverse problem of planar array capacitive imaging reduces quality of reconstructed images. In this paper, a total variation regularization model with an L1-norm (TV-L1 model) of 3 × 4 planar array capacitance imaging is established for imaging the defects detected in the inner layers of multi-layer composite components. Considering the solution instability caused by the non-differentiability of the TV-L1 model, a variable splitting self-adaptive augmented Lagrange alternating direction algorithm (VS-SALAD) is proposed. An augmented Lagrange method enhances model splitability, and a series of subproblems are obtained by variable splitting operation. The subproblems are solved iteratively using alternating minimization method with self-adaptive penalty parameter. Experimental results demonstrate that TV-L1 model effectively alleviates the ill-posed problem, and the proposed algorithm significantly improves both the quality of reconstructed images and solving speed of the TV-L1 model.

Large Field-like Spin-Orbit Torque and Enhanced Magnetization Switching Efficiency Utilizing Amorphous Mo.

Spin-orbit torque magnetic random access memory (SOT-MRAM) has great promise in high write speed and low power consumption. Mo can play a vital role in constructing a CoFeB/MgO-based MRAM cell because of its ability to enhance the perpendicular magnetic anisotropy (PMA), thermal tolerance, and tunneling magnetoresistance. However, Mo is often considered as a less favorable candidate among SOT materials because of its weak spin-orbit coupling. In this study, we experimentally investigate the SOT efficiencies in Mo/CoFeB/MgO heterostructures over a wide range of Mo thicknesses and temperature. Decent damping-like SOT efficiency |ξDL| = 0.015 ± 0.001 and field-like SOT efficiency |ξFL| = 0.050 ± 0.001 are found in amorphous Mo. The ξFL/ξDL ratio is greater than 3. Furthermore, efficient current-induced magnetization switching is demonstrated with the critical current density comparable with heavy metal Ir and W. Our work reveals new understanding and possibilities for Mo as both an SOT source component and PMA buffer layer in the implementation of SOT-MRAMs.

Optimization of Magnetic Tunnel Junction Structure through Component Analysis and Deposition Parameters Adjustment.

In this work, we focus on a detailed study of the role of each component layer in the multilayer structure of a magnetic tunnel junction (MTJ) as well as the analysis of the effects that the deposition parameters of the thin films have on the performance of the structure. Various techniques including atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to investigate the effects of deposition parameters on the surface roughness and thickness of individual layers within the MTJ structure. Furthermore, this study investigates the influence of thin films thickness on the magnetoresistive properties of the MTJ structure, focusing on the free ferromagnetic layer and the barrier layer (MgO). Through systematic analysis and optimization of the deposition parameters, this study demonstrates a significant improvement in the tunnel magnetoresistance (TMR) of the MTJ structure of 10% on average, highlighting the importance of precise control over thin films properties for enhancing device performance.