Search

The induced Pt magnetization in a Pt/Co/Pt thin film structure is studied. The normally nonmagnetic Pt acquires a magnetic moment due to the magnetic proximity effect at the Co–Pt interfaces. Element specific Pt structural and magnetic properties are characterized by synchrotron-based resonant x-ray reflectivity and x-ray resonant magnetic reflectivity measurements. An advanced analysis method based on Bayesian inference is used for model fitting of the x-ray data. Using this method, we retrieve the best fit values of material parameters (e.g., thickness, interfacial roughness) from the data. Analysis of x-ray reflectivity data of this specific system shows that the Pt magnetization and Co–Pt interfacial roughness is significantly different between the top and bottom Pt layers, with both values being larger in the top Pt. The successful application of this Bayesian method to study the magnetic and structural properties of a thin film system demonstrates its effectiveness for x-ray reflectivity data analysis.

The vapour etching of silicon sacrificial layers is often a critical process in the fabrication of micro/nanosystems. This method has a number of attractive features, in particular, high etch rates of sacrificial silicon layers and good selectivities associated with photoresist, SiO2, stoichiometric Si3N4 and a number of regularly used metal films. However, materials that are commonly inert to XeF2 are etched when located in the proximity of a silicon sacrificial layer. This proximity is a common situation in the fabrication of such systems and can become a critical issue affecting process control and device reliability. This work uses test structures that have been designed to be very sensitive, thereby delivering much lower selectivities then are typically reported in the literature. This sensitive quantification of the proximity effect is used to evaluate methods designed to improve the selectivity. This work suggests that a reduction in the processing temperature from 25°C to 10°C increases the Si: PECVD SiN selectivity by 68%. However, a more easily implemented modification is to flow hydrogen into the reaction chamber. This method improves the Si: PECVD SiN selectivity by an order of magnitude and the Si: LPCVD SiN selectivity between 200% and 600%. [2020-0346]

Previous studies on the forward problem of magnetic induction tomography (MIT) have used simplified Maxwell's equations which assume a constant and position-independent total current density (TCD) inside the coils (ignoring skin effect). Moreover, they assume that TCD is independent of relative position of the coils (ignoring proximity effect). This article presents an improved finite element (FE) modeling for the two-dimensional (2D) forward problem of MIT by incorporating skin and proximity effects in the exciter and sensor coils. Consideration of skin and proximity effects requires the use of a position-dependent TCD in Maxwell's equations inside the coil domain. The FE method implementation of the improved forward method is validated with a simple analytical test problem. To evaluate the performance of the improved method in possible medical and industrial applications with low conductivity regions, a 16 coils 2D MIT system is modeled and the FE method is employed to solve the forward problem using a synthetic phantom. Results show the difference between the real parts of induced voltages obtained from the early and improved method falls into the range which is meaningful in terms of achievable conductivity contrast from the improved one. This discrepancy can generate considerable errors in image reconstruction. By considering skin and proximity effects, the improved method generates lower voltages in the coils suggesting the use of more precise hardware to detect inclusion. Findings show the importance and necessity of using improved method for modeling 2D MIT coils especially at low conductivity applications where measured signals are inherently weak.

In this paper, an efficient adaptive cross approximation (ACA) method is employed for the skin effect and proximity effect analysis. Multi-layer stranded cables with multiple strands and different materials are used for analysis to approximate the effect. The skin and proximity matrices are computed by the ACA low-rank matrix approximation technique. The ACA method can provide better solutions through different iterations. The ACA algorithm is very stable and useful for calculating a low rank matrix approximation, because the adaptive mesh refinement for generating optimal computation. The ACA approach provides the less computational memory and less CPU time. Compare the calculated results with standard work results (such as reference) to verify the effectiveness of the adaptive cross-approximation algorithm.

Superconducting electronics are promising candidates for complementing semiconductor electronics. However, a comprehensive suite of superconducting design and simulation tools that is necessary to streamline and automate the design process is either nonexistent or very limited. Here, we describe Synopsys' advances in the technology computer-aided design (TCAD) front for physics-based simulation of superconducting electronics based on Josephson junctions (JJs). We employ Keldysh-Gor'kov-Nambu Green's function formalism within the context of the self-consistent mean-field theory of Bogoliubov and de-Gennes to simulate the equilibrium and transport properties of JJ-based devices in one dimension. Using these Green's functions, we calculate various electrical properties and effects, including order parameter and proximity effect, current-phase characteristics and current-density distribution for arbitrary temperatures, material properties and composition, and device dimensions. We further expand the TCAD simulator using the Floquet-Keldysh-Gor'kov-Nambu Green's function for calculating current-voltage characteristics of JJs in nonequilibrium and capture various quantum mechanical effects including multiple Andreev reflections (MAR) for constant applied voltage.

We investigate the sedimentation of colloidal micro-spheres and red blood cells (RBCs) in non-Newtonian fluid - silicone oil with different viscosities. We use digital holographic microscopy (DHM) to obtain volumetric information of the sedimenting micro-objects. Especially, the numerical refocusing feature of DHM is used to extract the depth information of multiple particles moving inside the fluid. The effects of proximity to a flat wall and the non-Newtonian behavior on the sedimenting micro-spheres and RBCs are studied by trajectory analyzing and velocimetry. We observe that for lower viscosity values the proximity effect is more pronounced. The variation rate of the particle falling velocities versus their distance to the flat wall decreases by increasing the viscosity of the fluid. For RBCs, however, the decreasing of the velocity variations have a smoother trend. The experimental results verify the theoretical prediction that, similar to Newtonian case, a correction factor in Stokes’ law suffices for describing the wall effect.

With the construction of a large number of hydropower stations, transmission lines crossing a river and urban utility tunnels, gas insulated transmission line (GIL) has been applied widely due to its large transmission capacity, low environmental impact and high reliability. Accurate modelling of physical quantities and their characteristics of GIL provides a theoretical basis for its design and operation, which is of great significance to ensure the safety and reliability of GIL operation. The mathematical model and their relationship of GIL multi-physical fields are analyzed at first, upon which simulation model of GIL is built. Secondly, multi-physical coupling field model of electric, magnetic, thermal, fluid and stress field for GIL is studied, while simulation results are basically in consistent with experimental data to verify effectiveness of the model. Thirdly, distribution of multi-physical fields and their relationship are simulated and analyzed, while proximity effect, edge effect and compression factor of GIL multi-physical field are discussed. The results show that the radial temperature inside GIL is higher at the top, lower at the bottom, leading to uneven distribution of thermal expansion displacement, while the axial temperature distribution is basically uniform, which falls firstly and then rises near basin insulator thus results in edge effect. Proximity effect leads to asymmetric distribution and a slight increase of temperature inside GIL as well as a dramatic increase of air velocity around GIL. In addition, when ambient temperature is lower than -5 °C, the compression factor is much lower than 1 and the effect of compression factor should be considered in simulation.

Ferromagnetic (FM) electrocatalysts have been demonstrated to reduce the kinetic barrier of oxygen evolution reaction (OER) by spin-dependent kinetics and thus enhance the efficiency fundamentally. Accordingly, FM two-dimensional (2D) materials with unique physicochemical properties are expected to be promising oxygen-evolution catalysts; however, related research is yet to be reported due to their air-instabilities and low Curie temperatures (TC). Here, based on the synthesis of 2D air-stable FM Cr2Te3 nanosheets with a low TC around 200 K, room-temperature ferromagnetism is achieved in Cr2Te3 by proximity to an antiferromagnetic (AFM) CrOOH, demonstrating the accomplishment of long-ranged FM ordering in Cr2Te3 because the magnetic proximity effect stems from paramagnetic (PM)/AFM heterostructure. Therefore, the OER performance can be permanently promoted (without applied magnetic field due to nonvolatile nature of spin) after magnetization. This work demonstrates that a representative PM/AFM 2D heterostructure, Cr2Te3/CrOOH, is expected to be a high-efficient magnetic heterostructure catalysts for oxygen-evolution.

In focused ion beam (FIB) fabrication process, the scan method is seldom cared about. the choice of scan method can make a difference in the microstructure. In this paper, a proximity effect that is caused by the scan strategy is observed. In order to control the proximity effect, the model of this phenomenon needs to be clarified. To this end, this study proposed a numerical model considering the scan method and dwell time. By catching the transient profile in the fabrication process, a new incident angle relating to the scan method and dwell time is gained, with which the model is expected to estimate the size of the effect. In reality, the calculation results show a good match with experiments of crossed rectangles. Based on the model, we successfully fabricate a slightly complicated but controllable structure that has application prospects in the optical area.

Higher-order topological insulators (HOTIs), with topological corner or hinge states, have emerged as a thriving topic in the field of topological physics. However, few connections have been found for HOTIs with well-explored first-order topological insulators. Recently a proposal asserted that a significant bridge can be established between the HOTIs and Z 2 topological insulators. When subjected to an in-plane Zeeman field, corner states, the signature of the HOTIs, can be induced in a Z 2 topological insulator. Such Zeeman fields can be produced, for example, by the ferromagnetic proximity effect or magnetic atom doping, which drastically increases the experimental complexity. Here, we show that a phononic crystal, designed as a bilayer of coupled acoustic cavities, exactly hosts the Kane-Mele model with built-in in-plane Zeeman fields. The helical edge states along the zigzag edges are gapped, and the corner states, localized spatially at the corners of the samples, appear in the gap. This verifies the Zeeman field induced higher-order topology. We further demonstrate the intriguing contrast properties of the corner states at the outer and inner corners in a hexagonal ring-shaped sample.

We experimentally observed an ultrahigh blocking temperature, above 600 K, in an exchange-biased Fe/FeO bilayer after field annealing at 773 K. This is far above the 198 K N\'eel temperature of bulk FeO. By comparing with an Fe/FeO/Fe trilayer and studying the Fe thickness dependence, we find that the magnetic proximity effect, due to coupling between the Fe layer and the ultrathin amorphous FeO layer, is responsible for the high blocking temperature. The realization of high-temperature exchange bias using an ultrathin antiferromagnet paves the way to further miniaturize magnetic devices for high-information-density applications.

Topological insulators (TIs) provide intriguing prospects for the future of spintronics due to their large spin-orbit coupling and dissipationless, counter-propagating conduction channels in the surface state. The combination of topological properties and magnetic order can lead to new quantum states including the quantum anomalous Hall effect that was first experimentally realized in Cr-doped (Bi,Sb)2 Te3 films. Since magnetic doping can introduce detrimental effects, requiring very low operational temperatures, alternative approaches are explored. Proximity coupling to magnetically ordered systems is an obvious option, with the prospect to raise the temperature for observing the various quantum effects. Here, an overview of proximity coupling and interfacial effects in TI heterostructures is presented, which provides a versatile materials platform for tuning the magnetic and topological properties of these exciting materials. An introduction is first given to the heterostructure growth by molecular beam epitaxy and suitable structural, electronic, and magnetic characterization techniques. Going beyond transition-metal-doped and undoped TI heterostructures, examples of heterostructures are discussed, including rare-earth-doped TIs, magnetic insulators, and antiferromagnets, which lead to exotic phenomena such as skyrmions and exchange bias. Finally, an outlook on novel heterostructures such as intrinsic magnetic TIs and systems including 2D materials is given.

Ferromagnetic insulators are widely employed to induce magnetic phenomena in adjacent layers via proximity effect. This approach could make non-magnetic materials (ranging from silicon to graphene) available for spintronic applications. Eu chalcogenides, EuO in particular, are highly efficient spin generators but suffer from low Curie temperatures. Here, experiments aimed at TC increase in EuO by its integration with the ferromagnetic metal Gd are reported. The epitaxial bilayers Gd/EuO are synthesized on different substrates and characterized by a combination of diffraction and microscopy techniques. Their magnetic structure – established with magnetization and transport measurements as well as element-selective X-ray magnetic circular dichroism study – comprises coupled magnetic orders of EuO and Gd. EuO is robust against proximity effects – its TC is still low, increased at most by a few tens of K. Nevertheless, the results encourage further studies of proximity-enhanced ferromagnetism to extend the range of applications of ultrathin layers of EuO in spintronics.

The effect of the thicknesses of Pt and the insertion of Al layer on the effective magnetic damping constant of CoFeB/Pt thin films caused by the spin-pumping effect has been studied by an angular-dependent ferromagnetic resonance method. In CoFeB/Pt bilayers, a roughly linear dependence of the effective damping constant on Pt thickness ( $t{\mathbf {Pt}}$ ) was observed before saturated at $t_{\mathbf {Pt}} = 2$ nm. While in CoFeB/Al/Pt trilayers, a sharp drop of damping constant was observed while Al thickness is around 0.5 nm, then the damping constant nearly remains when Al thickness further increases to 5 nm. It indicates a decreased spin pumping efficiency due to Al insertion between CoFeB and Pt layers. The decreased spin pumping efficiency was ascribed to the spin memory loss at CoFeB/Al and/or Al/Pt interfaces rather than the spin backflow effect. The results also suggest that the linearly increased damping constant in CoFeB/Pt layers mainly comes from the magnetic proximity effect (MPE) of Pt, which could be eliminated by insertion a thin layer of Al. However, in order to obtain a large-spin current injection efficiency and less MPE to improve the spin-pumping effect in CoFeB/Pt, a proper insertion layer rather than Al with small-spin memory loss need to be investigated.

In this paper, a broadband closed-form expression for the parasitic inductance of Through-X Vias (TXVs) with a frequency up to 100 GHz is proposed. The rigorous formulas related to the geometrical parameters are derived considering the proximity effect and the skin effect. The proposed model can accurately reflect the change in inductance caused by magnetic flux variation at high frequency. The inductance model is verified by comparing with the 3-D full-wave electromagnetic solver High Frequency Simulator Structure (HFSS) in whole frequency range considered. The proposed model and HFSS results show accordance with each other over large radius range, with a maximum error of 4.6%.

Accurate and reliable models can support Through Silicon Via (TSV) testing methods and improve the quality of 3D ICs. A model for expressing resistance and inductance of TSVs at frequencies...

The biaxial strain effect on the electronic structure and valleytronic properties, such as valley splitting and Berry curvature, of monolayer MoS2 induced by the magnetic proximity effect of an antiferromagnetic CoO(111) substrate is investigated by density functional theory. The biaxial tensile strain could continually tune the magnitude of spin and valley splitting of the MoS2/CoO(111) heterostructure, because the spin splitting at the K and K' valleys decreases, whereas the valley splitting increases slightly in the tensile strain range of 0-6%. The ferromagnetic order of MoS2 in the heterostructure induced by the magnetic CoO substrate is retained under a biaxial tensile strain of 2% to 6% compared with the unstrained case. In particular, the intensity of the exchange field due to the magnetic proximity effect of CoO weakens monotonously with biaxial tensile strain increasing from 0% to 6%, thereby also leading to a monotonous reduction of the Berry curvature. The regulation of valley splitting and Berry curvature by biaxial tensile strain will provide the MoS2/CoO(111) heterostructure with high potential in future valleytronic applications.

Heterojunctions between two crystalline semiconductor layers or regions can always lead to engineering the electronic energy bands in various devices, including transistors, solar cells, lasers, and organic electronic devices. The performance of these heterojunction devices depends crucially on the band alignments and their bending at the interfaces, which have been investigated for years according to Anderson’s rule, Schottky-Mott rule, Lindhard theory, quantum capacitance, and so on. Here, we demonstrate that by engineering two different acoustic waveguides with forbidden bands, one can achieve an acoustic heterojunction with an extraordinary transmission peak arising in the middle of the former gaps. We experimentally reveal that such a transmission is spatially dependent and disappears for a special junction structure. The junction proximity effect has been realized by manipulating the acoustic impedance ratios, which have been proven to be related to the geometrical (Zak) phases of the bulk bands. Acoustic heterojunctions bring the concepts of quantum physics into the classical waves and the macroscopic scale, opening up the investigations of phononic, photonic, and microwave innovation devices.

The influences of proximity effect and complex dielectric permittivity on per-unit-length parameter matrices of three-core power line are analyzed. Based on the symmetrical structure of three-core cable, the per-unit-length parameter matrices are decomposed into common mode and differential mode parameters by phase-mode transformation. Taking the electromagnetic simulation results of finite element method as the initial values, a method of correcting per-unit-length parameters based on open-circuit impedance measurement in mode domain is proposed. Based on the theory of multi-conductor transmission line, the channel model of three-core power line in the frequency range from 30 kHz up to 15 MHz is established. The test results under the branch network show that the channel model has high accuracy, and the influence of the network structure on the impedance and transmission characteristics is further analyzed. The model can accurately take into account the coupling effect between multiple-input multiple-output channels.

A broadband Foster-type circuit model for skin and proximity effect in arbitrarily shaped parallel conductors is presented. Based on a quasi-static partial element equivalent circuit approach, a modal multiport circuit is derived with a minimal computational effort, offering fast convergence and inherent stability for time-domain simulations with arbitrary active/passive nonlinear loads. The model order can be estimated rigorously for a given frequency range. The proposed model is validated in the frequency and time domain.

Controlling the optical response of two-dimensional (2D) layered materials is critical for their optoelectronic and photonic applications. Current transient optical modulation of 2D semiconductors is mainly based on the band filling effect, which requires internal exciton/charge occupation from photoexcitation or charge injection. However, 2D atomically thin layers exhibit a strong excitonic effect and environmental sensitivity, offering exciting opportunities to engineer their optical properties through an external dielectric or electronic environment. Here, using femtosecond transient absorption spectroscopy as a tool and transition-metal dichalcogenide (TMD) van der Waals heterostructures with type I band alignment, we show the transient absorption modulation of the TMD layer by excitons at ultimate proximity without direct photoexcitation or exciton/charge occupation. Further layer-dependent study indicates the presence of excitons reduces the exciton oscillator strength in adjacent layers through the electric field effect because of environmental sensitivity and proximity of 2D materials. This result demonstrates the transient optical modulation with decoupled light absorption and modulation components and suggests an alternative approach to control the optical response of 2D materials for optoelectronic and photonic applications.

Holographic displays and computer-generated holography offer a unique opportunity in improving optical resolutions and depth characteristics of near-eye displays. The thermally-modulated Nanopho-tonic Phased Array (NPA), a new type of holographic display, affords several advantages, including integrated light source and higher refresh rates, over other holographic display technologies. However, the thermal phase modulation of the NPA makes it susceptible to the thermal proximity effect where heating one pixel affects the temperature of nearby pixels. Proximity effect correction (PEC) methods have been proposed for 2D Fourier holograms in the far field but not for Fresnel holograms at user-specified depths. Here we extend an existing PEC method for the NPA to Fresnel holograms with phase-only hologram optimization and validate it through computational simulations. Our method is not only effective in correcting the proximity effect for the Fresnel holograms of 2D images at desired depths but can also leverage the fast refresh rate of the NPA todisplay 3D scenes with time-division multiplexing.

We consider a quantum dot weakly tunnel coupled to superconducting reservoirs. A finite superconducting pair amplitude can be induced on the dot via the proximity effect. We investigate the dynamics of the induced pair amplitude after a quench and under periodic driving of the system by means of a real-time diagrammatic approach. We find that the quench dynamics is dominated by an exponential decay towards equilibrium In contrast, the periodically driven system can sustain coherent oscillations of both the amplitude and the phase of the induced pair amplitude in analogy to Higgs and Nambu-Goldstone modes in driven bulk superconductors., Comment: 11 pages, 7 figures

We have studied the effects of optical-frequency light on proximitized InAs/Al Josephson junctions based on highly n-doped InAs nanowires at varying incident photon flux and at three different photon wavelengths. The experimentally obtained IV curves were modeled using a resistively shunted junction model which takes scattering at the contact interfaces into account. Despite the fact that the InAs weak link is photosensitive, the Josephson junctions were found to be surprisingly robust, interacting with the incident radiation only through heating, whereas above the critical current our devices showed non-thermal effects resulting from photon exposure. Our work indicates that Josephson junctions based on highly-doped InAs nanowires can be integrated in close proximity to photonic circuits. The results also suggest that such junctions can be used for optical-frequency photon detection through thermal processes by measuring a shift in critical current.

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. In (Pt/Co)n/FeMnmultilayers, the magnitude of exchange bias,HE, can be considerably enhanced by placing an ultrathin nonmagnetic Pt spacer between the multilayer (ML) and the antiferromagnetic(AFM) layer. The bias is maximum for a spacer layer thickness, t, of a few angstroms and it decreases progressively as t is further increased. This bias enhancement is accompanied by an increase of coercivity,HC. This behavior is due to the role of the Pt spacer in enhancing the perpendicular effective anisotropy of the last Co layer in the ML, which has the effect of increasing the net ferromagnetic (FM)/AFM spin projection, thus leading to the HE and HC enhancements. The decrease of HE and HC for thicker spacer layers is due to the limited range of the FM-AFM proximity effect.

In-plane anisotropy (IPA) refers to in-plane angle-dependent properties defined by asymmetric structure, which renders an additional control for precise modulation of properties. In contrast, most known materials are of isotropic structure without obvious IPA. Thus, the introduction of anisotropy into isotropic materials, integrating the merits of both, is becoming an interesting and worthwhile area of study. Herein, we demonstrate experimentally the spread of IPA from anisotropic ReS2 to isotropic cubic CsPbBr3 (CPB) based on epitaxially grown CPB/ReS2 heterostructures. Angle-resolved photoluminescence (PL) spectra reveal that the PL pattern of the CPB single crystal evolves from an individual isotropic round shape into an anisotropic dumb-bell shape, with its polar axis oriented along the b-axis of ReS2 beneath CPB in heterostructures, indicating a significant substrate-induced optical isotropy–anisotropy transition. This study verifies the feasibility of spreading IPA with proximity effects in ultrathin heterostructures, extending the applications of intrinsic isotropic two-dimensional materials in angle-dependent fields.

We report the analog simulation of an ergodic-localized junction by using an array of 12 coupled superconducting qubits. To perform the simulation, we fabricated a superconducting quantum processor that is divided into two domains: one is a driven domain representing an ergodic system, while the second is localized under the effect of disorder. Because of the overlap between localized and delocalized states, for a small disorder there is a proximity effect and localization is destroyed. To experimentally investigate this, we prepare a microwave excitation in the driven domain and explore how deep it can penetrate the disordered region by probing its dynamics. Furthermore, we perform an ensemble average over 50 realizations of disorder, which clearly shows the proximity effect. Our work opens a new avenue to build quantum simulators of driven-disordered systems with applications in condensed matter physics and material science.

The manipulation of valley splitting has potential applications in valleytronics, which lacks in pristine two-dimensional (2D) InSe. Here, we demonstrate that valley physics in InSe can be activated via the magnetic proximity effect exerted by ferromagnetic FeI2 substrate with spin-orbit coupling. The valley splitting energy can reach 48 meV, corresponding to a magnetic exchange field of ~800 T. The system also presents magnetic anisotropy behavior with its easy magnetization axis tunable from in-plane to out-of-plane by the stacking configurations and biaxial tensile strain. The d-orbital-resolved magnetic anisotropic energy contributions indicate that the tensile strain effect arises from the increase of hybridization between minority Fe dxy and dx2&minus, y2 states. Our results reveal that the magnetic proximity effect is an effective approach to stimulate the valley properties in InSe to extend its spintronic applications, which is expected to be feasible in other group-III monochalcogenides.

The introduction of Extremely Ultra-Violet (EUV) lithography in the photolithographic process can simplify process flow at 7 nm or more advanced technology nodes, which includes good linewidth and overlay budget control and reduction of hard mask layers. In a typical 5 nm logic process, the Contact-Poly Pitch (CPP) is 44–50 nm, the Minimum Metal Pitch (MPP) is 30–32 nm. And the overlay budget is estimated to be 2.5 nm (On Product Overlay, OPO). We have studied the process window of the 5 nm lithographic process with a self-developed RCWA algorithm based EUV simulation program and will present our results on process window and defectivity.

A comprehensive mathematical model of electroslag remelting with two series-connected electrodes (TSCE-ESR) was constructed based on sequential coupling method. The influence of droplet effect on electroslag remelting process (ESR) was considered in this model. Compared with one-electrode electroslag remelting (OE-ESR), the multi-physics field, droplet formation and dripping behavior, and molten metal pool structure of TSCE-ESR process were studied. The results show that during the process of TSCE-ESR, the proximity effect of the electrodes suppresses the skin effect, and Joule heat is concentrated in the area between the two electrodes of slag pool, making the temperature distribution of the slag pool more uniform. The heat used to melt the electrode in the process of TSCE-ESR accounts for about 34% of the total Joule heat, which is lower than the OE-ESR (17%). Therefore, it makes a higher melting rate and a smaller droplet size in the process of TSCE-ESR. Compared with OE-ESR, TSCE-ESR process can realize the unification of higher melting rate and shallow flat molten metal pool. Compared with the results without droplet effect, it is found that in the simulation results with droplet effect, the depth and the cylindrical section of molten metal pool increased, and the width of the mushy zone is significantly reduced, which is more consistent with the actual electroslag remelting process.

Self-heating effect (SHE, ∆T sh ) has become a significant concern for device performance, variability and reliability co-optimization due to more confined layout geometry and lower-thermal-conductivity materials adopted in advanced technology, which substantially impacts on the integrated circuit (IC)’s design schemes. In this work, a new heat-dissipation-path based SHE model is proposed to describe the heat spreading to layout proximity by interactive thermal resistance (R th(i,j) ). Meanwhile, R th -matrix methodology is employed to account for SHE layout proximity effect by linear superposition algorithm. Therefore, ∆T sh profile can be more accurately reckoned with account for thermal interaction effect.

Insight into quasar ages may be obtained from the proximity effect, but so far only in a limited number of bright quasars. Based on ~2600 SDSS quasar spectra at 2.5 ~ 10 Mpc. Their composite spectrum displays strong narrow cores and large equivalent widths in Ly-alpha and other major UV emission lines. If the proximity zones along lines of sight are indicative of quasar ages, these features may be the signatures of old quasars. Another group of quasars are selected as they show no proximity zone and exhibit intrinsic absorption lines at z_{ab} > z_{em}. They are likely young quasars and exhibit weaker narrow emission-line components. The significant difference of spectral features between the two groups may reflect an evolution pattern over quasars' lifetimes., 22 pages, 10 figures, 3 tables

We study the impact of relativistic effects in the 3-dimensional cross-correlation between Lyman-$\alpha$ forest and quasars. Apart from the relativistic effects, which are dominated by the Doppler contribution, several systematic effects are also included in our analysis (intervening metals, unidentified high column density systems, transverse proximity effect and effect of the UV fluctuations). We compute the signal-to-noise ratio for the Baryonic Oscillation Spectroscopic Survey (BOSS), the extended Baryonic Oscillation Spectroscopic Survey (eBOSS) and the Dark Energy Spectroscopic Instrument (DESI) surveys, showing that DESI will be able to detect the Doppler contribution in a Large Scale Structure (LSS) survey for the first time, with a S/N $>7$ for $r_{\rm min} > 10$ Mpc$/h$, where r$_{\rm min}$ denotes the minimum comoving separation between sources. We demonstrate that several physical parameters, introduced to provide a full modelling of the cross-correlation function, are affected by the Doppler contribution. By using a Fisher matrix approach, we establish that if the Doppler contribution is neglected in the data analysis, the derived parameters will be shifted by a non-negligible amount for the upcoming surveys., Comment: 22 pages, 10 figures; added appendix on lensing; version matches one published in JCAP

International audience; This paper mainly discusses the fabrication and characterization of proximity-coupled Al/Au bilayer kinetic inductance detectors (KIDs). The proximity effect is used to optimize the critical temperature of the superconducting film and to increase the kinetic inductance fraction of the film. An Al/Au bilayer with thickness equal to 30 nm and 10 nm, respectively, is evaporated on a silicon substrate. The KIDs are cooled down to about 90 mK in an adiabatic demagnetization refrigerator. The measured average internal quality factor of the resonances is around 27,000. The critical temperature is 0.8 K, and the kinetic inductance is estimated to be about 2 ${\text{pH}}/\square$. The minimum detectable frequency of the chip is estimated to be about 60 GHz. The critical temperature can be further tuned by optimizing the thickness of the aluminum and gold films. The proximity-coupled Al/Au KIDs represent an appealing detector technology for photon detection at frequencies below 90 GHz.

Magnetic skyrmions are topologically protected whirling spin texture. Their nanoscale dimensions, topologically protected stability and solitonic nature, together are promising for future spintronics applications. To translate these compelling features into practical spintronic devices, a key challenge lies in achieving effective control of skyrmion properties, such as size, density and thermodynamic stability. Here, we report the discovery of ferroelectrically tunable skyrmions in ultrathin BaTiO3/SrRuO3 bilayer heterostructures. The ferroelectric proximity effect at the BaTiO3/SrRuO3 heterointerface triggers a sizeable Dzyaloshinskii-Moriya interaction, thus stabilizing robust skyrmions with diameters less than a hundred nanometres. Moreover, by manipulating the ferroelectric polarization of the BaTiO3 layer, we achieve local, switchable and nonvolatile control of both skyrmion density and thermodynamic stability. This ferroelectrically tunable skyrmion system can simultaneously enhance the integratability and addressability of skyrmion-based functional devices.

Reliable fabrication of multiscale metallic patterns with precise geometry and size at both the nanoscale and macroscale is of importance for various applications in electronic and optical devices. The existing fabrication processes, which usually involve film deposition in combination with electron-beam patterning, are either time-consuming or offer limited precision. Inspired by the kirigami, an ancient handicraft art of paper cutting, this work demonstrates an electron-beam patterning process for multiscale metallic structures with significantly enhanced efficiency and precision. Similar to the kirigami, in which the final pattern is defined by cutting its contour in a paper and then removing the unwanted parts, we define the target multiscale structures by first creating nanotrench contours in a metallic film via an electron-beam-based process and then selectively peeling the separated film outside the contours. Compared with the conventional approach, which requires the exposure of the whole pattern, much less exposure area is needed for nanotrench contours, thus enabling reduced exposure time and enhanced geometric precision due to the mitigated proximity effect. A theoretical model based on interface mechanics allows a clear understanding of the nanotrench-assisted selective debonding behaviour in the peeling process. By using this fabrication process, multiscale metallic structures with sub-10-nm up to submillimetre features can be reliably achieved, having potential applications for anti-counterfeiting and gap-plasmon-enhanced spectroscopy., Ancient art informs cutting-edge manufacturing method A centuries-old papercrafting technique has inspired an approach for the reproducible manufacture of metal structures with precisely defined macro- and nanoscale features. Many electronic devices incorporate such elements, but current production processes struggle with the ability to accurately sculpt both millimeter- and nanometer-sized design elements. Researchers led by Yihui Zhang of Tsinghua University and Huigao Duan of Hunan University tackled this challenge with a 21st century version of ‘kirigami’, an ancient aesthetic pursuit of artistic paper-cutting. The authors used an electron beam to precisely cut multiscale patterns into a thin metallic film, and then used adhesive tape to peel away unwanted elements of the film. Using this technique, the authors demonstrate the capability to produce a range of designs with both sub-millimeter and nanometer-scale features, which could prove useful in applications including anti-counterfeiting or optical detection.

A new model for fixed ground-signal-ground (GSG) pad is presented in this paper. The circuit model of RL ladder and RL series is used to model the skin and proximity effect of the GSG pad. This lumped element circuit model does not only characterize the skin and proximity effect of the pad but also explicitly models the series impedance effect of the pad at millimeter-wave frequencies. The pad has been designed and fabricated based on 40 nm CMOS technology. The HFSS EM simulation result shows that the maximum radiation pattern of the pad at 50 GHz of phi 90° is at the right angles with the axis of the pad field. The model parameters are directly derived through processed parameter optimization algorithms. The performance of the proposed model illustrates excellent agreement with the measurement data up to 50 GHz. Hence the root-mean-square error of the model with measured data is 0.02356.

The proximity effect as well as the roughness of the conductor can increase the conductive loss in differential lines. A trench structure design introduced in [1] has been shown to reduce the negative effects of the proximity effect, however calculating the differential impedance of such structure is not straightforward. In this work, a methodology based on Schwartz-Christoffel transformation is discussed and introduced to ease the derivation of an analytical description of the differential impedance of the trench lines. The results show that the analytical calculation is much faster than the numerical counterpart and produces errors below 10% for a large number of possible cases. It is also shown that for the practical and manufacturable structures the error can be kept below 5%.

Gain enhancement of a microstrip antenna (MSA) set on the surface of a human body is investigated. Antenna characteristics based on the distance between the ground plane of the antenna and the surface of a human phantom are simulated, and measurements with a human subject are examined. In order to obtain maximum gain of the MSA, different sizes of the ground plane are used. The effect of gain enhancement of MSA close to the human body is discussed by comparing the numerical simulation with measurement results.

The magnetization properties of a ferromagnet-semiconductor Co/CdMgTe/CdTe quantum well hybrid structure are investigated by several techniques. Exploiting the proximity effect between acceptor bound holes and magnetic ions we detect the magnetization curves by measuring the circular polarization of photoluminescence in an out-of-plane magnetic field. We show that magnetization originates from interfacial ferromagnet on Co-CdMgTe interface and the proximity effect is caused by magnetization of interfacial Co-CdMgTe ferromagnetic layer whose magnetic properties are very different from Co.

A novel high frequency electric cooperated arc welding method (HFAW) was developed to join aluminium and steel of 3.0 mm thickness without groove. Owing to the skin effect and proximity effect of h...

This article presents a lumped-parameter model combined with external sound pressure field simulation, based on the boundary element method (BEM) for utilization in a directional microphone. A study about microphone capsule of a typical handheld moving-coil microphone with hyper-cardioid pattern has been conducted. In the BEM simulation, a simplified 3D model of the capsule that met sound waves which radiated from a point sound source has been taken into account. The blocked average pressure at the openings of the capsule is used to drive the lumped element equivalent circuit model. Through the model, the sensitivity, directivity, and impedance of the microphone were analyzed. Hence, the proximity effect is observed and discussed. To verify our simulation, the microphone characteristics were experimentally measured by B&K devices with SoundCheck software in an anechoic chamber. The simulation data are in good agreement with the measurement data at low and medium frequencies below 13 kHz, and there were larger errors at higher frequencies, which may indicate that the lumped parameters is less applicable at higher frequencies. The proposed method gains more precise and comprehensive prediction for the microphone characteristics, which therefore could be utilized in optimizing the choice of materials and size of the microphone capsule design.