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A four-layer canted-cosine-theta 16-T dipole has been designed as a possible candidate for future hadron colliders. The design maintains part of the future-circular-collider magnet requirements, i.e., a 50 mm clear bore and 16 T operating at 1.9 K. The magnet intercepts Lorentz forces with an internal structure of ribs and spars, minimizes conductor, and reduces the number of layers and magnet size by using wide cables. The role of iron and its impact on field and magnet size is discussed. A three-dimensional magnetic analysis was carried out for 1-in-1 and 2-in-1 designs including a structural analysis for the 1-in-1 case. Thoughts on future improvements during winding are also discussed.

This paper presents a theoretical study of structural, mechanical, electronic, vibrational and superconducting properties of full Heusler compounds Ni 2 ZrZ (Z= Al and Ga) using the norm conserving pseudo potential within the framework of Density Functional Theory (DFT) and Density Functional Perturbation Theory (DFPT). Our finding reveal that the non-magnetic L2 1 phase structure is energetically more stable for both compounds. The band structure shows that these compounds have a metallic behavior with a saddle point (Van Hove Singularity) at L -point. Elastic and vibrational properties analysis confirm the mechanical and dynamical stability of our studied compounds. The Ni 2 ZrAl and Ni 2 ZrGa exhibit BCS weak coupling superconductivity with critical temperatures of 1.78 K and 2.68 K, respectively. The study extends to explore the impact of Hf concentrations, providing valuable insights into the superconducting properties of Ni 2 Zr (1-x) Hf x Ga alloys. [ABSTRACT FROM AUTHOR]

One of the main problems in creating Superconducting Magnetic Energy Storage (SMES) Systems is mechanical loads. This article shows that there is an effective way to solve this problem. For this, an SMES system in the form of a single superconducting loop located in a plane perpendicular to the magnetic lines of force of an external magnetic field is considered. The direction of circulation of the electric current is chosen so that the magnetic induction vectors of the superconducting loop and the external magnetic field have the opposite directions. From the side of the external magnetic field, a compressive force will act on the superconducting loop. Under certain conditions, the tensile force and the compressive force balance each other. It is shown that the elimination of mechanical loads allows increasing the energy density to ~ 237 MJ/kg. The energy storage in a superconducting loop (levitating above Earth's magnetic pole) and its use for deliver cargos to outer space is considered. [ABSTRACT FROM AUTHOR]

In this paper we summarize the evolution and contributions of superconducting magnets to particle accelerators as chronicled over the last 50 years of Particle Accelerator Conferences (PAC, NA-PAC and IPAC). We begin with an historical overview based primarily on PAC Proceedings augmented with references to key milestones in the development of superconducting magnets for particle accelerators. We then provide some illustrative examples of applications that have occurred over the past 50 years, focusing on those that have either been realized in practice or provided technical development for other projects, with discussion of possible future applications.

In this brief, a high-order dual-band differential bandpass filter (BPF) with two controllable passbands and attractive common-mode (CM) rejection is proposed. The designed filter is constructed by a novel symmetric stub loaded shunted-line resonator (SLSLR). The differential-mode (DM) circuit and CM circuit of the proposed resonator are investigated detailedly by employing the even- and odd-mode method for two times. By properly designing the resonator, two reasonable DM resonances can be obtained to build dual DM passbands. In addition, the DM bisection has two independent parameters for adjusting internal coupling, leading to the individual control of the bandwidths of two passbands. Attributing to the intrinsic transversal interference paths, multiple transmission zeros are produced, resulting in a high selectivity of passbands. Additionally, a broadband CM rejection is achieved by utilizing the frequency discrepancy technique. Lastly, an eighth-order superconducting dual-band differential filter is realized. Its two passbands are respectively working at 1.9 and 4.9 GHz. MgO substrate with deposited YBCO material is used to process the filter. Good agreement between the simulation and measured results is obtained, which clearly verifies the demonstrated structure and the designing method. [ABSTRACT FROM AUTHOR]

We report the experimental nondemolition measurement of coherence, predictability and concurrence on a system of two qubits. The quantum circuits proposed by De Melo et al. (Phys Rev Lett 98(25):250501, 2007) are implemented on IBM Q (superconducting circuit) and IonQ (trapped ion) quantum computers. Three criteria are used to compare the performance of the different machines on this task: measurement accuracy, nondemolition of the observable, and quantum state preparation. We find that the IonQ quantum computer provides constant state fidelity through the nondemolition process, outperforming IBM Q systems on which the fidelity consequently drops after the measurement. Our study compares the current performance of these two technologies at different stages of the nondemolition measurement of bipartite complementarity. [ABSTRACT FROM AUTHOR]

Here, we report results of the investigation of the lattice dynamics of the sylvanite mineral AuAgTe4 in a wide temperature and pressure range by Raman spectroscopy, together with the first-principle calculations. At ambient pressure, the experimental spectrum agrees well with the calculation data. The temperature behavior of the phonon self-energies (frequencies and linewidths) are described by an anharmonic mechanism and imply negligible contributions of electron–phonon interaction at low temperatures. A structural phase transition was recorded in the pressure range of 4–6 GPa, which is in accordance with theoretical predictions. At higher pressures, evidence of local structural disorder was found that made it possible to experimentally observe the spectrum of the density of vibrational states of AuAgTe4, which becomes superconducting under pressure.

Superconducting electronics (SCE) is uniquely suited to implement neuromorphic systems. As a result, SCE has the potential to enable a new generation of neuromorphic architectures that can simultaneously provide scalability, programmability, biological fidelity, on-line learning support, efficiency and speed. Supporting all of these capabilities simultaneously has thus far proven to be difficult using existing semiconductor technologies. However, as the fields of computational neuroscience and artificial intelligence (AI) continue to advance, the need for architectures that can provide combinations of these capabilities will grow. In this paper, we will explain how superconducting electronics could be used to address this need by combining analog and digital SCE circuits to build large scale neuromorphic systems. In particular, we will show through detailed analysis that the available SCE technology is suitable for near term neuromorphic demonstrations. Furthermore, this analysis will establish that neuromorphic architectures built using SCE will have the potential to be significantly faster and more efficient than current approaches, all while supporting capabilities such as biologically suggestive neuron models and on-line learning. In the future, SCE-based neuromorphic systems could serve as experimental platforms supporting investigations that are not feasible with current approaches. Ultimately, these systems and the experiments that they support would enable the advancement of neuroscience and the development of more sophisticated AI. [ABSTRACT FROM AUTHOR]

A multilayer high field dipole magnet has been designed for future particle accelerators. The magnet has eight layers of a Nb3Sn outsert coil and four layers of a Bi-2212 insert coil (see Figs. 1 and 2). The layers are graded, delivering a short-sample field of 17.7 T in a 40-mm bore. The coil layers are of a canted cosine-theta design - with ribs and spars that guide and support the coil windings, shape the field, intercept Lorentz forces, and minimize conductor prestress. We present a general overview of the concept and report on the magnetic and mechanical design including an initial cost estimate and construction plan.

A two-layer Canted-Cosine-Theta (CCT) superconducting dipole magnet was built and tested. The magnet's unique mandrel design uses machined channels and spars to guide the windings, intercept Lorentz forces, and circumvent tangential stress accumulation. The CCT magnet design provides a "near-perfect" current density distribution and requires minimal coil prestress. The CCT magnet design, with these inherent features, makes it a desirable option for a high field accelerator magnet. A two layer dipole (CCT1) using NbTi cable and a 50.8-mm clear bore was built and tested generating a 2.4 T dipole field. We report on the winding experience, measured field quality and quench history.

Superconducting electronics (SCE) is uniquely suited to implement neuromorphic systems. As a result, SCE has the potential to enable a new generation of neuromorphic architectures that can simultaneously provide scalability, programmability, biological fidelity, on-line learning support, efficiency and speed. Supporting all of these capabilities simultaneously has thus far proven to be difficult using existing semiconductor technologies. However, as the fields of computational neuroscience and artificial intelligence (AI) continue to advance, the need for architectures that can provide combinations of these capabilities will grow. In this paper, we will explain how superconducting electronics could be used to address this need by combining analog and digital SCE circuits to build large scale neuromorphic systems. In particular, we will show through detailed analysis that the available SCE technology is suitable for near term neuromorphic demonstrations. Furthermore, this analysis will establish that neuromorphic architectures built using SCE will have the potential to be significantly faster and more efficient than current approaches, all while supporting capabilities such as biologically suggestive neuron models and on-line learning. In the future, SCE-based neuromorphic systems could serve as experimental platforms supporting investigations that are not feasible with current approaches. Ultimately, these systems and the experiments that they support would enable the advancement of neuroscience and the development of more sophisticated AI.

The hybrid architecture of the driven qubit–photon–magnon system has recently emerged as a promising candidate for novel quantum technologies. In this paper, we introduce the effective wave-function of a superconducting single qubit and a magnon mode contained within a cavity resonator and an external field. The non-classicality of the magnon and resonator modes are investigated by using the negative values of the Wigner function. Additionally, we discuss the non-classicality of the qubit state via the Wigner–Yanase skew information. We find that the mixture angle of the qubit–resonator plays a controllable role in non-classicality. However, the strength of the magnon–photon increases the non-classical behaviour of the system.

Understanding the behaviour of vortices under nanoscale confinement in superconducting circuits is important for the development of superconducting electronics and quantum technologies. Using numerical simulations based on the Ginzburg–Landau theory for non-homogeneous superconductivity in the presence of magnetic fields, we detail how lateral confinement organises vortices in a long superconducting nanostripe, presenting a phase diagram of vortex configurations as a function of the stripe width and magnetic field. We discuss why the average vortex density is reduced and reveal that confinement influences vortex dynamics in the dissipative regime under sourced electrical current, mapping out transitions between asynchronous and synchronous vortex rows crossing the nanostripe as the current is varied. Synchronous crossings are of particular interest, since they cause single-mode modulations in the voltage drop along the stripe in a high (typically GHz to THz) frequency range.

We report the single crystal growth and characterization of the quasi-one-dimensional superconductor Li 0.9 Mo 6 O 17 via temperature-gradient flux method. The grown single crystals show a clear ab plane identified by the x-ray diffraction (XRD) pattern. Temperature dependent resistivities reveal a metallic to semiconducting crossover at T M = 24 K followed by a superconducting transition at T c = 2.2 K for ρ a and ρ c. In addition, the upper critical fields demonstrate a large anisotropy with H c 2 b > H c 2 a > H c 2 c both at ρ a and ρ c. Particularly, an upper critical field H c 2 b of about 16.2 T at zero temperature limit was deduced from the field dependence of resistivity measurements, which is notably larger than the estimated Pauli paramagnetic limit 3.1 T and supports the existence of the spin-triplet superconducting pairing and unconventional superconductivity in Li 0.9 Mo 6 O 17. The XRD, resistivities and upper critical field measurements all imply a high quality of the as-grown Li 0.9 Mo 6 O 17 samples. Furthermore, the interlayer and in-plane magnetoresistivity (MR) up to 60 T reveal the possible phase transition driven by the density-wave gap suppression and Zeeman split effect in the high field state. [ABSTRACT FROM AUTHOR]

Here, we review the different series of (super)conducting and magnetic radical salts prepared with organic donors of the tetrathiafulvalene (TTF) family and oxalato-based metal complexes (ox = oxalate = C2O42−). Although most of these radical salts have been prepared with the donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF = ET), we also include all the salts prepared with other TTF-type donors such as tetrathiafulvalene (TTF), tetramethyl-tetrathiafulvalene (TM-TTF), bis(ethylenediseleno)tetrathiafulvalene (BEST), bis(ethylenedithio)tetraselenafulvalene (BETS) and 4,5-bis((2S)-2-hydroxypropylthio)-4′,5′-(ethylenedithio)tetrathiafulvalene (DMPET). Most of the oxalate-based complexes are monomers of the type [MIII(C2O4)3]3−, [Ge(C2O4)3]2− or [Cu(C2O4)2]2−, but we also include the reported salts with [Fe2(C2O4)5]4− dimers, [MII(H2O)2[MIII(C2O4)3]2]4− trimers and homo- or heterometallic extended 2D layers such as [MIIMIII(C2O4)3]− and [MII2(C2O4)3]2−. We will present the different structural families and their magnetic properties (such as diamagnetism, paramagnetism, antiferromagnetism, ferromagnetism and even long-range magnetic ordering) that coexist with interesting electrical properties (such as semiconductivity, metallic conductivity and even superconductivity). We will focus on the electrical and magnetic properties of the so-called Day series formulated as β″-(BEDT-TTF)4[A+MIII(C2O4)3]·G, which represents the largest family of paramagnetic metals and superconductors reported to date, with more than fifty reported examples. [ABSTRACT FROM AUTHOR]

In Free Electron Lasers (FEL), the electron trajectory through the undulator must meet stringent requirements in terms of trajectory wander and phase variation. This paper analyzes the feasibility of using line current pairs as correctors for superconducting undulators given a set of expected fabrication errors. A tolerance study has first been performed to investigate the impact of geometrical errors on the field quality. These errors are corrected with line currents that increase or decrease the magnetic field locally. Once the uncorrected trajectory is known, an algorithm finds the minimum number of correctors required to fulfill the trajectory specifications, and gives the corrector locations. All the correctors can be powered with the same current, greatly simplifying the implementation. The current then offers a degree of freedom to correct the trajectory and can be tuned dynamically as a function of the magnetic deflection.

The Superconducting Magnet Group, at Lawrence Berkeley National Laboratory (LBNL), has been developing a canted cosine-theta (CCT) superconducting dipole coil as well as the coil's supporting magnet structure. This contribution reports on the progress in the development of the coil's winding mandrel and its fabrication options. A comprehensive study of the coil's Lorentz forces was performed to validate the winding mandrel's "stress interception" attributes. The design of the external structure and the application of the "Bladder & Key" technology is also discussed. Additionally, the application of these studies to a curved ion-therapy CCT dipole magnet is reported.

In the quench protection (QP) process of superconducting fusion devices, the operating reliability and efficiency of power components are affected by stray parameters of the fast discharge resistor (FDR) system, especially the system stray inductance. In this paper, the fundamental condition of the QP operating process and the large power FDR system structure layout for the Large-scale Superconductor Test Facility (LSTF) are presented. The negative affected VCB, CPC circuit action, and the energy discharging process are further analyzed. The stray inductance optimization method of the resistor module and structure connections are proposed to reduce the stray inductance value. Finally, the optimization results are presented by the Q3D module of the FEA software.

Predicting analytically the coupling losses generated in a cable for fusion magnets is still a significant challenge. Difficulties are related to the complex geometry of the system: several multi-strand stages embedded in one another with different twist pitches length, difficulty to model multiplets of strands, including compaction to the final shape. A two-stage analytical geometry based model (COLISEUM) has previously been developed at CEA. We try to extend it to any n-stage cables We detail here an iterative enhancement method to an n-stage model. We validated it against experimental data and shown that it is robust enough to fit our measured coupling losses. Finally, this upgraded model can be used to assess coupling losses in fusion n-stage cables in a particularly precise way from only geometrical information and analytical tools. [ABSTRACT FROM AUTHOR]

The paper proposed double-sided superconducting linear generator with YBCO tape windings. An analytical model of linear generator was developed based on electromagnetic field theory. A parameter-scanning method is used to search for optimal dimension parameters with the purpose of minimizing the non-sinusoidal components of the induced voltage curve. The results obtained show a significant improvement in the quality of air-gap magnetic field, and reduction of the higher harmonic in voltage wave obviously. The induction voltage in the generator coils at the speed of 130 m/s are studied. Finally, the feasibility of the superconducting linear generator was analyzed and confirmed. [ABSTRACT FROM AUTHOR]

We have investigated Al2O3 as a thin interface material between Nb and polyimide, deposited using a relatively low temperature thermal atomic layer deposition (ALD) process to preserve the superconducting properties of the Nb layer. 250 nm thick Nb traces, with $\sim$ 20 nm thick layers of Al2O3 were used for this work. HD-4110 spin-on polyimide by HD MicroSystems with a thickness of ~ 20 μm was used with different curing temperatures of 225 °C and 375 °C. DC electrical characterization of patterned Nb lines were carried out using a pulse-tube based cryostat to determine Tc and Ic for the samples at different steps in the fabrication process. Details of the fabrication processes, experimental procedures and performance results are included. Results of these experiments provide insight into materials stack-ups and fabrication process options for robust, multi-layer superconducting flexible cables that can be used for signal transmission in future densely-integrated cryogenic electronics systems. [ABSTRACT FROM AUTHOR]

This paper describes the microfabrication and electrical characterization of aluminum-coated superconducting through-silicon vias (TSVs) with sharp superconducting transition above 1 K. The sharp superconducting transition was achieved by means of fully conformal and void-free DC-sputtering of the TSVs with Al, and is here demonstrated in up to 500 μm-deep vias. Full conformality of Al sputtering was made possible by shaping the vias with a tailored hourglass profile, which allowed a metallic layer as thick as 430 nm to be deposited in the center of the vias. Single-via electric resistance as low as 160 mΩ at room temperature and superconductivity at 1.27 K were measured by a three-dimensional (3D) cross-bridge Kelvin resistor structure. This work establishes a CMOS-compatible fabrication process suitable for arrays of superconducting TSVs and 3D integration of superconducting silicon-based devices. [2020-0354] [ABSTRACT FROM AUTHOR]

Superconducting microwave circuits are composed of components made from superconducting microstrip transmission lines (SMTLs). The spatial features of the superconductors provide the system operation at high speed and low noise floor. However, coupling the external electromagnetic field in these systems reduces or nullifies their performance. This article presents a general solution for evaluating the electromagnetic behavior of multiconductor SMTLs under plane wave excitation. The analysis is portrayed in the spectral domain. Using the proposed approach, the electromagnetic susceptibility of the lines is evaluated for two proximity SMTLs. It is then investigated in different scenarios where the effect of film thickness, film spacing, and operating temperature is investigated. The study reveals that by increasing the film thickness or film spacing or decreasing the operating temperature, the lines’ susceptibility is increased. Further, it is shown that for small film spacing, the susceptibility dependency on temperature or film thickness of one line can affect the susceptibility of the other line. [ABSTRACT FROM AUTHOR]

The size and weight of ion-beam cancer therapy gantries are frequently determined by a large aperture, curved, ninety degree, dipole magnet. The higher fields achievable with superconducting technology promise to greatly reduce the size and weight of this magnet and therefore also the gantry as a whole. This paper reports advances in the design of winding mandrels for curved, canted cosine-theta (CCT) magnets in the context of a preliminary magnet design for a proton gantry. The winding mandrel is integral to the CCT design and significantly affects the construction cost, stress management, winding feasibility, eddy current power losses, and field quality of the magnet. A laminated mandrel design using a minimum symmetry in the winding path is introduced and its feasibility demonstrated by a rapid prototype model. Piecewise construction of the mandrel using this laminated approach allows for increased manufacturing techniques and material choices. Sectioning the mandrel also reduces eddy currents produced during field changes accommodating the scan of beam energies during treatment. This symmetry concept can also greatly reduce the computational resources needed for 3D finite element calculations. It is shown that the small region of symmetry forming the laminations combined with periodic boundary conditions can model the entire magnet geometry disregarding the ends. © 2013 Elsevier B.V.

The ability to correct magnetic field errors in a superconducting undulator is critical for the successful application of these devices in future and existing light sources. These field errors, which can emanate from sources such as machining and coil winding imperfections, can lead to reduced light source performance by introducing errors in both the electron trajectory and the relative phase relationship between the oscillating electrons and the emitted photons. In this work, correction schemes are presented, which use a single power supply along with a superconducting switch network to define the path for the current during undulator tuning. The basic switching concept was previously designed and successfully tested at Lawrence Berkeley National Laboratory; the approach presented here is a significant advancement in generalizing and scaling that core concept. A new fabrication method is presented here, which uses lithographic methods to produce current paths and switch heaters on a superconducting film. The effect of an example corrector current path design on the magnetic field is investigated using the Finite Element Method, and the results at various undulator and corrector energization levels are presented. Experimental results from the heater switch concept are also presented. © 2002-2011 IEEE.

In this article, the operating current and torque of surface-mounted permanent magnet (SPM) wind power generators with high-temperature superconducting (HTS) armature windings are analyzed. The influence of coil location and current angle on the electromagnetic performance is investigated systematically. The results show that the location of the HTS coils significantly affects the operating current and torque. Furthermore, the maximum torque current angle of SPM wind power generators with HTS armature windings can be different from 180° due to the interaction between the armature and magnet fields. A design optimization method for wind power generators with HTS armature windings is developed in this article. The optimal design is then identified with consideration of the coupling influence of coil location and current angle. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) tetragonal FeSe has sparked extensive research interest owing to its tunable superconductivity, providing valuable insights into the design of high-temperature superconductors. Currently, the intricate Fe-Se phase diagram poses a challenge to the controlled synthesis of superconducting 2D FeSe in a pure tetragonal phase. Here, we exploit the ion-exchange property of fluorophlogopite mica to devise a straightforward approach for the phase-controlled synthesis of tetragonal FeSe on an Fe-enriched mica surface within a molten salt environment. This method successfully produces highly crystalline FeSe in a pure tetragonal phase with adjustable thickness. We investigated the surface composition of the postgrowth mica substrate using various microscopic and spectroscopic characterizations to highlight the importance of the Fe-enriched growth interface in the phase-selective synthesis of 2D tetragonal FeSe. The obtained 2D FeSe exhibited 2D superconductivity, comparable to that of FeSe mechanically exfoliated from bulk crystals, confirming the high quality of our samples. Beyond tetragonal FeSe, 2D antiferromagnetic FeTe and superconducting FeS x Se y Te 1- x - y have been phase-selectively synthesized via this approach. Our study elucidates the significance of the growth interface on the phase-selective synthesis of 2D materials and presents potential opportunities for the phase-controlled synthesis of 2D multiphase materials via the rational design of the growth interface.

2D materials possess wide‐tuning properties ranging from semiconducting and metallization to superconducting, etc., which are determined by their structure, empowering them to be appealing in optoelectronic and photovoltaic applications. Pressure is an effective and clean tool that allows modifications of the electronic structure, crystal structure, morphologies, and compositions of 2D materials through van der Waals (vdW) interaction engineering. This enables an insightful understanding of the variable vdW interaction induced structural changes, structure–property relations as well as contributes to the versatile implications of 2D materials. Here, the recent progress of high‐pressure research toward 2D materials and heterostructures, involving graphene, boron nitride, transition metal dichalcogenides, 2D perovskites, black phosphorene, MXene, and covalent–organic frameworks, using diamond anvil cell is summarized. A detailed analysis of pressurized structure, phonon dynamics, superconducting, metallization, doping together with optical property is performed. Further, the pressure‐induced optimized properties and potential applications as well as the vision of engineering the vdW interactions in heterostructures are highlighted. Finally, conclusions and outlook are presented on the way forward. [ABSTRACT FROM AUTHOR]

The aim of this article is to develop a risk management procedure, which could be applied to the magnet design process, for both superconducting and normal magnets at the Jefferson Laboratory (JLab). This procedure allowed us to identify the key risks at each of the critical phases of design and propose procedures, tests, and checks to mitigate each risk. In this article, we present a qualitative and quantitative risk management procedure commonly referred to a “failure modes and effects analysis.” As part of this procedure, we calculated a risk priority number (RPN) for each activity of the process, identified the most critical activities and proposed mitigation activities, which in turn resulted in a revised RPN. Another benefit of this procedure was the identification of appropriate “control and hold” points within the design process, which allowed one to review and approve a particular outcome before proceeding to the next sequential activity. [ABSTRACT FROM AUTHOR]

Several studies have been conducted on an externally-excited microstrip transmission line; however, no study, to the best knowledge of the researchers, has examined the superconducting microstrip transmission lines (SMTL), which are the main part of the superconducting circuits. This article aims to investigate the radiated susceptibility of SMTL under plane wave excitation. The analysis is based on modeling the superconducting film as a current sheet with specified impedance. It is revealed that the equivalent sheet impedance depends on the current distribution within the film; hence, London's second equation is employed to obtain an integral equation to acquire the current distribution and, subsequently, the equivalent sheet impedance. Then, the susceptibility of the SMTL is calculated after applying the boundary condition at the equivalent impedance surface. The procedure is performed using spectral-domain approach and verified by COMSOL software. Finally, the susceptibility of the SMTL is examined at different temperatures and for different film thicknesses. The results show that the lower temperature makes the SMTL more susceptible to an external electromagnetic field. Moreover, the same behavior is observed for increased film thickness. [ABSTRACT FROM AUTHOR]

A scanning electron microscope transition edge sensor has been developed to analyze the minor or trace constituents contained in a bulk sample and small particles on the sample under a low accelerating voltage (typically <3 keV). The low accelerating voltage enables to improve the spatial analysis resolution because the primary electron diffusion length is limited around the sample surface. The characteristic points of our transition edge sensor are 1) high-energy resolution at 7.2 eV@Al-Kα, 2) continuous operation by using a cryogen-free dilution refrigerator and 3) improvement of transmission efficiency at B-Kα by using thin X-ray film windows between the sample and detector (about 30 times better than our previous system). Our system could achieve a stabilization of the peak shift at Nd-Mα (978 eV) within 1 eV during an operation time of 27 000 s. The detection limits with B-Kα for detection times 600 and 27 000 s were 0.27 and 0.038 wt%, respectively. We investigated the peak separation ability by measuring the peak intensity ratio between the major constitute (silicon) and the minor constitute (tungsten) because the Si-Kα line differs from the W-Mα line by only 35 eV and a small W-Mα peak superimposed on the tail of the large Si-Kα peak. The peak intensity ratio (I(W-Mα)/I(Si-Kα)) was adjusted by the W particle area ratio compared with the Si substrate area. The transition edge sensor could clearly separate the Si-Kα and W-Mα lines even under a peak intensity ratio of 0.01. [ABSTRACT FROM AUTHOR]

Superconducting-insulating-superconducting trilayers have been produced for Josephson Junction fabrication by thermal atomic layer deposition (ALD) processes. The trilayers are composed of alternating layers of Ti0.4N0.6/Al2O3/Ti0.4N0.6, deposited at 450 °C, in a thermal ALD reactor on Al2O3-coated silicon. The conformal nature of the ALD process provides excellent step coverage of superconducting and insulating films. The film thickness of a single ALD cycle, being one mono-layer, allows us to precisely control the tunnel-barrier insulator thickness by counting the number of ALD cycles during the insulator deposition step. Tunnel junctions with critical current approximately 500 A/cm2 are reported. Fabrication of Josephson Junctions and progress toward development of a single-element ALD superconducting quantum interference device are discussed. [ABSTRACT FROM AUTHOR]

This paper presents the fabrication and electrical characterization of superconducting high-aspect ratio through-silicon vias DC-sputtered with aluminum. Fully conformal and void-free coating of $300~\mu \text{m}$ -deep and $50~\mu \text{m}$ -wide vias with Al, a CMOS-compatible and widely available superconductor, was made possible by tailoring a funneled sidewall profile for the axisymmetric vias. Single-via electric resistance as low as 80.44 $\text{m}\Omega $ at room temperature and superconductivity below 1.28 K were measured by a cross-bridge Kelvin resistor structure. This work thus demonstrates the fabrication of functional superconducting interposer layers, suitable for high-density 3D integration of silicon-based quantum computing architectures. [ABSTRACT FROM AUTHOR]

In this paper, a double cantilever beam (DCB) specimen incorporating cohesive crack is developed for superconductors which have potential applications in high temperature superconducting cables in space solar power station. The cohesive interface is introduced along the crack front of the DCB model under electromagnetic force. The load-separation relation (i.e. the crack opening displacement) is used as the fracture mechanics parameter and the corresponding curves during fracture process are obtained and verified by the finite element numerical method. Results show that the presence of tensile electromagnetic force makes crack propagate easily. Superconductors with small cracks have good adaptability to the oscillation of magnetic fields while that with large cracks are easier to fracture during the descent of the magnetic field. In addition, the ductility ratio of the cohesive interface can significantly increase the fracture strength. The length of fracture zone decreases as the crack length increases. [ABSTRACT FROM AUTHOR]