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- 实验方案
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Focused Ion Beam
摘要： Hybrid superconducting-spin systems offer the potential to combine highly coherent atomic quantum systems with the scalability of superconducting circuits. To fully exploit this potential requires a high-quality-factor microwave resonator, tunable in frequency and able to operate at magnetic fields optimal for the spin system. Such magnetic fields typically rule out conventional Al-based Josephson-junction devices that have previously been used for tunable high-Q microwave resonators. The larger critical field of Nb allows microwave resonators with large field resilience to be fabricated. Here we demonstrate how constriction-type weak links, patterned in parallel into the central conductor of a Nb coplanar resonator with a neon focused ion beam, can be used to implement a frequency-tunable resonator. We study transmission through two such devices and show how they realize high-quality-factor, tunable, field-resilient devices that hold promise for future applications coupling to spin systems.
关键词： magnetic field resilience,focused ion beam,superconducting,tunable resonator,Nb,nano-SQUID
更新于2025-09-23 15:23:52
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Properties of Porous Silicon Precipitated with Nickel for Gas Sensors
摘要： The preparation and properties of modified porous silicon is discussed and a proposal of a sensitive layer for a gas detector is presented. The modification is done by precipitation and electrochemical deposition of nickel. The morphology of sample surfaces is examined by atomic force microscopy and scanning electron microscopy (SEM). SEM-coupled energy dispersive spectroscopy is used to analyse the chemical composition of the samples. Magnetic response is measured with a SQUID magnetometer. Electrochemical impedance spectroscopy is used to study the sensitivity of the samples to isopropanol vapour in the presence of alternating electric current. A series of samples prepared with a higher anodic current density show higher sensitivity to isopropanol vapours in comparison to a lower anodic current.
关键词： Electrochemical Impedance Spectroscopy,Porous Silicon,Gas Sensors,SQUID,Electroless Nickel Deposition,Atomic Force Microscopy
更新于2025-09-23 15:22:29
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Controlled generation of chimera states in SQUID metasurfaces using DC flux gradients
摘要： SQUID (Superconducting QUantum Interference Device) metasurfaces, subject to a time-independent (dc) flux gradient and driven by a sinusoidal (ac) flux field, support chimera states that can be generated with zero initial conditions. The dc flux gradient and the amplitude of the ac flux can thus control the number of desynchronized clusters of such a generated chimera state (i.e., its “heads”) as well as their location and size. The combination of three measures, i.e., the synchronization parameter averaged over the period of the driving flux, the strength of incoherence, and the discontinuity measure, is used to predict the emergence or not of a chimera state and its multiplicity on the parameter plane of the dc flux gradient and the ac flux amplitude. Moreover, the full-width half-maximum of the distribution of the values of the synchronization parameter averaged over the period of the ac driving flux, allows to distinguish chimera states from non-chimera, partially synchronized states. Our findings are relevant from the pointview of both theory and applications. The SQUID oscillator provides an excellent physical example of systems with inertia and driving, for which chimera states have been under-examined. Finally, in the parameter regime under consideration, SQUID lattices are systems which are experimentally realisable and have very important applications in metamaterials science.
关键词： Flux gradient,SQUID Metasurfaces,Chimera states,Superconducting metamaterials
更新于2025-09-12 10:27:22
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Niobium Nano-SQUIDs for Inductive Superconducting Transition Edge Detectors
摘要： Nano-SQUIDs which can be the readout for inductive superconducting transition edge detectors (ISTED) were fabricated on monolayer niobium (Nb) film by focus ion beam (FIB) milling. The dimension of the nanobridges which formed the junctions was less than 60 nm and the diameter of the loop was 20 μm. The properties of this nano-SQUID were investigated. The design of ISTED was introduced and the transition temperature (Tc) of the absorbing layer was adjusted by both the thickness and the proportion Si doping of Nb.
关键词： ISTED,measurement,niobium,Nano-SQUID
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Compact Cryogenic Current Comparator and Null Detector Assembly
摘要： A compact design of a combined cryogenic current comparator and null detector assembly is described. The system is intended for integration in a four-terminal resistance ratio bridge to provide both current ratio and voltage ratio balance. The comparator and null detector are contained within the same superconducting shield having an overall diameter of less than 50 mm. The assembly is suitable for use in a wide-neck liquid helium cryostat or can be integrated in a cryogen-free apparatus.
关键词： cryogenic current comparator,Resistance measurement,SQUID
更新于2025-09-10 09:29:36
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Heat-Treatment Induced Magnetic Anisotropy of GaMnSb Films
摘要： Conditions and mechanisms of controlled variation of the magnetic anisotropy of GaMnSb films containing magnetic MnSb nanoinclusions by means of heat treatment have been determined. For this purpose, the temperature and magnetic-field dependences of the magnetic moments of samples before and after thermal annealing were measured using a SQUID magnetometer. It is established that the heat treatment of GaMnSb films leads to a significant increase in the values of characteristics determined by the magnetic anisotropy, including the growth of blocking temperature (from 95 to 390 K) and the magnetic anisotropy field (from 330 to 630 Oe). Results of transmission electron microscopy investigation indicate that a change in the magnetic anisotropy of GaMnSb films as a result of their thermal annealing can be related to a transition of the crystalline structure of magnetic MnSb nanoinclusions from hexagonal (space group P62/mmc) to cubic (space group F-43m).
关键词： magnetic anisotropy,GaMnSb films,SQUID magnetometer,transmission electron microscopy,MnSb nanoinclusions,heat treatment
更新于2025-09-10 09:29:36
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Error-Correcting Codes for Code-Division Multiplexed TES Detectors
摘要： Transition edge sensors (TESs) have proven to be highly sensitive and versatile X-ray spectrometers. Upcoming missions, including Athena X-IFU, will rely on highly multiplexed focal planes where more than 32 TES pixels are read out using a single SQUID amplifier channel. We have implemented an error correction algorithm for code-division multiplexed TES signals that can compensate for potential failures of individual SQUID readout channels and that is both scalable and easily implemented in hardware. We present this algorithm for error correction and show results of laboratory tests to assess algorithm performance at recovering TES channels after a SQUID failure.
关键词： Error correction,Multiplexing,SQUID,Code-division,TES
更新于2025-09-09 09:28:46