200 research outputs found
Evidence of Vortex Jamming in Abrikosov Vortex Flux Flow Regime
We report on dynamics of non-local Abrikosov vortex flow in mesoscopic
superconducting Nb channels. Magnetic field dependence of the non-local voltage
induced by the flux flow shows that vortices form ordered vortex chains.
Voltage asymmetry (rectification) with respect to the direction of vortex flow
is evidence that vortex jamming strongly moderates vortex dynamics in
mesoscopic geometries. The findings can be applied to superconducting devices
exploiting vortex dynamics and vortex manipulation, including superconducting
wires with engineered pinning centers.Comment: 5 pages, 3 figure
Controlling of Iridium films using interfacial proximity effects
High precision calorimetry using superconducting transition edge sensors
requires the use of superconducting films with a suitable , depending on
the application. To advance high-precision macrocalorimetry, we require
low- films that are easy to fabricate. A simple and effective way to
suppress of superconducting Iridium through the proximity effect is
demonstrated by using Ir/Pt bilayers as well as Au/Ir/Au trilayers. While Ir/Au
films fabricated by applying heat to the substrate during Ir deposition have
been used in the past for superconducting sensors, we present results of
suppression on Iridium by deposition at room temperature in Au/Ir/Au trilayers
and Ir/Pt bilayers in the range of 20-100~mK. Measurements of the
relative impedance between the Ir/Pt bilayers and Au/Ir/Au trilayers fabricated
show factor of 10 higher values in the Ir/Pt case. These new films could
play a key role in the development of scalable superconducting transition edge
sensors that require low- films to minimize heat capacity and maximize
energy resolution, while keeping high-yield fabrication methods.Comment: 5 journal pages, 4 figure
Low-loss Si-based Dielectrics for High Frequency Components of Superconducting Detectors
Silicon-based dielectric is crucial for many superconducting devices,
including high-frequency transmission lines, filters, and resonators. Defects
and contaminants in the amorphous dielectric and at the interfaces between the
dielectric and metal layers can cause microwave losses and degrade device
performance. Optimization of the dielectric fabrication, device structure, and
surface morphology can help mitigate this problem. We present the fabrication
of silicon oxide and nitride thin film dielectrics. We then characterized them
using Scanning Electron Microscopy, Atomic Force Microscopy, and
spectrophotometry techniques. The samples were synthesized using various
deposition methods, including Plasma-Enhanced Chemical Vapor Deposition and
magnetron sputtering. The films morphology and structure were modified by
adjusting the deposition pressure and gas flow. The resulting films were used
in superconducting resonant systems consisting of planar inductors and
capacitors. Measurements of the resonator properties, including their quality
factor, were performed.Comment: 4 pages, 5 figures, conferenc
Quasiparticle Generation-Recombination Noise in the Limit of Low Detector Volume
We have measured the quasiparticle generation-recombination (GR) noise in
aluminium lumped element kinetic inductors with a wide range of detector
volumes at various temperatures. The basic detector consists of meandering
inductor and interdigitated capacitor fingers. The inductor volume is varied
from 2 to 153 {\mu}m^{3} by changing the inductor width and length to maintain
a constant inductance. We started with measuring the power spectrum density
(PSD) of the detectors frequency noise which is a function of GR noise and we
clearly observed the spectrum roll off at 10 kHz which corresponds to the
quasiparticle lifetime. Using data from a temperature sweep of the resonator
frequency we convert the frequency fluctuation to quasiparticle fluctuation and
observe its strong dependence on detector volume: detectors with smaller volume
display less quasiparticle noise amplitude. Meanwhile we observe a saturated
quasiparticle density at low temperature from all detectors as the
quasiparticle life time {\tau}qp approaches a constant value at low
temperature
Controlling of Iridium Films Using the Proximity Effect
A superconducting Transition-Edge Sensor (TES) with low- is essential in
a high resolution calorimetric detection. With a motivation of developing
sensitive calorimeters for applications in cryogenic neutrinoless double beta
decay searches, we have been investigating methods to reduce the of an Ir
film down to 20 mK. Utilizing the proximity effect between a superconductor and
a normal metal, we found two room temperature fabrication recipes of making
Ir-based low- films. In the first approach, an Ir film sandwiched between
two Au films, a Au/Ir/Au trilayer, has a tunable in the range of 20-100
mK depending on the relative thicknesses. In the second approach, a
paramagnetic Pt thin film is used to create Ir/Pt bilayer with a tunable
in the same range. We present detailed study of fabrication and
characterization of Ir-based low- films, and compare the experimental
results to theoretical models. We show that Ir-based films with predictable and
reproducible critical temperature can be consistently fabricated for use in
large scale detector applications.Comment: 5 figures, accepted in the Journal of Applied Physic
Strengthening students’ health in the process of sports and health tourism engagement
Is to investigate the level and dynamics of students’ physical health in the process of sports and health tourism engagement.The high level of physical development, functional status and the state of students’ health formed in the process of sports and health tourism will ensure the effectiveness of their learning in higher educational institutions owing to improving their mental and physical performance, as well as help to improve indicators of their life-sustaining and future professional activities
Fabrication Development for SPT-SLIM, a Superconducting Spectrometer for Line Intensity Mapping
Line Intensity Mapping (LIM) is a new observational technique that uses
low-resolution observations of line emission to efficiently trace the
large-scale structure of the Universe out to high redshift. Common mm/sub-mm
emission lines are accessible from ground-based observatories, and the
requirements on the detectors for LIM at mm-wavelengths are well matched to the
capabilities of large-format arrays of superconducting sensors. We describe the
development of an R = 300 on-chip superconducting filter-bank spectrometer
covering the 120--180 GHz band optimized for future mm-LIM experiments,
focusing on SPT-SLIM, a pathfinder LIM instrument for the South Pole Telescope.
Radiation is coupled from the telescope optical system to the spectrometer chip
via an array of feedhorn-coupled orthomode transducers. Superconducting
microstrip transmission lines then carry the signal to an array of channelizing
half-wavelength resonators, and the output of each spectral channel is sensed
by a lumped element kinetic inductance detector (leKID). Key areas of
development include incorporating new low-loss dielectrics to improve both the
achievable spectral resolution and optical efficiency and development of a
robust fabrication process to create a galvanic connection between ultra-pure
superconducting thin-films to realize multi-material (hybrid) leKIDs. We
provide an overview of the spectrometer design, fabrication process, and
prototype devices.Comment: 7 pages, 7 figures, presented at 2022 Applied Superconductivity
Conferenc
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