Similar Journals
|
Journal of Low Temperature Physics
Journal Prestige (SJR): 0.471  Citation Impact (citeScore): 1 Number of Followers: 7  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1573-7357 - ISSN (Online) 0022-2291 Published by Springer-Verlag  [2468 journals]
|
- The Magnetic Microbolometer: A Proposal for QUBIC Next Gen
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In this paper, the proposal for a new multichroic pixel camera for the QUBIC instrument is presented, which aims to measure the B-mode polarization of the cosmic microwave background. The camera features antenna-coupled magnetic microbolometers (MMB) read out by a microwave SQUID multiplexer and software-defined radio-based room-temperature electronics, which are specifically optimized for MMB readout. The architecture of the detectors and their readout system is introduced, and the main design considerations are also discussed. The initial results of the simulation study suggest that MMBs are capable of achieving background-limited detection of the sky when used in an instrument like QUBIC. Additionally, the time response of these detectors appears to be sufficiently fast for the given telescope scan speed and beam size.
PubDate: 2024-08-28
-
- Kinetic Inductance Detectors for the CADEx Experiment: Searching for
Axions in the W-Band-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract This paper presents the detector developments for the Canfrac Axion Detection Experiment (CADEx), aiming at detecting dark matter axions and dark photons within the W-band. A proof of concept of the detection system is based on an array of lumped-element kinetic inductance detectors (LEKIDs). Microstrip technology is used as read-out scheme, and the ground plane acts as backshort for optimizing optical absorption in the W-band. A titanium/aluminum bilayer is used for ensuring detection below 100 GHz. The detector array design includes an inner active section consisting of 36 detectors for direct detection of the axion signal and an additional outer rim of 28 blind pixels for calibration purposes. The nanofabrication process and a preliminary cryogenic characterization are presented, being the results in good agreement with the frequency design. Measured devices exhibit coupling quality factors of the order of 6 × 104, internal quality factors above 105 and an estimated kinetic inductance of 3.3 pH/□.
PubDate: 2024-08-27
-
- Improving the Magnetocaloric Effect of a Composite Based on Pr0.8Sr0.2MnO3
Compound-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In this research work, samples of Pr0.8Sr0.2MnO3 were prepared using two methods: the conventional high-temperature ceramic method (sample R1) and the sol–gel method (sample R2) in order to form a composite. The Curie temperatures were found to be 161 K and 210 K for R1 and R2, respectively. We conducted a theoretical investigation of the magnetic and magnetocaloric (MC) properties of a composite constructed from R1 and R2 compounds to enhance the MC effect.The results suggest that our composite, with a Curie temperature evaluated at 190 K, could be a potential candidate for magnetic refrigeration. Refined values of the critical exponents β, γ, and δ, determined from the modified Arrott plots and the Kouvel–Fisher method, indicate that the behavior of the composite compound is consistent with the 3D Heisenberg model for T ≤ TC and with the mean-field model for T > TC.
PubDate: 2024-08-24
-
- The Gross–Pitaevskii Equation for an Infinite Square Well with a
Delta-Function Barrier-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The Gross–Pitaevskii equation is solved by analytic methods for an external double-well potential, that is, an infinite square well plus a \(\delta\) -function central barrier. We find solutions that have the symmetry of the non-interacting Hamiltonian as well as asymmetric solutions that bifurcate from the symmetric solutions for attractive interactions and from the antisymmetric solutions for repulsive interactions. We present a variational approximation to the asymmetric state as well as an approximate numerical approach. We compare with other approximate methods. Stability of the states is considered.
PubDate: 2024-08-23
-
- A Voltage Monitoring Approach for Faster Reducing Flux Trapping in
Josephson Junction Arrays-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Based on the characteristic change in the resistance of superconducting devices during the superconducting transition, a quantitative method to determine the temperature of superconducting devices has been proposed. This method can detect in real time whether the temperature of the superconducting device exceeds the superconducting transition temperature, thereby enabling quick reduction of the trapped magnetic flux in devices. We apply this method in our experiment, which uses a superconducting 22 subarrays programmable Josephson voltage standard device and obtains satisfactory results. We conclude that this method can efficiently reduce the trapped magnetic flux in superconducting devices and facilitate testing for measurement systems which do not possess thermometers.
PubDate: 2024-08-22
-
- A Cryogenic Testbed for Polarization Modulators and Cryogenic Mechanisms
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract We developed a cryogenic facility to assess the performance of different types of cryogenic mechanisms. The facility can host very large (up to \(\sim {1}\,\hbox {m}^{3}\) ) and heavy (up to \(\sim {30}\,\hbox {kg}\) ) instrumentation, cooled down below 10 K. The operation of moving components can be visually monitored by means of two webcams looking inside the 4 K volume. In addition a large number of electrical feedthroughs (444 lines) allow the operation of a set of hall and capacitive sensors to measure both the magnetic field, the position of moving devices with an accuracy of tens of microns and their temperatures with an accuracy of few \(\%\) . We present the results of the first tests on a large aperture (500 mm diameter) superconducting magnetic bearing for the SWIPE/LSPE experiment currently under test.
PubDate: 2024-08-13
-
- Hubbard Model on a Triangular Lattice at Finite Temperatures
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Using the strong coupling diagram technique, we find three phases of the half-filled isotropic Hubbard model on a triangular lattice at finite temperatures. The weak-interaction ( \(U\lesssim 5t\) ) and strong-interaction ( \(U\gtrsim 9t\) ) phases are similar to those obtained by zero-temperature methods—the former is a metal without perceptible spin excitations; the latter is a Mott insulator with the 120 \(^\circ\) short-range spin ordering. Zero-temperature approaches predict a nonmagnetic insulating spin-liquid phase sandwiched between these two regions. In our finite-temperature calculations, the Mott gap in the intermediate phase is filled by the Fermi-level peak, which is a manifestation of the bound states of electrons with pronounced spin excitations. We relate the appearance of these excitations at finite temperatures to the Pomeranchuk effect.
PubDate: 2024-08-04
-
- Effect of the Screening Parameter on Shannon Entropy and Thermal
Properties for Exponential Kratzer–Feus Potential-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In this study, we propose the exponential Kratzer–Feus potential and study the effect of the screening parameter on the diatomic molecules of CH, \(H_2\) , NO, HCL, and LiH. We first solve the Schrödinger equation using the Nikiforov–Uvarov functional analysis method to obtain the energy eigenvalue. Interestingly, the proposed exponential Kratzer–Feus potential exhibits a repulsive interaction for diatomic molecules. We also compute the energy spectra for diatomic molecules for different values of the screening parameter \(\alpha = 0\) , 0.2, 0.4, 0.8, and 1.0. For a more complete study, we analyse the thermodynamic properties of the model. Furthermore, the quantum information measurements are calculated and used to study particle locations.
PubDate: 2024-08-01
-
- Modeling and Analysis of Flow Through the Orifice of Still in Dilution
Refrigerator-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The cooling capacity of a typical dilution refrigerator is mainly determined by the circulating flow of the He-3 in the system, which is usually realized by the external circulation pump. In order to increase the concentration of circulating He-3, the still often take the orifice structure to limit the influence of the superfluid helium film, and this structure will also have a certain impact on the flow rate of He-3. This paper summarizes the flow rate models of each part of the orifice structure, and establishes a model related to the influence of pumping speed and the diameter of orifice on the flow rate of circulating He-3. The relationship between pumping speed and flow rate is developed and the relation is divided into three phases for detailed analysis. It is found that the flow rate and the concentration of circulating He-3 increase first and then decrease with the increasing diameter of orifice at a certain pumping speed, and the possible reasons for this phenomenon are analyzed. The results indicate that there is an optimal orifice diameter at a determined pumping speed.
PubDate: 2024-08-01
-
- Detection of Quantized Vortices Using Fourth Sound Attenuation
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Superfluid helium confined to nanofluidic systems is emerging as an important system for studies of two-dimensional turbulence and as the basis for novel quantum technologies. In fully enclosed nanofluidic geometries, only the fourth sound can propagate, which we show can be used for probing quantized vortices pinned in well-defined slab geometry. We show that similarly to well-established second sound attenuation, fourth sound attenuation can be used to infer the number of quantized vortices in a unit area. We experimentally verify fourth sound attenuation as a probe of vortex line density by injecting a known number of quantized vortices into a nanofluidic slab using a rotating cryostat.
PubDate: 2024-08-01
-
- Experimental Study on Catalytic Conversion of Ortho and Para Hydrogen
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In this paper, the experimental research on high-efficiency ortho-para (O-P) hydrogen conversion is carried out. By designing and building a low-temperature O-P hydrogen conversion experimental device, the low-temperature catalytic conversion and pressure drop flow characteristics are studied. The experimental data show that under the same conditions, the catalytic performance of iron hydroxide is the best among the three iron-based catalysts, and the hydrogen flow rate is an important factor affecting the conversion efficiency. The pressure drop formula for the porous region filled with catalyst suitable for the experimental device is proposed. This study has reference significance for the design of high-efficiency O-P hydrogen converter and the optimization design of hydrogen liquefaction process.
PubDate: 2024-08-01
-
- Dispersion Law for a One-Dimensional Weakly Interacting Bose Gas with Zero
Boundary Conditions-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract From the time-dependent Gross equation, we find the quasiparticle dispersion law for a one-dimensional weakly interacting Bose gas with a non-point interatomic potential and zero boundary conditions (BCs). The result coincides with the dispersion law for periodic BCs, i.e., the Bogoliubov law \(E_{B}(k) = \sqrt{\left( \frac{\hbar ^{2} k^2}{2\,m}\right) ^{2} + n_{0}\nu (k)\frac{\hbar ^2 k^2}{m}}\) . In the case of periodic BCs, the dispersion law can be easily derived from Gross’ equation. However, for zero BCs, the analysis is not so simple.
PubDate: 2024-08-01
-
- Electron–Phonon Coupling in Copper-Substituted Lead Phosphate
Apatite-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Recent reports of room-temperature, ambient pressure superconductivity in copper-substituted lead phosphate apatite, commonly referred to as LK99, have prompted numerous theoretical and experimental studies into its properties. As the electron–phonon interaction is a common mechanism for superconductivity, the electron–phonon coupling strength is an important quantity to compute for LK99. In this work, we compare the electron–phonon coupling strength among the proposed compositions of LK99. The results of our study are in alignment with the conclusion that LK99 is a candidate for low-temperature, not room-temperature, superconductivity if electron–phonon interaction is to serve as the mechanism.
PubDate: 2024-08-01
-
- Exploring the Potential of Residual Impurities in Germanium Detectors for
MeV-Scale Dark Matter Detection-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The direct detection of MeV-scale dark matter (DM) particles hinges on achieving an exceptionally low-energy detection threshold. Germanium (Ge) detectors, meticulously tailored with precise impurity compositions, hold the potential to enhance sensitivity to energy levels below the sub-electronvolt (sub-eV) range. This study explores the behavior of residual impurities inherent to Ge detectors at helium temperatures, unveiling a captivating freeze-out phenomenon leading to the formation of excited localized states known as dipole states. Using compelling evidence from relative capacitance measurements obtained from two detectors, we elucidate the transition of impurity atoms from free charge states to these dipole states as the temperature drops from 11 to 6.5 K. Our investigation comprehensively covers the intricate formation of these dipole states in both n-type and p-type impurities. Furthermore, we shed light on the electric field generated by these dipole states, revealing their ability to trap charges and facilitate the creation of cluster dipole states. Confirming findings from previous measurements, we establish that these excited dipole states exhibit a binding energy of less than 10 meV, offering an exceptionally low detection threshold for MeV-scale DM. Building upon this concept, we propose the development of a 1-kg Ge detector with internal charge amplification—an innovative approach poised to surpass electrical noise and enable the detection of MeV-scale DM with unprecedented sensitivity.
PubDate: 2024-08-01
-
- Readout System for Frequency-Division Multiplexing Superconducting
Detector Arrays-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Superconducting detectors have great potential in detecting microwaves and infrared waves due to their high sensitivity and accuracy in observational results. We have proposed and designed a readout system for frequency-division multiplexing superconducting detector arrays, along with corresponding backend processing and control software. The readout system consists of a baseband signal transmission board, a baseband signal receiver board, an intermediate frequency board, and a server. The baseband signal transmission board and the baseband signal receiver board are designed based on Xilinx radio frequency systems-on-chip. The backend processing and control software has been developed using the Browser/Server architecture. In this study, our designed readout system covers a resonator frequency range of 4–6 GHz or 6–8 GHz, with a multiplexing ratio of 1000:1 for each signal line. The corresponding backend processing and control software can implement functionalities such as system startup, data acquisition, real-time data flow display, I–Q sweep, and nonlinear compensation of the readout system. In the recent experiments, we tested the performance of the entire system and provided the test results for the radio frequency loop test and connecting with superconducting detector array. The experimental results showed that our proposed readout system, aided by the backend processing and control software, is capable of multiplexing readout of large-array frequency-division multiplexing resonators and can be applied in various superconducting detector arrays as well. This system lays a solid foundation for future frequency-division multiplexing readout and large-array readout of superconducting detectors.
PubDate: 2024-08-01
-
- Exploring the Dielectric Response of Borophene Core–Shell Structure
through Monte Carlo Simulations-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract This study employs comprehensive Monte Carlo simulations to gain detailed insights into the dielectric response of borophene core–shell structures. Key parameters, including exchange coupling interactions, external electric fields, temperature, and crystal fields, were systematically explored, providing a nuanced understanding of the system's behavior. The dynamics revealed by this study lays the foundation for future research, guiding efforts toward optimizing and customizing the dielectric properties of this structure. This exploration holds promise for potential applications tailored to sophisticated electronic devices.
PubDate: 2024-08-01
-
- Annealing Effects and Insulator-to-Metal Transition in Nb Doped Sr2IrO4
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The effects of vacuum and oxygen annealing on Sr2-xNbxIrO4 samples have been systematically investigated. The annealing under vacuum leads to an enhanced insulating state of the Sr2-xNbxIrO4 compounds, which could be due to the evaporation of oxygen atoms which breaks the superexchange interaction between Ir and O ions. The annealing under oxygen atmosphere results in substantial straightening of the in-plane Ir–O–Ir bond and rapid depression of the canted antiferromagnetic ordering state. Importantly, the insulator-to-metal transition has been achieved by oxygen annealing of the Sr2-xNbxIrO4 samples, which could be due to the enhanced hybridization of Ir 5d orbitals with the neighboring O 2p orbitals. The present results suggest that the annealing treatment could be an effective way for exploring of novel physical phenomena in Sr2IrO4 and related compounds.
PubDate: 2024-07-08
-
- Low Working Temperature of Erbium Orthophosphate ErPO4 with Large
Magnetocaloric Effect-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Erbium orthophosphate ErPO4 was successfully prepared. The XRD pattern analyses have proved that the ErPO4 crystallizes in the tetragonal structure (I41/amd). Under a magnetic field of 50 kOe, the magnetic entropy change (− ΔSM) reaches 23.78 J/kg K at 2.6 K for ErPO4. The value of the relative cooling power is 475 J/kg. The lowest temperature and the large MCE have inferred that ErPO4 is a potential candidate for sub-kelvin magnetic refrigeration applications.
PubDate: 2024-07-04
-
- Cross-Coupling First-Order Gradient Superconducting Quantum Interference
Device for Current Sensing-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract High sensitivity and low noise of superconducting quantum interference devices make them ideal for reading the minute changes in resistance of a transition-edge sensor, which occurs when it absorbs energy or power. A series of first-order gradient, cross-coupling octagonal SQUIDs specifically tailored for use in TES were developed and fabricated for the advantage of lower parasitic capacitance compared with the overlap-coupling ones. It is obtained that a lower screening parameter and increased shunt resistance per junction lead to a higher flux-to-voltage transfer coefficient. This enhancement significantly boosts detection sensitivity and effectively minimizes noise contributions from electronics operating at room temperature. The low-temperature measurement results of the sample with an input coil of 3.5 turns indicate that a small device current white noise of 4.8 pA/√Hz, a device flux white noise of 1.1 μΦ0/√Hz, and an optimal flux-to-voltage transfer coefficient of 338.2 μV/Φ0 are achieved. The bandwidth of a SQUID current sensor with a smaller inductance of the input coil and a larger shunt resistance exceeds 10 MHz. SQUID current sensors, featuring octagonal structures with the first-order gradient cross-coupling, exhibit low flux noise, low current noise, and a high flux-to-voltage transfer coefficient, which can satisfy the requirements of TES applications.
PubDate: 2024-07-04
-
- Study of the Magnetocaloric Effect and Critical Behavior in Double
Perovskite Manganese Oxides Pr1.5A0.5Mn2O6 (A = Mg, Ba)-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In this study, polycrystalline samples of Pr2Mn2O6 (parent phase) and Pr1.5A0.5Mn2O6 (A = Mg, Ba) were prepared using the high-temperature solid-phase reaction method. The effects of Mg and Ba doping on magnetocaloric properties and critical behavior of the parent phase were systematically investigated. Under a magnetic field of 7 T, the relative cooling power (RCP) values of Pr2Mn2O6, Pr1.5Mg0.5Mn2O6, and Pr1.5Ba0.5Mn2O6 were approximately 483.46 J·kg−1, 428.22 J·kg−1, and 479.88 J·kg−1, respectively. The critical behavior analysis revealed that the parent phase showed short-range exchange interactions, while Pr1.5A0.5Mn2O6 (A = Mg, Ba) exhibited long-range exchange interactions. The temperature dependence of the order parameter n was studied under different magnetic fields, confirming the phase transition types and validating the accuracy of the critical exponents obtained. The research findings suggest that both the parent phase and Ba-doped ceramics at the A-site hold promise as magnetic refrigeration materials.
PubDate: 2024-07-02
-
