Josephson junctions based on amorphous MoGe: prospects for use in superconducting electronics

2022 ◽  
Author(s):  
Ivan P Nevirkovets ◽  
Mikhail A Belogolovskii ◽  
John B Ketterson
Keyword(s):  
Experimental Data ◽  
Surface Morphology ◽  
Temperature Dependence ◽  
Josephson Junctions ◽  
Tunnel Junctions ◽  
Theoretical Calculations ◽  
Superconducting Transition ◽  
High Uniformity ◽  
Josephson Tunnel ◽  
Superconducting Electronics

Abstract We have fabricated and characterized all-MoGe Josephson junctions with a very thin Al/AlOx/(Al) barrier, where the amorphous MoGe films exhibit superconducting transition temperatures up to 7 K. Due to the uniformity of the surface morphology of the MoGe films, the junctions demonstrate high uniformity of their tunneling properties. The experimental data on the temperature dependence of the subgap current agree well with theoretical calculations. The results obtained imply that Josephson tunnel junctions based on amorphous superconductors are promising candidates for use in superconducting electronics, especially in applications requiring multiple stacked junctions or the creation of a nonequilibrium quasiparticle distribution.

scholarly journals Josephson Effect in MgB2/Pd/Nb Trilayer Josephson Junctions

2021 ◽  
Vol 47 (3) ◽  
pp. 1062-1072
Author(s):  
Anayesu B Malisa
Keyword(s):  
Josephson Junctions ◽  
Josephson Effect ◽  
Molecular Beam ◽  
Bottom Electrode ◽  
Tunnel Junctions ◽  
Rf Sputtering ◽  
Ex Situ ◽  
Shapiro Steps ◽  
Josephson Tunnel ◽  
Junction Plane

This paper reports fabrication techniques and results of MgB2/Pd/Nb trilayer Josephson junctions. The MgB2 bottom electrode was co-evaporated by molecular beam epitaxy (MBE) technique from both magnesium and boron sources at a low substrate temperature ~ 300 °C, while the interlayer and the top niobium electrode (Pd/Nb bilayer) were deposited ex-situ using RF sputtering. The junctions exhibited  and  Josephson effect as well as a modulation of the critical current in a magnetic field applied in a direction normal to the junction plane. Fractional and integer Shapiro steps were observed at voltages corresponding to the frequency of the applied microwave radiation field. The  products of the junctions compare well with the previously reported values. The results suggest that it should be possible to fabricate all-MgB2 and MgB2 as one of the electrodes Superconductor/Normal/Superconductor (SNS), Superconductor/Insulator/Superconductor (SIS) or even Superconductor/Ferromagnet/Superconductor (SFS) tunnel junctions with interesting characteristics and for various applications. Keywords: MgB2; all-MgB2; Josephson Tunnel junctions; trilayer devices; Niobium

scholarly journals Phase-dependent noise in Josephson junctions

2018 ◽  
Vol 81 (1) ◽  
pp. 10601
Author(s):  
Forrest Sheldon ◽  
Sebastiano Peotta ◽  
Massimiliano Di Ventra
Keyword(s):  
Stationary Phase ◽  
Tunnel Junction ◽  
Josephson Junctions ◽  
Thermal Noise ◽  
Tunnel Junctions ◽  
Microscopic Theory ◽  
Phase Dependence ◽  
Dynamic Noise ◽  
Josephson Tunnel ◽  
Superconducting Current

In addition to the usual superconducting current, Josephson junctions (JJs) support a phase-dependent conductance related to the retardation effect of tunneling quasi-particles. This introduces a dissipative current with a memory-resistive (memristive) character that should also affect the current noise. By means of the microscopic theory of tunnel junctions we compute the complete current autocorrelation function of a Josephson tunnel junction and show that this memristive component gives rise to both a previously noted phase-dependent thermal noise, and an undescribed non-stationary, phase-dependent dynamic noise. As experiments are approaching ranges in which these effects may be observed, we examine the form and magnitude of these processes. Their phase dependence can be realized experimentally as a hysteresis effect and may be used to probe defects present in JJ based qubits and in other superconducting electronics applications.

TEMPERATURE DEPENDENCE BEHAVIOR OF ELECTRICAL RESISTIVITY IN NOBLE METALS AT LOW TEMPERATURES

2014 ◽  
Vol 5 (3) ◽  
pp. 982-992 ◽  
Author(s):  
M AL-Jalali
Keyword(s):  
Experimental Data ◽  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Low Temperatures ◽  
Noble Metals ◽  
Phonon Scattering ◽  
Theoretical Models ◽  
Residual Resistivity ◽  
Electron Phonon Scattering

Resistivity temperature – dependence and residual resistivity concentration-dependence in pure noble metals(Cu, Ag, Au) have been studied at low temperatures. Dominations of electron – dislocation and impurity, electron-electron, and electron-phonon scattering were analyzed, contribution of these mechanisms to resistivity were discussed, taking into consideration existing theoretical models and available experimental data, where some new results and ideas were investigated.

scholarly journals Ability of Constitutive Models to Characterize the Temperature Dependence of Rubber Hyperelasticity and to Predict the Stress-Strain Behavior of Filled Rubber under Different Defor Mation States

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 369
Author(s):  
Xintao Fu ◽  
Zepeng Wang ◽  
Lianxiang Ma
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Mechanical Response ◽  
Constitutive Models ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Chain Model ◽  
Stress Strain ◽  
Filled Rubber ◽  
Yeoh Model

In this paper, some representative hyperelastic constitutive models of rubber materials were reviewed from the perspectives of molecular chain network statistical mechanics and continuum mechanics. Based on the advantages of existing models, an improved constitutive model was developed, and the stress–strain relationship was derived. Uniaxial tensile tests were performed on two types of filled tire compounds at different temperatures. The physical phenomena related to rubber deformation were analyzed, and the temperature dependence of the mechanical behavior of filled rubber in a larger deformation range (150% strain) was revealed from multiple angles. Based on the experimental data, the ability of several models to describe the stress–strain mechanical response of carbon black filled compound was studied, and the application limitations of some constitutive models were revealed. Combined with the experimental data, the ability of Yeoh model, Ogden model (n = 3), and improved eight-chain model to characterize the temperature dependence was studied, and the laws of temperature dependence of their parameters were revealed. By fitting the uniaxial tensile test data and comparing it with the Yeoh model, the improved eight-chain model was proved to have a better ability to predict the hyperelastic behavior of rubber materials under different deformation states. Finally, the improved eight-chain model was successfully applied to finite element analysis (FEA) and compared with the experimental data. It was found that the improved eight-chain model can accurately describe the stress–strain characteristics of filled rubber.

Temperature dependence of the energy barrier in X/1X nm shape-anisotropy magnetic tunnel junctions

2021 ◽  
Vol 118 (1) ◽  
pp. 012409
Author(s):  
Junta Igarashi ◽  
Butsurin Jinnai ◽  
Valentin Desbuis ◽  
Stéphane Mangin ◽  
Shunsuke Fukami ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Energy Barrier ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Shape Anisotropy
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