Exploratory research for a high temperature superconducting integrated circuit (original) (raw)
Related papers
IEEE Transactions on Applied Superconductivity, 1995
A unique normal-metal (N) layer construction was used to fabricate high temperature superconducting (S) YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// SNS Josephson junctions. The normal-metal included a gradient Pr-doped Y/sub 1-x/Pr/sub x/Ba/sub 2/Cu/sub 3/O/sub 7-/spl delta// layer which was composed of a light doping (x=0.1) next to both YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// electrodes, a slightly higher doping (x=0.3) towards the center, and a doping concentration of x=0.5 in the middle of the N-layer. A gradient of the doping profile of the N-layer instead of an abrupt one provides good thermal, structural, and chemical compatibility between adjacent regions. The multilayer configuration of the gradient Pr-doped N-layers on YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// showed good growth structure as confirmed by X-ray diffraction and Rutherford backscattering channeling tests. The SNS junctions fabricated in such a way showed resistively shunted junction current vs voltage characteristics above 77 K. Microwave induced Shapiro steps above 77 K and voltage modulation of dc SQUIDs at 77 K were both demonstrated with this technology.>
Application of High-Tc Superconducting Josephson Junction Devices
2019
Abstract: The application of superconducting devices based on Josephson junction has been investigated for many years. Josephson junction is based on quantum mechanical tunneling of electrons between weakly coupled two superconducting regions. Its unique properties make it a building block for future superconducting electronic circuits. In this paper, attempt has been made to highlight the wide range of application of Josephson junction including Josephson voltage standard, SQUIDs, Quantum Computer, analog to digital converter, RSFQ digital electronics, terahertz emitter and detector etc.
Hybrid Josephson Junctions with Iron-based and Conventional Superconductor Electrodes
Journal of Superconductivity and Novel Magnetism, 2014
We investigate the iron-based superconductor Ba(Fe 1−x Co x ) 2 As 2 (Ba-122) regarding its superconducting properties and possible applications. Therefore Ba-122 thin films are used as base electrode to prepare different kinds of hybrid Josephson junctions with a counter electrode of the conventional superconductor Pb. Additionally, we use both c-axis and ab-plane transport geometries and different kinds of barriers like interface-engineered surfaces, sputtered titanium oxide and gold layers. Temperature dependent I-V characteristics as well as magnetic field dependence and microwave response of the junctions are shown. The examined I-V characteristics and I c R n -T behaviours of each junction type are compared and described according to the electrical behaviour of the respective normal conducting or insulating barrier. While the I c R n product of the interface-engineered barrier junction was 12 µV and the planar junction with Au barrier showed 18 µV, we could increase the I c R n to 90 µV for planar TiO x barrier junctions.
A novel buffered high- T c superconducting step-edge Josephson junction
Superconductor Science and Technology, 2007
A novel high-T c superconducting (HTS) buffered step-edge Josephson junction is fabricated. A 250 nm PrBa 2 Cu 3 O 7 (PBCO) layer was epitaxially grown on a (001) MgO substrate by PLD, which acts as a buffered template for a step-edge. Argon-ion milling was used to obtain a step-edge with a step angle of 25 • . The step-edge is analysed in terms of an extended Wu and Chen model (Wu and Chen 2006 Rev. Sci. Instrum. 77 1). The model validity is confirmed by the correspondence between the theoretically proposed and experimentally observed step angles. A 150 nm YBa 2 Cu 3 O 7−δ (YBCO) thin film was accordingly grown over the PBCO step-edge and patterned by standard photolithography. I -V characteristics were obtained by DC and AC excitation of the patterned junctions. The I c R n product values are of the order of 1.6 mV and 0.36 mV at 53 K and 77 K, respectively. These values are higher than typical values found in the literature. The observation of Shapiro steps confirms the presence of the Josephson effect in this novel junction topology.
Applied Physics Letters, 1994
High-temperature superconductor YBa2Cu3O7−δ based superconducting-normal-superconducting (SNS) Josephson junctions were fabricated using a unique device design. The normal material included a gradient Pr-doped Y1−xPrxBa2Cu3O7−δ layer which was composed of a light doping (x=0.1) next to both YBa2Cu3O7−δ electrodes, a slightly higher doping (x=0.3) towards the center, and a doping concentration of x=0.5 in the middle of the N layer. This design graded the lattice mismatch between YBa2Cu3O7−δ and the N layer, thus avoiding the accumulation of all the lattice strain at one interface. It also results in good chemical, thermal, and structural compatibility between adjacent layers for the desired multilayer structures. The SNS junctions fabricated in this way showed resistively shunted junction current-voltage characteristics under dc bias and Shapiro steps under microwave irradiation at a temperature in the range of 75–87 K. Direct current superconducting quantum interference devices show...
1993
9 94-05114 94 2 15 100 NOTICE When Government drawings, specifications, or other data are used for any purpose other than in connection with a definitely Government-related procurement, the United States Government incurs no responsibility or any obligation whatsoever. The fact that the government may have formulated or in any way supplied the said drawings, specifications, or other data, is not to be regarded by implication, or otherwise in any manner construed, as licensing the holder, or any other person or corporation; or as conveying any rights or permission to manufacture, use, or sell any patented invention that may in any way be related thereto. 42 Microwaves Superconductors Josephsons junctions 1. PRICE CODE 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT
Improving the Josephson energy in high-Tc superconducting junctions for ultra-fast electronics
Nanotechnology, 2019
We report the electrical transport of thin vertically-stacked Josephson tunnel junctions. The devices were fabricated using 16 nm thick GdBa2Cu3O7−δ electrodes and 1–4 nm SrTiO3 as an insulating barrier. The results show Josephson coupling for junctions with SrTiO3 barriers of 1 and 2 nm. Subtracting the residual current in the Fraunhofer patterns, energies of 3.1 mV and 5.7 mV at 12 K are obtained for STO barriers of 1 nm and 2 nm, respectively. The residual current may be related to the contribution of pinholes and thickness fluctuations in the STO barrier. These values are promising for reducing the influence of thermal noise and increasing the frequency operation rate in superconducting devices using high-temperature superconductors.
Materials Research, 2016
A homemade Josephson junction was successfully obtained using a superconductor thin film of the BSCCO system. The film was deposited on a lanthanum aluminate, produced from a commercial powder with a nominal composition Bi 1.8 Pb 0.4 Sr 2 CaCu 2 O x , was thermally treated by a domestic microwave oven. The XRD analysis of the film indicated the coexistence of Bi-2212 and Bi-2223 phases and SEM images revealed that a typical superconductor plate-like morphology was formed. From the electrical characterization, performed using DC four probes technique, it was observed an onset superconducting transition temperature measured around 81K. At the current-voltage characteristics curve, a step of electric current at zero-voltage could be observed, an indicative that the tunneling Josephson occurred.