Superconductor-normal metal-superconductor Josephson junctions with Ti interlayer

Fritzsch, L.; Schubert, M.; Wende, G.; Meyer, H.‐G.

doi:10.1063/1.122211

Cited by 18 publications

(11 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, this value of suppression parameter is difficult to implement. It is, for this reason, the experimentally obtained magnitudes of characteristic voltage is rather small [18,[44][45][46][47][48][49][50][51][52][53]. Note that a simple decrease in the N -layer thickness is not a solution of this problem.…”

Section: Scalability Of Josephson Junctionsmentioning

confidence: 95%

Miniaturization of Josephson Junctions for Digital Superconducting Circuits

et al. 2021

View full text Add to dashboard Cite

In this work, we briefly overview various options for Josephson junctions, which should be scalable down to nanometer range for utilization in nanoscale digital superconducting technology. Such junctions should possess high values of critical current, I c , and normal state resistance, R N . Another requirement is the high reproducibility of the junction parameters across a wafer in a fabrication process. We argue that superconductor-normal metal-superconductor (SN -N -NS) Josephson junction of "variable thickness bridge" geometry is a promising choice to meet these requirements. Theoretical analysis of the SN -N -NS junction is performed in the case where the distance between the S electrodes is comparable to the coherence length of the N material. The restriction on the junction geometrical parameters providing the existence of superconductivity in the S electrodes is derived for the current flowing through the junction of an order of I c . The junction heating, as well as available mechanisms for the heat removal, is analyzed. The obtained results show that a SN -N -NS junction with a high (submillivolt) value of I c R N product can be fabricated from a broadly utilized combination of materials like Nb/Cu using well-established technological processes. The junction area can be scaled down to that of semiconductor transistors fabricated in the frame of a 40-nm process.

show abstract

Section: Scalability Of Josephson Junctionsmentioning

confidence: 95%

Miniaturization of Josephson Junctions for Digital Superconducting Circuits

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The preparation process of the Nb-Ti SNS junction arrays is strongly comparable with that one described for single junctions [ 5 ] . It starts with the deposition of a four layer film stack onto a 4 inch silicon wafer.…”

Section: Junction Preparationmentioning

confidence: 96%

SNS junction on Nb-Ti base for microwave circuits

Schubert¹,

Fritzsch²,

Wende³

et al. 2001

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

Superconductor -normal metal -superconductor (SNS) junctions a r e well-suited for large-scale integrated superconducting circuits. Potential applications a r e programmable voltage standards, digital-to-analog converters a n d large-scale RSFQ circuits. T h e application of SNS junctions provides some advantages, e.g. a simplified fabrication technology a n d reduced parasitic inductances. But it requires a technological process with dimensions down to the submicrometer region to achieve sufficiently high characteristic voltages IcRN.In our process the normal metal interlayer is titanium. Therefore the sidewall insulation of the junctions can be made by anodization, as it is known from the Nb-AI technology. NbTi-Nb Josephson junctions a n d junction a r r a y s were fabricated down t o the submicrometer range with I,R, values up to 87 microvolt depending on the titanium thickness. Their measured critical currents have a small spread of about 10 percent.Shapiro steps a r e observed under the influence of microwave irradiation. For the application of such junctions in a programmable Josephson voltage standard a new type of microwave circuit using coplanar strips is proposed a n d successfully tested in 10 V SIS circuits.

show abstract

“…3(b) shows conductance spectra of a NbN-Ti(9 nm)-GdN(2.6 nm)-NbN tunnel junction. As the thickness of the Ti (∼9 nm) in this type of device is larger than both the superconducting coherence length ξ N bN ∼4.1 nm [38] and ξ N T i ∼3.6 nm [54](ξ N T i ; Normal state coherence length of Ti), this type of tunnel junction can be considered as NIS-type tunnel junction. The red solid line shows fitting of the NIS tunnel model to the conductance spectra with fitting parameter ∆ = 1.38 meV and γ = 0.325 (see supplementary material for more detailed study of NIStype tunnel junctions) [45].…”

Section: A Tunneling Behaviormentioning

confidence: 99%

Spin-polarized quasiparticle control in a double spin-filter tunnel junction

Muduli

2017

Phys. Rev. B

View full text Add to dashboard Cite

Spin-polarized quasiparticles can be easily created during spin-filtering through a ferromagnetic insulator (FI) in contact with a superconductor due to pair breaking effects at the interface. A combination FI-N-FI sandwiched between two superconductors can be used to create and analyze such spin-polarized quasiparticles through their nonequilibrium accumulation in the middle metallic (N) layer. We report spin-polarized quasiparticle regulation in a double spin-filter tunnel junction in the configuration NbN-GdN1-Ti-GdN2-NbN. The middle Ti layer provides magnetic decoupling between two ferromagnetic GdN and a place for nonequilibrium quasiparticle accumulation. The two GdN(1,2) layers were deposited under different conditions to introduce coercive contrast. The quasiparticle tunneling spectra has been measured at different temperatures to understand the tunneling mechanism in these double spin-filter junctions. The conductance spectra were found to be comparable to an asymmetric SINI'S-type tunnel junction. A hysteretic R-H loop with higher resistance for the antiparallel configuration compared to parallel state was observed asserting the spin-polarized nature of quasiparticles. The hysteresis in the R-H loop was found to disappear for sub-gap bias current. This difference can be understood by considering suppression of the interlayer coupling due to nonequilibrium spin-polarized quasiparticle accumulation in the Ti layer.

show abstract

Superconductor-normal metal-superconductor Josephson junctions with Ti interlayer

Cited by 18 publications

References 8 publications

Miniaturization of Josephson Junctions for Digital Superconducting Circuits

Miniaturization of Josephson Junctions for Digital Superconducting Circuits

SNS junction on Nb-Ti base for microwave circuits

Spin-polarized quasiparticle control in a double spin-filter tunnel junction

Contact Info

Product

Resources

About