Low capacitance HTS junctions for single electron transistors

Gustafsson, David; Nawaz, Shahid; Mumtaz, M.; Signorello, G.; Lombardi, Floriana

doi:10.1016/j.physc.2009.11.040

Cited by 3 publications

(5 citation statements)

References 9 publications

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“…This result is consistent with the study on small-capacitance Josephson junctions in literature where the specific capacitance, C s is on the order of 20-100 fF/µm 2 (i.e. 20-100 mF/m 2 ) [21,22,23]. Also, it has been determined that the specific capacitance values of the Josephson junctions at the non-superconducting state are much bigger than that of the superconducting state.…”

Section: Discussionsupporting

confidence: 91%

Süperiletken Durumda Cıva Bazlı Bakır Oksit Katmanlı Süperiletkenin Özgül Kapasitanslarının Tespiti

Çataltepe

2018

Cumhuriyet Science Journal

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Mercury based copper oxide layered high temperature superconductor, which consists of superconductor-insulator-superconductor (SIS) layers, can be considered as a stack of nearly ideal, intrinsic Josephson junctions (IJJ). The SIS junction, where the electrical field is confined, topologically resembles a parallel-plate capacitor. As is known, the coupling between junctions in superconductors is capacitive. Hence, the determination of the specific capacitance (C s) of the IJJ at the superconducting state has a crucial importance in order to give information about superconductivity mechanism. In this study, the C s values of the investigated sample have been calculated by means of the critical current density, J c and plasma frequency, that have been obtained from magnetic measurements taken at the below temperatures than the critical transition temperature, T c. Moreover, C s values at superconducting temperature have been compared to that of the normal temperature.

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Section: Discussionsupporting

confidence: 91%

Süperiletken Durumda Cıva Bazlı Bakır Oksit Katmanlı Süperiletkenin Özgül Kapasitanslarının Tespiti

Çataltepe

2018

Cumhuriyet Science Journal

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“…The amount of greenphase increases for nonoptimal deposition conditions and in the presence of grain boundaries. 8,21,22 Nanosized superconducting Y123 connections embedded in a greenphase matrix are expected to be formed at the grain boundary, see Fig. 1(a).…”

Section: B Soft Nanostructuringmentioning

confidence: 99%

“…For typical JJ-based devices, which operate in the quantum limit (typically at temperatures below 100 mK), the requirements on junction critical currents and capacitances are met for lateral dimensions on a length scale of 100 nm. 7,8 The realization of reproducible HTS JJs at the nanoscale can also be instrumental to fabricate sensors with a quantum limited sensitivity like nano-SQUIDs, which can allow the detection of magnetic nanoparticles in a much wider temperature and magnetic field range compared to its low-criticaltemperature superconductor (LTS) counterpart.…”

Section: Introductionmentioning

confidence: 99%

Noise properties of nanoscale YBa2Cu3O7−δJosephson

Gustafsson

Lombardi

2011

Phys. Rev. B

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We present electric noise measurements of nanoscale biepitaxial YBa 2 Cu 3 O 7−δ (YBCO) Josephson junctions fabricated by two different lithographic methods. The first (conventional) technique defines the junctions directly by ion milling etching through an amorphous carbon mask. The second (soft patterning) method makes use of the phase competition between the superconducting YBCO (Y123) and the insulating Y 2 BaCuO 5 (Y211) phase at the grain boundary interface on MgO (110) substrates. The voltage noise properties of the two methods are compared in this study. For all junctions (having a thickness of 100 nm and widths of 250-500 nm), we see a significant amount of individual charge traps. We have extracted an approximate value for the effective area of the charge traps from the noise data. From the noise measurements, we infer that the soft-patterned junctions with a grain-boundary (GB) interface manifesting a large c-axis tunneling component have a uniform barrier and a superconductor-insulator-superconductor (SIS) -like behavior. The noise properties of soft-patterned junctions having a GB interface dominated by transport parallel to the ab planes are in accordance with a resonant tunneling barrier model. The conventionally patterned junctions, instead, have suppressed superconducting transport channels with an area much less than the nominal junction area. These findings are important for the implementation of nanosized Josephson junctions in quantum circuits.

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“…To fabricate the junctions we use the fact that for certain deposition conditions secondary insulating phases like Y 2 BaCuO 5 (Y211, also called greenphase) can nucleate on MgO(110) in addition to the superconducting YBa 2 Cu 3 O 7−δ (Y123). The amount of greenphase increases for non optimal deposition conditions and in the presence of grain boundaries [8,21,22]. Nano sized superconducting Y123 connections embedded in a greenphase matrix are expected to be formed at the grain boundary, see Figure 1 (a).…”

Section: B Soft Nanostructuringmentioning

confidence: 99%

“…Recent advances in the thin film technology and nano-fabrication of HTS made it possible to observe macroscopic quantum phenomena in YBa 2 Cu 3 O 7−δ (YBCO) biepitaxial grain boundary Josephson junctions [5,6] opening the way for the realization of HTS quantum circuits. For typical JJ-based devices, which operate in the quantum limit (typically at temperatures below 100 mK), the requirements on junc- * Electronic address: dagust@chalmers.se tion critical currents and capacitances are met for lateral dimensions on a length scale of 100 nm [7,8].…”

Section: Introductionmentioning

confidence: 99%

Noise properties of nanoscale YBCO Josephson junctions

Gustafsson,

Lombardi,

Bauch

2011

Preprint

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We present electric noise measurements of nanoscale biepitaxial YBa2Cu3O 7−δ (YBCO) Josephson junctions fabricated by two different lithographic methods. The first (conventional) technique defines the junctions directly by ion milling etching through an amorphous carbon mask. The second (soft patterning) method makes use of the phase competition between the superconducting YBCO (Y123) and the insulating Y2BaCuO5 (Y211) phase at the grain boundary interface on MgO (110) substrates. The voltage noise properties of the two methods are compared in this study. For all junctions (having a thickness of 100 nm and widths of 250-500 nm) we see a significant amount of individual charge traps. We have extracted an approximate value for the effective area of the charge traps from the noise data. From the noise measurements we infer that the soft patterned junctions with a grain boundary (GB) interface manifesting a large c-axis tunneling component have a uniform barrier and a SIS like behavior. The noise properties of soft patterned junctions having a GB interface dominated by transport parallel to the ab-planes are in accordance with a resonant tunneling barrier model. The conventionally patterned junctions, instead, have suppressed superconducting transport channels with an area much less than the nominal junction area. These findings are important for the implementation of nanosized Josephson junctions in quantum circuits.

show abstract

Low capacitance HTS junctions for single electron transistors

Cited by 3 publications

References 9 publications

Süperiletken Durumda Cıva Bazlı Bakır Oksit Katmanlı Süperiletkenin Özgül Kapasitanslarının Tespiti

Süperiletken Durumda Cıva Bazlı Bakır Oksit Katmanlı Süperiletkenin Özgül Kapasitanslarının Tespiti

Noise properties of nanoscale YBa2Cu3O7−δJosephson

Noise properties of nanoscale YBCO Josephson junctions

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