Records |
Author |
Navarro, H.; Sirena, M.; Kim, J.; Haberkorn, N. |
Title |
Josephson coupling in high-Tc superconducting junctions using ultra-thin BaTiO3 barriers |
Type |
Journal Article |
Year  |
2020 |
Publication |
Materials Science and Engineering: B |
Abbreviated Journal |
Mater. Sci. Eng. B |
Volume |
262 |
Issue |
|
Pages |
114714 |
Keywords |
Josephson junctionsHigh-Tc superconductorsThin films |
Abstract |
We study the electrical transport of vertically-stacked Josephson tunnel junctions using GdBa2Cu3O7−δ electrodes and a BaTiO3 barrier with thicknesses between 1 nm and 3 nm. Current-voltage measurements at low temperatures show a Josephson coupling for junctions with BaTiO3 barriers of 1 nm and 2 nm. Reducing the barrier thickness bellow a critical thickness seems to suppress the ferroelectric nature of the BaTiO3. The Josephson coupling temperature reduces as the barrier thicknesses increases. The Josephson energies at 12 K are of ≈ 1.5 mV and ≈ 7.5 mV for BaTiO3 barriers of 1 nm and 2 nm, respectively. Fraunhofer patterns are consistent with fluctuations in the critical current due to structural inhomogeneities in the barriers. Our results are promising for the development of Josephson junctions using high-Tc electrodes with energy gaps much higher than those usually present in conventional low-temperature superconductors. |
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ISSN |
0921-5107 |
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Call Number |
BT @ pedrazp @ |
Serial |
858 |
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Author |
Hofer, J.A.; Ginzburg, M.; Bengio, S.; Haberkorn, N. |
Title |
Nanocrystalline superconducting γ-Mo2N ultra-thin films for single photon detectors |
Type |
Journal Article |
Year  |
2022 |
Publication |
Materials Science and Engineering: B |
Abbreviated Journal |
Materials Science and Engineering: B |
Volume |
275 |
Issue |
|
Pages |
115499 |
Keywords |
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Abstract |
We analyze the influence of the surface passivation produced by oxides on the superconducting properties of γ-Mo2N ultra-thin films. The superconducting critical temperature of thin films grown directly on Si (100) with those using a buffer and a capping layer of AlN are compared. The results show that the cover layer avoids the presence of surface oxides, maximizing the superconducting critical temperature for films with thicknesses of a few nanometers. We characterize the flux-flow instability measuring current-voltage curves in a 6.4 nm thick Mo2N film with a superconducting critical temperature of 6.4 K. The data is analyzed using the Larkin and Ovchinnikov model. Considering self-heating effects due to finite heat removal from the substrate, we determine a fast quasiparticle relaxation time ≈ 45 ps. This value is promising for its applications in single-photon detectors. |
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ISSN |
0921-5107 |
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Call Number |
BT @ pedrazp @ |
Serial |
871 |
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