Properties of niobium-based Josephson tunneling elements in junction microstructures

Albrecht, Günter; Richter, Jessica; Weber, P.

doi:10.1007/bf00681718

Cited by 15 publications

(1 citation statement)

References 49 publications

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“…Hence, other materials with higher operating temperature are still under active investigations [4]. Among them, Manuscript [5], while I c of Nb junctions changes obviously due to temperature fluctuations [7]. This indicates that NbN dc SQUID show lower device performance degradation due to temperature fluctuation compared to Nb SQUID.…”

Section: Introductionmentioning

confidence: 97%

All-NbN DC-SQUID Magnetometer Based on NbN/AlN/NbN Josephson Junctions

Liu

Wang

Zhang

et al. 2017

IEEE Trans. Appl. Supercond.

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We have developed an all-NbN-integrated dc SQUID magnetometer for future applications in the higher operating temperature by taking advantage of NbN films' higher critical temperature about 16 K. Our NbN dc SQUID magnetometer is fabricated on a single crystal MgO (100) substrate, consisting of epitaxial NbN/AlN/NbN Josephson junctions, Ti/Pd shunt resistors, and a top 400-nm-thick NbN wiring layer. The critical current, inductance, and shunt resistance of NbN SQUID are set at 20 μA, 240 pH, and 1 Ω, respectively. We measured the current-voltage characteristics, voltage-flux characteristics and flux noise of the NbN SQUID magnetometer in a superconductive niobium shield at 4.2 K. In a flux locked loop operation mode, the NbN SQUID magnetometer exhibits excellent performances with a flux noise level of 6 μΦ 0 /ÝHz in the white region. The corner frequency is only 10 Hz. Based on the calibrated magnetic field sensitivity of 1.7 nT/Φ 0 at magnetically shielded room, the magnetic field resolution of 10 fT/ÝHz is achieved.

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Section: Introductionmentioning

confidence: 97%

All-NbN DC-SQUID Magnetometer Based on NbN/AlN/NbN Josephson Junctions

Liu

Wang

Zhang

et al. 2017

IEEE Trans. Appl. Supercond.

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Barrier inhomogeneities of Nb–NbOx–Pb Josephson tunnel junctions caused by preparation and storage

Hädrich¹,

Kohler²

1985

phys. stat. sol. (a)

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Inhomogeneities of the current density distribution of Nb–NbOx–Pb‐Josephson tunnel junctions are caused by contaminations from boundary materials during the sputter cleaning process of the Nb‐surface. The variations of the current density distributions of various junction types during storage in dry air or in open air are dependent on the kind of the impurity. Window type junctions show a smaller influence on the current density at the edges of the barrier area by penetrating water than crossed type junctions. The reason is that the edges are covered by the SiO‐window mask. Furthermore, with a high spatial resolution the current density distribution shows a fine structure independent of junction preparation.

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