Temperature dependence measurements of the supercurrent-phase relationship in niobium nanobridges

Troeman, A.G.P.; Ploeg, S. H. W. van der; Il’ichev, E.; Meyer, H.‐G.; Golubov, A. A.; Kupriyanov, M. Yu.; Hilgenkamp, H.

doi:10.1103/physrevb.77.024509

Cited by 46 publications

(49 citation statements)

References 25 publications

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“…electrical properties, demanding precise control of the film thickness and quality on the sub-nanometer level. Moreover, the progress in the field of integrated SQUID technology has substantially driven the development of nanostructured ultrathin niobium films, currently reaching lateral feature sizes of tens of nanometers 24 25 26 27 . In contrast to gold, niobium films reveal substantially better adhesion to glass, in particular to silica, leading to solid metallic films which cannot be mechanically removed from glass surfaces without destroying the actual sample surface.…”

mentioning

confidence: 99%

Ultrathin niobium nanofilms on fiber optical tapers – a new route towards low-loss hybrid plasmonic modes

Wieduwilt

Tuniz

Linzen

et al. 2015

Sci Rep

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Due to the ongoing improvement in nanostructuring technology, ultrathin metallic nanofilms have recently gained substantial attention in plasmonics, e.g. as building blocks of metasurfaces. Typically, noble metals such as silver or gold are the materials of choice, due to their excellent optical properties, however they also possess some intrinsic disadvantages. Here, we introduce niobium nanofilms (~10 nm thickness) as an alternate plasmonic platform. We demonstrate functionality by depositing a niobium nanofilm on a plasmonic fiber taper, and observe a dielectric-loaded niobium surface-plasmon excitation for the first time, with a modal attenuation of only 3–4 dB/mm in aqueous environment and a refractive index sensitivity up to 15 μm/RIU if the analyte index exceeds 1.42. We show that the niobium nanofilm possesses bulk optical properties, is continuous, homogenous, and inert against any environmental influence, thus possessing several superior properties compared to noble metal nanofilms. These results demonstrate that ultrathin niobium nanofilms can serve as a new platform for biomedical diagnostics, superconducting photonics, ultrathin metasurfaces or new types of optoelectronic devices.

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mentioning

confidence: 99%

Ultrathin niobium nanofilms on fiber optical tapers – a new route towards low-loss hybrid plasmonic modes

Wieduwilt

Tuniz

Linzen

et al. 2015

Sci Rep

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“…Since ( ) varies with temperature while remains fixed, the CPR of such weak links is strongly temperature dependent. Generally, lowering the temperature transforms the CPR from sinusoidal to a sawtooth-like function, which ultimately turns into multivalued relations once ≳ 3.5 ( ), corresponding to the nucleation of phase-slip centres [33,34,35]. The multivalued CPR manifests itself as a hysteretic ( ) relation, which is a well-known characteristic of constriction junctions at ≪ [36,37].…”

Section: Discussionmentioning

confidence: 99%

Spontaneous emergence of Josephson junctions in homogeneous rings of single-crystal Sr2RuO4

et al. 2020

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The chiral p-wave order parameter in Sr2RuO4 would make it a special case amongst the unconventional superconductors. A consequence of this symmetry is the possible existence of superconducting domains of opposite chirality. At the boundary of such domains, the locally supressed condensate can produce an intrinsic Josephson junction. Here, we provide evidence of such junctions using mesoscopic rings, structured from Sr2RuO4 single crystals. Our order parameter simulations predict such rings to host stable domain walls across their arms. This is verified with transport experiments on loops, with a sharp transition at 1.5 K, which show distinct critical current oscillations with periodicity corresponding to the flux quantum. In contrast, loops with broadened transitions at around 3 K are void of such junctions and show standard Little-Parks oscillations. Our analysis demonstrates the junctions are of intrinsic origin and makes a compelling case for the existence of superconducting domains. seems probable, domains or edge currents have not been observed directly. Indications for their existence, however, have been found in transport experiments, which utilize Ru inclusions to form proximity junctions between Sr2RuO4 and a conventional s-wave superconductor [10,11]. A complication in the physics of Sr2RuO4 is that breaking of the tetragonal crystal symmetry due to Ru inclusions or a uniaxial strain can induce a different superconducting state with an enhanced superconducting transition temperature ≈ 3 K [13,14]. Recent experiments suggest that this so-called 3-K phase may exhibit a non-chiral state with a single-component order parameter [15,16]. In this paper, we refer to the multicomponent phase with of around 1.5 K, associated with the pure bulk limit, as the "intrinsic phase" and the possible single-component phase, characterized by ≈ 3 K, as the "extrinsic phase".The vast majority of experiments in the past two decades have been limited to bulk crystals, typically hundreds of microns in dimension. This is partly due to the unavailability of superconducting Sr2RuO4 films. The chiral domains, however, are expected to be no more than a few microns in size [5,11]. Moreover, the time-dependent switching noise observed in transport measurements suggests the domains are mobile [10,11]. We note here that the role of chiral domains resulting in hysteretic behaviour has been discussed in the Bi-Ni bilayer system [12]. The arbitrary configuration of the domains introduces an element of uncertainty.On the other hand, the energy cost associated with a chiral domain wall (ChDW), grows per area [17]. It has been recently discussed that mesoscopic samples made of chiral p-wave superconductors could host multichiral states [18,19], where the two ± chiral components are divided into superconducting domains, separated by ChDWs. This makes mesoscopic structures a promising platform to verify and potentially control the domains.

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“…The side length of the square detection area (washer hole) is 200 nm while the length and width of the nano-bridge are 100 nm and 80 nm respectively. Note that the Dayem bridges have a hyperbolic shape, therefore the effective length can be significantly larger than geometrical one and the ratio can be different from one structure to the other [9].…”

Section: Sensor Design and Fabrication Proceduresmentioning

confidence: 99%

“…In spite of its low intrinsic capacitance a SQUID based on Dayem bridges typically shows a hysteretic behavior which prevents its use as a flux to voltage converter. Such hysteresis is probably due to thermal heating associated to the phase slippage of the superconducting order parameter of the superconducting structure [9]; however it can be eliminated by shunting the superconducting film by a normal one (W, Al, Au) [1], [2], [5] or by decreasing the critical current of the sensor to a value where the phase slippage does not occur ( for niobium based sensor) [9]. In spite of the above difficulties, recently reliable and low noise nano-SQUIDs have been fabricated and characterized [1]- [5].…”

Section: Introductionmentioning

confidence: 99%

Performance of High-Sensitivity Nano-SQUIDs Based on Niobium Dayem Bridges

Vettoliere

Granata

Esposito

et al. 2009

IEEE Trans. Appl. Supercond.

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Measurements and noise performances of integrated nano superconducting quantum interference devices (nano-SQUIDs) are presented. The nano-sensors are based on nanometric niobium constrictions (Dayem bridges) inserted in a square loop having a side length of 200 nm. Integrated micrometric niobium coils located close to the sensor allow both an easy tuning/calibration and the optimization of the working point. Improved measurements of voltage-flux characteristic, flux to voltage transfer factor and noise performances are reported. In small signal mode, the sensors have shown a magnetic flux noise spectral density of 1.5 8 0 Hz 1 2 . Furthermore, preliminary measurements concerning the critical current vs. temperature dependence and the switching probability of the critical current are shown. Index Terms-Dayem bridge, magnetic sensor, nano-SQUID.

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Temperature dependence measurements of the supercurrent-phase relationship in niobium nanobridges

Cited by 46 publications

References 25 publications

Ultrathin niobium nanofilms on fiber optical tapers – a new route towards low-loss hybrid plasmonic modes

Ultrathin niobium nanofilms on fiber optical tapers – a new route towards low-loss hybrid plasmonic modes

Spontaneous emergence of Josephson junctions in homogeneous rings of single-crystal Sr2RuO4

Performance of High-Sensitivity Nano-SQUIDs Based on Niobium Dayem Bridges

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