Bistable superconducting quantum interference device with built-in switchable π∕2 phase shift

Smilde, Henk-Jan H.; Ariando, Ariando; Rogalla, Horst; Hilgenkamp, H.

doi:10.1063/1.1812813

Cited by 14 publications

(8 citation statements)

References 18 publications

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“…Such nanoSQUIDs can potentially be used for the nondestructive measurement of distributions of stray fields of magnetic nanoparticles and nanostructures, as well as for the nondestructive readout of the final states of superconducting flux qubits after their protection by sufficiently high potential barriers. The self-biasing of SQUIDs using YBCO-Nb JJs has also been realized [60]. NanoSQUIDs based on YBCO films and step-edge or bicrystal JJs should be able to operate at liquid nitrogen temperature or have a large I c R n product at lower temperatures [27,61].…”

Section: High-tc Squid Microscope System With a Ferromagnetic Fluxmentioning

confidence: 99%

Superconducting Quantum Interferometers for Nondestructive Evaluation

Faley

Kostyurina

Kalashnikov

et al. 2017

Sensors

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We review stationary and mobile systems that are used for the nondestructive evaluation of room temperature objects and are based on superconducting quantum interference devices (SQUIDs). The systems are optimized for samples whose dimensions are between 10 micrometers and several meters. Stray magnetic fields from small samples (10 µm–10 cm) are studied using a SQUID microscope equipped with a magnetic flux antenna, which is fed through the walls of liquid nitrogen cryostat and a hole in the SQUID’s pick-up loop and returned sidewards from the SQUID back to the sample. The SQUID microscope does not disturb the magnetization of the sample during image recording due to the decoupling of the magnetic flux antenna from the modulation and feedback coil. For larger samples, we use a hand-held mobile liquid nitrogen minicryostat with a first order planar gradiometric SQUID sensor. Low-Tc DC SQUID systems that are designed for NDE measurements of bio-objects are able to operate with sufficient resolution in a magnetically unshielded environment. High-Tc DC SQUID magnetometers that are operated in a magnetic shield demonstrate a magnetic field resolution of ~4 fT/√Hz at 77 K. This sensitivity is improved to ~2 fT/√Hz at 77 K by using a soft magnetic flux antenna.

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Section: High-tc Squid Microscope System With a Ferromagnetic Fluxmentioning

confidence: 99%

Superconducting Quantum Interferometers for Nondestructive Evaluation

Faley

Kostyurina

Kalashnikov

et al. 2017

Sensors

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“…For magnetic field measurement the optimal flux bias of DC SQUID is 0.25Φ 0 where the derivative ∂V/∂F reaches its maximal value. DC SQUIDs with built-in switchable π/2-phase shift were made in a construction that includes ten ds-JJs [32]. For the sake of miniaturization of self-biased nanoscale DC SQUID magnetometers number of junctions should be reduced to two ds-JJs.…”

Section: Semmentioning

confidence: 99%

MoRe/YBCO Josephson junctions and π-loops

Faley

Reith

Satrya

et al. 2020

Supercond. Sci. Technol.

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We have developed Josephson junctions between the d-wave superconductor YBa2Cu3O7−x (YBCO) and the s-wave Mo0.6Re0.4 (MoRe) alloy superconductor (ds-JJs). Such ds Josephson junctions are of interest for superconducting electronics making use of incorporated π-phase shifts. The I(V)-characteristics of the ds-JJs demonstrate a twice larger critical current along the [100] axis of the YBCO film compared to similarly-oriented ds-JJs made with a Nb top electrode. The characteristic voltage I c R n of the YBCO–Au–MoRe ds-JJs is 750 μV at 4.2 K. The ds-JJs that are oriented along the [100] or [010] axes of the YBCO film exhibit a 200 times higher critical current than similar ds-JJs oriented along the [110] axis of the same YBCO film. A critical current density J c = 20 kA cm−2 at 4.2 K was achieved. Different layouts of π-loops based on the novel ds-JJs were arranged in various mutual coupling configurations. Spontaneous persistent currents in the π-loops were investigated using scanning SQUID microscopy. Magnetic states of the π-loops were manipulated by currents in integrated bias lines. Higher flux states up to ±2.5Φ0 were induced and stabilized in the π-loops. Crossover temperatures between thermally activated and quantum tunneling switching processes in the ds-JJs were estimated. The demonstrated ability to stabilise and manipulate states of π-loops paves the way towards new computing concepts such as quantum annealing computing.

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“…The p-junction may be the first example where the novel symmetry properties of high temperature superconductors are exploited positively in an application. Recently in Twente p-SQUIDs were fabricated using a thin film technology [44]. Here the base electrode consists of YBCO into which two orthogonal ramps are etched.…”

Section: Superconductor Electronics In Quantum Computingmentioning

confidence: 99%