Search results for "conductivity"
showing 10 items of 1988 documents
Advanced Beam Dynamics Design for the Superconducting Heavy Ion Accelerator HELIAC
2019
The 10th International Particle Accelerator Conference, IPAC2019, Melbourne, Australia, 19 May 2019 - 24 May 2019; JACoW Publishing, Geneva, Switzerland 928-931 (2019). doi:10.18429/JACOW-IPAC2019-MOPTS034
Development of an Inductive NIS Thermometer
2012
We have studied an inductive readout for normal metal-insulator-superconductor (NIS) tunnel junctions by using on-chip planar inductors and a DC SQUID (superconducting quantum interference device) to develop a sensitive and fast thermometer for studies of nanoscale heat conduction and bolometry. Our initial results show the feasibility of the concept, with a good sensitivity for temperatures below 1 K for aluminum as the superconductor when voltage biased close to the superconductor energy gap. peerReviewed
Method for finding the critical temperature of the island in a SET structure
2008
We present a method to measure the critical temperature of the island of a superconducting single electron transistor. The method is based on a sharp change in the slope of the zero-bias conductance as a function of temperature. We have used this method to determine the superconducting phase transition temperature of the Nb island of an superconducting single electron transistor with Al leads. We obtain $T_\mathrm{c}^\mathrm{Nb}$ as high as 8.5 K and gap energies up to $\Delta_\mathrm{Nb}\simeq 1.45$ meV. By looking at the zero bias conductance as a function of magnetic field instead of temperature, also the critical field of the island can be determined. Using the orthodox theory, we have …
Patterning of Suitable Structures for the Investigation of the Josephson Effect in YBa2Cu3O7/PrBa2Cu3O7 Superlattices
1996
The aim of our work is to investigate the Josephson effect in YBa 2 Cu 3 O 7-δ /PrBa 2 Cu 3 O 7-δ superlattices. In the case of current flow along c axis direction the superlattice forms an array of artificial Josephson junctions where the YBa 2 Cu 3 O 7-δ layers are the superconducting electrodes which are separated but Josephson coupled by the PrBa 2 Cu 3 O 7-δ sheets. In this paper we report on the preparation, characterisation and patterning of the superlattices into suitable structures via standard photolithograpy and lift-off technique.
Josephson effect in superfluid atomic Fermi-gases
2002
We consider an analog of the internal Josephson effect in superfluid atomic Fermi-gases. Four different hyperfine states of the atoms are assumed to be trapped and to form two superfluids via the BCS-type pairing. Weshow that Josephson oscillations can be realized by coupling the superfluids with two laser fields. Choosing the laser detunings in a suitable way leads to an asymmetric below-gap tunneling effect for which there exists no analogue in the context of solid-state superconductivity.
Characterisation of Cooper pair boxes for quantum computing
2001
We have measured and characterised superconducting single Cooper pair boxes (SCB) using superconducting single electron transistor (SET) fabricated on the same chip as an electrometer. The electrometer is sensitive to the potential changes of the SCB island and thus measures the number of excess Cooper pairs on the island. The boxes were of the Al/AlOx/Al Josephson junction type. The SCB and SET were characterised separately and the box storage performance for Cooper pairs was analysed by observing the changes in the SCB island potential while sweeping the gate voltage.
Low-field diamagnetic response of granular superconductors at finite temperatures
1994
We study the low-field diamagnetic response of granular superconductors at finite temperatures by means of a simple two-dimensional Josephson-junction array. The temperature effects are taken into account by inserting white-noise current sources in parallel to the resistively shunted junction circuit models of the Josephson junctions of the network. By this analysis we argue that a simplified one-dimensional description of the equivalent circuit, proposed by the authors for cylindrical granular superconductors, is still valid even in the presence of thermally activated flux jumps. A flux-creep picture for intergranular flux motion follows.
Macroscopic entanglement in Josephson nanocircuits
2001
We propose a scheme to generate and detect entanglement between charge states in superconducting nanocircuits. We discuss different procedures to discriminate such entanglement from classical correlations. The case of maximally entangled states of two and three coupled Josephson junctions is discussed as example.
Measurement and dephasing of a flux qubit due to heat currents
2013
We study a flux qubit, made of a superconducting loop interrupted by three Josephson junctions, which is subject to a temperature gradient. We show that the heat current induced by the temperature gradient, being sensitive to the superconducting phase differences at the junctions, depends significantly on the state of the qubit. We furthermore investigate the impact of the heat current on the coherence properties of the qubit state. We have found that even small temperature gradients can lead to dephasing times of the order of microseconds for the Delft-qubit design.
θ0 thermal Josephson junction
2017
We predict the thermal counterpart of the anomalous Josephson effect in superconductor/ferromagnet/superconductor junctions with non-coplanar magnetic texture. The heat current through the junction is shown to have the phase-sensitive interference component proportional to $\cos(\theta - \theta_0)$, where $\theta$ is the Josephson phase difference and $\theta_0$ is the texture-dependent phase shift. In the generic tri-layer magnetic structure with the spin-filtering tunnel barrier $\theta_0$ is determined by the spin chirality of magnetic configuration and can be considered as the direct manifestation of the energy transport with participation of spin-triplet Cooper pairs. In case of the id…