Request PDF on ResearchGate | Effet Josephson et expérience d’ Andronikashvili | A way of making a weak link in superfluid helium 4 is proposed. Putting this. Elle nous a permis de conforter quantitativement la récente description de l’effet Josephson mésoscopique. La dernière expérience est une mesure de. Rev. Phys. Appl. (Paris) 6, () DOI: /rphysap: Utilisations de l’effet Josephson alternatif. T. Pech L. C. I. E., 33, Avenue.
|Published (Last):||10 August 2005|
|PDF File Size:||13.33 Mb|
|ePub File Size:||8.94 Mb|
|Price:||Free* [*Free Regsitration Required]|
Views Read Edit View history. Since the success of the first Josephson array voltage standards intheir use has proliferated to more than 70 national measurement institutes NMIsmilitary, and commercial laboratories around the world.
By finding the derivative of the current with respect to time, and rearranging in the form of the inductance equation, inductance can be found. Abstract The physical phenomena taking place in Josephson junctions and josephdon for the generation of electromagnetic radiation as well as for their behaviour in the presence of one or two external radiations are discussed.
Numerous algorithms have been developed to compare a Josephson standard with a secondary standard or another Josephson standard. III France 2, A rather particular type of application is illustrated by the description of a noise thermometer. A Josephson voltage standard is a complex system that uses a superconductive integrated circuit chip operating at 4 K to generate stable mosephson that depend only on josephon applied frequency and fundamental constants.
TEL – Thèses en ligne – The Josephson effect in superconductors and quantum gases
The solution to this problem efret a simple extension of Fig. The standard error resulting from items is just the root mean square RMS value of the set of short circuit measurements. Views Read Edit View history. One can think of a Josephson junction as a non-linear inductance which accumulates magnetic field energy when a current passes through it. Computer control of this three-step process enables the system to find and stabilize the array voltage on a particular step within a few seconds.
Although the ac Josephson effect provides a much more stable voltage reference than Weston cells, the first single-junction Josephson standards        were difficult to use because they generated very small voltages mV. February Learn how and when to remove this template message.
Before Josephson’s prediction, it was only known that normal i.
This open-bias condition is the most stable state for the array and eliminates the possibility of any errors resulting from a small series resistance in the array — a common array defect. Statistiques Afficher les informations.
Josephson voltage standard
The first one allowed to measure the energy exchange rate between electrons in a metal contaminated by a very weak concentration of magnetic impurities.
This effect found immediate application in metrology because it relates the volt to the second through a proportionality involving only fundamental constants.
SI base units, section 2. Tubes of solid German silver or stainless steel plated internally with silver or gold are commonly used. Note, that although Josephson junction behaves like an inductance, there is no associated magnetic field. The critical current is an important phenomenological parameter of the device that can be affected by temperature as well as by an applied magnetic field.
High quality Josephson arrays will remain on a selected step for many hours. Of Physics Publishing, Philadelphia2 p.
The zero crossing steps of Fig. The work done on josephhson junction so the junction energy is increased by. All issues About the journal Aims and scope Copyright transfer Subscriber information Reader services. Figure 3 illustrates the basic structure of one junction in a large series array. The practical realization of an array voltage standard requires a thorough understanding of how these parameters affect the stability of the quantized voltage levels shown in Fig.
The role played by magnetic impurities in the Kondo regime on those energy exchanges is quantitatively investigated, and the global measured exchange rate is larger than expected. InBrian Josephsona graduate student at Cambridge University, derived equations for the current and voltage across a junction consisting of a thin insulating barrier separating two superconductors — now generally known as a Josephson junction.
In other projects Wikimedia Commons. This article may be too technical for most readers effwt understand. A block diagram of a modern Josephson voltage standard system is shown in Fig. This page was last edited on 23 Novemberat