No abstract

No abstract

We study the current-voltage characteristic of a current biased array of normal tunnel junctions with small capacitance, 8/2C > kB T. It shows a Coulomb gap, which is found to scale with the number of junctions in series and to be independent of the number of junctions in parallel. The probability of single-electron tunnelling (SET) depends on the energy difference before and after the transition. This makes the Coulomb gap depend strongly on the size of the region probed by the electron in the tunnelling process. The amplitude of SET resonances is reduced compared to a single junction.

No abstract

No abstract

No abstract

2014 Ce travail est une étude de l'influence des interactions magnétiques dans des suspensions diluées de sphères supraconductrices surchauffées qui sont placées dans un champ magnétique externe. Les sphères deviennent normales quand le champ magnétique augmente. Des expressions, dépendant de la configuration des sphères et du champ externe, sont obtenues pour la fraction de sphères qui restent supraconductrices à une valeur du champ magnétique, ainsi que pour la distribution de champs magnétiques à la surface d'une sphère. Les valeurs moyennes de ces quantités sont évaluées au premier ordre dans la concentration des sphères. Les résultats sont comparés aux résultats d'expériences et de simulations numériques.Abstract. 2014 A study is made of the influence of magnetic interactions in dilute suspensions of superheated superconducting spheres, which are placed in a homogeneous external magnetic field. The spheres become normal conducting as the external field is increased. Expressions, depending on the configuration of the spheres and the external field, are derived for the fraction of spheres which still are superconducting at a given external field strength, as well as for the probability distribution of the maximum field strength on the surface of a sphere. The averages of these quantities are evaluated to first order in the volume fraction occupied by the spheres. The results are compared to experiments and to a computer simulation.

No abstract