The Josephson critical current in a long mesoscopic S-N-S junction

We carry out an extensive experimental and theoretical study of the Josephson effect in S-N-S junctions made of a diffusive normal metal (N) embedded between two superconducting electrodes (S). Our experiments are performed on Nb-Cu-Nb junctions with highly-transparent interfaces. We give the predictions of the quasiclassical theory in various regimes on a precise and quantitative level. We describe the crossover between the short and the long junction regimes and provide the temperature dependence of the critical current using dimensionless units $eR_{N}I_{c}/\epsilon_{c}$ and $k_{B}T/\epsilon_{c}$ where $\epsilon_{c}$ is the Thouless energy. Experimental and theoretical results are in excellent quantitative agreement.Comment: 5 pages, 4 figures, slighly modified version, publishe

Coherent low-energy charge transport in a diffusive S-N-S junction

We have studied the current voltage characteristics of diffusive mesoscopic Nb-Cu-Nb Josephson junctions with highly-transparent Nb-Cu interfaces. We consider the low-voltage and high-temperature regime eV<\epsilon_{c}<k_{B}T where epsilon_{c} is the Thouless energy. The observed excess current as well as the observed sub-harmonic Shapiro steps under microwave irradiation suggest the occurrence of low-energy coherent Multiple Andreev Reflection (MAR).Comment: 4 pages, 4 figures, final versio

A thermostable trilayer resist for niobium lift-off

We have developped a novel lift-off process for fabrication of high quality superconducting submicron niobium structures. The process makes use of a thermostable polymer with a high transition temperature T_{g}= 235 C and an excellent chemical stability. The superconducting critical temperature of 100 nm wide niobium lines is above 7 K. An example of shadow evaporation of a Nb-Cu submicron hybrid structure is given. A potential application of this process is the fabrication of very small single electron devices using refratory metals.Comment: 6 pages, 6 eps figures, submitted to Journal of Vacuum Science and Technology

Erratum

Evolution des teneurs en polyamines dans les boutons floraux, les fleurs et les jeunes baies de Vitis villifera L. (cv. Cabernet Sauvignon) atteints d'eutypioseVitis 43 (3), 139-144 (2004

Les teneurs en acides gras, en eau et en acide abscissique des feuilles de vigne (Vitis vinifera L. var. Cabernet Sauvignon) infectées par Eutypa lata

Water, fatty acids and abscisic acid contents of grapevine leaves (Vitis vinifera, cv. Cabernet Sauvignon) infected by Eutypa lataEytypiose of grapevines led to a lowering of the water content and to an accumulation of abscisic acid (ABA) in the leaves of Cabernet Sauvignon known to be susceptible to Eutypiose. The accumulation of ABA in the leaves of infected plants possibly causes changes in the composition of fatty acids, in partiular by reducing their degree of insaturation and by elongating their aliphatic chains. These changes may lower the permeability of membranes and, as a consequence, exchanges with the environment, which possibly intensifies dehydration of infected leaves during their development.