996 research outputs found
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 and where
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.
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