RESISTIVE STATE MEASUREMENTS OF QUASI-0-DIMENSIONAL SUPERCONDUCTING STRUCTURES

High resolution e-beam lithographic process has been used to fabricate thin film aluminum nanostructures with the line width up to 40 nm. Si ngle crystalline samples (tin whiskers with (sub)micron spaced probes) has been also prepared. In a wide temperature range below the superco nducting transition such small objects could be considered as quasi-0- dimensional, as their physical dimensions are comparable to the charac teristic value of the coherence length. Conventional 4-probes measurem ents were performed at helium temperatures. It was observed that at th e top of the superconducting transition the resistance may significant ly exceed its normal state value. The magnitude of this ''resistance b ump'' depends upon the bias current and the external magnetic field. N o anomaly has been observed for samples longer than several microns. T he results are discussed within the models of the phase-slip centers a ctivation (strong current limit) and the N/S boundary propagation (zer o current limit).