Josephson-Like Behaviour of Granular Carbon Films
This work presents the study of some new anomalous electromagnetic effects in graphite-like thin carbon films. These are: The fast switching (1nanosecond) of electrical conductivity The detection of microwave radiation and its temperature dependence The oscillations of film stack magnetization in the magnetic field of 1-5 T. The optical radiation under process of spasmodic switching of conductivity Results of magnetic force microscopy (MFM), DC SQUID magnetization, reversed Josephson effect (RJE), and resistance measurements in thin carbon arc (CA) films are presented. The observation of a RJE induced voltage as well as its rf frequency, input amplitude, and temperature dependence reveals the existence of Josephson-like Junction arrays. Oscillating behavior of the DC SQUID magnetization reminiscent of the Fraunhofer-like behavior of superconducting (SC) critical current in the range of 10000-50000 Oe has been observed. The DC SQUID magnetization measurement indicates a possible elementary 102 nm SC loop; this is compared to MFM direct observations of magnetic clusters with a median size of 165 nm. The results obtained provides a basis for non-cryogenic elecrtonic devices utilizing the Josephson effect.