Particle irradiation for verification of superconducting-like behavior in carbon arc films

The 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 an RJE-induced voltage, its RF frequency, input amplitude, and temperature dependence reveal the existence of Josephson 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 Oe (800 kamp/m) 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. All these data are consistent with the existence of a high-temperature SC-like phase or fluctuations up to 650 K. It is proposed to expose such a CA film to energetic particle (neutron or ion) bombardment to verify this hypothesis. Such bombardment would change both the structure of the film and consequently the experimental measurements. In addition, such bombardment-induced changes will provide a basis for particle detectors utilizing the Josephson effect.