Josephson Effect in Nanographite Films

In nanographite films, for the first time, when measuring the current–voltage characteristics, the Josephson current at room temperature has been detected, which confirms the earlier observations in nanographite films of the effects of weak superconductivity: zeroing of the temperature dependence at 650 K of the constant voltage on the sample when exposed to an alternating microwave voltage due to the inverse Josephson effect, as well as observation in a magnetic force microscope of local regions with the structure of magnetic vortices at room temperature. The obtained value of the critical current of 0.8 μA is significantly lower than the expected value for the superconducting gap, as well as for pinning at the Bean–Levingston barrier. Measures for increasing the critical current are proposed.