  An unusual enhancement of resistance (i.e., superresistivity) below a certain
characteristic temperature Tsr was observed in granular Bi nanowires. This
superresistive state was found to be dependent on the applied magnetic field
(H) as well as the excitation current (I). The suppression of Tsr by magnetic
field resembles that of a superconductor. The observed superresistivity appears
to be related to the nucleation of local superconductivity inside the granular
nanowire without long-range phase coherence. The phenomenon is reminiscent of
the Bose-insulator observed previously in ultra thin two-dimensional (2D)
superconducting films and 3D percolative superconducting films.
