  In this work, we report that when ferromagnetic metals (Fe, Co and Ni) are
thermally evaporated onto n-layer graphenes and graphite, a metal nanowire and
adjacent nanogaps can be found along the edges regardless of its zigzag or
armchair structure. Similar features can also be observed for paramagnetic
metals, such as Mn, Al and Pd. Meanwhile, metal nanowires and adjacent nanogaps
can not be found for diamagnetic metals (Au and Ag). An external magnetic field
during the evaporation of metals can make these unique features disappear for
ferromagnetic and paramagnetic metal; and the morphologies of diamagnetic metal
do not change after the application of an external magnetic field. We discuss
the possible reasons for these novel and interesting results, which include
possible one dimensional ferromagnets along the edge and edge-related binding
energy.
