Observation of field-induced fragmentation of nickel clusters using scanning tunneling microscopy

Thin films of nickel deposited on mica have a surface structure in the form of a uniform distribution of clusters of ∼ 30 nm size. When an electrical pulse is applied to the film by the tip of an STM, these clusters get fragmented into smaller clusters. The fragmented clusters so produced were observed to coalesce together to regain the original morphology of the surface. The restoration process takes about 6 to 12 min depending on the height and width of the electrical pulse.