Fabrication and magnetic force microscopy study of isolated nanoscale nickel balls

With the carbon nanotube nets being chosen as a substrate, the nanoscale ni ckel balls have been fabricated by using electroless plating method. In thi s article, a sample with well dispersed nanoscale nickel balls was prepared by ultrasonically dispersing them in PVK polymer solution and spraying the m on a new cleavage of mica. Their images of topography and micromagnetic s tructure were obtained by transmission electron microscopy, and magnetic fo rce microscopy with the magnetic tips coated with cobalt film. The balls wi th the diameter ranging from 200 to 400 nm present the same type of magneti c force image pattern, indicating that they are all single crystals with a single domain. Computer simulation was carried out by integrating the inter actions between the tip and the balls. The simulated images are consistent with the real patterns. (C) 1999 American Institute of Physics. [S0021-8979 (99)66408-8].