Domain nucleation in arrays of perpendicularly magnetized dots

Magnetization reversal processes in Co55Ni45/Pt multilayer dots was studied with the magneto-optical Kerr effect and magneto-optical Kerr microscope. With decreasing dot diameter, a dramatic increase of coercive field distribution and macroscopic coercivity in the dot arrays was observed. Direct triggering with submicron wire channels indicates that the coercive field distributions and the enhancement of macroscopic coercivity are caused by nucleation isolation due to high density patterning. We show that this phenomenon is analogous to the solidification process of an undercooled liquid. (C) 2002 American Institute of Physics.