We demonstrate that magnetic reversal in perpendicularly magnetized nanostructures is highly dependent on the nature and condition of the edges. To understand the impact of edge damage, we compare nanostructures created by ion milling to those prepared on prepatterned substrates. The size- and temperature-dependent reversal properties of 25 nm–$1\mu \text{m}$ diameter nanodots show that reversal in prepatterned nanostructures is controlled by nucleation within the interior, whereas ion milling results in an edge nucleation process with an unpredicted temperature dependence of the reversal field.

• Received 28 April 2008

DOI:https://doi.org/10.1103/PhysRevB.78.024414