Role of patterning induced defect on the switching field in magnetic nanostructure

摘要

We report a systematic micromagnetic study on the variation of switching field in magnetic nanostructure in presence of defect or magnetic inclusion. The switching behavior of single individual island is very important when the dipolar coupling between them is minimal. We highlighted effects of geometry, size of a single magnetic island in the magnetic array on switching field. Change in switching behavior of a single magnetic island is studied as a function of defects having different magnetic anisotropy, dimension, position, projection of easy axis on to the x-y plane in the island. It is seen that the size of the defect and the variation of anisotropy of defects over a feasible range play an important role on switching field. We also noticed that the projection of easy axis on to the x-y plane in defects decreases the switching field significantly, whereas there was no such strong effect of their position inside the island. In the single domain regime, the island reversal is dominated by coherent rotation of magnetization. The micromagnetic modeling of edge damage in a single magnetic island due to focussed ion milling which is one of the common techniques for patterning such nanos-tructures showed a drastic fall in switching field and thus proved that the switching field also largely depends on the method of nanostructuring.