Variation of the magnetic energy barrier with the cell shape of nanostructured magnetic thin films

The variation of the magnetic energy barrier of nanostructured single-layered thin films according to the cell shape is calculated by a micromagnetic simulation. The magnetic energy barrier increases significantly as the cell shape varies from a rectangle to an ellipse. This behaviour, which can raise a serious reliability issue considering the difficulty in the precise shape control of the nanostructured cells, is due to the fact that the magnetization process occurs in a more coherent way as the cell shape more closely resembles an ellipse. The simple assumption of the single domain state significantly overestimates the magnetic energy barrier, in particular, near the rectangular geometry.