Mapping orientations of easy axes in nanodot arrays by magnetic force microscopy

An experimental method has been developed for mapping the three-dimensional (3D) orientations of easy axes in nanodot arrays by means of magnetic force microscopy. This method was applied to a CoCrPt-patterned medium to measure 3D easy-axes orientations of individual cylindrical dots of an average of 36 nm in diameter and 40 nm in height. A main easy-axes orientation was found according to the planar number distribution of dots being in the same range of easy-axes orientations. The dot-number dependence on inclining angles of magnetocrystalline easy axes from the perpendicular direction agreed well with the x-ray diffraction result. The magnetization reversal mechanism in the medium was also discussed.