Effect of the Dot Separation on the Switching Behavior of Ni-Fe Elliptical Dot Arrays

We have studied the effect of the dot separation on the switching behavior of Ni-Fe elliptical dot arrays with major axial distances between the adjacent dots. The magnetization process and the magnetic configuration in the dot arrays apparently differ according to the distance between the adjacent dots. These differences are due to the fact that the dipole-dipole interaction becomes stronger while decreasing the major axial distance between the adjacent dots. From these results, it is evident that the optimal distance at which the magnetization between the adjacent dots couples by the dipole-dipole interaction is below 30 nm.