Magnetic Nanostructures Patterned by Focused Ion Beam in an ultrathin Pt/Co/Pt film

Abstract

The magnetic properties of Co/Pt films can be modified and even controlled by ion beam irradiation. For example, the coercivity and magnetic anisotropy of a 1.4nm thick Co layer are reduced with increasing the Ga⁺ ion dose. Images of the demagnetized states and remanent hysteresis loops are obtained for arrays of dots or tracks patterned by the focused ion beam technique. 20 nm wide sharp non-magnetic irradiated lines separate the magnetic dots or the tracks, the size of the dots or the width of the tracks varying from 1.8 μm down to 70 nm. The efficiency of the dipolar interaction is studied, and the use of such dot arrays for magnetic or magneto-optical recorrding discussed.