Perpendicular quantized magnetic disks with 45 Gbits on a 4×4 cm2 area

Abstract

Quantized magnetic disks consisting of an array of single domain Ni pillars with a density of 18 Gbits/in.2 were fabricated using nanoimprint lithography (NIL) and electroplating. The total disk area, limited by the NIL mold, is 4 cm×4 cm, leading to a total 45 Gbits. Magnetic force microscope (MFM) images show that all pillars 70 nm in diameter and 400 nm in height are single domain. The magnetostatic interaction between adjacent pillars is fairly strong. The pillars have an average switching field of 360 Oe and can be switched by a MFM tip with a large magnetic moment.