Fabrication and magnetic force microscopy (MFM) observation of nano scale ferromagnetic nanodot arrays

Abstract

A novel electron beam lithography technique was utilized to fabricate nano scale magnetic dots array with high periodicity. C60 film (fullerine) was used as an electron beam sensitive resist for electron beam patterning carried out under a high accelerating voltage of 200 kV in a transmission electron microscope with a scanning mode. 50 nm sized permalloy (Py) nanodot arrays were successfully fabricated using the method followed by ion-milling. An array of Co nanodots having a size of 100×70 nm was alternatively prepared by liftoff instead of ion milling so as to prevent surface damage by ion milling. Lift-off does not yield any surface roughness, which is important for device fabrication. Magnetic force microscopy (MFM) observations were carried out on the fabricated Co nanodot arrays. A single domain state could be realized in patterned Co nanodots. MFM tip induced magnetization effects were also clearly demonstrated in the array of Co nanodots.