Ferromagnetic Co-C nanodot arrays produced by direct interferometric laserannealing

Magnetic properties of Co-C nanodot arrays produced by direct interferometr ic laser annealing are investigated by magnetic force microscopy (MFM) and magnetization measurements. The dots are formed by locally annealing sputte red amorphous Co-C films in regions where the laser intensity is highest. A s-sputtered Co-C films do not exhibit ferromagnetic order at room temperatu re, but MFM shows that the dots become magnetic upon annealing, possibly du e to the agglomeration or phase separation of Co-rich clusters. The dots ar e, embedded in either a paramagnetic or weakly magnetic matrix. The magneti c properties of the generated pattern can be changed by varying the laser p ower. The present results show that direct interferometric lithography may become a useful tool for fabricating future patterned magnetic nanostructur es.