With laser interference lithography Co50Ni50/Pt multilayers with perpe
ndicular magnetic anisotropy have been patterned into regular matrices
of submicron sized dots. Their magnetic properties have been studied
with Vibrating Sample Magnetometry, Compared to continuous multilayers
(H-c, = 15 kA/m) the coercivity for the patterned multilayers is much
larger (H-c, = 115-270 kA/m), Though the hysteresis curves of 180 nm
dots and 60 nm dots have identical shapes, virgin curves seem to indic
ate that the 180 nm dots are multidomain while the 60 nm dots are sing
le domain. The latter has been confirmed with Magnetic Force Microscop
y observations.