It has been recently suggested that periodic antidot arrays in magnetic med
ia could be a suitable system for high density data storage because hard ax
is magnetic switching has remanence and hence, memory. In this work a numer
ical micromagnetic study of periodic antidot permalloy arrays is presented.
Remanent states are obtained after saturation of the sample along the hard
axis direction for different antidot sizes w (0.32 mu m less than or equal
to w less than or equal to 2.16 mu m) and different separation distances d
between antidots (w/2 less than or equal to d less than or equal to 3w). O
ur micromagnetic model allows us to study these systems beyond the experime
ntal results presently available so that we can explore the high density li
mit. The signal to noise ratio decreases significantly for separation dista
nces d greater than or equal to w and increases steadily with the antidot s
ize w in the range analyzed. The remanent configurations are similar to the
experimental data obtained by scanning Kerr microscopy. (C) 1999 American
Institute of Physics. [S0021-8979(99)72708-8].