  Hysteresis curves for finite arrays of $N\times N$ ferromagnetic nano dots
subject to the dipole-dipole interaction are investigated for $N=2... 13$. Spin
arrangements up to N=6 are presented, which indicate the onset of bulk-like
behavior associated with odd (N=5) and even (N=6) systems. The effect of field
misalignment on the hysteresis loops is also studied for $N=3... 6$. The area
$A_N$ of the hysteresis loop is studied as a function of $N$. We find that
$A_N-A_\infty$ approximately scales as $N^{-{3/2}}$ for $N$ odd and as $N^{-2}$
for $N$ even.

Mesoscale and Nanoscale Physics;Materials Science