The magnetic susceptibility and spin-spin correlation of the double-exchang
e model for doped manganites are investigated through the Monte Carlo calcu
lations on the three-dimensional lattice model. Deviations of the susceptib
ility from the Curie-Weiss behavior above the ferromagnetic ordering temper
ature T-c seem to indicate a formation of local ferromagnetic clusters in t
he vicinity of T-c which is consistent with recent electron paramagnetic re
sonance experiments for La2/3Ca1/3MnO3. A further analysis of the spin-spin
correlations show the ferromagnetic cluster size to be three-to-four latti
ce spacings, suggesting that the charge carriers may form magnetic polarons
.