  We study the possibility of nanoscale phase separation in manganites in the
framework of the double exchange model. The homogeneous canted state of this
model is proved to be unstable toward the formation of small ferromagnetic
droplets inside an antiferromagnetic insulating matrix. For the ferromagnetic
polaronic state we analyze the quantum effects related to the tails of
electronic wave function and a possibility of electron hopping in the
antiferromagnetic background. We find that these effects lead to the formation
of the threshold for the polaronic state.
