  Computational studies show the generation of large coexisting metallic and
insulating clusters with equal electronic density in models for manganites. The
clusters are induced by disorder on exchange and hopping amplitudes near
first-order transitions of the non-disordered strongly coupled system. The
random-field Ising model is used to explain the qualitative aspects of our
results. Percolative characteristics are natural in this context. Our results
explain the recently experimentally discovered micrometer size inhomogeneities
in manganites. The conclusions are general and apply to a variety of compounds.
