  We show that an interplay of double exchange and impurity randomness can
explain the competition between metal-ferromagnetic and insulating charge
ordered states in doped manganites. The double exchange is simplified in the
Ising type, whereas the randomness is modeled by the Falicov-Kimball binary
distribution. The combined model is considered in a framework of dynamical
mean-field theory. Using the Kubo-Greenwood formalism, the transport
coefficients are explicitly expressed in terms of single particle spectral
functions. Dividing the system into two sublattices we have pointed out a
direct calculation to the checkerboard charge order parameter and the
magnetizations. Numerical results show us that the checkerboard charge order
can settle inside the ferromagnetic state at low temperature. An
insulator-metal transition is also found at the point of the checkerboard
charge order-ferromagnetic transition.
