  From general arguments, it is shown that a magnetic Kronig-Penney model based
on the thermodynamics of an Ising model can be used for describing the Colossal
Magnetoresistance (CMR) phenomenon. The model considers a tunneling-like
transmission process of hopping electrons through a dynamic lattice
characterized by evolving magnetic clusters. In this model, correlations
between the magnetic states are considered to be more relevant than the lattice
strain effects for obtaining the CMR features. Physical arguments lead to the
theoretical description of the intrinsic temperature and field dependences of
the CMR observed in typical manganite materials.
