  The ferromagnetic spin exchange interaction between the itinerant electrons
and localized moments on a periodic lattice, studied within the so-called Kondo
lattice model (KLM), is considered for multiband situation where the hopping
integral is a matrix, in general. The modified RKKY theory, wherein one can map
such a model onto an effective Heisenberg-like system, is extended to a
multi-band case with finite bandwidth and hybridization on a simple cubic
lattice. As an input for the evaluation of the effective exchange integrals,
one requires the multi-band electronic self energy which is taken from an
earlier proposed ansatz. Using the above procedure, we determine the magnetic
properties of the system like Curie temperature while calculating the chemical
potential and magnetization within a self consistent scheme for various values
of system parameters. The results are discussed in detail and the model is
motivated in order to study the electronic, transport and magnetic properties
of real materials like GdN.
