Magnetic phase diagram of the Kondo lattice model

We use the Kondo lattice model to investigate the possibility of ferromagnetism in local moment systems. Using the spectral density approach and making use of the fact that the spontaneous magnetization of local moment and the itinerant electron polarization are coupled, we derive the expression for the paramagnetic susceptibility. The magnetic ordering temperature is determined from the singularities of the susceptibility. The magnetic phase diagram is constructed in T - n (band filling) plane. It is found that ferromagnetism is possible only for small values of n. (author)