MAGNETIC AND TRANSPORT-PROPERTIES OF THE EXTENDED S-F MODEL

On the basis of the extended s-f model including 5d-4f electron-hole attraction and the hybridization between the 4f and 5d electrons the coexistence between ferromagnetism and fluctuating valence has been considered. The Curie temperature, effective magnetic moment, the phase diagram of the system and dc conductivity (resistivity) has been found by using in all numerical calculations the triple integration over the Brillouin zone (s.c. lattice). The calculations of the dc conductivity (resistivity) as a function of temperature has been performed for the semiconducting and metallic state of the system by using different parameter constellations of the model. The calculated conductivities and resistivities show great similarities in shape to the experimentally observed in the real mixed-valent or heavy fermion systems as e.g. EuO, US, UN, NpAl2, NpOS2, CePd3, CeAl3, PuAl2, EuNi2P2, CexLa1-xAl2, CeCu6, CeCu2Si2,...