  To understand the halfmetallic ferromagnet EuB6 we use the Kondo lattice
model for valence and conduction band. By means of a recently developed
many-body theory we calculate the electronic properties in the ferromagnetic
regime up to the Curie temperature. The decreasing magnetic order induces a
transition from halfmetallic to semiconducting behavior along with a band
broadening. We show the temperature dependence of the quasiparticle density of
states and the quasiparticle dispersion as well as the effective mass, the
number of carriers and the plasma frequency which are in good agreement with
the experimental data.
