FERROMAGNETISM IN THE LARGE-U HUBBARD-MODEL

We study the Hubbard model on a hypercubic lattice with regard to the possibility of itinerant ferromagnetism. Dynamical mean-field theory i s used to map the lattice model on an effective local problem, which i s treated with the help of the noncrossing approximation. By investiga ting spin-dependent one-particle Green's functions and the magnetic su sceptibility, a region with nonvanishing ferromagnetic polarization is found in the limit U-->infinity. The delta-T phase diagram as well as thermodynamic quantities are discussed. The dependence of the Curie t emperature on the Coulomb interaction and the competition between ferr omagnetism and antiferromagnetism are studied in the large-Ci Limit of the Hubbard model.