Understanding and predicting rare earth and actinide correlated electron magnetism

Magnetism in partially delocalized f electron cerium and light actinide materials exhibits extraordinarily large anisotropy, unusual magnetic structures and excitations, and giant magneto-optic effects. These can all be understood on the basis of correlated electron orbitally driven magnetic ordering. By including the band-f Coulomb exchange and the band-f hybridization on an equal ab initio footing, we obtain absolute evaluation of parameters in a model hamiltonian giving the correct absolute scale of energy for magnetic ordering. This means we can correctly predict the decrease in TN (or Tc) and ordered moment on approaching heavy fermion behavior in an isostructural system, where we have developed a technique to do this both for weakly delocalized cerium systems and for more strongly delocalized uranium systems.