  The effects of magnetism on high pressure properties of transition metals and
transition metal compounds can be quite important. In the case of Fe, magnetism
is responsible for stability of the body-centered cubic (bcc) phase at ambient
conditions, and the large thermal expansivity in face-centered cubic (fcc)
iron, and also has large effects on the equation of state and elasticity of
hexagonal close-packed (hcp) iron. In transition metal oxides, local magnetic
moments are responsible for their insulating behavior. LDA+U results are
presented for CoO and FeO, and predictions are made for high pressure
metallization. The inclusion of a local Coulomb repulsion, U, greatly inhibits
the high-spin low-spin transitions found with conventional exchange-correlation
functionals (i.e. generalized gradient corrections, GGA). We discuss theory and
computations for the effects of magnetism on high pressure cohesive properties.
