Tight-binding approach to the orbital magnetic moment and magnetocrystalline anisotropy of transition-metal monolayers

A perturbative theory of magnetocrystalline anisotropy and orbital moment in itinerant ferromagnets is presented that clearly outlines the close connection between these two quantities. The theory is used to study the magnetocrystalline anisotropy in transition-metal monolayers. The importance of the crystal-field energy and of the filling of the valence band is emphasized. For the first time the orbital contribution to the magnetization in monolayers is estimated; it is shown that it may produce an anisotropy in the magnetization of the order of 0. 1 per atom.