Charge screening and magnetic anisotropy in RCo5 compounds

An analysis of magnetic anisotropy in RCo5 compounds is performed with account of screening of ion point charges by conduction electrons. A crucial role of non-uniform distribution of screening electrons (the terms containing derivatives of charge density) is demonstrated. Influence of anisotropy of screening, that is connected with the anisotropy of the Fermi surface, on the magnetic anisotropy sign is discussed.