Mechanisms selecting between (100) or (111) alignment and between antiferromagnetism or ferromagnetism in cerium and light actinide metallic systems

We discuss the competing roles of the highly anisotropic Coqblin-Schrieffer-type (CS) interaction and of the crystal-field interaction in determining the nature of magnetic ordering in cerium and uranium monopnictides and monochalcogenides of NaCl-structure. The CS interaction between cerium or uranium ions effectively treats the mixing of f and conduction electrons. We especially emphasize the geometrical aspects of the CS interaction in determining the selection between (100) and (111) alignment and between ferromagnetism and antiferromagnetism. (orig.)