Magnetic Properties of Rare Earth Tetraborides

Abstract

The magnetic properties and the lattice constants of the rare earth tetraborides RB₄ have been determined. The compound PrB₄ is ferromagnetic. The compounds in which R represents Nd, Sm, Gd, Tb, Dy, and Ho are antiferromagnetic while ErB₄ and YbB₄ show metamagnetic behavior. The element Ce and to some extent also the element Yb show an abnormal valency in the tetraborides. The magnetic properties of the RB₄ compounds are discussed in terms of the RKKY formalism. It is shown that the ferromagnetic behavior of PrB₄ is probably the result of a strong participating of the orbital angular momentum to the indirect exchange coupling between the localized moments.