Magnetic properties of some rare earth silicides: GdSi, Gd 5Si 3, Dy 5−xNd xSi 3

Abstract

The magnetic susceptibilities and magnetization behavior as functions of temperature and field strength were investigated for the compounds GdSi, Gd 5Si 3 and Dy 5−xNd xSi 3, 0 ⩽ x ⩽ 5. The 1 χ vs . T curves apparently indicate antiferromagnetic behavior but the Weiss temperature is always positive. The compounds have hexagonal structures and a series of interactions are postulated to exist among the magnetic atoms in the crystallographic sites. When these exchange integrals are substituted in the Heisenberg exchange Hamiltonian it is shown that the lowest energy spin configuration is a helical arrangement. It is concluded that, in general, an antiferromagnetic susceptibility behavior with a positive Weiss constant may be indicative of a helical spin arrangement.