INTERPLAY BETWEEN QUADRUPOLAR AND BILINEAR INTERACTIONS IN RARE-EARTH INTERMETALLICS

A survey of the properties of 4f quadrupolar moments in rare earth intermetallic compounds is proposed. The double nature, one-ion magnetoelasticity and pair interactions, of the quadrupolar couplings as well as the different types of ferro-and antiferroquadrupolar orderings are first reviewed. The quadrupolar consequences on the magnetic properties, such as the order of the magnetic transition and the nature of the magnetic structure are then discussed. This interplay between quadrupoles and spins is illustrated by the competitions between collinear and multiaxial structures or between commensurate and modulated ones, sometimes in a same compound.