MAGNETOELASTICITY AND QUADRUPOLAR INTERACTIONS IN TMGA3

Magnetoelastic and magnetic studies in the paramagnetic phase of TmGa//3 have allowed us to determine both the magnetoelastic coefficients and the strength of the ferroquadrupolar pair interactions. For the tetragonal and trigonal symmetries, these interactions are too weak to explain the first-order transition observed at 4. 29 K as a ferroquadrupolar ordering. On the contrary, antiferroquadrupolar interactions appear to be dominant and to stabilize a multiaxial spin structure. In comparison with previous studies on CsCl-type rare earth intermetallics, the magnetoelasticity and the quadrupolar pair coupling appear to be smaller in the AuCu//3-type compounds.