Helical magnetic ordering in Tb completely suppressed by uniaxial tension:Evidence of electronic topological transition and support for the nesting hypothesis

A single crystal of Tb was examined under uniaxial tension applied along th e hexagonal axis by means of magnetic susceptibility vs temperature. The te mperature range within which helical ordering occurs was determined from ch i (T) curves. This range diminishes rapidly as uniaxial tension is applied, and at tensions over p*=680 bar the helical ordering is completely suppres sed. The experiment supports the hypothesis that the type of magnetic order ing in rare-earth metals is determined by Fermi surface topology, which can in turn be altered by uniaxial deformation.