Elastic anomaly in Tb under uniaxial tension: Evidence of the change in the Fermi surface topology responsible for the magnetic ordering type

A single crystal of Tb was examined under uniaxial tension applied along the hexagonal axis by a x-ray dilatometry and resistive strain sensors. The experiment was carried out well above the magnetic ordering temperature. The strain-stress dependencies obtained exhibit the characteristic violation of linearity that is evidently due to the change in the Fermi surface topology caused by strain. This electron-topological transition is presumably responsible for the recently observed change in the magnetic ordering type in the same sample.