Velocity dispersion at the metamagnetic transition in UPt_3

摘要

The longitudinal ultrasonic attenuation and velocity were measured on a single crystal of UPt_3 in magnetic fields up to 27 T. Earlier measurements had reported metamagnetic behavior in the vicinity of 20 T, where a pronounced velocity dip (softening of the lattice) is seen. Simultaneous measurements at three frequencies during the same run were possible. A small dispersion in the velocity is seen at the metamagnetic transition.